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bigdataelephants/scikit-learn | sklearn/preprocessing/label.py | 8 | 28313 | # Authors: Alexandre Gramfort <[email protected]>
# Mathieu Blondel <[email protected]>
# Olivier Grisel <[email protected]>
# Andreas Mueller <[email protected]>
# Joel Nothman <[email protected]>
# Hamzeh Alsalhi <[email protected]>
# License: BSD 3 clause
from collections import defaultdict
import itertools
import array
import warnings
import numpy as np
import scipy.sparse as sp
from ..base import BaseEstimator, TransformerMixin
from ..utils.fixes import np_version
from ..utils.fixes import sparse_min_max
from ..utils.fixes import astype
from ..utils.fixes import in1d
from ..utils import deprecated, column_or_1d
from ..utils.validation import check_array
from ..utils.multiclass import unique_labels
from ..utils.multiclass import type_of_target
from ..externals import six
zip = six.moves.zip
map = six.moves.map
__all__ = [
'label_binarize',
'LabelBinarizer',
'LabelEncoder',
'MultiLabelBinarizer',
]
def _check_numpy_unicode_bug(labels):
"""Check that user is not subject to an old numpy bug
Fixed in master before 1.7.0:
https://github.com/numpy/numpy/pull/243
"""
if np_version[:3] < (1, 7, 0) and labels.dtype.kind == 'U':
raise RuntimeError("NumPy < 1.7.0 does not implement searchsorted"
" on unicode data correctly. Please upgrade"
" NumPy to use LabelEncoder with unicode inputs.")
class LabelEncoder(BaseEstimator, TransformerMixin):
"""Encode labels with value between 0 and n_classes-1.
Attributes
----------
classes_ : array of shape (n_class,)
Holds the label for each class.
Examples
--------
`LabelEncoder` can be used to normalize labels.
>>> from sklearn import preprocessing
>>> le = preprocessing.LabelEncoder()
>>> le.fit([1, 2, 2, 6])
LabelEncoder()
>>> le.classes_
array([1, 2, 6])
>>> le.transform([1, 1, 2, 6]) #doctest: +ELLIPSIS
array([0, 0, 1, 2]...)
>>> le.inverse_transform([0, 0, 1, 2])
array([1, 1, 2, 6])
It can also be used to transform non-numerical labels (as long as they are
hashable and comparable) to numerical labels.
>>> le = preprocessing.LabelEncoder()
>>> le.fit(["paris", "paris", "tokyo", "amsterdam"])
LabelEncoder()
>>> list(le.classes_)
['amsterdam', 'paris', 'tokyo']
>>> le.transform(["tokyo", "tokyo", "paris"]) #doctest: +ELLIPSIS
array([2, 2, 1]...)
>>> list(le.inverse_transform([2, 2, 1]))
['tokyo', 'tokyo', 'paris']
"""
def _check_fitted(self):
if not hasattr(self, "classes_"):
raise ValueError("LabelEncoder was not fitted yet.")
def fit(self, y):
"""Fit label encoder
Parameters
----------
y : array-like of shape (n_samples,)
Target values.
Returns
-------
self : returns an instance of self.
"""
y = column_or_1d(y, warn=True)
_check_numpy_unicode_bug(y)
self.classes_ = np.unique(y)
return self
def fit_transform(self, y):
"""Fit label encoder and return encoded labels
Parameters
----------
y : array-like of shape [n_samples]
Target values.
Returns
-------
y : array-like of shape [n_samples]
"""
y = column_or_1d(y, warn=True)
_check_numpy_unicode_bug(y)
self.classes_, y = np.unique(y, return_inverse=True)
return y
def transform(self, y):
"""Transform labels to normalized encoding.
Parameters
----------
y : array-like of shape [n_samples]
Target values.
Returns
-------
y : array-like of shape [n_samples]
"""
self._check_fitted()
classes = np.unique(y)
_check_numpy_unicode_bug(classes)
if len(np.intersect1d(classes, self.classes_)) < len(classes):
diff = np.setdiff1d(classes, self.classes_)
raise ValueError("y contains new labels: %s" % str(diff))
return np.searchsorted(self.classes_, y)
def inverse_transform(self, y):
"""Transform labels back to original encoding.
Parameters
----------
y : numpy array of shape [n_samples]
Target values.
Returns
-------
y : numpy array of shape [n_samples]
"""
self._check_fitted()
y = np.asarray(y)
return self.classes_[y]
class LabelBinarizer(BaseEstimator, TransformerMixin):
"""Binarize labels in a one-vs-all fashion
Several regression and binary classification algorithms are
available in the scikit. A simple way to extend these algorithms
to the multi-class classification case is to use the so-called
one-vs-all scheme.
At learning time, this simply consists in learning one regressor
or binary classifier per class. In doing so, one needs to convert
multi-class labels to binary labels (belong or does not belong
to the class). LabelBinarizer makes this process easy with the
transform method.
At prediction time, one assigns the class for which the corresponding
model gave the greatest confidence. LabelBinarizer makes this easy
with the inverse_transform method.
Parameters
----------
neg_label : int (default: 0)
Value with which negative labels must be encoded.
pos_label : int (default: 1)
Value with which positive labels must be encoded.
sparse_output : boolean (default: False)
True if the returned array from transform is desired to be in sparse
CSR format.
Attributes
----------
classes_ : array of shape [n_class]
Holds the label for each class.
y_type_ : str,
Represents the type of the target data as evaluated by
utils.multiclass.type_of_target. Possible type are 'continuous',
'continuous-multioutput', 'binary', 'multiclass',
'mutliclass-multioutput', 'multilabel-sequences',
'multilabel-indicator', and 'unknown'.
multilabel_ : boolean
True if the transformer was fitted on a multilabel rather than a
multiclass set of labels. The multilabel_ attribute is deprecated
and will be removed in 0.18
sparse_input_ : boolean,
True if the input data to transform is given as a sparse matrix, False
otherwise.
indicator_matrix_ : str
'sparse' when the input data to tansform is a multilable-indicator and
is sparse, None otherwise. The indicator_matrix_ attribute is
deprecated as of version 0.16 and will be removed in 0.18
Examples
--------
>>> from sklearn import preprocessing
>>> lb = preprocessing.LabelBinarizer()
>>> lb.fit([1, 2, 6, 4, 2])
LabelBinarizer(neg_label=0, pos_label=1, sparse_output=False)
>>> lb.classes_
array([1, 2, 4, 6])
>>> lb.transform([1, 6])
array([[1, 0, 0, 0],
[0, 0, 0, 1]])
Binary targets transform to a column vector
>>> lb = preprocessing.LabelBinarizer()
>>> lb.fit_transform(['yes', 'no', 'no', 'yes'])
array([[1],
[0],
[0],
[1]])
Passing a 2D matrix for multilabel classification
>>> import numpy as np
>>> lb.fit(np.array([[0, 1, 1], [1, 0, 0]]))
LabelBinarizer(neg_label=0, pos_label=1, sparse_output=False)
>>> lb.classes_
array([0, 1, 2])
>>> lb.transform([0, 1, 2, 1])
array([[1, 0, 0],
[0, 1, 0],
[0, 0, 1],
[0, 1, 0]])
See also
--------
label_binarize : function to perform the transform operation of
LabelBinarizer with fixed classes.
"""
def __init__(self, neg_label=0, pos_label=1, sparse_output=False):
if neg_label >= pos_label:
raise ValueError("neg_label={0} must be strictly less than "
"pos_label={1}.".format(neg_label, pos_label))
if sparse_output and (pos_label == 0 or neg_label != 0):
raise ValueError("Sparse binarization is only supported with non "
"zero pos_label and zero neg_label, got "
"pos_label={0} and neg_label={1}"
"".format(pos_label, neg_label))
self.neg_label = neg_label
self.pos_label = pos_label
self.sparse_output = sparse_output
@property
@deprecated("Attribute indicator_matrix_ is deprecated and will be "
"removed in 0.17. Use 'y_type_ == 'multilabel-indicator'' "
"instead")
def indicator_matrix_(self):
return self.y_type_ == 'multilabel-indicator'
@property
@deprecated("Attribute multilabel_ is deprecated and will be removed "
"in 0.17. Use 'y_type_.startswith('multilabel')' "
"instead")
def multilabel_(self):
return self.y_type_.startswith('multilabel')
def _check_fitted(self):
if not hasattr(self, "classes_"):
raise ValueError("LabelBinarizer was not fitted yet.")
def fit(self, y):
"""Fit label binarizer
Parameters
----------
y : numpy array of shape (n_samples,) or (n_samples, n_classes)
Target values. The 2-d matrix should only contain 0 and 1,
represents multilabel classification.
Returns
-------
self : returns an instance of self.
"""
self.y_type_ = type_of_target(y)
if 'multioutput' in self.y_type_:
raise ValueError("Multioutput target data is not supported with "
"label binarization")
self.sparse_input_ = sp.issparse(y)
self.classes_ = unique_labels(y)
return self
def transform(self, y):
"""Transform multi-class labels to binary labels
The output of transform is sometimes referred to by some authors as the
1-of-K coding scheme.
Parameters
----------
y : numpy array or sparse matrix of shape (n_samples,) or
(n_samples, n_classes) Target values. The 2-d matrix should only
contain 0 and 1, represents multilabel classification. Sparse
matrix can be CSR, CSC, COO, DOK, or LIL.
Returns
-------
Y : numpy array or CSR matrix of shape [n_samples, n_classes]
Shape will be [n_samples, 1] for binary problems.
"""
self._check_fitted()
y_is_multilabel = type_of_target(y).startswith('multilabel')
if y_is_multilabel and not self.y_type_.startswith('multilabel'):
raise ValueError("The object was not fitted with multilabel"
" input.")
return label_binarize(y, self.classes_,
pos_label=self.pos_label,
neg_label=self.neg_label,
sparse_output=self.sparse_output)
def inverse_transform(self, Y, threshold=None):
"""Transform binary labels back to multi-class labels
Parameters
----------
Y : numpy array or sparse matrix with shape [n_samples, n_classes]
Target values. All sparse matrices are converted to CSR before
inverse transformation.
threshold : float or None
Threshold used in the binary and multi-label cases.
Use 0 when:
- Y contains the output of decision_function (classifier)
Use 0.5 when:
- Y contains the output of predict_proba
If None, the threshold is assumed to be half way between
neg_label and pos_label.
Returns
-------
y : numpy array or CSR matrix of shape [n_samples] Target values.
Notes
-----
In the case when the binary labels are fractional
(probabilistic), inverse_transform chooses the class with the
greatest value. Typically, this allows to use the output of a
linear model's decision_function method directly as the input
of inverse_transform.
"""
self._check_fitted()
if threshold is None:
threshold = (self.pos_label + self.neg_label) / 2.
if self.y_type_ == "multiclass":
y_inv = _inverse_binarize_multiclass(Y, self.classes_)
else:
y_inv = _inverse_binarize_thresholding(Y, self.y_type_,
self.classes_, threshold)
if self.sparse_input_:
y_inv = sp.csr_matrix(y_inv)
elif sp.issparse(y_inv):
y_inv = y_inv.toarray()
return y_inv
def label_binarize(y, classes, neg_label=0, pos_label=1,
sparse_output=False, multilabel=None):
"""Binarize labels in a one-vs-all fashion
Several regression and binary classification algorithms are
available in the scikit. A simple way to extend these algorithms
to the multi-class classification case is to use the so-called
one-vs-all scheme.
This function makes it possible to compute this transformation for a
fixed set of class labels known ahead of time.
Parameters
----------
y : array-like
Sequence of integer labels or multilabel data to encode.
classes : array-like of shape [n_classes]
Uniquely holds the label for each class.
neg_label : int (default: 0)
Value with which negative labels must be encoded.
pos_label : int (default: 1)
Value with which positive labels must be encoded.
sparse_output : boolean (default: False),
Set to true if output binary array is desired in CSR sparse format
Returns
-------
Y : numpy array or CSR matrix of shape [n_samples, n_classes]
Shape will be [n_samples, 1] for binary problems.
Examples
--------
>>> from sklearn.preprocessing import label_binarize
>>> label_binarize([1, 6], classes=[1, 2, 4, 6])
array([[1, 0, 0, 0],
[0, 0, 0, 1]])
The class ordering is preserved:
>>> label_binarize([1, 6], classes=[1, 6, 4, 2])
array([[1, 0, 0, 0],
[0, 1, 0, 0]])
Binary targets transform to a column vector
>>> label_binarize(['yes', 'no', 'no', 'yes'], classes=['no', 'yes'])
array([[1],
[0],
[0],
[1]])
See also
--------
LabelBinarizer : class used to wrap the functionality of label_binarize and
allow for fitting to classes independently of the transform operation
"""
if not isinstance(y, list):
# XXX Workaround that will be removed when list of list format is
# dropped
y = check_array(y, accept_sparse='csr', ensure_2d=False)
if neg_label >= pos_label:
raise ValueError("neg_label={0} must be strictly less than "
"pos_label={1}.".format(neg_label, pos_label))
if (sparse_output and (pos_label == 0 or neg_label != 0)):
raise ValueError("Sparse binarization is only supported with non "
"zero pos_label and zero neg_label, got "
"pos_label={0} and neg_label={1}"
"".format(pos_label, neg_label))
if multilabel is not None:
warnings.warn("The multilabel parameter is deprecated as of version "
"0.15 and will be removed in 0.17. The parameter is no "
"longer necessary because the value is automatically "
"inferred.", DeprecationWarning)
# To account for pos_label == 0 in the dense case
pos_switch = pos_label == 0
if pos_switch:
pos_label = -neg_label
y_type = type_of_target(y)
if 'multioutput' in y_type:
raise ValueError("Multioutput target data is not supported with label "
"binarization")
n_samples = y.shape[0] if sp.issparse(y) else len(y)
n_classes = len(classes)
classes = np.asarray(classes)
if y_type == "binary":
if len(classes) == 1:
Y = np.zeros((len(y), 1), dtype=np.int)
Y += neg_label
return Y
elif len(classes) >= 3:
y_type = "multiclass"
sorted_class = np.sort(classes)
if (y_type == "multilabel-indicator" and classes.size != y.shape[1]):
raise ValueError("classes {0} missmatch with the labels {1}"
"found in the data".format(classes, unique_labels(y)))
if y_type in ("binary", "multiclass"):
y = column_or_1d(y)
# pick out the known labels from y
y_in_classes = in1d(y, classes)
y_seen = y[y_in_classes]
indices = np.searchsorted(sorted_class, y_seen)
indptr = np.hstack((0, np.cumsum(y_in_classes)))
data = np.empty_like(indices)
data.fill(pos_label)
Y = sp.csr_matrix((data, indices, indptr),
shape=(n_samples, n_classes))
elif y_type == "multilabel-indicator":
Y = sp.csr_matrix(y)
if pos_label != 1:
data = np.empty_like(Y.data)
data.fill(pos_label)
Y.data = data
elif y_type == "multilabel-sequences":
Y = MultiLabelBinarizer(classes=classes,
sparse_output=sparse_output).fit_transform(y)
if sp.issparse(Y):
Y.data[:] = pos_label
else:
Y[Y == 1] = pos_label
return Y
if not sparse_output:
Y = Y.toarray()
Y = astype(Y, int, copy=False)
if neg_label != 0:
Y[Y == 0] = neg_label
if pos_switch:
Y[Y == pos_label] = 0
else:
Y.data = astype(Y.data, int, copy=False)
# preserve label ordering
if np.any(classes != sorted_class):
indices = np.argsort(classes)
Y = Y[:, indices]
if y_type == "binary":
if sparse_output:
Y = Y.getcol(-1)
else:
Y = Y[:, -1].reshape((-1, 1))
return Y
def _inverse_binarize_multiclass(y, classes):
"""Inverse label binarization transformation for multiclass.
Multiclass uses the maximal score instead of a threshold.
"""
classes = np.asarray(classes)
if sp.issparse(y):
# Find the argmax for each row in y where y is a CSR matrix
y = y.tocsr()
n_samples, n_outputs = y.shape
outputs = np.arange(n_outputs)
row_max = sparse_min_max(y, 1)[1]
row_nnz = np.diff(y.indptr)
y_data_repeated_max = np.repeat(row_max, row_nnz)
# picks out all indices obtaining the maximum per row
y_i_all_argmax = np.flatnonzero(y_data_repeated_max == y.data)
# For corner case where last row has a max of 0
if row_max[-1] == 0:
y_i_all_argmax = np.append(y_i_all_argmax, [len(y.data)])
# Gets the index of the first argmax in each row from y_i_all_argmax
index_first_argmax = np.searchsorted(y_i_all_argmax, y.indptr[:-1])
# first argmax of each row
y_ind_ext = np.append(y.indices, [0])
y_i_argmax = y_ind_ext[y_i_all_argmax[index_first_argmax]]
# Handle rows of all 0
y_i_argmax[np.where(row_nnz == 0)[0]] = 0
# Handles rows with max of 0 that contain negative numbers
samples = np.arange(n_samples)[(row_nnz > 0) &
(row_max.ravel() == 0)]
for i in samples:
ind = y.indices[y.indptr[i]:y.indptr[i+1]]
y_i_argmax[i] = classes[np.setdiff1d(outputs, ind)][0]
return classes[y_i_argmax]
else:
return classes.take(y.argmax(axis=1), mode="clip")
def _inverse_binarize_thresholding(y, output_type, classes, threshold):
"""Inverse label binarization transformation using thresholding."""
if output_type == "binary" and y.ndim == 2 and y.shape[1] > 2:
raise ValueError("output_type='binary', but y.shape = {0}".
format(y.shape))
if output_type != "binary" and y.shape[1] != len(classes):
raise ValueError("The number of class is not equal to the number of "
"dimension of y.")
classes = np.asarray(classes)
# Perform thresholding
if sp.issparse(y):
if threshold > 0:
if y.format not in ('csr', 'csc'):
y = y.tocsr()
y.data = np.array(y.data > threshold, dtype=np.int)
y.eliminate_zeros()
else:
y = np.array(y.toarray() > threshold, dtype=np.int)
else:
y = np.array(y > threshold, dtype=np.int)
# Inverse transform data
if output_type == "binary":
if sp.issparse(y):
y = y.toarray()
if y.ndim == 2 and y.shape[1] == 2:
return classes[y[:, 1]]
else:
if len(classes) == 1:
y = np.empty(len(y), dtype=classes.dtype)
y.fill(classes[0])
return y
else:
return classes[y.ravel()]
elif output_type == "multilabel-indicator":
return y
elif output_type == "multilabel-sequences":
warnings.warn('Direct support for sequence of sequences multilabel '
'representation will be unavailable from version 0.17. '
'Use sklearn.preprocessing.MultiLabelBinarizer to '
'convert to a label indicator representation.',
DeprecationWarning)
mlb = MultiLabelBinarizer(classes=classes).fit([])
return mlb.inverse_transform(y)
else:
raise ValueError("{0} format is not supported".format(output_type))
class MultiLabelBinarizer(BaseEstimator, TransformerMixin):
"""Transform between iterable of iterables and a multilabel format
Although a list of sets or tuples is a very intuitive format for multilabel
data, it is unwieldy to process. This transformer converts between this
intuitive format and the supported multilabel format: a (samples x classes)
binary matrix indicating the presence of a class label.
Parameters
----------
classes : array-like of shape [n_classes] (optional)
Indicates an ordering for the class labels
sparse_output : boolean (default: False),
Set to true if output binary array is desired in CSR sparse format
Attributes
----------
classes_ : array of labels
A copy of the `classes` parameter where provided,
or otherwise, the sorted set of classes found when fitting.
Examples
--------
>>> mlb = MultiLabelBinarizer()
>>> mlb.fit_transform([(1, 2), (3,)])
array([[1, 1, 0],
[0, 0, 1]])
>>> mlb.classes_
array([1, 2, 3])
>>> mlb.fit_transform([set(['sci-fi', 'thriller']), set(['comedy'])])
array([[0, 1, 1],
[1, 0, 0]])
>>> list(mlb.classes_)
['comedy', 'sci-fi', 'thriller']
"""
def __init__(self, classes=None, sparse_output=False):
self.classes = classes
self.sparse_output = sparse_output
def fit(self, y):
"""Fit the label sets binarizer, storing `classes_`
Parameters
----------
y : iterable of iterables
A set of labels (any orderable and hashable object) for each
sample. If the `classes` parameter is set, `y` will not be
iterated.
Returns
-------
self : returns this MultiLabelBinarizer instance
"""
if self.classes is None:
classes = sorted(set(itertools.chain.from_iterable(y)))
else:
classes = self.classes
dtype = np.int if all(isinstance(c, int) for c in classes) else object
self.classes_ = np.empty(len(classes), dtype=dtype)
self.classes_[:] = classes
return self
def fit_transform(self, y):
"""Fit the label sets binarizer and transform the given label sets
Parameters
----------
y : iterable of iterables
A set of labels (any orderable and hashable object) for each
sample. If the `classes` parameter is set, `y` will not be
iterated.
Returns
-------
y_indicator : array or CSR matrix, shape (n_samples, n_classes)
A matrix such that `y_indicator[i, j] = 1` iff `classes_[j]` is in
`y[i]`, and 0 otherwise.
"""
if self.classes is not None:
return self.fit(y).transform(y)
# Automatically increment on new class
class_mapping = defaultdict(int)
class_mapping.default_factory = class_mapping.__len__
yt = self._transform(y, class_mapping)
# sort classes and reorder columns
tmp = sorted(class_mapping, key=class_mapping.get)
# (make safe for tuples)
dtype = np.int if all(isinstance(c, int) for c in tmp) else object
class_mapping = np.empty(len(tmp), dtype=dtype)
class_mapping[:] = tmp
self.classes_, inverse = np.unique(class_mapping, return_inverse=True)
yt.indices = np.take(inverse, yt.indices)
if not self.sparse_output:
yt = yt.toarray()
return yt
def transform(self, y):
"""Transform the given label sets
Parameters
----------
y : iterable of iterables
A set of labels (any orderable and hashable object) for each
sample. If the `classes` parameter is set, `y` will not be
iterated.
Returns
-------
y_indicator : array or CSR matrix, shape (n_samples, n_classes)
A matrix such that `y_indicator[i, j] = 1` iff `classes_[j]` is in
`y[i]`, and 0 otherwise.
"""
class_to_index = dict(zip(self.classes_, range(len(self.classes_))))
yt = self._transform(y, class_to_index)
if not self.sparse_output:
yt = yt.toarray()
return yt
def _transform(self, y, class_mapping):
"""Transforms the label sets with a given mapping
Parameters
----------
y : iterable of iterables
class_mapping : Mapping
Maps from label to column index in label indicator matrix
Returns
-------
y_indicator : sparse CSR matrix, shape (n_samples, n_classes)
Label indicator matrix
"""
indices = array.array('i')
indptr = array.array('i', [0])
for labels in y:
indices.extend(set(class_mapping[label] for label in labels))
indptr.append(len(indices))
data = np.ones(len(indices), dtype=int)
return sp.csr_matrix((data, indices, indptr),
shape=(len(indptr) - 1, len(class_mapping)))
def inverse_transform(self, yt):
"""Transform the given indicator matrix into label sets
Parameters
----------
yt : array or sparse matrix of shape (n_samples, n_classes)
A matrix containing only 1s ands 0s.
Returns
-------
y : list of tuples
The set of labels for each sample such that `y[i]` consists of
`classes_[j]` for each `yt[i, j] == 1`.
"""
if yt.shape[1] != len(self.classes_):
raise ValueError('Expected indicator for {0} classes, but got {1}'
.format(len(self.classes_), yt.shape[1]))
if sp.issparse(yt):
yt = yt.tocsr()
if len(yt.data) != 0 and len(np.setdiff1d(yt.data, [0, 1])) > 0:
raise ValueError('Expected only 0s and 1s in label indicator.')
return [tuple(self.classes_.take(yt.indices[start:end]))
for start, end in zip(yt.indptr[:-1], yt.indptr[1:])]
else:
unexpected = np.setdiff1d(yt, [0, 1])
if len(unexpected) > 0:
raise ValueError('Expected only 0s and 1s in label indicator. '
'Also got {0}'.format(unexpected))
return [tuple(self.classes_.compress(indicators)) for indicators
in yt]
| bsd-3-clause |
wlamond/scikit-learn | examples/manifold/plot_manifold_sphere.py | 89 | 5055 | #!/usr/bin/python
# -*- coding: utf-8 -*-
"""
=============================================
Manifold Learning methods on a severed sphere
=============================================
An application of the different :ref:`manifold` techniques
on a spherical data-set. Here one can see the use of
dimensionality reduction in order to gain some intuition
regarding the manifold learning methods. Regarding the dataset,
the poles are cut from the sphere, as well as a thin slice down its
side. This enables the manifold learning techniques to
'spread it open' whilst projecting it onto two dimensions.
For a similar example, where the methods are applied to the
S-curve dataset, see :ref:`sphx_glr_auto_examples_manifold_plot_compare_methods.py`
Note that the purpose of the :ref:`MDS <multidimensional_scaling>` is
to find a low-dimensional representation of the data (here 2D) in
which the distances respect well the distances in the original
high-dimensional space, unlike other manifold-learning algorithms,
it does not seeks an isotropic representation of the data in
the low-dimensional space. Here the manifold problem matches fairly
that of representing a flat map of the Earth, as with
`map projection <https://en.wikipedia.org/wiki/Map_projection>`_
"""
# Author: Jaques Grobler <[email protected]>
# License: BSD 3 clause
print(__doc__)
from time import time
import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
from matplotlib.ticker import NullFormatter
from sklearn import manifold
from sklearn.utils import check_random_state
# Next line to silence pyflakes.
Axes3D
# Variables for manifold learning.
n_neighbors = 10
n_samples = 1000
# Create our sphere.
random_state = check_random_state(0)
p = random_state.rand(n_samples) * (2 * np.pi - 0.55)
t = random_state.rand(n_samples) * np.pi
# Sever the poles from the sphere.
indices = ((t < (np.pi - (np.pi / 8))) & (t > ((np.pi / 8))))
colors = p[indices]
x, y, z = np.sin(t[indices]) * np.cos(p[indices]), \
np.sin(t[indices]) * np.sin(p[indices]), \
np.cos(t[indices])
# Plot our dataset.
fig = plt.figure(figsize=(15, 8))
plt.suptitle("Manifold Learning with %i points, %i neighbors"
% (1000, n_neighbors), fontsize=14)
ax = fig.add_subplot(251, projection='3d')
ax.scatter(x, y, z, c=p[indices], cmap=plt.cm.rainbow)
ax.view_init(40, -10)
sphere_data = np.array([x, y, z]).T
# Perform Locally Linear Embedding Manifold learning
methods = ['standard', 'ltsa', 'hessian', 'modified']
labels = ['LLE', 'LTSA', 'Hessian LLE', 'Modified LLE']
for i, method in enumerate(methods):
t0 = time()
trans_data = manifold\
.LocallyLinearEmbedding(n_neighbors, 2,
method=method).fit_transform(sphere_data).T
t1 = time()
print("%s: %.2g sec" % (methods[i], t1 - t0))
ax = fig.add_subplot(252 + i)
plt.scatter(trans_data[0], trans_data[1], c=colors, cmap=plt.cm.rainbow)
plt.title("%s (%.2g sec)" % (labels[i], t1 - t0))
ax.xaxis.set_major_formatter(NullFormatter())
ax.yaxis.set_major_formatter(NullFormatter())
plt.axis('tight')
# Perform Isomap Manifold learning.
t0 = time()
trans_data = manifold.Isomap(n_neighbors, n_components=2)\
.fit_transform(sphere_data).T
t1 = time()
print("%s: %.2g sec" % ('ISO', t1 - t0))
ax = fig.add_subplot(257)
plt.scatter(trans_data[0], trans_data[1], c=colors, cmap=plt.cm.rainbow)
plt.title("%s (%.2g sec)" % ('Isomap', t1 - t0))
ax.xaxis.set_major_formatter(NullFormatter())
ax.yaxis.set_major_formatter(NullFormatter())
plt.axis('tight')
# Perform Multi-dimensional scaling.
t0 = time()
mds = manifold.MDS(2, max_iter=100, n_init=1)
trans_data = mds.fit_transform(sphere_data).T
t1 = time()
print("MDS: %.2g sec" % (t1 - t0))
ax = fig.add_subplot(258)
plt.scatter(trans_data[0], trans_data[1], c=colors, cmap=plt.cm.rainbow)
plt.title("MDS (%.2g sec)" % (t1 - t0))
ax.xaxis.set_major_formatter(NullFormatter())
ax.yaxis.set_major_formatter(NullFormatter())
plt.axis('tight')
# Perform Spectral Embedding.
t0 = time()
se = manifold.SpectralEmbedding(n_components=2,
n_neighbors=n_neighbors)
trans_data = se.fit_transform(sphere_data).T
t1 = time()
print("Spectral Embedding: %.2g sec" % (t1 - t0))
ax = fig.add_subplot(259)
plt.scatter(trans_data[0], trans_data[1], c=colors, cmap=plt.cm.rainbow)
plt.title("Spectral Embedding (%.2g sec)" % (t1 - t0))
ax.xaxis.set_major_formatter(NullFormatter())
ax.yaxis.set_major_formatter(NullFormatter())
plt.axis('tight')
# Perform t-distributed stochastic neighbor embedding.
t0 = time()
tsne = manifold.TSNE(n_components=2, init='pca', random_state=0)
trans_data = tsne.fit_transform(sphere_data).T
t1 = time()
print("t-SNE: %.2g sec" % (t1 - t0))
ax = fig.add_subplot(2, 5, 10)
plt.scatter(trans_data[0], trans_data[1], c=colors, cmap=plt.cm.rainbow)
plt.title("t-SNE (%.2g sec)" % (t1 - t0))
ax.xaxis.set_major_formatter(NullFormatter())
ax.yaxis.set_major_formatter(NullFormatter())
plt.axis('tight')
plt.show()
| bsd-3-clause |
raghavrv/scikit-learn | sklearn/cluster/spectral.py | 11 | 19173 | # -*- coding: utf-8 -*-
"""Algorithms for spectral clustering"""
# Author: Gael Varoquaux [email protected]
# Brian Cheung
# Wei LI <[email protected]>
# License: BSD 3 clause
import warnings
import numpy as np
from ..base import BaseEstimator, ClusterMixin
from ..utils import check_random_state, as_float_array
from ..utils.validation import check_array
from ..metrics.pairwise import pairwise_kernels
from ..neighbors import kneighbors_graph
from ..manifold import spectral_embedding
from .k_means_ import k_means
def discretize(vectors, copy=True, max_svd_restarts=30, n_iter_max=20,
random_state=None):
"""Search for a partition matrix (clustering) which is closest to the
eigenvector embedding.
Parameters
----------
vectors : array-like, shape: (n_samples, n_clusters)
The embedding space of the samples.
copy : boolean, optional, default: True
Whether to copy vectors, or perform in-place normalization.
max_svd_restarts : int, optional, default: 30
Maximum number of attempts to restart SVD if convergence fails
n_iter_max : int, optional, default: 30
Maximum number of iterations to attempt in rotation and partition
matrix search if machine precision convergence is not reached
random_state : int, RandomState instance or None, optional, default: None
If int, random_state is the seed used by the random number generator;
If RandomState instance, random_state is the random number generator;
If None, the random number generator is the RandomState instance used
by `np.random`.
Returns
-------
labels : array of integers, shape: n_samples
The labels of the clusters.
References
----------
- Multiclass spectral clustering, 2003
Stella X. Yu, Jianbo Shi
http://www1.icsi.berkeley.edu/~stellayu/publication/doc/2003kwayICCV.pdf
Notes
-----
The eigenvector embedding is used to iteratively search for the
closest discrete partition. First, the eigenvector embedding is
normalized to the space of partition matrices. An optimal discrete
partition matrix closest to this normalized embedding multiplied by
an initial rotation is calculated. Fixing this discrete partition
matrix, an optimal rotation matrix is calculated. These two
calculations are performed until convergence. The discrete partition
matrix is returned as the clustering solution. Used in spectral
clustering, this method tends to be faster and more robust to random
initialization than k-means.
"""
from scipy.sparse import csc_matrix
from scipy.linalg import LinAlgError
random_state = check_random_state(random_state)
vectors = as_float_array(vectors, copy=copy)
eps = np.finfo(float).eps
n_samples, n_components = vectors.shape
# Normalize the eigenvectors to an equal length of a vector of ones.
# Reorient the eigenvectors to point in the negative direction with respect
# to the first element. This may have to do with constraining the
# eigenvectors to lie in a specific quadrant to make the discretization
# search easier.
norm_ones = np.sqrt(n_samples)
for i in range(vectors.shape[1]):
vectors[:, i] = (vectors[:, i] / np.linalg.norm(vectors[:, i])) \
* norm_ones
if vectors[0, i] != 0:
vectors[:, i] = -1 * vectors[:, i] * np.sign(vectors[0, i])
# Normalize the rows of the eigenvectors. Samples should lie on the unit
# hypersphere centered at the origin. This transforms the samples in the
# embedding space to the space of partition matrices.
vectors = vectors / np.sqrt((vectors ** 2).sum(axis=1))[:, np.newaxis]
svd_restarts = 0
has_converged = False
# If there is an exception we try to randomize and rerun SVD again
# do this max_svd_restarts times.
while (svd_restarts < max_svd_restarts) and not has_converged:
# Initialize first column of rotation matrix with a row of the
# eigenvectors
rotation = np.zeros((n_components, n_components))
rotation[:, 0] = vectors[random_state.randint(n_samples), :].T
# To initialize the rest of the rotation matrix, find the rows
# of the eigenvectors that are as orthogonal to each other as
# possible
c = np.zeros(n_samples)
for j in range(1, n_components):
# Accumulate c to ensure row is as orthogonal as possible to
# previous picks as well as current one
c += np.abs(np.dot(vectors, rotation[:, j - 1]))
rotation[:, j] = vectors[c.argmin(), :].T
last_objective_value = 0.0
n_iter = 0
while not has_converged:
n_iter += 1
t_discrete = np.dot(vectors, rotation)
labels = t_discrete.argmax(axis=1)
vectors_discrete = csc_matrix(
(np.ones(len(labels)), (np.arange(0, n_samples), labels)),
shape=(n_samples, n_components))
t_svd = vectors_discrete.T * vectors
try:
U, S, Vh = np.linalg.svd(t_svd)
svd_restarts += 1
except LinAlgError:
print("SVD did not converge, randomizing and trying again")
break
ncut_value = 2.0 * (n_samples - S.sum())
if ((abs(ncut_value - last_objective_value) < eps) or
(n_iter > n_iter_max)):
has_converged = True
else:
# otherwise calculate rotation and continue
last_objective_value = ncut_value
rotation = np.dot(Vh.T, U.T)
if not has_converged:
raise LinAlgError('SVD did not converge')
return labels
def spectral_clustering(affinity, n_clusters=8, n_components=None,
eigen_solver=None, random_state=None, n_init=10,
eigen_tol=0.0, assign_labels='kmeans'):
"""Apply clustering to a projection to the normalized laplacian.
In practice Spectral Clustering is very useful when the structure of
the individual clusters is highly non-convex or more generally when
a measure of the center and spread of the cluster is not a suitable
description of the complete cluster. For instance when clusters are
nested circles on the 2D plan.
If affinity is the adjacency matrix of a graph, this method can be
used to find normalized graph cuts.
Read more in the :ref:`User Guide <spectral_clustering>`.
Parameters
-----------
affinity : array-like or sparse matrix, shape: (n_samples, n_samples)
The affinity matrix describing the relationship of the samples to
embed. **Must be symmetric**.
Possible examples:
- adjacency matrix of a graph,
- heat kernel of the pairwise distance matrix of the samples,
- symmetric k-nearest neighbours connectivity matrix of the samples.
n_clusters : integer, optional
Number of clusters to extract.
n_components : integer, optional, default is n_clusters
Number of eigen vectors to use for the spectral embedding
eigen_solver : {None, 'arpack', 'lobpcg', or 'amg'}
The eigenvalue decomposition strategy to use. AMG requires pyamg
to be installed. It can be faster on very large, sparse problems,
but may also lead to instabilities
random_state : int, RandomState instance or None, optional, default: None
A pseudo random number generator used for the initialization of the
lobpcg eigen vectors decomposition when eigen_solver == 'amg' and by
the K-Means initialization. If int, random_state is the seed used by
the random number generator; If RandomState instance, random_state is
the random number generator; If None, the random number generator is
the RandomState instance used by `np.random`.
n_init : int, optional, default: 10
Number of time the k-means algorithm will be run with different
centroid seeds. The final results will be the best output of
n_init consecutive runs in terms of inertia.
eigen_tol : float, optional, default: 0.0
Stopping criterion for eigendecomposition of the Laplacian matrix
when using arpack eigen_solver.
assign_labels : {'kmeans', 'discretize'}, default: 'kmeans'
The strategy to use to assign labels in the embedding
space. There are two ways to assign labels after the laplacian
embedding. k-means can be applied and is a popular choice. But it can
also be sensitive to initialization. Discretization is another
approach which is less sensitive to random initialization. See
the 'Multiclass spectral clustering' paper referenced below for
more details on the discretization approach.
Returns
-------
labels : array of integers, shape: n_samples
The labels of the clusters.
References
----------
- Normalized cuts and image segmentation, 2000
Jianbo Shi, Jitendra Malik
http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.160.2324
- A Tutorial on Spectral Clustering, 2007
Ulrike von Luxburg
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.165.9323
- Multiclass spectral clustering, 2003
Stella X. Yu, Jianbo Shi
http://www1.icsi.berkeley.edu/~stellayu/publication/doc/2003kwayICCV.pdf
Notes
------
The graph should contain only one connect component, elsewhere
the results make little sense.
This algorithm solves the normalized cut for k=2: it is a
normalized spectral clustering.
"""
if assign_labels not in ('kmeans', 'discretize'):
raise ValueError("The 'assign_labels' parameter should be "
"'kmeans' or 'discretize', but '%s' was given"
% assign_labels)
random_state = check_random_state(random_state)
n_components = n_clusters if n_components is None else n_components
maps = spectral_embedding(affinity, n_components=n_components,
eigen_solver=eigen_solver,
random_state=random_state,
eigen_tol=eigen_tol, drop_first=False)
if assign_labels == 'kmeans':
_, labels, _ = k_means(maps, n_clusters, random_state=random_state,
n_init=n_init)
else:
labels = discretize(maps, random_state=random_state)
return labels
class SpectralClustering(BaseEstimator, ClusterMixin):
"""Apply clustering to a projection to the normalized laplacian.
In practice Spectral Clustering is very useful when the structure of
the individual clusters is highly non-convex or more generally when
a measure of the center and spread of the cluster is not a suitable
description of the complete cluster. For instance when clusters are
nested circles on the 2D plan.
If affinity is the adjacency matrix of a graph, this method can be
used to find normalized graph cuts.
When calling ``fit``, an affinity matrix is constructed using either
kernel function such the Gaussian (aka RBF) kernel of the euclidean
distanced ``d(X, X)``::
np.exp(-gamma * d(X,X) ** 2)
or a k-nearest neighbors connectivity matrix.
Alternatively, using ``precomputed``, a user-provided affinity
matrix can be used.
Read more in the :ref:`User Guide <spectral_clustering>`.
Parameters
-----------
n_clusters : integer, optional
The dimension of the projection subspace.
affinity : string, array-like or callable, default 'rbf'
If a string, this may be one of 'nearest_neighbors', 'precomputed',
'rbf' or one of the kernels supported by
`sklearn.metrics.pairwise_kernels`.
Only kernels that produce similarity scores (non-negative values that
increase with similarity) should be used. This property is not checked
by the clustering algorithm.
gamma : float, default=1.0
Kernel coefficient for rbf, poly, sigmoid, laplacian and chi2 kernels.
Ignored for ``affinity='nearest_neighbors'``.
degree : float, default=3
Degree of the polynomial kernel. Ignored by other kernels.
coef0 : float, default=1
Zero coefficient for polynomial and sigmoid kernels.
Ignored by other kernels.
n_neighbors : integer
Number of neighbors to use when constructing the affinity matrix using
the nearest neighbors method. Ignored for ``affinity='rbf'``.
eigen_solver : {None, 'arpack', 'lobpcg', or 'amg'}
The eigenvalue decomposition strategy to use. AMG requires pyamg
to be installed. It can be faster on very large, sparse problems,
but may also lead to instabilities
random_state : int, RandomState instance or None, optional, default: None
A pseudo random number generator used for the initialization of the
lobpcg eigen vectors decomposition when eigen_solver == 'amg' and by
the K-Means initialization. If int, random_state is the seed used by
the random number generator; If RandomState instance, random_state is
the random number generator; If None, the random number generator is
the RandomState instance used by `np.random`.
n_init : int, optional, default: 10
Number of time the k-means algorithm will be run with different
centroid seeds. The final results will be the best output of
n_init consecutive runs in terms of inertia.
eigen_tol : float, optional, default: 0.0
Stopping criterion for eigendecomposition of the Laplacian matrix
when using arpack eigen_solver.
assign_labels : {'kmeans', 'discretize'}, default: 'kmeans'
The strategy to use to assign labels in the embedding
space. There are two ways to assign labels after the laplacian
embedding. k-means can be applied and is a popular choice. But it can
also be sensitive to initialization. Discretization is another approach
which is less sensitive to random initialization.
kernel_params : dictionary of string to any, optional
Parameters (keyword arguments) and values for kernel passed as
callable object. Ignored by other kernels.
n_jobs : int, optional (default = 1)
The number of parallel jobs to run.
If ``-1``, then the number of jobs is set to the number of CPU cores.
Attributes
----------
affinity_matrix_ : array-like, shape (n_samples, n_samples)
Affinity matrix used for clustering. Available only if after calling
``fit``.
labels_ :
Labels of each point
Notes
-----
If you have an affinity matrix, such as a distance matrix,
for which 0 means identical elements, and high values means
very dissimilar elements, it can be transformed in a
similarity matrix that is well suited for the algorithm by
applying the Gaussian (RBF, heat) kernel::
np.exp(- dist_matrix ** 2 / (2. * delta ** 2))
Where ``delta`` is a free parameter representing the width of the Gaussian
kernel.
Another alternative is to take a symmetric version of the k
nearest neighbors connectivity matrix of the points.
If the pyamg package is installed, it is used: this greatly
speeds up computation.
References
----------
- Normalized cuts and image segmentation, 2000
Jianbo Shi, Jitendra Malik
http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.160.2324
- A Tutorial on Spectral Clustering, 2007
Ulrike von Luxburg
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.165.9323
- Multiclass spectral clustering, 2003
Stella X. Yu, Jianbo Shi
http://www1.icsi.berkeley.edu/~stellayu/publication/doc/2003kwayICCV.pdf
"""
def __init__(self, n_clusters=8, eigen_solver=None, random_state=None,
n_init=10, gamma=1., affinity='rbf', n_neighbors=10,
eigen_tol=0.0, assign_labels='kmeans', degree=3, coef0=1,
kernel_params=None, n_jobs=1):
self.n_clusters = n_clusters
self.eigen_solver = eigen_solver
self.random_state = random_state
self.n_init = n_init
self.gamma = gamma
self.affinity = affinity
self.n_neighbors = n_neighbors
self.eigen_tol = eigen_tol
self.assign_labels = assign_labels
self.degree = degree
self.coef0 = coef0
self.kernel_params = kernel_params
self.n_jobs = n_jobs
def fit(self, X, y=None):
"""Creates an affinity matrix for X using the selected affinity,
then applies spectral clustering to this affinity matrix.
Parameters
----------
X : array-like or sparse matrix, shape (n_samples, n_features)
OR, if affinity==`precomputed`, a precomputed affinity
matrix of shape (n_samples, n_samples)
"""
X = check_array(X, accept_sparse=['csr', 'csc', 'coo'],
dtype=np.float64)
if X.shape[0] == X.shape[1] and self.affinity != "precomputed":
warnings.warn("The spectral clustering API has changed. ``fit``"
"now constructs an affinity matrix from data. To use"
" a custom affinity matrix, "
"set ``affinity=precomputed``.")
if self.affinity == 'nearest_neighbors':
connectivity = kneighbors_graph(X, n_neighbors=self.n_neighbors, include_self=True,
n_jobs=self.n_jobs)
self.affinity_matrix_ = 0.5 * (connectivity + connectivity.T)
elif self.affinity == 'precomputed':
self.affinity_matrix_ = X
else:
params = self.kernel_params
if params is None:
params = {}
if not callable(self.affinity):
params['gamma'] = self.gamma
params['degree'] = self.degree
params['coef0'] = self.coef0
self.affinity_matrix_ = pairwise_kernels(X, metric=self.affinity,
filter_params=True,
**params)
random_state = check_random_state(self.random_state)
self.labels_ = spectral_clustering(self.affinity_matrix_,
n_clusters=self.n_clusters,
eigen_solver=self.eigen_solver,
random_state=random_state,
n_init=self.n_init,
eigen_tol=self.eigen_tol,
assign_labels=self.assign_labels)
return self
@property
def _pairwise(self):
return self.affinity == "precomputed"
| bsd-3-clause |
mikebenfield/scikit-learn | examples/linear_model/plot_sgd_loss_functions.py | 86 | 1234 | """
==========================
SGD: convex loss functions
==========================
A plot that compares the various convex loss functions supported by
:class:`sklearn.linear_model.SGDClassifier` .
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
def modified_huber_loss(y_true, y_pred):
z = y_pred * y_true
loss = -4 * z
loss[z >= -1] = (1 - z[z >= -1]) ** 2
loss[z >= 1.] = 0
return loss
xmin, xmax = -4, 4
xx = np.linspace(xmin, xmax, 100)
lw = 2
plt.plot([xmin, 0, 0, xmax], [1, 1, 0, 0], color='gold', lw=lw,
label="Zero-one loss")
plt.plot(xx, np.where(xx < 1, 1 - xx, 0), color='teal', lw=lw,
label="Hinge loss")
plt.plot(xx, -np.minimum(xx, 0), color='yellowgreen', lw=lw,
label="Perceptron loss")
plt.plot(xx, np.log2(1 + np.exp(-xx)), color='cornflowerblue', lw=lw,
label="Log loss")
plt.plot(xx, np.where(xx < 1, 1 - xx, 0) ** 2, color='orange', lw=lw,
label="Squared hinge loss")
plt.plot(xx, modified_huber_loss(xx, 1), color='darkorchid', lw=lw,
linestyle='--', label="Modified Huber loss")
plt.ylim((0, 8))
plt.legend(loc="upper right")
plt.xlabel(r"Decision function $f(x)$")
plt.ylabel("$L(y=1, f(x))$")
plt.show()
| bsd-3-clause |
huzq/scikit-learn | examples/svm/plot_separating_hyperplane_unbalanced.py | 44 | 2463 | """
=================================================
SVM: Separating hyperplane for unbalanced classes
=================================================
Find the optimal separating hyperplane using an SVC for classes that
are unbalanced.
We first find the separating plane with a plain SVC and then plot
(dashed) the separating hyperplane with automatically correction for
unbalanced classes.
.. currentmodule:: sklearn.linear_model
.. note::
This example will also work by replacing ``SVC(kernel="linear")``
with ``SGDClassifier(loss="hinge")``. Setting the ``loss`` parameter
of the :class:`SGDClassifier` equal to ``hinge`` will yield behaviour
such as that of a SVC with a linear kernel.
For example try instead of the ``SVC``::
clf = SGDClassifier(n_iter=100, alpha=0.01)
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from sklearn import svm
from sklearn.datasets import make_blobs
# we create two clusters of random points
n_samples_1 = 1000
n_samples_2 = 100
centers = [[0.0, 0.0], [2.0, 2.0]]
clusters_std = [1.5, 0.5]
X, y = make_blobs(n_samples=[n_samples_1, n_samples_2],
centers=centers,
cluster_std=clusters_std,
random_state=0, shuffle=False)
# fit the model and get the separating hyperplane
clf = svm.SVC(kernel='linear', C=1.0)
clf.fit(X, y)
# fit the model and get the separating hyperplane using weighted classes
wclf = svm.SVC(kernel='linear', class_weight={1: 10})
wclf.fit(X, y)
# plot the samples
plt.scatter(X[:, 0], X[:, 1], c=y, cmap=plt.cm.Paired, edgecolors='k')
# plot the decision functions for both classifiers
ax = plt.gca()
xlim = ax.get_xlim()
ylim = ax.get_ylim()
# create grid to evaluate model
xx = np.linspace(xlim[0], xlim[1], 30)
yy = np.linspace(ylim[0], ylim[1], 30)
YY, XX = np.meshgrid(yy, xx)
xy = np.vstack([XX.ravel(), YY.ravel()]).T
# get the separating hyperplane
Z = clf.decision_function(xy).reshape(XX.shape)
# plot decision boundary and margins
a = ax.contour(XX, YY, Z, colors='k', levels=[0], alpha=0.5, linestyles=['-'])
# get the separating hyperplane for weighted classes
Z = wclf.decision_function(xy).reshape(XX.shape)
# plot decision boundary and margins for weighted classes
b = ax.contour(XX, YY, Z, colors='r', levels=[0], alpha=0.5, linestyles=['-'])
plt.legend([a.collections[0], b.collections[0]], ["non weighted", "weighted"],
loc="upper right")
plt.show()
| bsd-3-clause |
Eric89GXL/scikit-learn | examples/applications/wikipedia_principal_eigenvector.py | 41 | 7742 | """
===============================
Wikipedia principal eigenvector
===============================
A classical way to assert the relative importance of vertices in a
graph is to compute the principal eigenvector of the adjacency matrix
so as to assign to each vertex the values of the components of the first
eigenvector as a centrality score:
http://en.wikipedia.org/wiki/Eigenvector_centrality
On the graph of webpages and links those values are called the PageRank
scores by Google.
The goal of this example is to analyze the graph of links inside
wikipedia articles to rank articles by relative importance according to
this eigenvector centrality.
The traditional way to compute the principal eigenvector is to use the
power iteration method:
http://en.wikipedia.org/wiki/Power_iteration
Here the computation is achieved thanks to Martinsson's Randomized SVD
algorithm implemented in the scikit.
The graph data is fetched from the DBpedia dumps. DBpedia is an extraction
of the latent structured data of the Wikipedia content.
"""
# Author: Olivier Grisel <[email protected]>
# License: BSD 3 clause
from __future__ import print_function
from bz2 import BZ2File
import os
from datetime import datetime
from pprint import pprint
from time import time
import numpy as np
from scipy import sparse
from sklearn.decomposition import randomized_svd
from sklearn.externals.joblib import Memory
print(__doc__)
###############################################################################
# Where to download the data, if not already on disk
redirects_url = "http://downloads.dbpedia.org/3.5.1/en/redirects_en.nt.bz2"
redirects_filename = redirects_url.rsplit("/", 1)[1]
page_links_url = "http://downloads.dbpedia.org/3.5.1/en/page_links_en.nt.bz2"
page_links_filename = page_links_url.rsplit("/", 1)[1]
resources = [
(redirects_url, redirects_filename),
(page_links_url, page_links_filename),
]
for url, filename in resources:
if not os.path.exists(filename):
import urllib
print("Downloading data from '%s', please wait..." % url)
opener = urllib.urlopen(url)
open(filename, 'wb').write(opener.read())
print()
###############################################################################
# Loading the redirect files
memory = Memory(cachedir=".")
def index(redirects, index_map, k):
"""Find the index of an article name after redirect resolution"""
k = redirects.get(k, k)
return index_map.setdefault(k, len(index_map))
DBPEDIA_RESOURCE_PREFIX_LEN = len("http://dbpedia.org/resource/")
SHORTNAME_SLICE = slice(DBPEDIA_RESOURCE_PREFIX_LEN + 1, -1)
def short_name(nt_uri):
"""Remove the < and > URI markers and the common URI prefix"""
return nt_uri[SHORTNAME_SLICE]
def get_redirects(redirects_filename):
"""Parse the redirections and build a transitively closed map out of it"""
redirects = {}
print("Parsing the NT redirect file")
for l, line in enumerate(BZ2File(redirects_filename)):
split = line.split()
if len(split) != 4:
print("ignoring malformed line: " + line)
continue
redirects[short_name(split[0])] = short_name(split[2])
if l % 1000000 == 0:
print("[%s] line: %08d" % (datetime.now().isoformat(), l))
# compute the transitive closure
print("Computing the transitive closure of the redirect relation")
for l, source in enumerate(redirects.keys()):
transitive_target = None
target = redirects[source]
seen = set([source])
while True:
transitive_target = target
target = redirects.get(target)
if target is None or target in seen:
break
seen.add(target)
redirects[source] = transitive_target
if l % 1000000 == 0:
print("[%s] line: %08d" % (datetime.now().isoformat(), l))
return redirects
# disabling joblib as the pickling of large dicts seems much too slow
#@memory.cache
def get_adjacency_matrix(redirects_filename, page_links_filename, limit=None):
"""Extract the adjacency graph as a scipy sparse matrix
Redirects are resolved first.
Returns X, the scipy sparse adjacency matrix, redirects as python
dict from article names to article names and index_map a python dict
from article names to python int (article indexes).
"""
print("Computing the redirect map")
redirects = get_redirects(redirects_filename)
print("Computing the integer index map")
index_map = dict()
links = list()
for l, line in enumerate(BZ2File(page_links_filename)):
split = line.split()
if len(split) != 4:
print("ignoring malformed line: " + line)
continue
i = index(redirects, index_map, short_name(split[0]))
j = index(redirects, index_map, short_name(split[2]))
links.append((i, j))
if l % 1000000 == 0:
print("[%s] line: %08d" % (datetime.now().isoformat(), l))
if limit is not None and l >= limit - 1:
break
print("Computing the adjacency matrix")
X = sparse.lil_matrix((len(index_map), len(index_map)), dtype=np.float32)
for i, j in links:
X[i, j] = 1.0
del links
print("Converting to CSR representation")
X = X.tocsr()
print("CSR conversion done")
return X, redirects, index_map
# stop after 5M links to make it possible to work in RAM
X, redirects, index_map = get_adjacency_matrix(
redirects_filename, page_links_filename, limit=5000000)
names = dict((i, name) for name, i in index_map.iteritems())
print("Computing the principal singular vectors using randomized_svd")
t0 = time()
U, s, V = randomized_svd(X, 5, n_iter=3)
print("done in %0.3fs" % (time() - t0))
# print the names of the wikipedia related strongest compenents of the the
# principal singular vector which should be similar to the highest eigenvector
print("Top wikipedia pages according to principal singular vectors")
pprint([names[i] for i in np.abs(U.T[0]).argsort()[-10:]])
pprint([names[i] for i in np.abs(V[0]).argsort()[-10:]])
def centrality_scores(X, alpha=0.85, max_iter=100, tol=1e-10):
"""Power iteration computation of the principal eigenvector
This method is also known as Google PageRank and the implementation
is based on the one from the NetworkX project (BSD licensed too)
with copyrights by:
Aric Hagberg <[email protected]>
Dan Schult <[email protected]>
Pieter Swart <[email protected]>
"""
n = X.shape[0]
X = X.copy()
incoming_counts = np.asarray(X.sum(axis=1)).ravel()
print("Normalizing the graph")
for i in incoming_counts.nonzero()[0]:
X.data[X.indptr[i]:X.indptr[i + 1]] *= 1.0 / incoming_counts[i]
dangle = np.asarray(np.where(X.sum(axis=1) == 0, 1.0 / n, 0)).ravel()
scores = np.ones(n, dtype=np.float32) / n # initial guess
for i in range(max_iter):
print("power iteration #%d" % i)
prev_scores = scores
scores = (alpha * (scores * X + np.dot(dangle, prev_scores))
+ (1 - alpha) * prev_scores.sum() / n)
# check convergence: normalized l_inf norm
scores_max = np.abs(scores).max()
if scores_max == 0.0:
scores_max = 1.0
err = np.abs(scores - prev_scores).max() / scores_max
print("error: %0.6f" % err)
if err < n * tol:
return scores
return scores
print("Computing principal eigenvector score using a power iteration method")
t0 = time()
scores = centrality_scores(X, max_iter=100, tol=1e-10)
print("done in %0.3fs" % (time() - t0))
pprint([names[i] for i in np.abs(scores).argsort()[-10:]])
| bsd-3-clause |
chrsrds/scikit-learn | sklearn/utils/tests/test_murmurhash.py | 21 | 2637 | # Author: Olivier Grisel <[email protected]>
#
# License: BSD 3 clause
import numpy as np
from sklearn.utils.murmurhash import murmurhash3_32
from numpy.testing import assert_array_almost_equal
from numpy.testing import assert_array_equal
def test_mmhash3_int():
assert murmurhash3_32(3) == 847579505
assert murmurhash3_32(3, seed=0) == 847579505
assert murmurhash3_32(3, seed=42) == -1823081949
assert murmurhash3_32(3, positive=False) == 847579505
assert murmurhash3_32(3, seed=0, positive=False) == 847579505
assert murmurhash3_32(3, seed=42, positive=False) == -1823081949
assert murmurhash3_32(3, positive=True) == 847579505
assert murmurhash3_32(3, seed=0, positive=True) == 847579505
assert murmurhash3_32(3, seed=42, positive=True) == 2471885347
def test_mmhash3_int_array():
rng = np.random.RandomState(42)
keys = rng.randint(-5342534, 345345, size=3 * 2 * 1).astype(np.int32)
keys = keys.reshape((3, 2, 1))
for seed in [0, 42]:
expected = np.array([murmurhash3_32(int(k), seed)
for k in keys.flat])
expected = expected.reshape(keys.shape)
assert_array_equal(murmurhash3_32(keys, seed), expected)
for seed in [0, 42]:
expected = np.array([murmurhash3_32(k, seed, positive=True)
for k in keys.flat])
expected = expected.reshape(keys.shape)
assert_array_equal(murmurhash3_32(keys, seed, positive=True),
expected)
def test_mmhash3_bytes():
assert murmurhash3_32(b'foo', 0) == -156908512
assert murmurhash3_32(b'foo', 42) == -1322301282
assert murmurhash3_32(b'foo', 0, positive=True) == 4138058784
assert murmurhash3_32(b'foo', 42, positive=True) == 2972666014
def test_mmhash3_unicode():
assert murmurhash3_32('foo', 0) == -156908512
assert murmurhash3_32('foo', 42) == -1322301282
assert murmurhash3_32('foo', 0, positive=True) == 4138058784
assert murmurhash3_32('foo', 42, positive=True) == 2972666014
def test_no_collision_on_byte_range():
previous_hashes = set()
for i in range(100):
h = murmurhash3_32(' ' * i, 0)
assert h not in previous_hashes, \
"Found collision on growing empty string"
def test_uniform_distribution():
n_bins, n_samples = 10, 100000
bins = np.zeros(n_bins, dtype=np.float64)
for i in range(n_samples):
bins[murmurhash3_32(i, positive=True) % n_bins] += 1
means = bins / n_samples
expected = np.full(n_bins, 1. / n_bins)
assert_array_almost_equal(means / expected, np.ones(n_bins), 2)
| bsd-3-clause |
joshloyal/scikit-learn | sklearn/cross_decomposition/cca_.py | 151 | 3192 | from .pls_ import _PLS
__all__ = ['CCA']
class CCA(_PLS):
"""CCA Canonical Correlation Analysis.
CCA inherits from PLS with mode="B" and deflation_mode="canonical".
Read more in the :ref:`User Guide <cross_decomposition>`.
Parameters
----------
n_components : int, (default 2).
number of components to keep.
scale : boolean, (default True)
whether to scale the data?
max_iter : an integer, (default 500)
the maximum number of iterations of the NIPALS inner loop
tol : non-negative real, default 1e-06.
the tolerance used in the iterative algorithm
copy : boolean
Whether the deflation be done on a copy. Let the default value
to True unless you don't care about side effects
Attributes
----------
x_weights_ : array, [p, n_components]
X block weights vectors.
y_weights_ : array, [q, n_components]
Y block weights vectors.
x_loadings_ : array, [p, n_components]
X block loadings vectors.
y_loadings_ : array, [q, n_components]
Y block loadings vectors.
x_scores_ : array, [n_samples, n_components]
X scores.
y_scores_ : array, [n_samples, n_components]
Y scores.
x_rotations_ : array, [p, n_components]
X block to latents rotations.
y_rotations_ : array, [q, n_components]
Y block to latents rotations.
n_iter_ : array-like
Number of iterations of the NIPALS inner loop for each
component.
Notes
-----
For each component k, find the weights u, v that maximizes
max corr(Xk u, Yk v), such that ``|u| = |v| = 1``
Note that it maximizes only the correlations between the scores.
The residual matrix of X (Xk+1) block is obtained by the deflation on the
current X score: x_score.
The residual matrix of Y (Yk+1) block is obtained by deflation on the
current Y score.
Examples
--------
>>> from sklearn.cross_decomposition import CCA
>>> X = [[0., 0., 1.], [1.,0.,0.], [2.,2.,2.], [3.,5.,4.]]
>>> Y = [[0.1, -0.2], [0.9, 1.1], [6.2, 5.9], [11.9, 12.3]]
>>> cca = CCA(n_components=1)
>>> cca.fit(X, Y)
... # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
CCA(copy=True, max_iter=500, n_components=1, scale=True, tol=1e-06)
>>> X_c, Y_c = cca.transform(X, Y)
References
----------
Jacob A. Wegelin. A survey of Partial Least Squares (PLS) methods, with
emphasis on the two-block case. Technical Report 371, Department of
Statistics, University of Washington, Seattle, 2000.
In french but still a reference:
Tenenhaus, M. (1998). La regression PLS: theorie et pratique. Paris:
Editions Technic.
See also
--------
PLSCanonical
PLSSVD
"""
def __init__(self, n_components=2, scale=True,
max_iter=500, tol=1e-06, copy=True):
super(CCA, self).__init__(n_components=n_components, scale=scale,
deflation_mode="canonical", mode="B",
norm_y_weights=True, algorithm="nipals",
max_iter=max_iter, tol=tol, copy=copy)
| bsd-3-clause |
elijah513/scikit-learn | sklearn/decomposition/truncated_svd.py | 199 | 7744 | """Truncated SVD for sparse matrices, aka latent semantic analysis (LSA).
"""
# Author: Lars Buitinck <[email protected]>
# Olivier Grisel <[email protected]>
# Michael Becker <[email protected]>
# License: 3-clause BSD.
import numpy as np
import scipy.sparse as sp
try:
from scipy.sparse.linalg import svds
except ImportError:
from ..utils.arpack import svds
from ..base import BaseEstimator, TransformerMixin
from ..utils import check_array, as_float_array, check_random_state
from ..utils.extmath import randomized_svd, safe_sparse_dot, svd_flip
from ..utils.sparsefuncs import mean_variance_axis
__all__ = ["TruncatedSVD"]
class TruncatedSVD(BaseEstimator, TransformerMixin):
"""Dimensionality reduction using truncated SVD (aka LSA).
This transformer performs linear dimensionality reduction by means of
truncated singular value decomposition (SVD). It is very similar to PCA,
but operates on sample vectors directly, instead of on a covariance matrix.
This means it can work with scipy.sparse matrices efficiently.
In particular, truncated SVD works on term count/tf-idf matrices as
returned by the vectorizers in sklearn.feature_extraction.text. In that
context, it is known as latent semantic analysis (LSA).
This estimator supports two algorithm: a fast randomized SVD solver, and
a "naive" algorithm that uses ARPACK as an eigensolver on (X * X.T) or
(X.T * X), whichever is more efficient.
Read more in the :ref:`User Guide <LSA>`.
Parameters
----------
n_components : int, default = 2
Desired dimensionality of output data.
Must be strictly less than the number of features.
The default value is useful for visualisation. For LSA, a value of
100 is recommended.
algorithm : string, default = "randomized"
SVD solver to use. Either "arpack" for the ARPACK wrapper in SciPy
(scipy.sparse.linalg.svds), or "randomized" for the randomized
algorithm due to Halko (2009).
n_iter : int, optional
Number of iterations for randomized SVD solver. Not used by ARPACK.
random_state : int or RandomState, optional
(Seed for) pseudo-random number generator. If not given, the
numpy.random singleton is used.
tol : float, optional
Tolerance for ARPACK. 0 means machine precision. Ignored by randomized
SVD solver.
Attributes
----------
components_ : array, shape (n_components, n_features)
explained_variance_ratio_ : array, [n_components]
Percentage of variance explained by each of the selected components.
explained_variance_ : array, [n_components]
The variance of the training samples transformed by a projection to
each component.
Examples
--------
>>> from sklearn.decomposition import TruncatedSVD
>>> from sklearn.random_projection import sparse_random_matrix
>>> X = sparse_random_matrix(100, 100, density=0.01, random_state=42)
>>> svd = TruncatedSVD(n_components=5, random_state=42)
>>> svd.fit(X) # doctest: +NORMALIZE_WHITESPACE
TruncatedSVD(algorithm='randomized', n_components=5, n_iter=5,
random_state=42, tol=0.0)
>>> print(svd.explained_variance_ratio_) # doctest: +ELLIPSIS
[ 0.07825... 0.05528... 0.05445... 0.04997... 0.04134...]
>>> print(svd.explained_variance_ratio_.sum()) # doctest: +ELLIPSIS
0.27930...
See also
--------
PCA
RandomizedPCA
References
----------
Finding structure with randomness: Stochastic algorithms for constructing
approximate matrix decompositions
Halko, et al., 2009 (arXiv:909) http://arxiv.org/pdf/0909.4061
Notes
-----
SVD suffers from a problem called "sign indeterminancy", which means the
sign of the ``components_`` and the output from transform depend on the
algorithm and random state. To work around this, fit instances of this
class to data once, then keep the instance around to do transformations.
"""
def __init__(self, n_components=2, algorithm="randomized", n_iter=5,
random_state=None, tol=0.):
self.algorithm = algorithm
self.n_components = n_components
self.n_iter = n_iter
self.random_state = random_state
self.tol = tol
def fit(self, X, y=None):
"""Fit LSI model on training data X.
Parameters
----------
X : {array-like, sparse matrix}, shape (n_samples, n_features)
Training data.
Returns
-------
self : object
Returns the transformer object.
"""
self.fit_transform(X)
return self
def fit_transform(self, X, y=None):
"""Fit LSI model to X and perform dimensionality reduction on X.
Parameters
----------
X : {array-like, sparse matrix}, shape (n_samples, n_features)
Training data.
Returns
-------
X_new : array, shape (n_samples, n_components)
Reduced version of X. This will always be a dense array.
"""
X = as_float_array(X, copy=False)
random_state = check_random_state(self.random_state)
# If sparse and not csr or csc, convert to csr
if sp.issparse(X) and X.getformat() not in ["csr", "csc"]:
X = X.tocsr()
if self.algorithm == "arpack":
U, Sigma, VT = svds(X, k=self.n_components, tol=self.tol)
# svds doesn't abide by scipy.linalg.svd/randomized_svd
# conventions, so reverse its outputs.
Sigma = Sigma[::-1]
U, VT = svd_flip(U[:, ::-1], VT[::-1])
elif self.algorithm == "randomized":
k = self.n_components
n_features = X.shape[1]
if k >= n_features:
raise ValueError("n_components must be < n_features;"
" got %d >= %d" % (k, n_features))
U, Sigma, VT = randomized_svd(X, self.n_components,
n_iter=self.n_iter,
random_state=random_state)
else:
raise ValueError("unknown algorithm %r" % self.algorithm)
self.components_ = VT
# Calculate explained variance & explained variance ratio
X_transformed = np.dot(U, np.diag(Sigma))
self.explained_variance_ = exp_var = np.var(X_transformed, axis=0)
if sp.issparse(X):
_, full_var = mean_variance_axis(X, axis=0)
full_var = full_var.sum()
else:
full_var = np.var(X, axis=0).sum()
self.explained_variance_ratio_ = exp_var / full_var
return X_transformed
def transform(self, X):
"""Perform dimensionality reduction on X.
Parameters
----------
X : {array-like, sparse matrix}, shape (n_samples, n_features)
New data.
Returns
-------
X_new : array, shape (n_samples, n_components)
Reduced version of X. This will always be a dense array.
"""
X = check_array(X, accept_sparse='csr')
return safe_sparse_dot(X, self.components_.T)
def inverse_transform(self, X):
"""Transform X back to its original space.
Returns an array X_original whose transform would be X.
Parameters
----------
X : array-like, shape (n_samples, n_components)
New data.
Returns
-------
X_original : array, shape (n_samples, n_features)
Note that this is always a dense array.
"""
X = check_array(X)
return np.dot(X, self.components_)
| bsd-3-clause |
ronny3050/MobileNet | retrain.py | 1 | 56996 | # Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
r"""Simple transfer learning with Inception v3 or Mobilenet models.
With support for TensorBoard.
This example shows how to take a Inception v3 or Mobilenet model trained on
ImageNet images, and train a new top layer that can recognize other classes of
images.
The top layer receives as input a 2048-dimensional vector (1001-dimensional for
Mobilenet) for each image. We train a softmax layer on top of this
representation. Assuming the softmax layer contains N labels, this corresponds
to learning N + 2048*N (or 1001*N) model parameters corresponding to the
learned biases and weights.
Here's an example, which assumes you have a folder containing class-named
subfolders, each full of images for each label. The example folder flower_photos
should have a structure like this:
~/flower_photos/daisy/photo1.jpg
~/flower_photos/daisy/photo2.jpg
...
~/flower_photos/rose/anotherphoto77.jpg
...
~/flower_photos/sunflower/somepicture.jpg
The subfolder names are important, since they define what label is applied to
each image, but the filenames themselves don't matter. Once your images are
prepared, you can run the training with a command like this:
```bash
bazel build tensorflow/examples/image_retraining:retrain && \
bazel-bin/tensorflow/examples/image_retraining/retrain \
--image_dir ~/flower_photos
```
Or, if you have a pip installation of tensorflow, `retrain.py` can be run
without bazel:
```bash
python tensorflow/examples/image_retraining/retrain.py \
--image_dir ~/flower_photos
```
You can replace the image_dir argument with any folder containing subfolders of
images. The label for each image is taken from the name of the subfolder it's
in.
This produces a new model file that can be loaded and run by any TensorFlow
program, for example the label_image sample code.
By default this script will use the high accuracy, but comparatively large and
slow Inception v3 model architecture. It's recommended that you start with this
to validate that you have gathered good training data, but if you want to deploy
on resource-limited platforms, you can try the `--architecture` flag with a
Mobilenet model. For example:
```bash
python tensorflow/examples/image_retraining/retrain.py \
--image_dir ~/flower_photos --architecture mobilenet_1.0_224
```
There are 32 different Mobilenet models to choose from, with a variety of file
size and latency options. The first number can be '1.0', '0.75', '0.50', or
'0.25' to control the size, and the second controls the input image size, either
'224', '192', '160', or '128', with smaller sizes running faster. See
https://research.googleblog.com/2017/06/mobilenets-open-source-models-for.html
for more information on Mobilenet.
To use with TensorBoard:
By default, this script will log summaries to /tmp/retrain_logs directory
Visualize the summaries with this command:
tensorboard --logdir /tmp/retrain_logs
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import argparse
from datetime import datetime
import hashlib
import os.path
import random
import re
import sys
import tarfile
from sklearn.model_selection import train_test_split
import numpy as np
from six.moves import urllib
import tensorflow as tf
from tensorflow.python.framework import graph_util
from tensorflow.python.framework import tensor_shape
from tensorflow.python.platform import gfile
from tensorflow.python.util import compat
FLAGS = None
# These are all parameters that are tied to the particular model architecture
# we're using for Inception v3. These include things like tensor names and their
# sizes. If you want to adapt this script to work with another model, you will
# need to update these to reflect the values in the network you're using.
MAX_NUM_IMAGES_PER_CLASS = 2 ** 27 - 1 # ~134M
def create_image_lists(image_dir, testing_percentage, validation_percentage):
"""Builds a list of training images from the file system.
Analyzes the sub folders in the image directory, splits them into stable
training, testing, and validation sets, and returns a data structure
describing the lists of images for each label and their paths.
Args:
image_dir: String path to a folder containing subfolders of images.
testing_percentage: Integer percentage of the images to reserve for tests.
validation_percentage: Integer percentage of images reserved for validation.
Returns:
A dictionary containing an entry for each label subfolder, with images split
into training, testing, and validation sets within each label.
"""
if not gfile.Exists(image_dir):
tf.logging.error("Image directory '" + image_dir + "' not found.")
return None
result = {}
sub_dirs = [x[0] for x in gfile.Walk(image_dir)]
# The root directory comes first, so skip it.
is_root_dir = True
for sub_dir in sub_dirs:
if is_root_dir:
is_root_dir = False
continue
extensions = ['jpg', 'jpeg', 'JPG', 'JPEG']
file_list = []
dir_name = os.path.basename(sub_dir)
if dir_name == image_dir:
continue
tf.logging.info("Looking for images in '" + dir_name + "'")
for extension in extensions:
file_glob = os.path.join(image_dir, dir_name, '*.' + extension)
file_list.extend(gfile.Glob(file_glob))
if not file_list:
tf.logging.warning('No files found')
continue
if len(file_list) < 20:
tf.logging.warning(
'WARNING: Folder has less than 20 images, which may cause issues.')
elif len(file_list) > MAX_NUM_IMAGES_PER_CLASS:
tf.logging.warning(
'WARNING: Folder {} has more than {} images. Some images will '
'never be selected.'.format(dir_name, MAX_NUM_IMAGES_PER_CLASS))
label_name = re.sub(r'[^a-z0-9]+', ' ', dir_name.lower())
training_images = []
testing_images = []
validation_images = []
file_names = [os.path.basename(file_name) for file_name in file_list]
training_images, validation_images = train_test_split(file_names,
test_size=validation_percentage/100.0)
## for file_name in file_list:
## base_name = os.path.basename(file_name)
## # We want to ignore anything after '_nohash_' in the file name when
## # deciding which set to put an image in, the data set creator has a way of
## # grouping photos that are close variations of each other. For example
## # this is used in the plant disease data set to group multiple pictures of
## # the same leaf.
## hash_name = re.sub(r'_nohash_.*$', '', file_name)
## # This looks a bit magical, but we need to decide whether this file should
## # go into the training, testing, or validation sets, and we want to keep
## # existing files in the same set even if more files are subsequently
## # added.
## # To do that, we need a stable way of deciding based on just the file name
## # itself, so we do a hash of that and then use that to generate a
## # probability value that we use to assign it.
## hash_name_hashed = hashlib.sha1(compat.as_bytes(hash_name)).hexdigest()
## percentage_hash = ((int(hash_name_hashed, 16) %
## (MAX_NUM_IMAGES_PER_CLASS + 1)) *
## (100.0 / MAX_NUM_IMAGES_PER_CLASS))
## if percentage_hash < validation_percentage:
## validation_images.append(base_name)
#### elif percentage_hash < (testing_percentage + validation_percentage):
#### testing_images.append(base_name)
## else:
## training_images.append(base_name)
result[label_name] = {
'dir': dir_name,
'training': training_images,
'testing': testing_images,
'validation': validation_images,
}
return result
def get_image_path(image_lists, label_name, index, image_dir, category):
""""Returns a path to an image for a label at the given index.
Args:
image_lists: Dictionary of training images for each label.
label_name: Label string we want to get an image for.
index: Int offset of the image we want. This will be moduloed by the
available number of images for the label, so it can be arbitrarily large.
image_dir: Root folder string of the subfolders containing the training
images.
category: Name string of set to pull images from - training, testing, or
validation.
Returns:
File system path string to an image that meets the requested parameters.
"""
if label_name not in image_lists:
tf.logging.fatal('Label does not exist %s.', label_name)
label_lists = image_lists[label_name]
if category not in label_lists:
tf.logging.fatal('Category does not exist %s.', category)
category_list = label_lists[category]
if not category_list:
tf.logging.fatal('Label %s has no images in the category %s.',
label_name, category)
mod_index = index % len(category_list)
base_name = category_list[mod_index]
sub_dir = label_lists['dir']
full_path = os.path.join(image_dir, sub_dir, base_name)
return full_path
def get_bottleneck_path(image_lists, label_name, index, bottleneck_dir,
category, architecture):
""""Returns a path to a bottleneck file for a label at the given index.
Args:
image_lists: Dictionary of training images for each label.
label_name: Label string we want to get an image for.
index: Integer offset of the image we want. This will be moduloed by the
available number of images for the label, so it can be arbitrarily large.
bottleneck_dir: Folder string holding cached files of bottleneck values.
category: Name string of set to pull images from - training, testing, or
validation.
architecture: The name of the model architecture.
Returns:
File system path string to an image that meets the requested parameters.
"""
return get_image_path(image_lists, label_name, index, bottleneck_dir,
category) + '_' + architecture + '.txt'
def create_model_graph(model_info):
""""Creates a graph from saved GraphDef file and returns a Graph object.
Args:
model_info: Dictionary containing information about the model architecture.
Returns:
Graph holding the trained Inception network, and various tensors we'll be
manipulating.
"""
with tf.Graph().as_default() as graph:
model_path = os.path.join(FLAGS.model_dir, model_info['model_file_name'])
with gfile.FastGFile(model_path, 'rb') as f:
graph_def = tf.GraphDef()
graph_def.ParseFromString(f.read())
bottleneck_tensor, resized_input_tensor = (tf.import_graph_def(
graph_def,
name='',
return_elements=[
model_info['bottleneck_tensor_name'],
model_info['resized_input_tensor_name'],
]))
return graph, bottleneck_tensor, resized_input_tensor
def run_bottleneck_on_image(sess, image_data, image_data_tensor,
decoded_image_tensor, resized_input_tensor,
bottleneck_tensor):
"""Runs inference on an image to extract the 'bottleneck' summary layer.
Args:
sess: Current active TensorFlow Session.
image_data: String of raw JPEG data.
image_data_tensor: Input data layer in the graph.
decoded_image_tensor: Output of initial image resizing and preprocessing.
resized_input_tensor: The input node of the recognition graph.
bottleneck_tensor: Layer before the final softmax.
Returns:
Numpy array of bottleneck values.
"""
# First decode the JPEG image, resize it, and rescale the pixel values.
resized_input_values = sess.run(decoded_image_tensor,
{image_data_tensor: image_data})
# Then run it through the recognition network.
bottleneck_values = sess.run(bottleneck_tensor,
{resized_input_tensor: resized_input_values})
bottleneck_values = np.squeeze(bottleneck_values)
return bottleneck_values
def maybe_download_and_extract(data_url):
"""Download and extract model tar file.
If the pretrained model we're using doesn't already exist, this function
downloads it from the TensorFlow.org website and unpacks it into a directory.
Args:
data_url: Web location of the tar file containing the pretrained model.
"""
dest_directory = FLAGS.model_dir
if not os.path.exists(dest_directory):
os.makedirs(dest_directory)
filename = data_url.split('/')[-1]
filepath = os.path.join(dest_directory, filename)
if not os.path.exists(filepath):
def _progress(count, block_size, total_size):
sys.stdout.write('\r>> Downloading %s %.1f%%' %
(filename,
float(count * block_size) / float(total_size) * 100.0))
sys.stdout.flush()
filepath, _ = urllib.request.urlretrieve(data_url, filepath, _progress)
print()
statinfo = os.stat(filepath)
tf.logging.info('Successfully downloaded', filename, statinfo.st_size,
'bytes.')
tarfile.open(filepath, 'r:gz').extractall(dest_directory)
def ensure_dir_exists(dir_name):
"""Makes sure the folder exists on disk.
Args:
dir_name: Path string to the folder we want to create.
"""
if not os.path.exists(dir_name):
os.makedirs(dir_name)
bottleneck_path_2_bottleneck_values = {}
def create_bottleneck_file(bottleneck_path, image_lists, label_name, index,
image_dir, category, sess, jpeg_data_tensor,
decoded_image_tensor, resized_input_tensor,
bottleneck_tensor):
"""Create a single bottleneck file."""
tf.logging.info('Creating bottleneck at ' + bottleneck_path)
image_path = get_image_path(image_lists, label_name, index,
image_dir, category)
if not gfile.Exists(image_path):
tf.logging.fatal('File does not exist %s', image_path)
image_data = gfile.FastGFile(image_path, 'rb').read()
try:
bottleneck_values = run_bottleneck_on_image(
sess, image_data, jpeg_data_tensor, decoded_image_tensor,
resized_input_tensor, bottleneck_tensor)
except Exception as e:
raise RuntimeError('Error during processing file %s (%s)' % (image_path,
str(e)))
bottleneck_string = ','.join(str(x) for x in bottleneck_values)
with open(bottleneck_path, 'w') as bottleneck_file:
bottleneck_file.write(bottleneck_string)
def get_or_create_bottleneck(sess, image_lists, label_name, index, image_dir,
category, bottleneck_dir, jpeg_data_tensor,
decoded_image_tensor, resized_input_tensor,
bottleneck_tensor, architecture):
"""Retrieves or calculates bottleneck values for an image.
If a cached version of the bottleneck data exists on-disk, return that,
otherwise calculate the data and save it to disk for future use.
Args:
sess: The current active TensorFlow Session.
image_lists: Dictionary of training images for each label.
label_name: Label string we want to get an image for.
index: Integer offset of the image we want. This will be modulo-ed by the
available number of images for the label, so it can be arbitrarily large.
image_dir: Root folder string of the subfolders containing the training
images.
category: Name string of which set to pull images from - training, testing,
or validation.
bottleneck_dir: Folder string holding cached files of bottleneck values.
jpeg_data_tensor: The tensor to feed loaded jpeg data into.
decoded_image_tensor: The output of decoding and resizing the image.
resized_input_tensor: The input node of the recognition graph.
bottleneck_tensor: The output tensor for the bottleneck values.
architecture: The name of the model architecture.
Returns:
Numpy array of values produced by the bottleneck layer for the image.
"""
label_lists = image_lists[label_name]
sub_dir = label_lists['dir']
sub_dir_path = os.path.join(bottleneck_dir, sub_dir)
ensure_dir_exists(sub_dir_path)
bottleneck_path = get_bottleneck_path(image_lists, label_name, index,
bottleneck_dir, category, architecture)
if not os.path.exists(bottleneck_path):
create_bottleneck_file(bottleneck_path, image_lists, label_name, index,
image_dir, category, sess, jpeg_data_tensor,
decoded_image_tensor, resized_input_tensor,
bottleneck_tensor)
with open(bottleneck_path, 'r') as bottleneck_file:
bottleneck_string = bottleneck_file.read()
did_hit_error = False
try:
bottleneck_values = [float(x) for x in bottleneck_string.split(',')]
except ValueError:
tf.logging.warning('Invalid float found, recreating bottleneck')
did_hit_error = True
if did_hit_error:
create_bottleneck_file(bottleneck_path, image_lists, label_name, index,
image_dir, category, sess, jpeg_data_tensor,
decoded_image_tensor, resized_input_tensor,
bottleneck_tensor)
with open(bottleneck_path, 'r') as bottleneck_file:
bottleneck_string = bottleneck_file.read()
# Allow exceptions to propagate here, since they shouldn't happen after a
# fresh creation
bottleneck_values = [float(x) for x in bottleneck_string.split(',')]
return bottleneck_values
def cache_bottlenecks(sess, image_lists, image_dir, bottleneck_dir,
jpeg_data_tensor, decoded_image_tensor,
resized_input_tensor, bottleneck_tensor, architecture):
"""Ensures all the training, testing, and validation bottlenecks are cached.
Because we're likely to read the same image multiple times (if there are no
distortions applied during training) it can speed things up a lot if we
calculate the bottleneck layer values once for each image during
preprocessing, and then just read those cached values repeatedly during
training. Here we go through all the images we've found, calculate those
values, and save them off.
Args:
sess: The current active TensorFlow Session.
image_lists: Dictionary of training images for each label.
image_dir: Root folder string of the subfolders containing the training
images.
bottleneck_dir: Folder string holding cached files of bottleneck values.
jpeg_data_tensor: Input tensor for jpeg data from file.
decoded_image_tensor: The output of decoding and resizing the image.
resized_input_tensor: The input node of the recognition graph.
bottleneck_tensor: The penultimate output layer of the graph.
architecture: The name of the model architecture.
Returns:
Nothing.
"""
how_many_bottlenecks = 0
ensure_dir_exists(bottleneck_dir)
for label_name, label_lists in image_lists.items():
for category in ['training', 'testing', 'validation']:
category_list = label_lists[category]
for index, unused_base_name in enumerate(category_list):
get_or_create_bottleneck(
sess, image_lists, label_name, index, image_dir, category,
bottleneck_dir, jpeg_data_tensor, decoded_image_tensor,
resized_input_tensor, bottleneck_tensor, architecture)
how_many_bottlenecks += 1
if how_many_bottlenecks % 100 == 0:
tf.logging.info(
str(how_many_bottlenecks) + ' bottleneck files created.')
def get_random_cached_bottlenecks(sess, image_lists, how_many, category,
bottleneck_dir, image_dir, jpeg_data_tensor,
decoded_image_tensor, resized_input_tensor,
bottleneck_tensor, architecture):
"""Retrieves bottleneck values for cached images.
If no distortions are being applied, this function can retrieve the cached
bottleneck values directly from disk for images. It picks a random set of
images from the specified category.
Args:
sess: Current TensorFlow Session.
image_lists: Dictionary of training images for each label.
how_many: If positive, a random sample of this size will be chosen.
If negative, all bottlenecks will be retrieved.
category: Name string of which set to pull from - training, testing, or
validation.
bottleneck_dir: Folder string holding cached files of bottleneck values.
image_dir: Root folder string of the subfolders containing the training
images.
jpeg_data_tensor: The layer to feed jpeg image data into.
decoded_image_tensor: The output of decoding and resizing the image.
resized_input_tensor: The input node of the recognition graph.
bottleneck_tensor: The bottleneck output layer of the CNN graph.
architecture: The name of the model architecture.
Returns:
List of bottleneck arrays, their corresponding ground truths, and the
relevant filenames.
"""
class_count = len(image_lists.keys())
bottlenecks = []
ground_truths = []
filenames = []
if how_many >= 0:
# Retrieve a random sample of bottlenecks.
for unused_i in range(how_many):
label_index = random.randrange(class_count)
label_name = list(image_lists.keys())[label_index]
image_index = random.randrange(MAX_NUM_IMAGES_PER_CLASS + 1)
image_name = get_image_path(image_lists, label_name, image_index,
image_dir, category)
bottleneck = get_or_create_bottleneck(
sess, image_lists, label_name, image_index, image_dir, category,
bottleneck_dir, jpeg_data_tensor, decoded_image_tensor,
resized_input_tensor, bottleneck_tensor, architecture)
ground_truth = np.zeros(class_count, dtype=np.float32)
ground_truth[label_index] = 1.0
bottlenecks.append(bottleneck)
ground_truths.append(ground_truth)
filenames.append(image_name)
else:
# Retrieve all bottlenecks.
for label_index, label_name in enumerate(image_lists.keys()):
for image_index, image_name in enumerate(
image_lists[label_name][category]):
image_name = get_image_path(image_lists, label_name, image_index,
image_dir, category)
bottleneck = get_or_create_bottleneck(
sess, image_lists, label_name, image_index, image_dir, category,
bottleneck_dir, jpeg_data_tensor, decoded_image_tensor,
resized_input_tensor, bottleneck_tensor, architecture)
ground_truth = np.zeros(class_count, dtype=np.float32)
ground_truth[label_index] = 1.0
bottlenecks.append(bottleneck)
ground_truths.append(ground_truth)
filenames.append(image_name)
return bottlenecks, ground_truths, filenames
def get_random_distorted_bottlenecks(
sess, image_lists, how_many, category, image_dir, input_jpeg_tensor,
distorted_image, resized_input_tensor, bottleneck_tensor):
"""Retrieves bottleneck values for training images, after distortions.
If we're training with distortions like crops, scales, or flips, we have to
recalculate the full model for every image, and so we can't use cached
bottleneck values. Instead we find random images for the requested category,
run them through the distortion graph, and then the full graph to get the
bottleneck results for each.
Args:
sess: Current TensorFlow Session.
image_lists: Dictionary of training images for each label.
how_many: The integer number of bottleneck values to return.
category: Name string of which set of images to fetch - training, testing,
or validation.
image_dir: Root folder string of the subfolders containing the training
images.
input_jpeg_tensor: The input layer we feed the image data to.
distorted_image: The output node of the distortion graph.
resized_input_tensor: The input node of the recognition graph.
bottleneck_tensor: The bottleneck output layer of the CNN graph.
Returns:
List of bottleneck arrays and their corresponding ground truths.
"""
class_count = len(image_lists.keys())
bottlenecks = []
ground_truths = []
for unused_i in range(how_many):
label_index = random.randrange(class_count)
label_name = list(image_lists.keys())[label_index]
image_index = random.randrange(MAX_NUM_IMAGES_PER_CLASS + 1)
image_path = get_image_path(image_lists, label_name, image_index, image_dir,
category)
if not gfile.Exists(image_path):
tf.logging.fatal('File does not exist %s', image_path)
jpeg_data = gfile.FastGFile(image_path, 'rb').read()
# Note that we materialize the distorted_image_data as a numpy array before
# sending running inference on the image. This involves 2 memory copies and
# might be optimized in other implementations.
distorted_image_data = sess.run(distorted_image,
{input_jpeg_tensor: jpeg_data})
bottleneck_values = sess.run(bottleneck_tensor,
{resized_input_tensor: distorted_image_data})
bottleneck_values = np.squeeze(bottleneck_values)
ground_truth = np.zeros(class_count, dtype=np.float32)
ground_truth[label_index] = 1.0
bottlenecks.append(bottleneck_values)
ground_truths.append(ground_truth)
return bottlenecks, ground_truths
def should_distort_images(flip_left_right, random_crop, random_scale,
random_brightness):
"""Whether any distortions are enabled, from the input flags.
Args:
flip_left_right: Boolean whether to randomly mirror images horizontally.
random_crop: Integer percentage setting the total margin used around the
crop box.
random_scale: Integer percentage of how much to vary the scale by.
random_brightness: Integer range to randomly multiply the pixel values by.
Returns:
Boolean value indicating whether any distortions should be applied.
"""
return (flip_left_right or (random_crop != 0) or (random_scale != 0) or
(random_brightness != 0))
def add_input_distortions(flip_left_right, random_crop, random_scale,
random_brightness, input_width, input_height,
input_depth, input_mean, input_std):
"""Creates the operations to apply the specified distortions.
During training it can help to improve the results if we run the images
through simple distortions like crops, scales, and flips. These reflect the
kind of variations we expect in the real world, and so can help train the
model to cope with natural data more effectively. Here we take the supplied
parameters and construct a network of operations to apply them to an image.
Cropping
~~~~~~~~
Cropping is done by placing a bounding box at a random position in the full
image. The cropping parameter controls the size of that box relative to the
input image. If it's zero, then the box is the same size as the input and no
cropping is performed. If the value is 50%, then the crop box will be half the
width and height of the input. In a diagram it looks like this:
< width >
+---------------------+
| |
| width - crop% |
| < > |
| +------+ |
| | | |
| | | |
| | | |
| +------+ |
| |
| |
+---------------------+
Scaling
~~~~~~~
Scaling is a lot like cropping, except that the bounding box is always
centered and its size varies randomly within the given range. For example if
the scale percentage is zero, then the bounding box is the same size as the
input and no scaling is applied. If it's 50%, then the bounding box will be in
a random range between half the width and height and full size.
Args:
flip_left_right: Boolean whether to randomly mirror images horizontally.
random_crop: Integer percentage setting the total margin used around the
crop box.
random_scale: Integer percentage of how much to vary the scale by.
random_brightness: Integer range to randomly multiply the pixel values by.
graph.
input_width: Horizontal size of expected input image to model.
input_height: Vertical size of expected input image to model.
input_depth: How many channels the expected input image should have.
input_mean: Pixel value that should be zero in the image for the graph.
input_std: How much to divide the pixel values by before recognition.
Returns:
The jpeg input layer and the distorted result tensor.
"""
jpeg_data = tf.placeholder(tf.string, name='DistortJPGInput')
decoded_image = tf.image.decode_jpeg(jpeg_data, channels=input_depth)
decoded_image_as_float = tf.cast(decoded_image, dtype=tf.float32)
decoded_image_4d = tf.expand_dims(decoded_image_as_float, 0)
margin_scale = 1.0 + (random_crop / 100.0)
resize_scale = 1.0 + (random_scale / 100.0)
margin_scale_value = tf.constant(margin_scale)
resize_scale_value = tf.random_uniform(tensor_shape.scalar(),
minval=1.0,
maxval=resize_scale)
scale_value = tf.multiply(margin_scale_value, resize_scale_value)
precrop_width = tf.multiply(scale_value, input_width)
precrop_height = tf.multiply(scale_value, input_height)
precrop_shape = tf.stack([precrop_height, precrop_width])
precrop_shape_as_int = tf.cast(precrop_shape, dtype=tf.int32)
precropped_image = tf.image.resize_bilinear(decoded_image_4d,
precrop_shape_as_int)
precropped_image_3d = tf.squeeze(precropped_image, squeeze_dims=[0])
cropped_image = tf.random_crop(precropped_image_3d,
[input_height, input_width, input_depth])
if flip_left_right:
flipped_image = tf.image.random_flip_left_right(cropped_image)
else:
flipped_image = cropped_image
brightness_min = 1.0 - (random_brightness / 100.0)
brightness_max = 1.0 + (random_brightness / 100.0)
brightness_value = tf.random_uniform(tensor_shape.scalar(),
minval=brightness_min,
maxval=brightness_max)
brightened_image = tf.multiply(flipped_image, brightness_value)
offset_image = tf.subtract(brightened_image, input_mean)
mul_image = tf.multiply(offset_image, 1.0 / input_std)
distort_result = tf.expand_dims(mul_image, 0, name='DistortResult')
return jpeg_data, distort_result
def variable_summaries(var):
"""Attach a lot of summaries to a Tensor (for TensorBoard visualization)."""
with tf.name_scope('summaries'):
mean = tf.reduce_mean(var)
tf.summary.scalar('mean', mean)
with tf.name_scope('stddev'):
stddev = tf.sqrt(tf.reduce_mean(tf.square(var - mean)))
tf.summary.scalar('stddev', stddev)
tf.summary.scalar('max', tf.reduce_max(var))
tf.summary.scalar('min', tf.reduce_min(var))
tf.summary.histogram('histogram', var)
def get_center_loss(features, labels, alpha, num_classes):
nrof_features = features.get_shape()[1]
centers = tf.get_variable('centers', [num_classes, nrof_features],
dtype=tf.float32,
initializer=tf.constant_initializer(0), trainable=False)
labels = tf.argmax(labels,1)
label = tf.reshape(labels, [-1])
centers_batch = tf.gather(centers, label)
diff = (1 - alpha) * (centers_batch - features)
centers = tf.scatter_sub(centers, label, diff)
with tf.control_dependencies([centers]):
loss = tf.reduce_mean(tf.square(features - centers_batch))
return loss, centers
def add_final_training_ops(class_count, labels, final_tensor_name, bottleneck_tensor,
bottleneck_tensor_size):
"""Adds a new softmax and fully-connected layer for training.
We need to retrain the top layer to identify our new classes, so this function
adds the right operations to the graph, along with some variables to hold the
weights, and then sets up all the gradients for the backward pass.
The set up for the softmax and fully-connected layers is based on:
https://www.tensorflow.org/versions/master/tutorials/mnist/beginners/index.html
Args:
class_count: Integer of how many categories of things we're trying to
recognize.
final_tensor_name: Name string for the new final node that produces results.
bottleneck_tensor: The output of the main CNN graph.
bottleneck_tensor_size: How many entries in the bottleneck vector.
Returns:
The tensors for the training and cross entropy results, and tensors for the
bottleneck input and ground truth input.
"""
with tf.name_scope('input'):
bottleneck_input = tf.placeholder_with_default(
bottleneck_tensor,
shape=[None, bottleneck_tensor_size],
name='BottleneckInputPlaceholder')
ground_truth_input = tf.placeholder(tf.int32,
[None, class_count],
name='GroundTruthInput')
# Organizing the following ops as `final_training_ops` so they're easier
# to see in TensorBoard
layer_name = 'final_training_ops'
with tf.name_scope(layer_name):
with tf.name_scope('weights'):
initial_value = tf.truncated_normal(
[bottleneck_tensor_size, class_count], stddev=0.001)
layer_weights = tf.Variable(initial_value, name='final_weights')
variable_summaries(layer_weights)
with tf.name_scope('biases'):
layer_biases = tf.Variable(tf.zeros([class_count]), name='final_biases')
variable_summaries(layer_biases)
with tf.name_scope('Wx_plus_b'):
logits = tf.matmul(bottleneck_input, layer_weights) + layer_biases
tf.summary.histogram('pre_activations', logits)
final_tensor = tf.nn.softmax(logits, name=final_tensor_name)
tf.summary.histogram('activations', final_tensor)
with tf.name_scope('center_loss'):
center_loss, centers = get_center_loss(bottleneck_input,
ground_truth_input,
FLAGS.center_loss_alpha,
class_count)
with tf.name_scope('cross_entropy'):
cross_entropy = tf.nn.softmax_cross_entropy_with_logits(
labels=ground_truth_input, logits=logits)
with tf.name_scope('total'):
cross_entropy_mean = tf.reduce_mean(cross_entropy)
total_loss = cross_entropy_mean + FLAGS.center_loss_factor * center_loss
tf.summary.scalar('center_loss', center_loss)
tf.summary.scalar('cross_entropy', cross_entropy_mean)
tf.summary.scalar('total_loss', total_loss)
with tf.name_scope('train'):
optimizer = tf.train.GradientDescentOptimizer(FLAGS.learning_rate)
train_step = optimizer.minimize(total_loss)
return (train_step, total_loss, bottleneck_input, ground_truth_input,
final_tensor)
def add_evaluation_step(result_tensor, ground_truth_tensor):
"""Inserts the operations we need to evaluate the accuracy of our results.
Args:
result_tensor: The new final node that produces results.
ground_truth_tensor: The node we feed ground truth data
into.
Returns:
Tuple of (evaluation step, prediction).
"""
with tf.name_scope('accuracy'):
with tf.name_scope('correct_prediction'):
prediction = tf.argmax(result_tensor, 1)
correct_prediction = tf.equal(
prediction, tf.argmax(ground_truth_tensor, 1))
with tf.name_scope('accuracy'):
evaluation_step = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
tf.summary.scalar('accuracy', evaluation_step)
return evaluation_step, prediction
def save_graph_to_file(sess, graph, graph_file_name):
output_graph_def = graph_util.convert_variables_to_constants(
sess, graph.as_graph_def(), [FLAGS.final_tensor_name])
with gfile.FastGFile(graph_file_name, 'wb') as f:
f.write(output_graph_def.SerializeToString())
return
def prepare_file_system():
# Setup the directory we'll write summaries to for TensorBoard
if tf.gfile.Exists(FLAGS.summaries_dir):
tf.gfile.DeleteRecursively(FLAGS.summaries_dir)
tf.gfile.MakeDirs(FLAGS.summaries_dir)
if FLAGS.intermediate_store_frequency > 0:
ensure_dir_exists(FLAGS.intermediate_output_graphs_dir)
return
def create_model_info(architecture):
"""Given the name of a model architecture, returns information about it.
There are different base image recognition pretrained models that can be
retrained using transfer learning, and this function translates from the name
of a model to the attributes that are needed to download and train with it.
Args:
architecture: Name of a model architecture.
Returns:
Dictionary of information about the model, or None if the name isn't
recognized
Raises:
ValueError: If architecture name is unknown.
"""
architecture = architecture.lower()
if architecture == 'inception_v3':
# pylint: disable=line-too-long
data_url = 'http://download.tensorflow.org/models/image/imagenet/inception-2015-12-05.tgz'
# pylint: enable=line-too-long
bottleneck_tensor_name = 'pool_3/_reshape:0'
bottleneck_tensor_size = 2048
input_width = 299
input_height = 299
input_depth = 3
resized_input_tensor_name = 'Mul:0'
model_file_name = 'classify_image_graph_def.pb'
input_mean = 128
input_std = 128
elif architecture.startswith('mobilenet_'):
parts = architecture.split('_')
if len(parts) != 3 and len(parts) != 4:
tf.logging.error("Couldn't understand architecture name '%s'",
architecture)
return None
version_string = parts[1]
if (version_string != '1.0' and version_string != '0.75' and
version_string != '0.50' and version_string != '0.25'):
tf.logging.error(
""""The Mobilenet version should be '1.0', '0.75', '0.50', or '0.25',
but found '%s' for architecture '%s'""",
version_string, architecture)
return None
size_string = parts[2]
if (size_string != '224' and size_string != '192' and
size_string != '160' and size_string != '128'):
tf.logging.error(
"""The Mobilenet input size should be '224', '192', '160', or '128',
but found '%s' for architecture '%s'""",
size_string, architecture)
return None
if len(parts) == 3:
is_quantized = False
else:
if parts[3] != 'quantized':
tf.logging.error(
"Couldn't understand architecture suffix '%s' for '%s'", parts[3],
architecture)
return None
is_quantized = True
data_url = 'http://download.tensorflow.org/models/mobilenet_v1_'
data_url += version_string + '_' + size_string + '_frozen.tgz'
bottleneck_tensor_name = 'MobilenetV1/Predictions/Reshape:0'
bottleneck_tensor_size = 1001
input_width = int(size_string)
input_height = int(size_string)
input_depth = 3
resized_input_tensor_name = 'input:0'
if is_quantized:
model_base_name = 'quantized_graph.pb'
else:
model_base_name = 'frozen_graph.pb'
model_dir_name = 'mobilenet_v1_' + version_string + '_' + size_string
model_file_name = os.path.join(model_dir_name, model_base_name)
input_mean = 127.5
input_std = 127.5
else:
tf.logging.error("Couldn't understand architecture name '%s'", architecture)
raise ValueError('Unknown architecture', architecture)
return {
'data_url': data_url,
'bottleneck_tensor_name': bottleneck_tensor_name,
'bottleneck_tensor_size': bottleneck_tensor_size,
'input_width': input_width,
'input_height': input_height,
'input_depth': input_depth,
'resized_input_tensor_name': resized_input_tensor_name,
'model_file_name': model_file_name,
'input_mean': input_mean,
'input_std': input_std,
}
def add_jpeg_decoding(input_width, input_height, input_depth, input_mean,
input_std):
"""Adds operations that perform JPEG decoding and resizing to the graph..
Args:
input_width: Desired width of the image fed into the recognizer graph.
input_height: Desired width of the image fed into the recognizer graph.
input_depth: Desired channels of the image fed into the recognizer graph.
input_mean: Pixel value that should be zero in the image for the graph.
input_std: How much to divide the pixel values by before recognition.
Returns:
Tensors for the node to feed JPEG data into, and the output of the
preprocessing steps.
"""
jpeg_data = tf.placeholder(tf.string, name='DecodeJPGInput')
decoded_image = tf.image.decode_jpeg(jpeg_data, channels=input_depth)
decoded_image_as_float = tf.cast(decoded_image, dtype=tf.float32)
decoded_image_4d = tf.expand_dims(decoded_image_as_float, 0)
resize_shape = tf.stack([input_height, input_width])
resize_shape_as_int = tf.cast(resize_shape, dtype=tf.int32)
resized_image = tf.image.resize_bilinear(decoded_image_4d,
resize_shape_as_int)
offset_image = tf.subtract(resized_image, input_mean)
mul_image = tf.multiply(offset_image, 1.0 / input_std)
return jpeg_data, mul_image
def get_numerical_labels(image_lists):
numerical_labels = []
cnt = 0
prev = ''
for i in image_lists.keys():
numerical_labels.append(cnt)
cnt = cnt + 1
return numerical_labels
def main(_):
# Needed to make sure the logging output is visible.
# See https://github.com/tensorflow/tensorflow/issues/3047
tf.logging.set_verbosity(tf.logging.INFO)
# Prepare necessary directories that can be used during training
prepare_file_system()
# Gather information about the model architecture we'll be using.
model_info = create_model_info(FLAGS.architecture)
if not model_info:
tf.logging.error('Did not recognize architecture flag')
return -1
# Set up the pre-trained graph.
maybe_download_and_extract(model_info['data_url'])
graph, bottleneck_tensor, resized_image_tensor = (
create_model_graph(model_info))
# Look at the folder structure, and create lists of all the images.
image_lists = create_image_lists(FLAGS.image_dir, FLAGS.testing_percentage,
FLAGS.validation_percentage)
f = open( 'image_lists.py', 'w' )
f.write( 'dict = ' + repr(image_lists) + '\n' )
f.close()
class_count = len(image_lists.keys())
if class_count == 0:
tf.logging.error('No valid folders of images found at ' + FLAGS.image_dir)
return -1
if class_count == 1:
tf.logging.error('Only one valid folder of images found at ' +
FLAGS.image_dir +
' - multiple classes are needed for classification.')
return -1
# See if the command-line flags mean we're applying any distortions.
do_distort_images = should_distort_images(
FLAGS.flip_left_right, FLAGS.random_crop, FLAGS.random_scale,
FLAGS.random_brightness)
numerical_labels = get_numerical_labels(image_lists)
with tf.Session(graph=graph) as sess:
# Set up the image decoding sub-graph.
jpeg_data_tensor, decoded_image_tensor = add_jpeg_decoding(
model_info['input_width'], model_info['input_height'],
model_info['input_depth'], model_info['input_mean'],
model_info['input_std'])
if do_distort_images:
# We will be applying distortions, so setup the operations we'll need.
(distorted_jpeg_data_tensor,
distorted_image_tensor) = add_input_distortions(
FLAGS.flip_left_right, FLAGS.random_crop, FLAGS.random_scale,
FLAGS.random_brightness, model_info['input_width'],
model_info['input_height'], model_info['input_depth'],
model_info['input_mean'], model_info['input_std'])
else:
# We'll make sure we've calculated the 'bottleneck' image summaries and
# cached them on disk.
cache_bottlenecks(sess, image_lists, FLAGS.image_dir,
FLAGS.bottleneck_dir, jpeg_data_tensor,
decoded_image_tensor, resized_image_tensor,
bottleneck_tensor, FLAGS.architecture)
# Add the new layer that we'll be training.
(train_step, total_loss, bottleneck_input, ground_truth_input,
final_tensor) = add_final_training_ops(
len(image_lists.keys()), get_numerical_labels(image_lists), FLAGS.final_tensor_name, bottleneck_tensor,
model_info['bottleneck_tensor_size'])
# Create the operations we need to evaluate the accuracy of our new layer.
evaluation_step, prediction = add_evaluation_step(
final_tensor, ground_truth_input)
# Merge all the summaries and write them out to the summaries_dir
merged = tf.summary.merge_all()
train_writer = tf.summary.FileWriter(FLAGS.summaries_dir + '/train',
sess.graph)
validation_writer = tf.summary.FileWriter(
FLAGS.summaries_dir + '/validation')
# Set up all our weights to their initial default values.
init = tf.global_variables_initializer()
sess.run(init)
# Run the training for as many cycles as requested on the command line.
for i in range(FLAGS.how_many_training_steps):
# Get a batch of input bottleneck values, either calculated fresh every
# time with distortions applied, or from the cache stored on disk.
if do_distort_images:
(train_bottlenecks,
train_ground_truth) = get_random_distorted_bottlenecks(
sess, image_lists, FLAGS.train_batch_size, 'training',
FLAGS.image_dir, distorted_jpeg_data_tensor,
distorted_image_tensor, resized_image_tensor, bottleneck_tensor)
else:
(train_bottlenecks,
train_ground_truth, _) = get_random_cached_bottlenecks(
sess, image_lists, FLAGS.train_batch_size, 'training',
FLAGS.bottleneck_dir, FLAGS.image_dir, jpeg_data_tensor,
decoded_image_tensor, resized_image_tensor, bottleneck_tensor,
FLAGS.architecture)
# Feed the bottlenecks and ground truth into the graph, and run a training
# step. Capture training summaries for TensorBoard with the `merged` op.
train_summary, _ = sess.run(
[merged, train_step],
feed_dict={bottleneck_input: train_bottlenecks,
ground_truth_input: train_ground_truth})
train_writer.add_summary(train_summary, i)
# Every so often, print out how well the graph is training.
is_last_step = (i + 1 == FLAGS.how_many_training_steps)
if (i % FLAGS.eval_step_interval) == 0 or is_last_step:
train_accuracy, total_loss_values = sess.run(
[evaluation_step, total_loss],
feed_dict={bottleneck_input: train_bottlenecks,
ground_truth_input: train_ground_truth})
tf.logging.info('%s: Step %d: Train accuracy = %.1f%%' %
(datetime.now(), i, train_accuracy * 100))
tf.logging.info('%s: Step %d: Total loss = %f' %
(datetime.now(), i, total_loss_values))
validation_bottlenecks, validation_ground_truth, _ = (
get_random_cached_bottlenecks(
sess, image_lists, FLAGS.validation_batch_size, 'validation',
FLAGS.bottleneck_dir, FLAGS.image_dir, jpeg_data_tensor,
decoded_image_tensor, resized_image_tensor, bottleneck_tensor,
FLAGS.architecture))
# Run a validation step and capture training summaries for TensorBoard
# with the `merged` op.
validation_summary, validation_accuracy = sess.run(
[merged, evaluation_step],
feed_dict={bottleneck_input: validation_bottlenecks,
ground_truth_input: validation_ground_truth})
validation_writer.add_summary(validation_summary, i)
tf.logging.info('%s: Step %d: Validation accuracy = %.1f%% (N=%d)' %
(datetime.now(), i, validation_accuracy * 100,
len(validation_bottlenecks)))
# Store intermediate results
intermediate_frequency = FLAGS.intermediate_store_frequency
if (intermediate_frequency > 0 and (i % intermediate_frequency == 0)
and i > 0):
intermediate_file_name = (FLAGS.intermediate_output_graphs_dir +
'intermediate_' + str(i) + '.pb')
tf.logging.info('Save intermediate result to : ' +
intermediate_file_name)
save_graph_to_file(sess, graph, intermediate_file_name)
# We've completed all our training, so run a final test evaluation on
# some new images we haven't used before.
if(FLAGS.testing_percentage > 0):
test_bottlenecks, test_ground_truth, test_filenames = (
get_random_cached_bottlenecks(
sess, image_lists, FLAGS.test_batch_size, 'testing',
FLAGS.bottleneck_dir, FLAGS.image_dir, jpeg_data_tensor,
decoded_image_tensor, resized_image_tensor, bottleneck_tensor,
FLAGS.architecture))
test_accuracy, predictions = sess.run(
[evaluation_step, prediction],
feed_dict={bottleneck_input: test_bottlenecks,
ground_truth_input: test_ground_truth})
tf.logging.info('Final test accuracy = %.1f%% (N=%d)' %
(test_accuracy * 100, len(test_bottlenecks)))
if FLAGS.print_misclassified_test_images:
tf.logging.info('=== MISCLASSIFIED TEST IMAGES ===')
for i, test_filename in enumerate(test_filenames):
if predictions[i] != test_ground_truth[i].argmax():
tf.logging.info('%70s %s' %
(test_filename,
list(image_lists.keys())[predictions[i]]))
# Write out the trained graph and labels with the weights stored as
# constants.
save_graph_to_file(sess, graph, FLAGS.output_graph)
with gfile.FastGFile(FLAGS.output_labels, 'w') as f:
f.write('\n'.join(image_lists.keys()) + '\n')
if __name__ == '__main__':
parser = argparse.ArgumentParser()
parser.add_argument(
'--image_dir',
type=str,
default='',
help='Path to folders of labeled images.'
)
parser.add_argument(
'--output_graph',
type=str,
default='tmp/output_graph.pb',
help='Where to save the trained graph.'
)
parser.add_argument(
'--intermediate_output_graphs_dir',
type=str,
default='',
help='Where to save the intermediate graphs.'
)
parser.add_argument(
'--intermediate_store_frequency',
type=int,
default=0,
help="""\
How many steps to store intermediate graph. If "0" then will not
store.\
"""
)
parser.add_argument(
'--center_loss',
default=False,
help="""\
Use center loss along with softmax?
"""
)
parser.add_argument(
'--output_labels',
type=str,
default='tmp/output_labels.txt',
help='Where to save the trained graph\'s labels.'
)
parser.add_argument(
'--summaries_dir',
type=str,
default='tmp/retrain_logs',
help='Where to save summary logs for TensorBoard.'
)
parser.add_argument(
'--how_many_training_steps',
type=int,
default=4000,
help='How many training steps to run before ending.'
)
parser.add_argument(
'--learning_rate',
type=float,
default=0.01,
help='How large a learning rate to use when training.'
)
parser.add_argument(
'--testing_percentage',
type=int,
default=10,
help='What percentage of images to use as a test set.'
)
parser.add_argument(
'--validation_percentage',
type=int,
default=10,
help='What percentage of images to use as a validation set.'
)
parser.add_argument(
'--eval_step_interval',
type=int,
default=10,
help='How often to evaluate the training results.'
)
parser.add_argument(
'--train_batch_size',
type=int,
default=100,
help='How many images to train on at a time.'
)
parser.add_argument(
'--test_batch_size',
type=int,
default=-1,
help="""\
How many images to test on. This test set is only used once, to evaluate
the final accuracy of the model after training completes.
A value of -1 causes the entire test set to be used, which leads to more
stable results across runs.\
"""
)
parser.add_argument(
'--validation_batch_size',
type=int,
default=100,
help="""\
How many images to use in an evaluation batch. This validation set is
used much more often than the test set, and is an early indicator of how
accurate the model is during training.
A value of -1 causes the entire validation set to be used, which leads to
more stable results across training iterations, but may be slower on large
training sets.\
"""
)
parser.add_argument(
'--print_misclassified_test_images',
default=False,
help="""\
Whether to print out a list of all misclassified test images.\
""",
action='store_true'
)
parser.add_argument(
'--model_dir',
type=str,
default='tmp/imagenet',
help="""\
Path to classify_image_graph_def.pb,
imagenet_synset_to_human_label_map.txt, and
imagenet_2012_challenge_label_map_proto.pbtxt.\
"""
)
parser.add_argument(
'--bottleneck_dir',
type=str,
default='tmp/bottleneck',
help='Path to cache bottleneck layer values as files.'
)
parser.add_argument(
'--final_tensor_name',
type=str,
default='final_result',
help="""\
The name of the output classification layer in the retrained graph.\
"""
)
parser.add_argument(
'--flip_left_right',
default=False,
help="""\
Whether to randomly flip half of the training images horizontally.\
""",
action='store_true'
)
parser.add_argument(
'--random_crop',
type=int,
default=0,
help="""\
A percentage determining how much of a margin to randomly crop off the
training images.\
"""
)
parser.add_argument(
'--random_scale',
type=int,
default=0,
help="""\
A percentage determining how much to randomly scale up the size of the
training images by.\
"""
)
parser.add_argument(
'--random_brightness',
type=int,
default=0,
help="""\
A percentage determining how much to randomly multiply the training image
input pixels up or down by.\
"""
)
parser.add_argument(
'--center_loss_alpha',
type=float,
default=0,
help="""\
A percentage determining how much to randomly multiply the training image
input pixels up or down by.\
"""
)
parser.add_argument(
'--center_loss_factor',
type=float,
default=0,
help="""\
A percentage determining how much to randomly multiply the training image
input pixels up or down by.\
"""
)
parser.add_argument(
'--architecture',
type=str,
default='inception_v3',
help="""\
Which model architecture to use. 'inception_v3' is the most accurate, but
also the slowest. For faster or smaller models, chose a MobileNet with the
form 'mobilenet_<parameter size>_<input_size>[_quantized]'. For example,
'mobilenet_1.0_224' will pick a model that is 17 MB in size and takes 224
pixel input images, while 'mobilenet_0.25_128_quantized' will choose a much
less accurate, but smaller and faster network that's 920 KB on disk and
takes 128x128 images. See https://research.googleblog.com/2017/06/mobilenets-open-source-models-for.html
for more information on Mobilenet.\
""")
FLAGS, unparsed = parser.parse_known_args()
tf.app.run(main=main, argv=[sys.argv[0]] + unparsed)
| mit |
nhejazi/scikit-learn | sklearn/linear_model/least_angle.py | 6 | 58438 | """
Least Angle Regression algorithm. See the documentation on the
Generalized Linear Model for a complete discussion.
"""
from __future__ import print_function
# Author: Fabian Pedregosa <[email protected]>
# Alexandre Gramfort <[email protected]>
# Gael Varoquaux
#
# License: BSD 3 clause
from math import log
import sys
import warnings
import numpy as np
from scipy import linalg, interpolate
from scipy.linalg.lapack import get_lapack_funcs
from .base import LinearModel
from ..base import RegressorMixin
from ..utils import arrayfuncs, as_float_array, check_X_y, deprecated
from ..model_selection import check_cv
from ..exceptions import ConvergenceWarning
from ..externals.joblib import Parallel, delayed
from ..externals.six.moves import xrange
from ..externals.six import string_types
solve_triangular_args = {'check_finite': False}
def lars_path(X, y, Xy=None, Gram=None, max_iter=500,
alpha_min=0, method='lar', copy_X=True,
eps=np.finfo(np.float).eps,
copy_Gram=True, verbose=0, return_path=True,
return_n_iter=False, positive=False):
"""Compute Least Angle Regression or Lasso path using LARS algorithm [1]
The optimization objective for the case method='lasso' is::
(1 / (2 * n_samples)) * ||y - Xw||^2_2 + alpha * ||w||_1
in the case of method='lars', the objective function is only known in
the form of an implicit equation (see discussion in [1])
Read more in the :ref:`User Guide <least_angle_regression>`.
Parameters
-----------
X : array, shape: (n_samples, n_features)
Input data.
y : array, shape: (n_samples)
Input targets.
Xy : array-like, shape (n_samples,) or (n_samples, n_targets), \
optional
Xy = np.dot(X.T, y) that can be precomputed. It is useful
only when the Gram matrix is precomputed.
Gram : None, 'auto', array, shape: (n_features, n_features), optional
Precomputed Gram matrix (X' * X), if ``'auto'``, the Gram
matrix is precomputed from the given X, if there are more samples
than features.
max_iter : integer, optional (default=500)
Maximum number of iterations to perform, set to infinity for no limit.
alpha_min : float, optional (default=0)
Minimum correlation along the path. It corresponds to the
regularization parameter alpha parameter in the Lasso.
method : {'lar', 'lasso'}, optional (default='lar')
Specifies the returned model. Select ``'lar'`` for Least Angle
Regression, ``'lasso'`` for the Lasso.
copy_X : bool, optional (default=True)
If ``False``, ``X`` is overwritten.
eps : float, optional (default=``np.finfo(np.float).eps``)
The machine-precision regularization in the computation of the
Cholesky diagonal factors. Increase this for very ill-conditioned
systems.
copy_Gram : bool, optional (default=True)
If ``False``, ``Gram`` is overwritten.
verbose : int (default=0)
Controls output verbosity.
return_path : bool, optional (default=True)
If ``return_path==True`` returns the entire path, else returns only the
last point of the path.
return_n_iter : bool, optional (default=False)
Whether to return the number of iterations.
positive : boolean (default=False)
Restrict coefficients to be >= 0.
When using this option together with method 'lasso' the model
coefficients will not converge to the ordinary-least-squares solution
for small values of alpha (neither will they when using method 'lar'
..). Only coefficients up to the smallest alpha value
(``alphas_[alphas_ > 0.].min()`` when fit_path=True) reached by the
stepwise Lars-Lasso algorithm are typically in congruence with the
solution of the coordinate descent lasso_path function.
Returns
--------
alphas : array, shape: [n_alphas + 1]
Maximum of covariances (in absolute value) at each iteration.
``n_alphas`` is either ``max_iter``, ``n_features`` or the
number of nodes in the path with ``alpha >= alpha_min``, whichever
is smaller.
active : array, shape [n_alphas]
Indices of active variables at the end of the path.
coefs : array, shape (n_features, n_alphas + 1)
Coefficients along the path
n_iter : int
Number of iterations run. Returned only if return_n_iter is set
to True.
See also
--------
lasso_path
LassoLars
Lars
LassoLarsCV
LarsCV
sklearn.decomposition.sparse_encode
References
----------
.. [1] "Least Angle Regression", Effron et al.
http://statweb.stanford.edu/~tibs/ftp/lars.pdf
.. [2] `Wikipedia entry on the Least-angle regression
<https://en.wikipedia.org/wiki/Least-angle_regression>`_
.. [3] `Wikipedia entry on the Lasso
<https://en.wikipedia.org/wiki/Lasso_(statistics)>`_
"""
n_features = X.shape[1]
n_samples = y.size
max_features = min(max_iter, n_features)
if return_path:
coefs = np.zeros((max_features + 1, n_features))
alphas = np.zeros(max_features + 1)
else:
coef, prev_coef = np.zeros(n_features), np.zeros(n_features)
alpha, prev_alpha = np.array([0.]), np.array([0.]) # better ideas?
n_iter, n_active = 0, 0
active, indices = list(), np.arange(n_features)
# holds the sign of covariance
sign_active = np.empty(max_features, dtype=np.int8)
drop = False
# will hold the cholesky factorization. Only lower part is
# referenced.
# We are initializing this to "zeros" and not empty, because
# it is passed to scipy linalg functions and thus if it has NaNs,
# even if they are in the upper part that it not used, we
# get errors raised.
# Once we support only scipy > 0.12 we can use check_finite=False and
# go back to "empty"
L = np.zeros((max_features, max_features), dtype=X.dtype)
swap, nrm2 = linalg.get_blas_funcs(('swap', 'nrm2'), (X,))
solve_cholesky, = get_lapack_funcs(('potrs',), (X,))
if Gram is None or Gram is False:
Gram = None
if copy_X:
# force copy. setting the array to be fortran-ordered
# speeds up the calculation of the (partial) Gram matrix
# and allows to easily swap columns
X = X.copy('F')
elif isinstance(Gram, string_types) and Gram == 'auto' or Gram is True:
if Gram is True or X.shape[0] > X.shape[1]:
Gram = np.dot(X.T, X)
else:
Gram = None
elif copy_Gram:
Gram = Gram.copy()
if Xy is None:
Cov = np.dot(X.T, y)
else:
Cov = Xy.copy()
if verbose:
if verbose > 1:
print("Step\t\tAdded\t\tDropped\t\tActive set size\t\tC")
else:
sys.stdout.write('.')
sys.stdout.flush()
tiny32 = np.finfo(np.float32).tiny # to avoid division by 0 warning
equality_tolerance = np.finfo(np.float32).eps
while True:
if Cov.size:
if positive:
C_idx = np.argmax(Cov)
else:
C_idx = np.argmax(np.abs(Cov))
C_ = Cov[C_idx]
if positive:
C = C_
else:
C = np.fabs(C_)
else:
C = 0.
if return_path:
alpha = alphas[n_iter, np.newaxis]
coef = coefs[n_iter]
prev_alpha = alphas[n_iter - 1, np.newaxis]
prev_coef = coefs[n_iter - 1]
alpha[0] = C / n_samples
if alpha[0] <= alpha_min + equality_tolerance: # early stopping
if abs(alpha[0] - alpha_min) > equality_tolerance:
# interpolation factor 0 <= ss < 1
if n_iter > 0:
# In the first iteration, all alphas are zero, the formula
# below would make ss a NaN
ss = ((prev_alpha[0] - alpha_min) /
(prev_alpha[0] - alpha[0]))
coef[:] = prev_coef + ss * (coef - prev_coef)
alpha[0] = alpha_min
if return_path:
coefs[n_iter] = coef
break
if n_iter >= max_iter or n_active >= n_features:
break
if not drop:
##########################################################
# Append x_j to the Cholesky factorization of (Xa * Xa') #
# #
# ( L 0 ) #
# L -> ( ) , where L * w = Xa' x_j #
# ( w z ) and z = ||x_j|| #
# #
##########################################################
if positive:
sign_active[n_active] = np.ones_like(C_)
else:
sign_active[n_active] = np.sign(C_)
m, n = n_active, C_idx + n_active
Cov[C_idx], Cov[0] = swap(Cov[C_idx], Cov[0])
indices[n], indices[m] = indices[m], indices[n]
Cov_not_shortened = Cov
Cov = Cov[1:] # remove Cov[0]
if Gram is None:
X.T[n], X.T[m] = swap(X.T[n], X.T[m])
c = nrm2(X.T[n_active]) ** 2
L[n_active, :n_active] = \
np.dot(X.T[n_active], X.T[:n_active].T)
else:
# swap does only work inplace if matrix is fortran
# contiguous ...
Gram[m], Gram[n] = swap(Gram[m], Gram[n])
Gram[:, m], Gram[:, n] = swap(Gram[:, m], Gram[:, n])
c = Gram[n_active, n_active]
L[n_active, :n_active] = Gram[n_active, :n_active]
# Update the cholesky decomposition for the Gram matrix
if n_active:
linalg.solve_triangular(L[:n_active, :n_active],
L[n_active, :n_active],
trans=0, lower=1,
overwrite_b=True,
**solve_triangular_args)
v = np.dot(L[n_active, :n_active], L[n_active, :n_active])
diag = max(np.sqrt(np.abs(c - v)), eps)
L[n_active, n_active] = diag
if diag < 1e-7:
# The system is becoming too ill-conditioned.
# We have degenerate vectors in our active set.
# We'll 'drop for good' the last regressor added.
# Note: this case is very rare. It is no longer triggered by
# the test suite. The `equality_tolerance` margin added in 0.16
# to get early stopping to work consistently on all versions of
# Python including 32 bit Python under Windows seems to make it
# very difficult to trigger the 'drop for good' strategy.
warnings.warn('Regressors in active set degenerate. '
'Dropping a regressor, after %i iterations, '
'i.e. alpha=%.3e, '
'with an active set of %i regressors, and '
'the smallest cholesky pivot element being %.3e.'
' Reduce max_iter or increase eps parameters.'
% (n_iter, alpha, n_active, diag),
ConvergenceWarning)
# XXX: need to figure a 'drop for good' way
Cov = Cov_not_shortened
Cov[0] = 0
Cov[C_idx], Cov[0] = swap(Cov[C_idx], Cov[0])
continue
active.append(indices[n_active])
n_active += 1
if verbose > 1:
print("%s\t\t%s\t\t%s\t\t%s\t\t%s" % (n_iter, active[-1], '',
n_active, C))
if method == 'lasso' and n_iter > 0 and prev_alpha[0] < alpha[0]:
# alpha is increasing. This is because the updates of Cov are
# bringing in too much numerical error that is greater than
# than the remaining correlation with the
# regressors. Time to bail out
warnings.warn('Early stopping the lars path, as the residues '
'are small and the current value of alpha is no '
'longer well controlled. %i iterations, alpha=%.3e, '
'previous alpha=%.3e, with an active set of %i '
'regressors.'
% (n_iter, alpha, prev_alpha, n_active),
ConvergenceWarning)
break
# least squares solution
least_squares, info = solve_cholesky(L[:n_active, :n_active],
sign_active[:n_active],
lower=True)
if least_squares.size == 1 and least_squares == 0:
# This happens because sign_active[:n_active] = 0
least_squares[...] = 1
AA = 1.
else:
# is this really needed ?
AA = 1. / np.sqrt(np.sum(least_squares * sign_active[:n_active]))
if not np.isfinite(AA):
# L is too ill-conditioned
i = 0
L_ = L[:n_active, :n_active].copy()
while not np.isfinite(AA):
L_.flat[::n_active + 1] += (2 ** i) * eps
least_squares, info = solve_cholesky(
L_, sign_active[:n_active], lower=True)
tmp = max(np.sum(least_squares * sign_active[:n_active]),
eps)
AA = 1. / np.sqrt(tmp)
i += 1
least_squares *= AA
if Gram is None:
# equiangular direction of variables in the active set
eq_dir = np.dot(X.T[:n_active].T, least_squares)
# correlation between each unactive variables and
# eqiangular vector
corr_eq_dir = np.dot(X.T[n_active:], eq_dir)
else:
# if huge number of features, this takes 50% of time, I
# think could be avoided if we just update it using an
# orthogonal (QR) decomposition of X
corr_eq_dir = np.dot(Gram[:n_active, n_active:].T,
least_squares)
g1 = arrayfuncs.min_pos((C - Cov) / (AA - corr_eq_dir + tiny32))
if positive:
gamma_ = min(g1, C / AA)
else:
g2 = arrayfuncs.min_pos((C + Cov) / (AA + corr_eq_dir + tiny32))
gamma_ = min(g1, g2, C / AA)
# TODO: better names for these variables: z
drop = False
z = -coef[active] / (least_squares + tiny32)
z_pos = arrayfuncs.min_pos(z)
if z_pos < gamma_:
# some coefficients have changed sign
idx = np.where(z == z_pos)[0][::-1]
# update the sign, important for LAR
sign_active[idx] = -sign_active[idx]
if method == 'lasso':
gamma_ = z_pos
drop = True
n_iter += 1
if return_path:
if n_iter >= coefs.shape[0]:
del coef, alpha, prev_alpha, prev_coef
# resize the coefs and alphas array
add_features = 2 * max(1, (max_features - n_active))
coefs = np.resize(coefs, (n_iter + add_features, n_features))
coefs[-add_features:] = 0
alphas = np.resize(alphas, n_iter + add_features)
alphas[-add_features:] = 0
coef = coefs[n_iter]
prev_coef = coefs[n_iter - 1]
alpha = alphas[n_iter, np.newaxis]
prev_alpha = alphas[n_iter - 1, np.newaxis]
else:
# mimic the effect of incrementing n_iter on the array references
prev_coef = coef
prev_alpha[0] = alpha[0]
coef = np.zeros_like(coef)
coef[active] = prev_coef[active] + gamma_ * least_squares
# update correlations
Cov -= gamma_ * corr_eq_dir
# See if any coefficient has changed sign
if drop and method == 'lasso':
# handle the case when idx is not length of 1
[arrayfuncs.cholesky_delete(L[:n_active, :n_active], ii) for ii in
idx]
n_active -= 1
m, n = idx, n_active
# handle the case when idx is not length of 1
drop_idx = [active.pop(ii) for ii in idx]
if Gram is None:
# propagate dropped variable
for ii in idx:
for i in range(ii, n_active):
X.T[i], X.T[i + 1] = swap(X.T[i], X.T[i + 1])
# yeah this is stupid
indices[i], indices[i + 1] = indices[i + 1], indices[i]
# TODO: this could be updated
residual = y - np.dot(X[:, :n_active], coef[active])
temp = np.dot(X.T[n_active], residual)
Cov = np.r_[temp, Cov]
else:
for ii in idx:
for i in range(ii, n_active):
indices[i], indices[i + 1] = indices[i + 1], indices[i]
Gram[i], Gram[i + 1] = swap(Gram[i], Gram[i + 1])
Gram[:, i], Gram[:, i + 1] = swap(Gram[:, i],
Gram[:, i + 1])
# Cov_n = Cov_j + x_j * X + increment(betas) TODO:
# will this still work with multiple drops ?
# recompute covariance. Probably could be done better
# wrong as Xy is not swapped with the rest of variables
# TODO: this could be updated
residual = y - np.dot(X, coef)
temp = np.dot(X.T[drop_idx], residual)
Cov = np.r_[temp, Cov]
sign_active = np.delete(sign_active, idx)
sign_active = np.append(sign_active, 0.) # just to maintain size
if verbose > 1:
print("%s\t\t%s\t\t%s\t\t%s\t\t%s" % (n_iter, '', drop_idx,
n_active, abs(temp)))
if return_path:
# resize coefs in case of early stop
alphas = alphas[:n_iter + 1]
coefs = coefs[:n_iter + 1]
if return_n_iter:
return alphas, active, coefs.T, n_iter
else:
return alphas, active, coefs.T
else:
if return_n_iter:
return alpha, active, coef, n_iter
else:
return alpha, active, coef
###############################################################################
# Estimator classes
class Lars(LinearModel, RegressorMixin):
"""Least Angle Regression model a.k.a. LAR
Read more in the :ref:`User Guide <least_angle_regression>`.
Parameters
----------
fit_intercept : boolean
Whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
verbose : boolean or integer, optional
Sets the verbosity amount
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
precompute : True | False | 'auto' | array-like
Whether to use a precomputed Gram matrix to speed up
calculations. If set to ``'auto'`` let us decide. The Gram
matrix can also be passed as argument.
n_nonzero_coefs : int, optional
Target number of non-zero coefficients. Use ``np.inf`` for no limit.
eps : float, optional
The machine-precision regularization in the computation of the
Cholesky diagonal factors. Increase this for very ill-conditioned
systems. Unlike the ``tol`` parameter in some iterative
optimization-based algorithms, this parameter does not control
the tolerance of the optimization.
copy_X : boolean, optional, default True
If ``True``, X will be copied; else, it may be overwritten.
fit_path : boolean
If True the full path is stored in the ``coef_path_`` attribute.
If you compute the solution for a large problem or many targets,
setting ``fit_path`` to ``False`` will lead to a speedup, especially
with a small alpha.
positive : boolean (default=False)
Restrict coefficients to be >= 0. Be aware that you might want to
remove fit_intercept which is set True by default.
Attributes
----------
alphas_ : array, shape (n_alphas + 1,) | list of n_targets such arrays
Maximum of covariances (in absolute value) at each iteration. \
``n_alphas`` is either ``n_nonzero_coefs`` or ``n_features``, \
whichever is smaller.
active_ : list, length = n_alphas | list of n_targets such lists
Indices of active variables at the end of the path.
coef_path_ : array, shape (n_features, n_alphas + 1) \
| list of n_targets such arrays
The varying values of the coefficients along the path. It is not
present if the ``fit_path`` parameter is ``False``.
coef_ : array, shape (n_features,) or (n_targets, n_features)
Parameter vector (w in the formulation formula).
intercept_ : float | array, shape (n_targets,)
Independent term in decision function.
n_iter_ : array-like or int
The number of iterations taken by lars_path to find the
grid of alphas for each target.
Examples
--------
>>> from sklearn import linear_model
>>> reg = linear_model.Lars(n_nonzero_coefs=1)
>>> reg.fit([[-1, 1], [0, 0], [1, 1]], [-1.1111, 0, -1.1111])
... # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
Lars(copy_X=True, eps=..., fit_intercept=True, fit_path=True,
n_nonzero_coefs=1, normalize=True, positive=False, precompute='auto',
verbose=False)
>>> print(reg.coef_) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
[ 0. -1.11...]
See also
--------
lars_path, LarsCV
sklearn.decomposition.sparse_encode
"""
method = 'lar'
def __init__(self, fit_intercept=True, verbose=False, normalize=True,
precompute='auto', n_nonzero_coefs=500,
eps=np.finfo(np.float).eps, copy_X=True, fit_path=True,
positive=False):
self.fit_intercept = fit_intercept
self.verbose = verbose
self.normalize = normalize
self.precompute = precompute
self.n_nonzero_coefs = n_nonzero_coefs
self.positive = positive
self.eps = eps
self.copy_X = copy_X
self.fit_path = fit_path
def _get_gram(self, precompute, X, y):
if (not hasattr(precompute, '__array__')) and (
(precompute is True) or
(precompute == 'auto' and X.shape[0] > X.shape[1]) or
(precompute == 'auto' and y.shape[1] > 1)):
precompute = np.dot(X.T, X)
return precompute
def _fit(self, X, y, max_iter, alpha, fit_path, Xy=None):
"""Auxiliary method to fit the model using X, y as training data"""
n_features = X.shape[1]
X, y, X_offset, y_offset, X_scale = self._preprocess_data(X, y,
self.fit_intercept,
self.normalize,
self.copy_X)
if y.ndim == 1:
y = y[:, np.newaxis]
n_targets = y.shape[1]
Gram = self._get_gram(self.precompute, X, y)
self.alphas_ = []
self.n_iter_ = []
self.coef_ = np.empty((n_targets, n_features))
if fit_path:
self.active_ = []
self.coef_path_ = []
for k in xrange(n_targets):
this_Xy = None if Xy is None else Xy[:, k]
alphas, active, coef_path, n_iter_ = lars_path(
X, y[:, k], Gram=Gram, Xy=this_Xy, copy_X=self.copy_X,
copy_Gram=True, alpha_min=alpha, method=self.method,
verbose=max(0, self.verbose - 1), max_iter=max_iter,
eps=self.eps, return_path=True,
return_n_iter=True, positive=self.positive)
self.alphas_.append(alphas)
self.active_.append(active)
self.n_iter_.append(n_iter_)
self.coef_path_.append(coef_path)
self.coef_[k] = coef_path[:, -1]
if n_targets == 1:
self.alphas_, self.active_, self.coef_path_, self.coef_ = [
a[0] for a in (self.alphas_, self.active_, self.coef_path_,
self.coef_)]
self.n_iter_ = self.n_iter_[0]
else:
for k in xrange(n_targets):
this_Xy = None if Xy is None else Xy[:, k]
alphas, _, self.coef_[k], n_iter_ = lars_path(
X, y[:, k], Gram=Gram, Xy=this_Xy, copy_X=self.copy_X,
copy_Gram=True, alpha_min=alpha, method=self.method,
verbose=max(0, self.verbose - 1), max_iter=max_iter,
eps=self.eps, return_path=False, return_n_iter=True,
positive=self.positive)
self.alphas_.append(alphas)
self.n_iter_.append(n_iter_)
if n_targets == 1:
self.alphas_ = self.alphas_[0]
self.n_iter_ = self.n_iter_[0]
self._set_intercept(X_offset, y_offset, X_scale)
return self
def fit(self, X, y, Xy=None):
"""Fit the model using X, y as training data.
Parameters
----------
X : array-like, shape (n_samples, n_features)
Training data.
y : array-like, shape (n_samples,) or (n_samples, n_targets)
Target values.
Xy : array-like, shape (n_samples,) or (n_samples, n_targets), \
optional
Xy = np.dot(X.T, y) that can be precomputed. It is useful
only when the Gram matrix is precomputed.
Returns
-------
self : object
returns an instance of self.
"""
X, y = check_X_y(X, y, y_numeric=True, multi_output=True)
alpha = getattr(self, 'alpha', 0.)
if hasattr(self, 'n_nonzero_coefs'):
alpha = 0. # n_nonzero_coefs parametrization takes priority
max_iter = self.n_nonzero_coefs
else:
max_iter = self.max_iter
self._fit(X, y, max_iter=max_iter, alpha=alpha, fit_path=self.fit_path,
Xy=Xy)
return self
class LassoLars(Lars):
"""Lasso model fit with Least Angle Regression a.k.a. Lars
It is a Linear Model trained with an L1 prior as regularizer.
The optimization objective for Lasso is::
(1 / (2 * n_samples)) * ||y - Xw||^2_2 + alpha * ||w||_1
Read more in the :ref:`User Guide <least_angle_regression>`.
Parameters
----------
alpha : float
Constant that multiplies the penalty term. Defaults to 1.0.
``alpha = 0`` is equivalent to an ordinary least square, solved
by :class:`LinearRegression`. For numerical reasons, using
``alpha = 0`` with the LassoLars object is not advised and you
should prefer the LinearRegression object.
fit_intercept : boolean
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
verbose : boolean or integer, optional
Sets the verbosity amount
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
precompute : True | False | 'auto' | array-like
Whether to use a precomputed Gram matrix to speed up
calculations. If set to ``'auto'`` let us decide. The Gram
matrix can also be passed as argument.
max_iter : integer, optional
Maximum number of iterations to perform.
eps : float, optional
The machine-precision regularization in the computation of the
Cholesky diagonal factors. Increase this for very ill-conditioned
systems. Unlike the ``tol`` parameter in some iterative
optimization-based algorithms, this parameter does not control
the tolerance of the optimization.
copy_X : boolean, optional, default True
If True, X will be copied; else, it may be overwritten.
fit_path : boolean
If ``True`` the full path is stored in the ``coef_path_`` attribute.
If you compute the solution for a large problem or many targets,
setting ``fit_path`` to ``False`` will lead to a speedup, especially
with a small alpha.
positive : boolean (default=False)
Restrict coefficients to be >= 0. Be aware that you might want to
remove fit_intercept which is set True by default.
Under the positive restriction the model coefficients will not converge
to the ordinary-least-squares solution for small values of alpha.
Only coefficients up to the smallest alpha value (``alphas_[alphas_ >
0.].min()`` when fit_path=True) reached by the stepwise Lars-Lasso
algorithm are typically in congruence with the solution of the
coordinate descent Lasso estimator.
Attributes
----------
alphas_ : array, shape (n_alphas + 1,) | list of n_targets such arrays
Maximum of covariances (in absolute value) at each iteration. \
``n_alphas`` is either ``max_iter``, ``n_features``, or the number of \
nodes in the path with correlation greater than ``alpha``, whichever \
is smaller.
active_ : list, length = n_alphas | list of n_targets such lists
Indices of active variables at the end of the path.
coef_path_ : array, shape (n_features, n_alphas + 1) or list
If a list is passed it's expected to be one of n_targets such arrays.
The varying values of the coefficients along the path. It is not
present if the ``fit_path`` parameter is ``False``.
coef_ : array, shape (n_features,) or (n_targets, n_features)
Parameter vector (w in the formulation formula).
intercept_ : float | array, shape (n_targets,)
Independent term in decision function.
n_iter_ : array-like or int.
The number of iterations taken by lars_path to find the
grid of alphas for each target.
Examples
--------
>>> from sklearn import linear_model
>>> reg = linear_model.LassoLars(alpha=0.01)
>>> reg.fit([[-1, 1], [0, 0], [1, 1]], [-1, 0, -1])
... # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
LassoLars(alpha=0.01, copy_X=True, eps=..., fit_intercept=True,
fit_path=True, max_iter=500, normalize=True, positive=False,
precompute='auto', verbose=False)
>>> print(reg.coef_) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
[ 0. -0.963257...]
See also
--------
lars_path
lasso_path
Lasso
LassoCV
LassoLarsCV
sklearn.decomposition.sparse_encode
"""
method = 'lasso'
def __init__(self, alpha=1.0, fit_intercept=True, verbose=False,
normalize=True, precompute='auto', max_iter=500,
eps=np.finfo(np.float).eps, copy_X=True, fit_path=True,
positive=False):
self.alpha = alpha
self.fit_intercept = fit_intercept
self.max_iter = max_iter
self.verbose = verbose
self.normalize = normalize
self.positive = positive
self.precompute = precompute
self.copy_X = copy_X
self.eps = eps
self.fit_path = fit_path
###############################################################################
# Cross-validated estimator classes
def _check_copy_and_writeable(array, copy=False):
if copy or not array.flags.writeable:
return array.copy()
return array
def _lars_path_residues(X_train, y_train, X_test, y_test, Gram=None,
copy=True, method='lars', verbose=False,
fit_intercept=True, normalize=True, max_iter=500,
eps=np.finfo(np.float).eps, positive=False):
"""Compute the residues on left-out data for a full LARS path
Parameters
-----------
X_train : array, shape (n_samples, n_features)
The data to fit the LARS on
y_train : array, shape (n_samples)
The target variable to fit LARS on
X_test : array, shape (n_samples, n_features)
The data to compute the residues on
y_test : array, shape (n_samples)
The target variable to compute the residues on
Gram : None, 'auto', array, shape: (n_features, n_features), optional
Precomputed Gram matrix (X' * X), if ``'auto'``, the Gram
matrix is precomputed from the given X, if there are more samples
than features
copy : boolean, optional
Whether X_train, X_test, y_train and y_test should be copied;
if False, they may be overwritten.
method : 'lar' | 'lasso'
Specifies the returned model. Select ``'lar'`` for Least Angle
Regression, ``'lasso'`` for the Lasso.
verbose : integer, optional
Sets the amount of verbosity
fit_intercept : boolean
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
positive : boolean (default=False)
Restrict coefficients to be >= 0. Be aware that you might want to
remove fit_intercept which is set True by default.
See reservations for using this option in combination with method
'lasso' for expected small values of alpha in the doc of LassoLarsCV
and LassoLarsIC.
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
max_iter : integer, optional
Maximum number of iterations to perform.
eps : float, optional
The machine-precision regularization in the computation of the
Cholesky diagonal factors. Increase this for very ill-conditioned
systems. Unlike the ``tol`` parameter in some iterative
optimization-based algorithms, this parameter does not control
the tolerance of the optimization.
Returns
--------
alphas : array, shape (n_alphas,)
Maximum of covariances (in absolute value) at each iteration.
``n_alphas`` is either ``max_iter`` or ``n_features``, whichever
is smaller.
active : list
Indices of active variables at the end of the path.
coefs : array, shape (n_features, n_alphas)
Coefficients along the path
residues : array, shape (n_alphas, n_samples)
Residues of the prediction on the test data
"""
X_train = _check_copy_and_writeable(X_train, copy)
y_train = _check_copy_and_writeable(y_train, copy)
X_test = _check_copy_and_writeable(X_test, copy)
y_test = _check_copy_and_writeable(y_test, copy)
if fit_intercept:
X_mean = X_train.mean(axis=0)
X_train -= X_mean
X_test -= X_mean
y_mean = y_train.mean(axis=0)
y_train = as_float_array(y_train, copy=False)
y_train -= y_mean
y_test = as_float_array(y_test, copy=False)
y_test -= y_mean
if normalize:
norms = np.sqrt(np.sum(X_train ** 2, axis=0))
nonzeros = np.flatnonzero(norms)
X_train[:, nonzeros] /= norms[nonzeros]
alphas, active, coefs = lars_path(
X_train, y_train, Gram=Gram, copy_X=False, copy_Gram=False,
method=method, verbose=max(0, verbose - 1), max_iter=max_iter, eps=eps,
positive=positive)
if normalize:
coefs[nonzeros] /= norms[nonzeros][:, np.newaxis]
residues = np.dot(X_test, coefs) - y_test[:, np.newaxis]
return alphas, active, coefs, residues.T
class LarsCV(Lars):
"""Cross-validated Least Angle Regression model
Read more in the :ref:`User Guide <least_angle_regression>`.
Parameters
----------
fit_intercept : boolean
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
verbose : boolean or integer, optional
Sets the verbosity amount
max_iter : integer, optional
Maximum number of iterations to perform.
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
precompute : True | False | 'auto' | array-like
Whether to use a precomputed Gram matrix to speed up
calculations. If set to ``'auto'`` let us decide. The Gram matrix
cannot be passed as argument since we will use only subsets of X.
cv : int, cross-validation generator or an iterable, optional
Determines the cross-validation splitting strategy.
Possible inputs for cv are:
- None, to use the default 3-fold cross-validation,
- integer, to specify the number of folds.
- An object to be used as a cross-validation generator.
- An iterable yielding train/test splits.
For integer/None inputs, :class:`KFold` is used.
Refer :ref:`User Guide <cross_validation>` for the various
cross-validation strategies that can be used here.
max_n_alphas : integer, optional
The maximum number of points on the path used to compute the
residuals in the cross-validation
n_jobs : integer, optional
Number of CPUs to use during the cross validation. If ``-1``, use
all the CPUs
eps : float, optional
The machine-precision regularization in the computation of the
Cholesky diagonal factors. Increase this for very ill-conditioned
systems.
copy_X : boolean, optional, default True
If ``True``, X will be copied; else, it may be overwritten.
positive : boolean (default=False)
Restrict coefficients to be >= 0. Be aware that you might want to
remove fit_intercept which is set True by default.
Attributes
----------
coef_ : array, shape (n_features,)
parameter vector (w in the formulation formula)
intercept_ : float
independent term in decision function
coef_path_ : array, shape (n_features, n_alphas)
the varying values of the coefficients along the path
alpha_ : float
the estimated regularization parameter alpha
alphas_ : array, shape (n_alphas,)
the different values of alpha along the path
cv_alphas_ : array, shape (n_cv_alphas,)
all the values of alpha along the path for the different folds
mse_path_ : array, shape (n_folds, n_cv_alphas)
the mean square error on left-out for each fold along the path
(alpha values given by ``cv_alphas``)
n_iter_ : array-like or int
the number of iterations run by Lars with the optimal alpha.
See also
--------
lars_path, LassoLars, LassoLarsCV
"""
method = 'lar'
def __init__(self, fit_intercept=True, verbose=False, max_iter=500,
normalize=True, precompute='auto', cv=None,
max_n_alphas=1000, n_jobs=1, eps=np.finfo(np.float).eps,
copy_X=True, positive=False):
self.max_iter = max_iter
self.cv = cv
self.max_n_alphas = max_n_alphas
self.n_jobs = n_jobs
super(LarsCV, self).__init__(fit_intercept=fit_intercept,
verbose=verbose, normalize=normalize,
precompute=precompute,
n_nonzero_coefs=500,
eps=eps, copy_X=copy_X, fit_path=True,
positive=positive)
def fit(self, X, y):
"""Fit the model using X, y as training data.
Parameters
----------
X : array-like, shape (n_samples, n_features)
Training data.
y : array-like, shape (n_samples,)
Target values.
Returns
-------
self : object
returns an instance of self.
"""
X, y = check_X_y(X, y, y_numeric=True)
X = as_float_array(X, copy=self.copy_X)
y = as_float_array(y, copy=self.copy_X)
# init cross-validation generator
cv = check_cv(self.cv, classifier=False)
# As we use cross-validation, the Gram matrix is not precomputed here
Gram = self.precompute
if hasattr(Gram, '__array__'):
warnings.warn("Parameter 'precompute' cannot be an array in "
"%s. Automatically switch to 'auto' instead."
% self.__class__.__name__)
Gram = 'auto'
cv_paths = Parallel(n_jobs=self.n_jobs, verbose=self.verbose)(
delayed(_lars_path_residues)(
X[train], y[train], X[test], y[test], Gram=Gram, copy=False,
method=self.method, verbose=max(0, self.verbose - 1),
normalize=self.normalize, fit_intercept=self.fit_intercept,
max_iter=self.max_iter, eps=self.eps, positive=self.positive)
for train, test in cv.split(X, y))
all_alphas = np.concatenate(list(zip(*cv_paths))[0])
# Unique also sorts
all_alphas = np.unique(all_alphas)
# Take at most max_n_alphas values
stride = int(max(1, int(len(all_alphas) / float(self.max_n_alphas))))
all_alphas = all_alphas[::stride]
mse_path = np.empty((len(all_alphas), len(cv_paths)))
for index, (alphas, active, coefs, residues) in enumerate(cv_paths):
alphas = alphas[::-1]
residues = residues[::-1]
if alphas[0] != 0:
alphas = np.r_[0, alphas]
residues = np.r_[residues[0, np.newaxis], residues]
if alphas[-1] != all_alphas[-1]:
alphas = np.r_[alphas, all_alphas[-1]]
residues = np.r_[residues, residues[-1, np.newaxis]]
this_residues = interpolate.interp1d(alphas,
residues,
axis=0)(all_alphas)
this_residues **= 2
mse_path[:, index] = np.mean(this_residues, axis=-1)
mask = np.all(np.isfinite(mse_path), axis=-1)
all_alphas = all_alphas[mask]
mse_path = mse_path[mask]
# Select the alpha that minimizes left-out error
i_best_alpha = np.argmin(mse_path.mean(axis=-1))
best_alpha = all_alphas[i_best_alpha]
# Store our parameters
self.alpha_ = best_alpha
self.cv_alphas_ = all_alphas
self.mse_path_ = mse_path
# Now compute the full model
# it will call a lasso internally when self if LassoLarsCV
# as self.method == 'lasso'
self._fit(X, y, max_iter=self.max_iter, alpha=best_alpha,
Xy=None, fit_path=True)
return self
@property
@deprecated("Attribute alpha is deprecated in 0.19 and "
"will be removed in 0.21. See ``alpha_`` instead")
def alpha(self):
# impedance matching for the above Lars.fit (should not be documented)
return self.alpha_
@property
@deprecated("Attribute ``cv_mse_path_`` is deprecated in 0.18 and "
"will be removed in 0.20. Use ``mse_path_`` instead")
def cv_mse_path_(self):
return self.mse_path_
class LassoLarsCV(LarsCV):
"""Cross-validated Lasso, using the LARS algorithm
The optimization objective for Lasso is::
(1 / (2 * n_samples)) * ||y - Xw||^2_2 + alpha * ||w||_1
Read more in the :ref:`User Guide <least_angle_regression>`.
Parameters
----------
fit_intercept : boolean
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
verbose : boolean or integer, optional
Sets the verbosity amount
max_iter : integer, optional
Maximum number of iterations to perform.
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
precompute : True | False | 'auto'
Whether to use a precomputed Gram matrix to speed up
calculations. If set to ``'auto'`` let us decide. The Gram matrix
cannot be passed as argument since we will use only subsets of X.
cv : int, cross-validation generator or an iterable, optional
Determines the cross-validation splitting strategy.
Possible inputs for cv are:
- None, to use the default 3-fold cross-validation,
- integer, to specify the number of folds.
- An object to be used as a cross-validation generator.
- An iterable yielding train/test splits.
For integer/None inputs, :class:`KFold` is used.
Refer :ref:`User Guide <cross_validation>` for the various
cross-validation strategies that can be used here.
max_n_alphas : integer, optional
The maximum number of points on the path used to compute the
residuals in the cross-validation
n_jobs : integer, optional
Number of CPUs to use during the cross validation. If ``-1``, use
all the CPUs
eps : float, optional
The machine-precision regularization in the computation of the
Cholesky diagonal factors. Increase this for very ill-conditioned
systems.
copy_X : boolean, optional, default True
If True, X will be copied; else, it may be overwritten.
positive : boolean (default=False)
Restrict coefficients to be >= 0. Be aware that you might want to
remove fit_intercept which is set True by default.
Under the positive restriction the model coefficients do not converge
to the ordinary-least-squares solution for small values of alpha.
Only coefficients up to the smallest alpha value (``alphas_[alphas_ >
0.].min()`` when fit_path=True) reached by the stepwise Lars-Lasso
algorithm are typically in congruence with the solution of the
coordinate descent Lasso estimator.
As a consequence using LassoLarsCV only makes sense for problems where
a sparse solution is expected and/or reached.
Attributes
----------
coef_ : array, shape (n_features,)
parameter vector (w in the formulation formula)
intercept_ : float
independent term in decision function.
coef_path_ : array, shape (n_features, n_alphas)
the varying values of the coefficients along the path
alpha_ : float
the estimated regularization parameter alpha
alphas_ : array, shape (n_alphas,)
the different values of alpha along the path
cv_alphas_ : array, shape (n_cv_alphas,)
all the values of alpha along the path for the different folds
mse_path_ : array, shape (n_folds, n_cv_alphas)
the mean square error on left-out for each fold along the path
(alpha values given by ``cv_alphas``)
n_iter_ : array-like or int
the number of iterations run by Lars with the optimal alpha.
Notes
-----
The object solves the same problem as the LassoCV object. However,
unlike the LassoCV, it find the relevant alphas values by itself.
In general, because of this property, it will be more stable.
However, it is more fragile to heavily multicollinear datasets.
It is more efficient than the LassoCV if only a small number of
features are selected compared to the total number, for instance if
there are very few samples compared to the number of features.
See also
--------
lars_path, LassoLars, LarsCV, LassoCV
"""
method = 'lasso'
def __init__(self, fit_intercept=True, verbose=False, max_iter=500,
normalize=True, precompute='auto', cv=None,
max_n_alphas=1000, n_jobs=1, eps=np.finfo(np.float).eps,
copy_X=True, positive=False):
self.fit_intercept = fit_intercept
self.verbose = verbose
self.max_iter = max_iter
self.normalize = normalize
self.precompute = precompute
self.cv = cv
self.max_n_alphas = max_n_alphas
self.n_jobs = n_jobs
self.eps = eps
self.copy_X = copy_X
self.positive = positive
# XXX : we don't use super(LarsCV, self).__init__
# to avoid setting n_nonzero_coefs
class LassoLarsIC(LassoLars):
"""Lasso model fit with Lars using BIC or AIC for model selection
The optimization objective for Lasso is::
(1 / (2 * n_samples)) * ||y - Xw||^2_2 + alpha * ||w||_1
AIC is the Akaike information criterion and BIC is the Bayes
Information criterion. Such criteria are useful to select the value
of the regularization parameter by making a trade-off between the
goodness of fit and the complexity of the model. A good model should
explain well the data while being simple.
Read more in the :ref:`User Guide <least_angle_regression>`.
Parameters
----------
criterion : 'bic' | 'aic'
The type of criterion to use.
fit_intercept : boolean
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
verbose : boolean or integer, optional
Sets the verbosity amount
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
precompute : True | False | 'auto' | array-like
Whether to use a precomputed Gram matrix to speed up
calculations. If set to ``'auto'`` let us decide. The Gram
matrix can also be passed as argument.
max_iter : integer, optional
Maximum number of iterations to perform. Can be used for
early stopping.
eps : float, optional
The machine-precision regularization in the computation of the
Cholesky diagonal factors. Increase this for very ill-conditioned
systems. Unlike the ``tol`` parameter in some iterative
optimization-based algorithms, this parameter does not control
the tolerance of the optimization.
copy_X : boolean, optional, default True
If True, X will be copied; else, it may be overwritten.
positive : boolean (default=False)
Restrict coefficients to be >= 0. Be aware that you might want to
remove fit_intercept which is set True by default.
Under the positive restriction the model coefficients do not converge
to the ordinary-least-squares solution for small values of alpha.
Only coefficients up to the smallest alpha value (``alphas_[alphas_ >
0.].min()`` when fit_path=True) reached by the stepwise Lars-Lasso
algorithm are typically in congruence with the solution of the
coordinate descent Lasso estimator.
As a consequence using LassoLarsIC only makes sense for problems where
a sparse solution is expected and/or reached.
Attributes
----------
coef_ : array, shape (n_features,)
parameter vector (w in the formulation formula)
intercept_ : float
independent term in decision function.
alpha_ : float
the alpha parameter chosen by the information criterion
n_iter_ : int
number of iterations run by lars_path to find the grid of
alphas.
criterion_ : array, shape (n_alphas,)
The value of the information criteria ('aic', 'bic') across all
alphas. The alpha which has the smallest information criterion is
chosen. This value is larger by a factor of ``n_samples`` compared to
Eqns. 2.15 and 2.16 in (Zou et al, 2007).
Examples
--------
>>> from sklearn import linear_model
>>> reg = linear_model.LassoLarsIC(criterion='bic')
>>> reg.fit([[-1, 1], [0, 0], [1, 1]], [-1.1111, 0, -1.1111])
... # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
LassoLarsIC(copy_X=True, criterion='bic', eps=..., fit_intercept=True,
max_iter=500, normalize=True, positive=False, precompute='auto',
verbose=False)
>>> print(reg.coef_) # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
[ 0. -1.11...]
Notes
-----
The estimation of the number of degrees of freedom is given by:
"On the degrees of freedom of the lasso"
Hui Zou, Trevor Hastie, and Robert Tibshirani
Ann. Statist. Volume 35, Number 5 (2007), 2173-2192.
https://en.wikipedia.org/wiki/Akaike_information_criterion
https://en.wikipedia.org/wiki/Bayesian_information_criterion
See also
--------
lars_path, LassoLars, LassoLarsCV
"""
def __init__(self, criterion='aic', fit_intercept=True, verbose=False,
normalize=True, precompute='auto', max_iter=500,
eps=np.finfo(np.float).eps, copy_X=True, positive=False):
self.criterion = criterion
self.fit_intercept = fit_intercept
self.positive = positive
self.max_iter = max_iter
self.verbose = verbose
self.normalize = normalize
self.copy_X = copy_X
self.precompute = precompute
self.eps = eps
self.fit_path = True
def fit(self, X, y, copy_X=True):
"""Fit the model using X, y as training data.
Parameters
----------
X : array-like, shape (n_samples, n_features)
training data.
y : array-like, shape (n_samples,)
target values. Will be cast to X's dtype if necessary
copy_X : boolean, optional, default True
If ``True``, X will be copied; else, it may be overwritten.
Returns
-------
self : object
returns an instance of self.
"""
X, y = check_X_y(X, y, y_numeric=True)
X, y, Xmean, ymean, Xstd = LinearModel._preprocess_data(
X, y, self.fit_intercept, self.normalize, self.copy_X)
max_iter = self.max_iter
Gram = self.precompute
alphas_, active_, coef_path_, self.n_iter_ = lars_path(
X, y, Gram=Gram, copy_X=copy_X, copy_Gram=True, alpha_min=0.0,
method='lasso', verbose=self.verbose, max_iter=max_iter,
eps=self.eps, return_n_iter=True, positive=self.positive)
n_samples = X.shape[0]
if self.criterion == 'aic':
K = 2 # AIC
elif self.criterion == 'bic':
K = log(n_samples) # BIC
else:
raise ValueError('criterion should be either bic or aic')
R = y[:, np.newaxis] - np.dot(X, coef_path_) # residuals
mean_squared_error = np.mean(R ** 2, axis=0)
sigma2 = np.var(y)
df = np.zeros(coef_path_.shape[1], dtype=np.int) # Degrees of freedom
for k, coef in enumerate(coef_path_.T):
mask = np.abs(coef) > np.finfo(coef.dtype).eps
if not np.any(mask):
continue
# get the number of degrees of freedom equal to:
# Xc = X[:, mask]
# Trace(Xc * inv(Xc.T, Xc) * Xc.T) ie the number of non-zero coefs
df[k] = np.sum(mask)
self.alphas_ = alphas_
eps64 = np.finfo('float64').eps
self.criterion_ = (n_samples * mean_squared_error / (sigma2 + eps64) +
K * df) # Eqns. 2.15--16 in (Zou et al, 2007)
n_best = np.argmin(self.criterion_)
self.alpha_ = alphas_[n_best]
self.coef_ = coef_path_[:, n_best]
self._set_intercept(Xmean, ymean, Xstd)
return self
| bsd-3-clause |
quoniammm/happy-machine-learning | Udacity-ML/boston_housing-master_0/visuals.py | 6 | 5008 | ###########################################
# Suppress matplotlib user warnings
# Necessary for newer version of matplotlib
import warnings
warnings.filterwarnings("ignore", category = UserWarning, module = "matplotlib")
#
# Display inline matplotlib plots with IPython
from IPython import get_ipython
get_ipython().run_line_magic('matplotlib', 'inline')
###########################################
import matplotlib.pyplot as pl
import numpy as np
from sklearn.model_selection import learning_curve, validation_curve
from sklearn.tree import DecisionTreeRegressor
from sklearn.model_selection import ShuffleSplit, train_test_split
def ModelLearning(X, y):
""" Calculates the performance of several models with varying sizes of training data.
The learning and testing scores for each model are then plotted. """
# Create 10 cross-validation sets for training and testing
cv = ShuffleSplit(n_splits = 10, test_size = 0.2, random_state = 0)
# Generate the training set sizes increasing by 50
train_sizes = np.rint(np.linspace(1, X.shape[0]*0.8 - 1, 9)).astype(int)
# Create the figure window
fig = pl.figure(figsize=(10,7))
# Create three different models based on max_depth
for k, depth in enumerate([1,3,6,10]):
# Create a Decision tree regressor at max_depth = depth
regressor = DecisionTreeRegressor(max_depth = depth)
# Calculate the training and testing scores
sizes, train_scores, test_scores = learning_curve(regressor, X, y, \
cv = cv, train_sizes = train_sizes, scoring = 'r2')
# Find the mean and standard deviation for smoothing
train_std = np.std(train_scores, axis = 1)
train_mean = np.mean(train_scores, axis = 1)
test_std = np.std(test_scores, axis = 1)
test_mean = np.mean(test_scores, axis = 1)
# Subplot the learning curve
ax = fig.add_subplot(2, 2, k+1)
ax.plot(sizes, train_mean, 'o-', color = 'r', label = 'Training Score')
ax.plot(sizes, test_mean, 'o-', color = 'g', label = 'Testing Score')
ax.fill_between(sizes, train_mean - train_std, \
train_mean + train_std, alpha = 0.15, color = 'r')
ax.fill_between(sizes, test_mean - test_std, \
test_mean + test_std, alpha = 0.15, color = 'g')
# Labels
ax.set_title('max_depth = %s'%(depth))
ax.set_xlabel('Number of Training Points')
ax.set_ylabel('Score')
ax.set_xlim([0, X.shape[0]*0.8])
ax.set_ylim([-0.05, 1.05])
# Visual aesthetics
ax.legend(bbox_to_anchor=(1.05, 2.05), loc='lower left', borderaxespad = 0.)
fig.suptitle('Decision Tree Regressor Learning Performances', fontsize = 16, y = 1.03)
fig.tight_layout()
fig.show()
def ModelComplexity(X, y):
""" Calculates the performance of the model as model complexity increases.
The learning and testing errors rates are then plotted. """
# Create 10 cross-validation sets for training and testing
cv = ShuffleSplit(n_splits = 10, test_size = 0.2, random_state = 0)
# Vary the max_depth parameter from 1 to 10
max_depth = np.arange(1,11)
# Calculate the training and testing scores
train_scores, test_scores = validation_curve(DecisionTreeRegressor(), X, y, \
param_name = "max_depth", param_range = max_depth, cv = cv, scoring = 'r2')
# Find the mean and standard deviation for smoothing
train_mean = np.mean(train_scores, axis=1)
train_std = np.std(train_scores, axis=1)
test_mean = np.mean(test_scores, axis=1)
test_std = np.std(test_scores, axis=1)
# Plot the validation curve
pl.figure(figsize=(7, 5))
pl.title('Decision Tree Regressor Complexity Performance')
pl.plot(max_depth, train_mean, 'o-', color = 'r', label = 'Training Score')
pl.plot(max_depth, test_mean, 'o-', color = 'g', label = 'Validation Score')
pl.fill_between(max_depth, train_mean - train_std, \
train_mean + train_std, alpha = 0.15, color = 'r')
pl.fill_between(max_depth, test_mean - test_std, \
test_mean + test_std, alpha = 0.15, color = 'g')
# Visual aesthetics
pl.legend(loc = 'lower right')
pl.xlabel('Maximum Depth')
pl.ylabel('Score')
pl.ylim([-0.05,1.05])
pl.show()
def PredictTrials(X, y, fitter, data):
""" Performs trials of fitting and predicting data. """
# Store the predicted prices
prices = []
for k in range(10):
# Split the data
X_train, X_test, y_train, y_test = train_test_split(X, y, \
test_size = 0.2, random_state = k)
# Fit the data
reg = fitter(X_train, y_train)
# Make a prediction
pred = reg.predict([data[0]])[0]
prices.append(pred)
# Result
print "Trial {}: ${:,.2f}".format(k+1, pred)
# Display price range
print "\nRange in prices: ${:,.2f}".format(max(prices) - min(prices)) | mit |
ZENGXH/scikit-learn | examples/applications/plot_stock_market.py | 227 | 8284 | """
=======================================
Visualizing the stock market structure
=======================================
This example employs several unsupervised learning techniques to extract
the stock market structure from variations in historical quotes.
The quantity that we use is the daily variation in quote price: quotes
that are linked tend to cofluctuate during a day.
.. _stock_market:
Learning a graph structure
--------------------------
We use sparse inverse covariance estimation to find which quotes are
correlated conditionally on the others. Specifically, sparse inverse
covariance gives us a graph, that is a list of connection. For each
symbol, the symbols that it is connected too are those useful to explain
its fluctuations.
Clustering
----------
We use clustering to group together quotes that behave similarly. Here,
amongst the :ref:`various clustering techniques <clustering>` available
in the scikit-learn, we use :ref:`affinity_propagation` as it does
not enforce equal-size clusters, and it can choose automatically the
number of clusters from the data.
Note that this gives us a different indication than the graph, as the
graph reflects conditional relations between variables, while the
clustering reflects marginal properties: variables clustered together can
be considered as having a similar impact at the level of the full stock
market.
Embedding in 2D space
---------------------
For visualization purposes, we need to lay out the different symbols on a
2D canvas. For this we use :ref:`manifold` techniques to retrieve 2D
embedding.
Visualization
-------------
The output of the 3 models are combined in a 2D graph where nodes
represents the stocks and edges the:
- cluster labels are used to define the color of the nodes
- the sparse covariance model is used to display the strength of the edges
- the 2D embedding is used to position the nodes in the plan
This example has a fair amount of visualization-related code, as
visualization is crucial here to display the graph. One of the challenge
is to position the labels minimizing overlap. For this we use an
heuristic based on the direction of the nearest neighbor along each
axis.
"""
print(__doc__)
# Author: Gael Varoquaux [email protected]
# License: BSD 3 clause
import datetime
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import finance
from matplotlib.collections import LineCollection
from sklearn import cluster, covariance, manifold
###############################################################################
# Retrieve the data from Internet
# Choose a time period reasonnably calm (not too long ago so that we get
# high-tech firms, and before the 2008 crash)
d1 = datetime.datetime(2003, 1, 1)
d2 = datetime.datetime(2008, 1, 1)
# kraft symbol has now changed from KFT to MDLZ in yahoo
symbol_dict = {
'TOT': 'Total',
'XOM': 'Exxon',
'CVX': 'Chevron',
'COP': 'ConocoPhillips',
'VLO': 'Valero Energy',
'MSFT': 'Microsoft',
'IBM': 'IBM',
'TWX': 'Time Warner',
'CMCSA': 'Comcast',
'CVC': 'Cablevision',
'YHOO': 'Yahoo',
'DELL': 'Dell',
'HPQ': 'HP',
'AMZN': 'Amazon',
'TM': 'Toyota',
'CAJ': 'Canon',
'MTU': 'Mitsubishi',
'SNE': 'Sony',
'F': 'Ford',
'HMC': 'Honda',
'NAV': 'Navistar',
'NOC': 'Northrop Grumman',
'BA': 'Boeing',
'KO': 'Coca Cola',
'MMM': '3M',
'MCD': 'Mc Donalds',
'PEP': 'Pepsi',
'MDLZ': 'Kraft Foods',
'K': 'Kellogg',
'UN': 'Unilever',
'MAR': 'Marriott',
'PG': 'Procter Gamble',
'CL': 'Colgate-Palmolive',
'GE': 'General Electrics',
'WFC': 'Wells Fargo',
'JPM': 'JPMorgan Chase',
'AIG': 'AIG',
'AXP': 'American express',
'BAC': 'Bank of America',
'GS': 'Goldman Sachs',
'AAPL': 'Apple',
'SAP': 'SAP',
'CSCO': 'Cisco',
'TXN': 'Texas instruments',
'XRX': 'Xerox',
'LMT': 'Lookheed Martin',
'WMT': 'Wal-Mart',
'WBA': 'Walgreen',
'HD': 'Home Depot',
'GSK': 'GlaxoSmithKline',
'PFE': 'Pfizer',
'SNY': 'Sanofi-Aventis',
'NVS': 'Novartis',
'KMB': 'Kimberly-Clark',
'R': 'Ryder',
'GD': 'General Dynamics',
'RTN': 'Raytheon',
'CVS': 'CVS',
'CAT': 'Caterpillar',
'DD': 'DuPont de Nemours'}
symbols, names = np.array(list(symbol_dict.items())).T
quotes = [finance.quotes_historical_yahoo(symbol, d1, d2, asobject=True)
for symbol in symbols]
open = np.array([q.open for q in quotes]).astype(np.float)
close = np.array([q.close for q in quotes]).astype(np.float)
# The daily variations of the quotes are what carry most information
variation = close - open
###############################################################################
# Learn a graphical structure from the correlations
edge_model = covariance.GraphLassoCV()
# standardize the time series: using correlations rather than covariance
# is more efficient for structure recovery
X = variation.copy().T
X /= X.std(axis=0)
edge_model.fit(X)
###############################################################################
# Cluster using affinity propagation
_, labels = cluster.affinity_propagation(edge_model.covariance_)
n_labels = labels.max()
for i in range(n_labels + 1):
print('Cluster %i: %s' % ((i + 1), ', '.join(names[labels == i])))
###############################################################################
# Find a low-dimension embedding for visualization: find the best position of
# the nodes (the stocks) on a 2D plane
# We use a dense eigen_solver to achieve reproducibility (arpack is
# initiated with random vectors that we don't control). In addition, we
# use a large number of neighbors to capture the large-scale structure.
node_position_model = manifold.LocallyLinearEmbedding(
n_components=2, eigen_solver='dense', n_neighbors=6)
embedding = node_position_model.fit_transform(X.T).T
###############################################################################
# Visualization
plt.figure(1, facecolor='w', figsize=(10, 8))
plt.clf()
ax = plt.axes([0., 0., 1., 1.])
plt.axis('off')
# Display a graph of the partial correlations
partial_correlations = edge_model.precision_.copy()
d = 1 / np.sqrt(np.diag(partial_correlations))
partial_correlations *= d
partial_correlations *= d[:, np.newaxis]
non_zero = (np.abs(np.triu(partial_correlations, k=1)) > 0.02)
# Plot the nodes using the coordinates of our embedding
plt.scatter(embedding[0], embedding[1], s=100 * d ** 2, c=labels,
cmap=plt.cm.spectral)
# Plot the edges
start_idx, end_idx = np.where(non_zero)
#a sequence of (*line0*, *line1*, *line2*), where::
# linen = (x0, y0), (x1, y1), ... (xm, ym)
segments = [[embedding[:, start], embedding[:, stop]]
for start, stop in zip(start_idx, end_idx)]
values = np.abs(partial_correlations[non_zero])
lc = LineCollection(segments,
zorder=0, cmap=plt.cm.hot_r,
norm=plt.Normalize(0, .7 * values.max()))
lc.set_array(values)
lc.set_linewidths(15 * values)
ax.add_collection(lc)
# Add a label to each node. The challenge here is that we want to
# position the labels to avoid overlap with other labels
for index, (name, label, (x, y)) in enumerate(
zip(names, labels, embedding.T)):
dx = x - embedding[0]
dx[index] = 1
dy = y - embedding[1]
dy[index] = 1
this_dx = dx[np.argmin(np.abs(dy))]
this_dy = dy[np.argmin(np.abs(dx))]
if this_dx > 0:
horizontalalignment = 'left'
x = x + .002
else:
horizontalalignment = 'right'
x = x - .002
if this_dy > 0:
verticalalignment = 'bottom'
y = y + .002
else:
verticalalignment = 'top'
y = y - .002
plt.text(x, y, name, size=10,
horizontalalignment=horizontalalignment,
verticalalignment=verticalalignment,
bbox=dict(facecolor='w',
edgecolor=plt.cm.spectral(label / float(n_labels)),
alpha=.6))
plt.xlim(embedding[0].min() - .15 * embedding[0].ptp(),
embedding[0].max() + .10 * embedding[0].ptp(),)
plt.ylim(embedding[1].min() - .03 * embedding[1].ptp(),
embedding[1].max() + .03 * embedding[1].ptp())
plt.show()
| bsd-3-clause |
nhejazi/scikit-learn | sklearn/utils/validation.py | 3 | 27241 | """Utilities for input validation"""
# Authors: Olivier Grisel
# Gael Varoquaux
# Andreas Mueller
# Lars Buitinck
# Alexandre Gramfort
# Nicolas Tresegnie
# License: BSD 3 clause
import warnings
import numbers
import numpy as np
import scipy.sparse as sp
from ..externals import six
from ..utils.fixes import signature
from .. import get_config as _get_config
from ..exceptions import NonBLASDotWarning
from ..exceptions import NotFittedError
from ..exceptions import DataConversionWarning
FLOAT_DTYPES = (np.float64, np.float32, np.float16)
# Silenced by default to reduce verbosity. Turn on at runtime for
# performance profiling.
warnings.simplefilter('ignore', NonBLASDotWarning)
def _assert_all_finite(X):
"""Like assert_all_finite, but only for ndarray."""
if _get_config()['assume_finite']:
return
X = np.asanyarray(X)
# First try an O(n) time, O(1) space solution for the common case that
# everything is finite; fall back to O(n) space np.isfinite to prevent
# false positives from overflow in sum method.
if (X.dtype.char in np.typecodes['AllFloat'] and not np.isfinite(X.sum())
and not np.isfinite(X).all()):
raise ValueError("Input contains NaN, infinity"
" or a value too large for %r." % X.dtype)
def assert_all_finite(X):
"""Throw a ValueError if X contains NaN or infinity.
Parameters
----------
X : array or sparse matrix
"""
_assert_all_finite(X.data if sp.issparse(X) else X)
def as_float_array(X, copy=True, force_all_finite=True):
"""Converts an array-like to an array of floats.
The new dtype will be np.float32 or np.float64, depending on the original
type. The function can create a copy or modify the argument depending
on the argument copy.
Parameters
----------
X : {array-like, sparse matrix}
copy : bool, optional
If True, a copy of X will be created. If False, a copy may still be
returned if X's dtype is not a floating point type.
force_all_finite : boolean (default=True)
Whether to raise an error on np.inf and np.nan in X.
Returns
-------
XT : {array, sparse matrix}
An array of type np.float
"""
if isinstance(X, np.matrix) or (not isinstance(X, np.ndarray)
and not sp.issparse(X)):
return check_array(X, ['csr', 'csc', 'coo'], dtype=np.float64,
copy=copy, force_all_finite=force_all_finite,
ensure_2d=False)
elif sp.issparse(X) and X.dtype in [np.float32, np.float64]:
return X.copy() if copy else X
elif X.dtype in [np.float32, np.float64]: # is numpy array
return X.copy('F' if X.flags['F_CONTIGUOUS'] else 'C') if copy else X
else:
if X.dtype.kind in 'uib' and X.dtype.itemsize <= 4:
return_dtype = np.float32
else:
return_dtype = np.float64
return X.astype(return_dtype)
def _is_arraylike(x):
"""Returns whether the input is array-like"""
return (hasattr(x, '__len__') or
hasattr(x, 'shape') or
hasattr(x, '__array__'))
def _num_samples(x):
"""Return number of samples in array-like x."""
if hasattr(x, 'fit') and callable(x.fit):
# Don't get num_samples from an ensembles length!
raise TypeError('Expected sequence or array-like, got '
'estimator %s' % x)
if not hasattr(x, '__len__') and not hasattr(x, 'shape'):
if hasattr(x, '__array__'):
x = np.asarray(x)
else:
raise TypeError("Expected sequence or array-like, got %s" %
type(x))
if hasattr(x, 'shape'):
if len(x.shape) == 0:
raise TypeError("Singleton array %r cannot be considered"
" a valid collection." % x)
return x.shape[0]
else:
return len(x)
def _shape_repr(shape):
"""Return a platform independent representation of an array shape
Under Python 2, the `long` type introduces an 'L' suffix when using the
default %r format for tuples of integers (typically used to store the shape
of an array).
Under Windows 64 bit (and Python 2), the `long` type is used by default
in numpy shapes even when the integer dimensions are well below 32 bit.
The platform specific type causes string messages or doctests to change
from one platform to another which is not desirable.
Under Python 3, there is no more `long` type so the `L` suffix is never
introduced in string representation.
>>> _shape_repr((1, 2))
'(1, 2)'
>>> one = 2 ** 64 / 2 ** 64 # force an upcast to `long` under Python 2
>>> _shape_repr((one, 2 * one))
'(1, 2)'
>>> _shape_repr((1,))
'(1,)'
>>> _shape_repr(())
'()'
"""
if len(shape) == 0:
return "()"
joined = ", ".join("%d" % e for e in shape)
if len(shape) == 1:
# special notation for singleton tuples
joined += ','
return "(%s)" % joined
def check_consistent_length(*arrays):
"""Check that all arrays have consistent first dimensions.
Checks whether all objects in arrays have the same shape or length.
Parameters
----------
*arrays : list or tuple of input objects.
Objects that will be checked for consistent length.
"""
lengths = [_num_samples(X) for X in arrays if X is not None]
uniques = np.unique(lengths)
if len(uniques) > 1:
raise ValueError("Found input variables with inconsistent numbers of"
" samples: %r" % [int(l) for l in lengths])
def indexable(*iterables):
"""Make arrays indexable for cross-validation.
Checks consistent length, passes through None, and ensures that everything
can be indexed by converting sparse matrices to csr and converting
non-interable objects to arrays.
Parameters
----------
*iterables : lists, dataframes, arrays, sparse matrices
List of objects to ensure sliceability.
"""
result = []
for X in iterables:
if sp.issparse(X):
result.append(X.tocsr())
elif hasattr(X, "__getitem__") or hasattr(X, "iloc"):
result.append(X)
elif X is None:
result.append(X)
else:
result.append(np.array(X))
check_consistent_length(*result)
return result
def _ensure_sparse_format(spmatrix, accept_sparse, dtype, copy,
force_all_finite):
"""Convert a sparse matrix to a given format.
Checks the sparse format of spmatrix and converts if necessary.
Parameters
----------
spmatrix : scipy sparse matrix
Input to validate and convert.
accept_sparse : string, boolean or list/tuple of strings
String[s] representing allowed sparse matrix formats ('csc',
'csr', 'coo', 'dok', 'bsr', 'lil', 'dia'). If the input is sparse but
not in the allowed format, it will be converted to the first listed
format. True allows the input to be any format. False means
that a sparse matrix input will raise an error.
dtype : string, type or None
Data type of result. If None, the dtype of the input is preserved.
copy : boolean
Whether a forced copy will be triggered. If copy=False, a copy might
be triggered by a conversion.
force_all_finite : boolean
Whether to raise an error on np.inf and np.nan in X.
Returns
-------
spmatrix_converted : scipy sparse matrix.
Matrix that is ensured to have an allowed type.
"""
if dtype is None:
dtype = spmatrix.dtype
changed_format = False
if isinstance(accept_sparse, six.string_types):
accept_sparse = [accept_sparse]
if accept_sparse is False:
raise TypeError('A sparse matrix was passed, but dense '
'data is required. Use X.toarray() to '
'convert to a dense numpy array.')
elif isinstance(accept_sparse, (list, tuple)):
if len(accept_sparse) == 0:
raise ValueError("When providing 'accept_sparse' "
"as a tuple or list, it must contain at "
"least one string value.")
# ensure correct sparse format
if spmatrix.format not in accept_sparse:
# create new with correct sparse
spmatrix = spmatrix.asformat(accept_sparse[0])
changed_format = True
elif accept_sparse is not True:
# any other type
raise ValueError("Parameter 'accept_sparse' should be a string, "
"boolean or list of strings. You provided "
"'accept_sparse={}'.".format(accept_sparse))
if dtype != spmatrix.dtype:
# convert dtype
spmatrix = spmatrix.astype(dtype)
elif copy and not changed_format:
# force copy
spmatrix = spmatrix.copy()
if force_all_finite:
if not hasattr(spmatrix, "data"):
warnings.warn("Can't check %s sparse matrix for nan or inf."
% spmatrix.format)
else:
_assert_all_finite(spmatrix.data)
return spmatrix
def check_array(array, accept_sparse=False, dtype="numeric", order=None,
copy=False, force_all_finite=True, ensure_2d=True,
allow_nd=False, ensure_min_samples=1, ensure_min_features=1,
warn_on_dtype=False, estimator=None):
"""Input validation on an array, list, sparse matrix or similar.
By default, the input is converted to an at least 2D numpy array.
If the dtype of the array is object, attempt converting to float,
raising on failure.
Parameters
----------
array : object
Input object to check / convert.
accept_sparse : string, boolean or list/tuple of strings (default=False)
String[s] representing allowed sparse matrix formats, such as 'csc',
'csr', etc. If the input is sparse but not in the allowed format,
it will be converted to the first listed format. True allows the input
to be any format. False means that a sparse matrix input will
raise an error.
.. deprecated:: 0.19
Passing 'None' to parameter ``accept_sparse`` in methods is
deprecated in version 0.19 "and will be removed in 0.21. Use
``accept_sparse=False`` instead.
dtype : string, type, list of types or None (default="numeric")
Data type of result. If None, the dtype of the input is preserved.
If "numeric", dtype is preserved unless array.dtype is object.
If dtype is a list of types, conversion on the first type is only
performed if the dtype of the input is not in the list.
order : 'F', 'C' or None (default=None)
Whether an array will be forced to be fortran or c-style.
When order is None (default), then if copy=False, nothing is ensured
about the memory layout of the output array; otherwise (copy=True)
the memory layout of the returned array is kept as close as possible
to the original array.
copy : boolean (default=False)
Whether a forced copy will be triggered. If copy=False, a copy might
be triggered by a conversion.
force_all_finite : boolean (default=True)
Whether to raise an error on np.inf and np.nan in X.
ensure_2d : boolean (default=True)
Whether to raise a value error if X is not 2d.
allow_nd : boolean (default=False)
Whether to allow X.ndim > 2.
ensure_min_samples : int (default=1)
Make sure that the array has a minimum number of samples in its first
axis (rows for a 2D array). Setting to 0 disables this check.
ensure_min_features : int (default=1)
Make sure that the 2D array has some minimum number of features
(columns). The default value of 1 rejects empty datasets.
This check is only enforced when the input data has effectively 2
dimensions or is originally 1D and ``ensure_2d`` is True. Setting to 0
disables this check.
warn_on_dtype : boolean (default=False)
Raise DataConversionWarning if the dtype of the input data structure
does not match the requested dtype, causing a memory copy.
estimator : str or estimator instance (default=None)
If passed, include the name of the estimator in warning messages.
Returns
-------
X_converted : object
The converted and validated X.
"""
# accept_sparse 'None' deprecation check
if accept_sparse is None:
warnings.warn(
"Passing 'None' to parameter 'accept_sparse' in methods "
"check_array and check_X_y is deprecated in version 0.19 "
"and will be removed in 0.21. Use 'accept_sparse=False' "
" instead.", DeprecationWarning)
accept_sparse = False
# store whether originally we wanted numeric dtype
dtype_numeric = isinstance(dtype, six.string_types) and dtype == "numeric"
dtype_orig = getattr(array, "dtype", None)
if not hasattr(dtype_orig, 'kind'):
# not a data type (e.g. a column named dtype in a pandas DataFrame)
dtype_orig = None
if dtype_numeric:
if dtype_orig is not None and dtype_orig.kind == "O":
# if input is object, convert to float.
dtype = np.float64
else:
dtype = None
if isinstance(dtype, (list, tuple)):
if dtype_orig is not None and dtype_orig in dtype:
# no dtype conversion required
dtype = None
else:
# dtype conversion required. Let's select the first element of the
# list of accepted types.
dtype = dtype[0]
if estimator is not None:
if isinstance(estimator, six.string_types):
estimator_name = estimator
else:
estimator_name = estimator.__class__.__name__
else:
estimator_name = "Estimator"
context = " by %s" % estimator_name if estimator is not None else ""
if sp.issparse(array):
array = _ensure_sparse_format(array, accept_sparse, dtype, copy,
force_all_finite)
else:
array = np.array(array, dtype=dtype, order=order, copy=copy)
if ensure_2d:
if array.ndim == 1:
raise ValueError(
"Expected 2D array, got 1D array instead:\narray={}.\n"
"Reshape your data either using array.reshape(-1, 1) if "
"your data has a single feature or array.reshape(1, -1) "
"if it contains a single sample.".format(array))
array = np.atleast_2d(array)
# To ensure that array flags are maintained
array = np.array(array, dtype=dtype, order=order, copy=copy)
# make sure we actually converted to numeric:
if dtype_numeric and array.dtype.kind == "O":
array = array.astype(np.float64)
if not allow_nd and array.ndim >= 3:
raise ValueError("Found array with dim %d. %s expected <= 2."
% (array.ndim, estimator_name))
if force_all_finite:
_assert_all_finite(array)
shape_repr = _shape_repr(array.shape)
if ensure_min_samples > 0:
n_samples = _num_samples(array)
if n_samples < ensure_min_samples:
raise ValueError("Found array with %d sample(s) (shape=%s) while a"
" minimum of %d is required%s."
% (n_samples, shape_repr, ensure_min_samples,
context))
if ensure_min_features > 0 and array.ndim == 2:
n_features = array.shape[1]
if n_features < ensure_min_features:
raise ValueError("Found array with %d feature(s) (shape=%s) while"
" a minimum of %d is required%s."
% (n_features, shape_repr, ensure_min_features,
context))
if warn_on_dtype and dtype_orig is not None and array.dtype != dtype_orig:
msg = ("Data with input dtype %s was converted to %s%s."
% (dtype_orig, array.dtype, context))
warnings.warn(msg, DataConversionWarning)
return array
def check_X_y(X, y, accept_sparse=False, dtype="numeric", order=None,
copy=False, force_all_finite=True, ensure_2d=True,
allow_nd=False, multi_output=False, ensure_min_samples=1,
ensure_min_features=1, y_numeric=False,
warn_on_dtype=False, estimator=None):
"""Input validation for standard estimators.
Checks X and y for consistent length, enforces X 2d and y 1d.
Standard input checks are only applied to y, such as checking that y
does not have np.nan or np.inf targets. For multi-label y, set
multi_output=True to allow 2d and sparse y. If the dtype of X is
object, attempt converting to float, raising on failure.
Parameters
----------
X : nd-array, list or sparse matrix
Input data.
y : nd-array, list or sparse matrix
Labels.
accept_sparse : string, boolean or list of string (default=False)
String[s] representing allowed sparse matrix formats, such as 'csc',
'csr', etc. If the input is sparse but not in the allowed format,
it will be converted to the first listed format. True allows the input
to be any format. False means that a sparse matrix input will
raise an error.
.. deprecated:: 0.19
Passing 'None' to parameter ``accept_sparse`` in methods is
deprecated in version 0.19 "and will be removed in 0.21. Use
``accept_sparse=False`` instead.
dtype : string, type, list of types or None (default="numeric")
Data type of result. If None, the dtype of the input is preserved.
If "numeric", dtype is preserved unless array.dtype is object.
If dtype is a list of types, conversion on the first type is only
performed if the dtype of the input is not in the list.
order : 'F', 'C' or None (default=None)
Whether an array will be forced to be fortran or c-style.
copy : boolean (default=False)
Whether a forced copy will be triggered. If copy=False, a copy might
be triggered by a conversion.
force_all_finite : boolean (default=True)
Whether to raise an error on np.inf and np.nan in X. This parameter
does not influence whether y can have np.inf or np.nan values.
ensure_2d : boolean (default=True)
Whether to make X at least 2d.
allow_nd : boolean (default=False)
Whether to allow X.ndim > 2.
multi_output : boolean (default=False)
Whether to allow 2-d y (array or sparse matrix). If false, y will be
validated as a vector. y cannot have np.nan or np.inf values if
multi_output=True.
ensure_min_samples : int (default=1)
Make sure that X has a minimum number of samples in its first
axis (rows for a 2D array).
ensure_min_features : int (default=1)
Make sure that the 2D array has some minimum number of features
(columns). The default value of 1 rejects empty datasets.
This check is only enforced when X has effectively 2 dimensions or
is originally 1D and ``ensure_2d`` is True. Setting to 0 disables
this check.
y_numeric : boolean (default=False)
Whether to ensure that y has a numeric type. If dtype of y is object,
it is converted to float64. Should only be used for regression
algorithms.
warn_on_dtype : boolean (default=False)
Raise DataConversionWarning if the dtype of the input data structure
does not match the requested dtype, causing a memory copy.
estimator : str or estimator instance (default=None)
If passed, include the name of the estimator in warning messages.
Returns
-------
X_converted : object
The converted and validated X.
y_converted : object
The converted and validated y.
"""
X = check_array(X, accept_sparse, dtype, order, copy, force_all_finite,
ensure_2d, allow_nd, ensure_min_samples,
ensure_min_features, warn_on_dtype, estimator)
if multi_output:
y = check_array(y, 'csr', force_all_finite=True, ensure_2d=False,
dtype=None)
else:
y = column_or_1d(y, warn=True)
_assert_all_finite(y)
if y_numeric and y.dtype.kind == 'O':
y = y.astype(np.float64)
check_consistent_length(X, y)
return X, y
def column_or_1d(y, warn=False):
""" Ravel column or 1d numpy array, else raises an error
Parameters
----------
y : array-like
warn : boolean, default False
To control display of warnings.
Returns
-------
y : array
"""
shape = np.shape(y)
if len(shape) == 1:
return np.ravel(y)
if len(shape) == 2 and shape[1] == 1:
if warn:
warnings.warn("A column-vector y was passed when a 1d array was"
" expected. Please change the shape of y to "
"(n_samples, ), for example using ravel().",
DataConversionWarning, stacklevel=2)
return np.ravel(y)
raise ValueError("bad input shape {0}".format(shape))
def check_random_state(seed):
"""Turn seed into a np.random.RandomState instance
Parameters
----------
seed : None | int | instance of RandomState
If seed is None, return the RandomState singleton used by np.random.
If seed is an int, return a new RandomState instance seeded with seed.
If seed is already a RandomState instance, return it.
Otherwise raise ValueError.
"""
if seed is None or seed is np.random:
return np.random.mtrand._rand
if isinstance(seed, (numbers.Integral, np.integer)):
return np.random.RandomState(seed)
if isinstance(seed, np.random.RandomState):
return seed
raise ValueError('%r cannot be used to seed a numpy.random.RandomState'
' instance' % seed)
def has_fit_parameter(estimator, parameter):
"""Checks whether the estimator's fit method supports the given parameter.
Parameters
----------
estimator : object
An estimator to inspect.
parameter: str
The searched parameter.
Returns
-------
is_parameter: bool
Whether the parameter was found to be a named parameter of the
estimator's fit method.
Examples
--------
>>> from sklearn.svm import SVC
>>> has_fit_parameter(SVC(), "sample_weight")
True
"""
return parameter in signature(estimator.fit).parameters
def check_symmetric(array, tol=1E-10, raise_warning=True,
raise_exception=False):
"""Make sure that array is 2D, square and symmetric.
If the array is not symmetric, then a symmetrized version is returned.
Optionally, a warning or exception is raised if the matrix is not
symmetric.
Parameters
----------
array : nd-array or sparse matrix
Input object to check / convert. Must be two-dimensional and square,
otherwise a ValueError will be raised.
tol : float
Absolute tolerance for equivalence of arrays. Default = 1E-10.
raise_warning : boolean (default=True)
If True then raise a warning if conversion is required.
raise_exception : boolean (default=False)
If True then raise an exception if array is not symmetric.
Returns
-------
array_sym : ndarray or sparse matrix
Symmetrized version of the input array, i.e. the average of array
and array.transpose(). If sparse, then duplicate entries are first
summed and zeros are eliminated.
"""
if (array.ndim != 2) or (array.shape[0] != array.shape[1]):
raise ValueError("array must be 2-dimensional and square. "
"shape = {0}".format(array.shape))
if sp.issparse(array):
diff = array - array.T
# only csr, csc, and coo have `data` attribute
if diff.format not in ['csr', 'csc', 'coo']:
diff = diff.tocsr()
symmetric = np.all(abs(diff.data) < tol)
else:
symmetric = np.allclose(array, array.T, atol=tol)
if not symmetric:
if raise_exception:
raise ValueError("Array must be symmetric")
if raise_warning:
warnings.warn("Array is not symmetric, and will be converted "
"to symmetric by average with its transpose.")
if sp.issparse(array):
conversion = 'to' + array.format
array = getattr(0.5 * (array + array.T), conversion)()
else:
array = 0.5 * (array + array.T)
return array
def check_is_fitted(estimator, attributes, msg=None, all_or_any=all):
"""Perform is_fitted validation for estimator.
Checks if the estimator is fitted by verifying the presence of
"all_or_any" of the passed attributes and raises a NotFittedError with the
given message.
Parameters
----------
estimator : estimator instance.
estimator instance for which the check is performed.
attributes : attribute name(s) given as string or a list/tuple of strings
Eg.:
``["coef_", "estimator_", ...], "coef_"``
msg : string
The default error message is, "This %(name)s instance is not fitted
yet. Call 'fit' with appropriate arguments before using this method."
For custom messages if "%(name)s" is present in the message string,
it is substituted for the estimator name.
Eg. : "Estimator, %(name)s, must be fitted before sparsifying".
all_or_any : callable, {all, any}, default all
Specify whether all or any of the given attributes must exist.
Returns
-------
None
Raises
------
NotFittedError
If the attributes are not found.
"""
if msg is None:
msg = ("This %(name)s instance is not fitted yet. Call 'fit' with "
"appropriate arguments before using this method.")
if not hasattr(estimator, 'fit'):
raise TypeError("%s is not an estimator instance." % (estimator))
if not isinstance(attributes, (list, tuple)):
attributes = [attributes]
if not all_or_any([hasattr(estimator, attr) for attr in attributes]):
raise NotFittedError(msg % {'name': type(estimator).__name__})
def check_non_negative(X, whom):
"""
Check if there is any negative value in an array.
Parameters
----------
X : array-like or sparse matrix
Input data.
whom : string
Who passed X to this function.
"""
X = X.data if sp.issparse(X) else X
if (X < 0).any():
raise ValueError("Negative values in data passed to %s" % whom)
| bsd-3-clause |
shusenl/scikit-learn | examples/ensemble/plot_adaboost_twoclass.py | 347 | 3268 | """
==================
Two-class AdaBoost
==================
This example fits an AdaBoosted decision stump on a non-linearly separable
classification dataset composed of two "Gaussian quantiles" clusters
(see :func:`sklearn.datasets.make_gaussian_quantiles`) and plots the decision
boundary and decision scores. The distributions of decision scores are shown
separately for samples of class A and B. The predicted class label for each
sample is determined by the sign of the decision score. Samples with decision
scores greater than zero are classified as B, and are otherwise classified
as A. The magnitude of a decision score determines the degree of likeness with
the predicted class label. Additionally, a new dataset could be constructed
containing a desired purity of class B, for example, by only selecting samples
with a decision score above some value.
"""
print(__doc__)
# Author: Noel Dawe <[email protected]>
#
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from sklearn.ensemble import AdaBoostClassifier
from sklearn.tree import DecisionTreeClassifier
from sklearn.datasets import make_gaussian_quantiles
# Construct dataset
X1, y1 = make_gaussian_quantiles(cov=2.,
n_samples=200, n_features=2,
n_classes=2, random_state=1)
X2, y2 = make_gaussian_quantiles(mean=(3, 3), cov=1.5,
n_samples=300, n_features=2,
n_classes=2, random_state=1)
X = np.concatenate((X1, X2))
y = np.concatenate((y1, - y2 + 1))
# Create and fit an AdaBoosted decision tree
bdt = AdaBoostClassifier(DecisionTreeClassifier(max_depth=1),
algorithm="SAMME",
n_estimators=200)
bdt.fit(X, y)
plot_colors = "br"
plot_step = 0.02
class_names = "AB"
plt.figure(figsize=(10, 5))
# Plot the decision boundaries
plt.subplot(121)
x_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1
y_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1
xx, yy = np.meshgrid(np.arange(x_min, x_max, plot_step),
np.arange(y_min, y_max, plot_step))
Z = bdt.predict(np.c_[xx.ravel(), yy.ravel()])
Z = Z.reshape(xx.shape)
cs = plt.contourf(xx, yy, Z, cmap=plt.cm.Paired)
plt.axis("tight")
# Plot the training points
for i, n, c in zip(range(2), class_names, plot_colors):
idx = np.where(y == i)
plt.scatter(X[idx, 0], X[idx, 1],
c=c, cmap=plt.cm.Paired,
label="Class %s" % n)
plt.xlim(x_min, x_max)
plt.ylim(y_min, y_max)
plt.legend(loc='upper right')
plt.xlabel('x')
plt.ylabel('y')
plt.title('Decision Boundary')
# Plot the two-class decision scores
twoclass_output = bdt.decision_function(X)
plot_range = (twoclass_output.min(), twoclass_output.max())
plt.subplot(122)
for i, n, c in zip(range(2), class_names, plot_colors):
plt.hist(twoclass_output[y == i],
bins=10,
range=plot_range,
facecolor=c,
label='Class %s' % n,
alpha=.5)
x1, x2, y1, y2 = plt.axis()
plt.axis((x1, x2, y1, y2 * 1.2))
plt.legend(loc='upper right')
plt.ylabel('Samples')
plt.xlabel('Score')
plt.title('Decision Scores')
plt.tight_layout()
plt.subplots_adjust(wspace=0.35)
plt.show()
| bsd-3-clause |
petosegan/scikit-learn | sklearn/semi_supervised/tests/test_label_propagation.py | 307 | 1974 | """ test the label propagation module """
import nose
import numpy as np
from sklearn.semi_supervised import label_propagation
from numpy.testing import assert_array_almost_equal
from numpy.testing import assert_array_equal
ESTIMATORS = [
(label_propagation.LabelPropagation, {'kernel': 'rbf'}),
(label_propagation.LabelPropagation, {'kernel': 'knn', 'n_neighbors': 2}),
(label_propagation.LabelSpreading, {'kernel': 'rbf'}),
(label_propagation.LabelSpreading, {'kernel': 'knn', 'n_neighbors': 2})
]
def test_fit_transduction():
samples = [[1., 0.], [0., 2.], [1., 3.]]
labels = [0, 1, -1]
for estimator, parameters in ESTIMATORS:
clf = estimator(**parameters).fit(samples, labels)
nose.tools.assert_equal(clf.transduction_[2], 1)
def test_distribution():
samples = [[1., 0.], [0., 1.], [1., 1.]]
labels = [0, 1, -1]
for estimator, parameters in ESTIMATORS:
clf = estimator(**parameters).fit(samples, labels)
if parameters['kernel'] == 'knn':
continue # unstable test; changes in k-NN ordering break it
assert_array_almost_equal(clf.predict_proba([[1., 0.0]]),
np.array([[1., 0.]]), 2)
else:
assert_array_almost_equal(np.asarray(clf.label_distributions_[2]),
np.array([.5, .5]), 2)
def test_predict():
samples = [[1., 0.], [0., 2.], [1., 3.]]
labels = [0, 1, -1]
for estimator, parameters in ESTIMATORS:
clf = estimator(**parameters).fit(samples, labels)
assert_array_equal(clf.predict([[0.5, 2.5]]), np.array([1]))
def test_predict_proba():
samples = [[1., 0.], [0., 1.], [1., 2.5]]
labels = [0, 1, -1]
for estimator, parameters in ESTIMATORS:
clf = estimator(**parameters).fit(samples, labels)
assert_array_almost_equal(clf.predict_proba([[1., 1.]]),
np.array([[0.5, 0.5]]))
| bsd-3-clause |
xwolf12/scikit-learn | sklearn/covariance/__init__.py | 389 | 1157 | """
The :mod:`sklearn.covariance` module includes methods and algorithms to
robustly estimate the covariance of features given a set of points. The
precision matrix defined as the inverse of the covariance is also estimated.
Covariance estimation is closely related to the theory of Gaussian Graphical
Models.
"""
from .empirical_covariance_ import empirical_covariance, EmpiricalCovariance, \
log_likelihood
from .shrunk_covariance_ import shrunk_covariance, ShrunkCovariance, \
ledoit_wolf, ledoit_wolf_shrinkage, \
LedoitWolf, oas, OAS
from .robust_covariance import fast_mcd, MinCovDet
from .graph_lasso_ import graph_lasso, GraphLasso, GraphLassoCV
from .outlier_detection import EllipticEnvelope
__all__ = ['EllipticEnvelope',
'EmpiricalCovariance',
'GraphLasso',
'GraphLassoCV',
'LedoitWolf',
'MinCovDet',
'OAS',
'ShrunkCovariance',
'empirical_covariance',
'fast_mcd',
'graph_lasso',
'ledoit_wolf',
'ledoit_wolf_shrinkage',
'log_likelihood',
'oas',
'shrunk_covariance']
| bsd-3-clause |
xavierwu/scikit-learn | doc/tutorial/text_analytics/skeletons/exercise_01_language_train_model.py | 254 | 2005 | """Build a language detector model
The goal of this exercise is to train a linear classifier on text features
that represent sequences of up to 3 consecutive characters so as to be
recognize natural languages by using the frequencies of short character
sequences as 'fingerprints'.
"""
# Author: Olivier Grisel <[email protected]>
# License: Simplified BSD
import sys
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.linear_model import Perceptron
from sklearn.pipeline import Pipeline
from sklearn.datasets import load_files
from sklearn.cross_validation import train_test_split
from sklearn import metrics
# The training data folder must be passed as first argument
languages_data_folder = sys.argv[1]
dataset = load_files(languages_data_folder)
# Split the dataset in training and test set:
docs_train, docs_test, y_train, y_test = train_test_split(
dataset.data, dataset.target, test_size=0.5)
# TASK: Build a an vectorizer that splits strings into sequence of 1 to 3
# characters instead of word tokens
# TASK: Build a vectorizer / classifier pipeline using the previous analyzer
# the pipeline instance should stored in a variable named clf
# TASK: Fit the pipeline on the training set
# TASK: Predict the outcome on the testing set in a variable named y_predicted
# Print the classification report
print(metrics.classification_report(y_test, y_predicted,
target_names=dataset.target_names))
# Plot the confusion matrix
cm = metrics.confusion_matrix(y_test, y_predicted)
print(cm)
#import pylab as pl
#pl.matshow(cm, cmap=pl.cm.jet)
#pl.show()
# Predict the result on some short new sentences:
sentences = [
u'This is a language detection test.',
u'Ceci est un test de d\xe9tection de la langue.',
u'Dies ist ein Test, um die Sprache zu erkennen.',
]
predicted = clf.predict(sentences)
for s, p in zip(sentences, predicted):
print(u'The language of "%s" is "%s"' % (s, dataset.target_names[p]))
| bsd-3-clause |
Garrett-R/scikit-learn | sklearn/cross_decomposition/pls_.py | 5 | 28683 | """
The :mod:`sklearn.pls` module implements Partial Least Squares (PLS).
"""
# Author: Edouard Duchesnay <[email protected]>
# License: BSD 3 clause
from ..base import BaseEstimator, RegressorMixin, TransformerMixin
from ..utils import check_array, check_consistent_length
from ..externals import six
import warnings
from abc import ABCMeta, abstractmethod
import numpy as np
from scipy import linalg
from ..utils import arpack
__all__ = ['PLSCanonical', 'PLSRegression', 'PLSSVD']
def _nipals_twoblocks_inner_loop(X, Y, mode="A", max_iter=500, tol=1e-06,
norm_y_weights=False):
"""Inner loop of the iterative NIPALS algorithm.
Provides an alternative to the svd(X'Y); returns the first left and right
singular vectors of X'Y. See PLS for the meaning of the parameters. It is
similar to the Power method for determining the eigenvectors and
eigenvalues of a X'Y.
"""
y_score = Y[:, [0]]
x_weights_old = 0
ite = 1
X_pinv = Y_pinv = None
# Inner loop of the Wold algo.
while True:
# 1.1 Update u: the X weights
if mode == "B":
if X_pinv is None:
X_pinv = linalg.pinv(X) # compute once pinv(X)
x_weights = np.dot(X_pinv, y_score)
else: # mode A
# Mode A regress each X column on y_score
x_weights = np.dot(X.T, y_score) / np.dot(y_score.T, y_score)
# 1.2 Normalize u
x_weights /= np.sqrt(np.dot(x_weights.T, x_weights))
# 1.3 Update x_score: the X latent scores
x_score = np.dot(X, x_weights)
# 2.1 Update y_weights
if mode == "B":
if Y_pinv is None:
Y_pinv = linalg.pinv(Y) # compute once pinv(Y)
y_weights = np.dot(Y_pinv, x_score)
else:
# Mode A regress each Y column on x_score
y_weights = np.dot(Y.T, x_score) / np.dot(x_score.T, x_score)
## 2.2 Normalize y_weights
if norm_y_weights:
y_weights /= np.sqrt(np.dot(y_weights.T, y_weights))
# 2.3 Update y_score: the Y latent scores
y_score = np.dot(Y, y_weights) / np.dot(y_weights.T, y_weights)
## y_score = np.dot(Y, y_weights) / np.dot(y_score.T, y_score) ## BUG
x_weights_diff = x_weights - x_weights_old
if np.dot(x_weights_diff.T, x_weights_diff) < tol or Y.shape[1] == 1:
break
if ite == max_iter:
warnings.warn('Maximum number of iterations reached')
break
x_weights_old = x_weights
ite += 1
return x_weights, y_weights, ite
def _svd_cross_product(X, Y):
C = np.dot(X.T, Y)
U, s, Vh = linalg.svd(C, full_matrices=False)
u = U[:, [0]]
v = Vh.T[:, [0]]
return u, v
def _center_scale_xy(X, Y, scale=True):
""" Center X, Y and scale if the scale parameter==True
Returns
-------
X, Y, x_mean, y_mean, x_std, y_std
"""
# center
x_mean = X.mean(axis=0)
X -= x_mean
y_mean = Y.mean(axis=0)
Y -= y_mean
# scale
if scale:
x_std = X.std(axis=0, ddof=1)
x_std[x_std == 0.0] = 1.0
X /= x_std
y_std = Y.std(axis=0, ddof=1)
y_std[y_std == 0.0] = 1.0
Y /= y_std
else:
x_std = np.ones(X.shape[1])
y_std = np.ones(Y.shape[1])
return X, Y, x_mean, y_mean, x_std, y_std
class _PLS(six.with_metaclass(ABCMeta), BaseEstimator, TransformerMixin,
RegressorMixin):
"""Partial Least Squares (PLS)
This class implements the generic PLS algorithm, constructors' parameters
allow to obtain a specific implementation such as:
- PLS2 regression, i.e., PLS 2 blocks, mode A, with asymmetric deflation
and unnormalized y weights such as defined by [Tenenhaus 1998] p. 132.
With univariate response it implements PLS1.
- PLS canonical, i.e., PLS 2 blocks, mode A, with symmetric deflation and
normalized y weights such as defined by [Tenenhaus 1998] (p. 132) and
[Wegelin et al. 2000]. This parametrization implements the original Wold
algorithm.
We use the terminology defined by [Wegelin et al. 2000].
This implementation uses the PLS Wold 2 blocks algorithm based on two
nested loops:
(i) The outer loop iterate over components.
(ii) The inner loop estimates the weights vectors. This can be done
with two algo. (a) the inner loop of the original NIPALS algo. or (b) a
SVD on residuals cross-covariance matrices.
n_components : int, number of components to keep. (default 2).
scale : boolean, scale data? (default True)
deflation_mode : str, "canonical" or "regression". See notes.
mode : "A" classical PLS and "B" CCA. See notes.
norm_y_weights: boolean, normalize Y weights to one? (default False)
algorithm : string, "nipals" or "svd"
The algorithm used to estimate the weights. It will be called
n_components times, i.e. once for each iteration of the outer loop.
max_iter : an integer, the maximum number of iterations (default 500)
of the NIPALS inner loop (used only if algorithm="nipals")
tol : non-negative real, default 1e-06
The tolerance used in the iterative algorithm.
copy : boolean
Whether the deflation should be done on a copy. Let the default
value to True unless you don't care about side effects.
Attributes
----------
x_weights_ : array, [p, n_components]
X block weights vectors.
y_weights_ : array, [q, n_components]
Y block weights vectors.
x_loadings_ : array, [p, n_components]
X block loadings vectors.
y_loadings_ : array, [q, n_components]
Y block loadings vectors.
x_scores_ : array, [n_samples, n_components]
X scores.
y_scores_ : array, [n_samples, n_components]
Y scores.
x_rotations_ : array, [p, n_components]
X block to latents rotations.
y_rotations_ : array, [q, n_components]
Y block to latents rotations.
coefs: array, [p, q]
The coefficients of the linear model: Y = X coefs + Err
n_iter_ : array-like
Number of iterations of the NIPALS inner loop for each
component. Not useful if the algorithm given is "svd".
References
----------
Jacob A. Wegelin. A survey of Partial Least Squares (PLS) methods, with
emphasis on the two-block case. Technical Report 371, Department of
Statistics, University of Washington, Seattle, 2000.
In French but still a reference:
Tenenhaus, M. (1998). La regression PLS: theorie et pratique. Paris:
Editions Technic.
See also
--------
PLSCanonical
PLSRegression
CCA
PLS_SVD
"""
@abstractmethod
def __init__(self, n_components=2, scale=True, deflation_mode="regression",
mode="A", algorithm="nipals", norm_y_weights=False,
max_iter=500, tol=1e-06, copy=True):
self.n_components = n_components
self.deflation_mode = deflation_mode
self.mode = mode
self.norm_y_weights = norm_y_weights
self.scale = scale
self.algorithm = algorithm
self.max_iter = max_iter
self.tol = tol
self.copy = copy
def fit(self, X, Y):
"""Fit model to data.
Parameters
----------
X : array-like, shape = [n_samples, n_features]
Training vectors, where n_samples in the number of samples and
n_features is the number of predictors.
Y : array-like of response, shape = [n_samples, n_targets]
Target vectors, where n_samples in the number of samples and
n_targets is the number of response variables.
"""
# copy since this will contains the residuals (deflated) matrices
check_consistent_length(X, Y)
X = check_array(X, dtype=np.float, copy=self.copy)
Y = check_array(Y, dtype=np.float, copy=self.copy)
n = X.shape[0]
p = X.shape[1]
q = Y.shape[1]
if n != Y.shape[0]:
raise ValueError(
'Incompatible shapes: X has %s samples, while Y '
'has %s' % (X.shape[0], Y.shape[0]))
if self.n_components < 1 or self.n_components > p:
raise ValueError('invalid number of components')
if self.algorithm not in ("svd", "nipals"):
raise ValueError("Got algorithm %s when only 'svd' "
"and 'nipals' are known" % self.algorithm)
if self.algorithm == "svd" and self.mode == "B":
raise ValueError('Incompatible configuration: mode B is not '
'implemented with svd algorithm')
if not self.deflation_mode in ["canonical", "regression"]:
raise ValueError('The deflation mode is unknown')
# Scale (in place)
X, Y, self.x_mean_, self.y_mean_, self.x_std_, self.y_std_\
= _center_scale_xy(X, Y, self.scale)
# Residuals (deflated) matrices
Xk = X
Yk = Y
# Results matrices
self.x_scores_ = np.zeros((n, self.n_components))
self.y_scores_ = np.zeros((n, self.n_components))
self.x_weights_ = np.zeros((p, self.n_components))
self.y_weights_ = np.zeros((q, self.n_components))
self.x_loadings_ = np.zeros((p, self.n_components))
self.y_loadings_ = np.zeros((q, self.n_components))
self.n_iter_ = []
# NIPALS algo: outer loop, over components
for k in range(self.n_components):
#1) weights estimation (inner loop)
# -----------------------------------
if self.algorithm == "nipals":
x_weights, y_weights, n_iter_ = \
_nipals_twoblocks_inner_loop(
X=Xk, Y=Yk, mode=self.mode, max_iter=self.max_iter,
tol=self.tol, norm_y_weights=self.norm_y_weights)
self.n_iter_.append(n_iter_)
elif self.algorithm == "svd":
x_weights, y_weights = _svd_cross_product(X=Xk, Y=Yk)
# compute scores
x_scores = np.dot(Xk, x_weights)
if self.norm_y_weights:
y_ss = 1
else:
y_ss = np.dot(y_weights.T, y_weights)
y_scores = np.dot(Yk, y_weights) / y_ss
# test for null variance
if np.dot(x_scores.T, x_scores) < np.finfo(np.double).eps:
warnings.warn('X scores are null at iteration %s' % k)
#2) Deflation (in place)
# ----------------------
# Possible memory footprint reduction may done here: in order to
# avoid the allocation of a data chunk for the rank-one
# approximations matrix which is then subtracted to Xk, we suggest
# to perform a column-wise deflation.
#
# - regress Xk's on x_score
x_loadings = np.dot(Xk.T, x_scores) / np.dot(x_scores.T, x_scores)
# - subtract rank-one approximations to obtain remainder matrix
Xk -= np.dot(x_scores, x_loadings.T)
if self.deflation_mode == "canonical":
# - regress Yk's on y_score, then subtract rank-one approx.
y_loadings = (np.dot(Yk.T, y_scores)
/ np.dot(y_scores.T, y_scores))
Yk -= np.dot(y_scores, y_loadings.T)
if self.deflation_mode == "regression":
# - regress Yk's on x_score, then subtract rank-one approx.
y_loadings = (np.dot(Yk.T, x_scores)
/ np.dot(x_scores.T, x_scores))
Yk -= np.dot(x_scores, y_loadings.T)
# 3) Store weights, scores and loadings # Notation:
self.x_scores_[:, k] = x_scores.ravel() # T
self.y_scores_[:, k] = y_scores.ravel() # U
self.x_weights_[:, k] = x_weights.ravel() # W
self.y_weights_[:, k] = y_weights.ravel() # C
self.x_loadings_[:, k] = x_loadings.ravel() # P
self.y_loadings_[:, k] = y_loadings.ravel() # Q
# Such that: X = TP' + Err and Y = UQ' + Err
# 4) rotations from input space to transformed space (scores)
# T = X W(P'W)^-1 = XW* (W* : p x k matrix)
# U = Y C(Q'C)^-1 = YC* (W* : q x k matrix)
self.x_rotations_ = np.dot(
self.x_weights_,
linalg.inv(np.dot(self.x_loadings_.T, self.x_weights_)))
if Y.shape[1] > 1:
self.y_rotations_ = np.dot(
self.y_weights_,
linalg.inv(np.dot(self.y_loadings_.T, self.y_weights_)))
else:
self.y_rotations_ = np.ones(1)
if True or self.deflation_mode == "regression":
# Estimate regression coefficient
# Regress Y on T
# Y = TQ' + Err,
# Then express in function of X
# Y = X W(P'W)^-1Q' + Err = XB + Err
# => B = W*Q' (p x q)
self.coefs = np.dot(self.x_rotations_, self.y_loadings_.T)
self.coefs = (1. / self.x_std_.reshape((p, 1)) * self.coefs *
self.y_std_)
return self
def transform(self, X, Y=None, copy=True):
"""Apply the dimension reduction learned on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q], optional
Training vectors, where n_samples in the number of samples and
q is the number of response variables.
copy : boolean
Whether to copy X and Y, or perform in-place normalization.
Returns
-------
x_scores if Y is not given, (x_scores, y_scores) otherwise.
"""
# Normalize
if copy:
Xc = (np.asarray(X) - self.x_mean_) / self.x_std_
if Y is not None:
Yc = (np.asarray(Y) - self.y_mean_) / self.y_std_
else:
X = np.asarray(X)
Xc -= self.x_mean_
Xc /= self.x_std_
if Y is not None:
Y = np.asarray(Y)
Yc -= self.y_mean_
Yc /= self.y_std_
# Apply rotation
x_scores = np.dot(Xc, self.x_rotations_)
if Y is not None:
y_scores = np.dot(Yc, self.y_rotations_)
return x_scores, y_scores
return x_scores
def predict(self, X, copy=True):
"""Apply the dimension reduction learned on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
copy : boolean
Whether to copy X and Y, or perform in-place normalization.
Notes
-----
This call requires the estimation of a p x q matrix, which may
be an issue in high dimensional space.
"""
# Normalize
if copy:
Xc = (np.asarray(X) - self.x_mean_)
else:
X = np.asarray(X)
Xc -= self.x_mean_
Xc /= self.x_std_
Ypred = np.dot(Xc, self.coefs)
return Ypred + self.y_mean_
def fit_transform(self, X, y=None, **fit_params):
"""Learn and apply the dimension reduction on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q], optional
Training vectors, where n_samples in the number of samples and
q is the number of response variables.
copy : boolean
Whether to copy X and Y, or perform in-place normalization.
Returns
-------
x_scores if Y is not given, (x_scores, y_scores) otherwise.
"""
return self.fit(X, y, **fit_params).transform(X, y)
class PLSRegression(_PLS):
"""PLS regression
PLSRegression implements the PLS 2 blocks regression known as PLS2 or PLS1
in case of one dimensional response.
This class inherits from _PLS with mode="A", deflation_mode="regression",
norm_y_weights=False and algorithm="nipals".
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q]
Training vectors, where n_samples in the number of samples and
q is the number of response variables.
n_components : int, (default 2)
Number of components to keep.
scale : boolean, (default True)
whether to scale the data
max_iter : an integer, (default 500)
the maximum number of iterations of the NIPALS inner loop (used
only if algorithm="nipals")
tol : non-negative real
Tolerance used in the iterative algorithm default 1e-06.
copy : boolean, default True
Whether the deflation should be done on a copy. Let the default
value to True unless you don't care about side effect
Attributes
----------
x_weights_ : array, [p, n_components]
X block weights vectors.
y_weights_ : array, [q, n_components]
Y block weights vectors.
x_loadings_ : array, [p, n_components]
X block loadings vectors.
y_loadings_ : array, [q, n_components]
Y block loadings vectors.
x_scores_ : array, [n_samples, n_components]
X scores.
y_scores_ : array, [n_samples, n_components]
Y scores.
x_rotations_ : array, [p, n_components]
X block to latents rotations.
y_rotations_ : array, [q, n_components]
Y block to latents rotations.
coefs: array, [p, q]
The coefficients of the linear model: Y = X coefs + Err
n_iter_ : array-like
Number of iterations of the NIPALS inner loop for each
component.
Notes
-----
For each component k, find weights u, v that optimizes:
``max corr(Xk u, Yk v) * var(Xk u) var(Yk u)``, such that ``|u| = 1``
Note that it maximizes both the correlations between the scores and the
intra-block variances.
The residual matrix of X (Xk+1) block is obtained by the deflation on
the current X score: x_score.
The residual matrix of Y (Yk+1) block is obtained by deflation on the
current X score. This performs the PLS regression known as PLS2. This
mode is prediction oriented.
This implementation provides the same results that 3 PLS packages
provided in the R language (R-project):
- "mixOmics" with function pls(X, Y, mode = "regression")
- "plspm " with function plsreg2(X, Y)
- "pls" with function oscorespls.fit(X, Y)
Examples
--------
>>> from sklearn.cross_decomposition import PLSRegression
>>> X = [[0., 0., 1.], [1.,0.,0.], [2.,2.,2.], [2.,5.,4.]]
>>> Y = [[0.1, -0.2], [0.9, 1.1], [6.2, 5.9], [11.9, 12.3]]
>>> pls2 = PLSRegression(n_components=2)
>>> pls2.fit(X, Y)
... # doctest: +NORMALIZE_WHITESPACE
PLSRegression(copy=True, max_iter=500, n_components=2, scale=True,
tol=1e-06)
>>> Y_pred = pls2.predict(X)
References
----------
Jacob A. Wegelin. A survey of Partial Least Squares (PLS) methods, with
emphasis on the two-block case. Technical Report 371, Department of
Statistics, University of Washington, Seattle, 2000.
In french but still a reference:
Tenenhaus, M. (1998). La regression PLS: theorie et pratique. Paris:
Editions Technic.
"""
def __init__(self, n_components=2, scale=True,
max_iter=500, tol=1e-06, copy=True):
_PLS.__init__(self, n_components=n_components, scale=scale,
deflation_mode="regression", mode="A",
norm_y_weights=False, max_iter=max_iter, tol=tol,
copy=copy)
class PLSCanonical(_PLS):
""" PLSCanonical implements the 2 blocks canonical PLS of the original Wold
algorithm [Tenenhaus 1998] p.204, referred as PLS-C2A in [Wegelin 2000].
This class inherits from PLS with mode="A" and deflation_mode="canonical",
norm_y_weights=True and algorithm="nipals", but svd should provide similar
results up to numerical errors.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples is the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q]
Training vectors, where n_samples is the number of samples and
q is the number of response variables.
n_components : int, number of components to keep. (default 2).
scale : boolean, scale data? (default True)
algorithm : string, "nipals" or "svd"
The algorithm used to estimate the weights. It will be called
n_components times, i.e. once for each iteration of the outer loop.
max_iter : an integer, (default 500)
the maximum number of iterations of the NIPALS inner loop (used
only if algorithm="nipals")
tol : non-negative real, default 1e-06
the tolerance used in the iterative algorithm
copy : boolean, default True
Whether the deflation should be done on a copy. Let the default
value to True unless you don't care about side effect
Attributes
----------
x_weights_ : array, shape = [p, n_components]
X block weights vectors.
y_weights_ : array, shape = [q, n_components]
Y block weights vectors.
x_loadings_ : array, shape = [p, n_components]
X block loadings vectors.
y_loadings_ : array, shape = [q, n_components]
Y block loadings vectors.
x_scores_ : array, shape = [n_samples, n_components]
X scores.
y_scores_ : array, shape = [n_samples, n_components]
Y scores.
x_rotations_ : array, shape = [p, n_components]
X block to latents rotations.
y_rotations_ : array, shape = [q, n_components]
Y block to latents rotations.
n_iter_ : array-like
Number of iterations of the NIPALS inner loop for each
component. Not useful if the algorithm provided is "svd".
Notes
-----
For each component k, find weights u, v that optimize::
max corr(Xk u, Yk v) * var(Xk u) var(Yk u), such that ``|u| = |v| = 1``
Note that it maximizes both the correlations between the scores and the
intra-block variances.
The residual matrix of X (Xk+1) block is obtained by the deflation on the
current X score: x_score.
The residual matrix of Y (Yk+1) block is obtained by deflation on the
current Y score. This performs a canonical symmetric version of the PLS
regression. But slightly different than the CCA. This is mostly used
for modeling.
This implementation provides the same results that the "plspm" package
provided in the R language (R-project), using the function plsca(X, Y).
Results are equal or collinear with the function
``pls(..., mode = "canonical")`` of the "mixOmics" package. The difference
relies in the fact that mixOmics implementation does not exactly implement
the Wold algorithm since it does not normalize y_weights to one.
Examples
--------
>>> from sklearn.cross_decomposition import PLSCanonical
>>> X = [[0., 0., 1.], [1.,0.,0.], [2.,2.,2.], [2.,5.,4.]]
>>> Y = [[0.1, -0.2], [0.9, 1.1], [6.2, 5.9], [11.9, 12.3]]
>>> plsca = PLSCanonical(n_components=2)
>>> plsca.fit(X, Y)
... # doctest: +NORMALIZE_WHITESPACE
PLSCanonical(algorithm='nipals', copy=True, max_iter=500, n_components=2,
scale=True, tol=1e-06)
>>> X_c, Y_c = plsca.transform(X, Y)
References
----------
Jacob A. Wegelin. A survey of Partial Least Squares (PLS) methods, with
emphasis on the two-block case. Technical Report 371, Department of
Statistics, University of Washington, Seattle, 2000.
Tenenhaus, M. (1998). La regression PLS: theorie et pratique. Paris:
Editions Technic.
See also
--------
CCA
PLSSVD
"""
def __init__(self, n_components=2, scale=True, algorithm="nipals",
max_iter=500, tol=1e-06, copy=True):
_PLS.__init__(self, n_components=n_components, scale=scale,
deflation_mode="canonical", mode="A",
norm_y_weights=True, algorithm=algorithm,
max_iter=max_iter, tol=tol, copy=copy)
class PLSSVD(BaseEstimator, TransformerMixin):
"""Partial Least Square SVD
Simply perform a svd on the crosscovariance matrix: X'Y
There are no iterative deflation here.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vector, where n_samples is the number of samples and
p is the number of predictors. X will be centered before any analysis.
Y : array-like of response, shape = [n_samples, q]
Training vector, where n_samples is the number of samples and
q is the number of response variables. X will be centered before any
analysis.
n_components : int, (default 2).
number of components to keep.
scale : boolean, (default True)
whether to scale X and Y.
Attributes
----------
x_weights_ : array, [p, n_components]
X block weights vectors.
y_weights_ : array, [q, n_components]
Y block weights vectors.
x_scores_ : array, [n_samples, n_components]
X scores.
y_scores_ : array, [n_samples, n_components]
Y scores.
See also
--------
PLSCanonical
CCA
"""
def __init__(self, n_components=2, scale=True, copy=True):
self.n_components = n_components
self.scale = scale
self.copy = copy
def fit(self, X, Y):
# copy since this will contains the centered data
check_consistent_length(X, Y)
X = check_array(X, dtype=np.float, copy=self.copy)
Y = check_array(Y, dtype=np.float, copy=self.copy)
p = X.shape[1]
if self.n_components < 1 or self.n_components > p:
raise ValueError('invalid number of components')
# Scale (in place)
X, Y, self.x_mean_, self.y_mean_, self.x_std_, self.y_std_ =\
_center_scale_xy(X, Y, self.scale)
# svd(X'Y)
C = np.dot(X.T, Y)
# The arpack svds solver only works if the number of extracted
# components is smaller than rank(X) - 1. Hence, if we want to extract
# all the components (C.shape[1]), we have to use another one. Else,
# let's use arpacks to compute only the interesting components.
if self.n_components == C.shape[1]:
U, s, V = linalg.svd(C, full_matrices=False)
else:
U, s, V = arpack.svds(C, k=self.n_components)
V = V.T
self.x_scores_ = np.dot(X, U)
self.y_scores_ = np.dot(Y, V)
self.x_weights_ = U
self.y_weights_ = V
return self
def transform(self, X, Y=None):
"""Apply the dimension reduction learned on the train data."""
Xr = (X - self.x_mean_) / self.x_std_
x_scores = np.dot(Xr, self.x_weights_)
if Y is not None:
Yr = (Y - self.y_mean_) / self.y_std_
y_scores = np.dot(Yr, self.y_weights_)
return x_scores, y_scores
return x_scores
def fit_transform(self, X, y=None, **fit_params):
"""Learn and apply the dimension reduction on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q], optional
Training vectors, where n_samples in the number of samples and
q is the number of response variables.
Returns
-------
x_scores if Y is not given, (x_scores, y_scores) otherwise.
"""
return self.fit(X, y, **fit_params).transform(X, y)
| bsd-3-clause |
madjelan/scikit-learn | sklearn/preprocessing/data.py | 113 | 56747 | # Authors: Alexandre Gramfort <[email protected]>
# Mathieu Blondel <[email protected]>
# Olivier Grisel <[email protected]>
# Andreas Mueller <[email protected]>
# Eric Martin <[email protected]>
# License: BSD 3 clause
from itertools import chain, combinations
import numbers
import warnings
import numpy as np
from scipy import sparse
from ..base import BaseEstimator, TransformerMixin
from ..externals import six
from ..utils import check_array
from ..utils.extmath import row_norms
from ..utils.fixes import combinations_with_replacement as combinations_w_r
from ..utils.sparsefuncs_fast import (inplace_csr_row_normalize_l1,
inplace_csr_row_normalize_l2)
from ..utils.sparsefuncs import (inplace_column_scale, mean_variance_axis,
min_max_axis, inplace_row_scale)
from ..utils.validation import check_is_fitted, FLOAT_DTYPES
zip = six.moves.zip
map = six.moves.map
range = six.moves.range
__all__ = [
'Binarizer',
'KernelCenterer',
'MinMaxScaler',
'MaxAbsScaler',
'Normalizer',
'OneHotEncoder',
'RobustScaler',
'StandardScaler',
'add_dummy_feature',
'binarize',
'normalize',
'scale',
'robust_scale',
'maxabs_scale',
'minmax_scale',
]
def _mean_and_std(X, axis=0, with_mean=True, with_std=True):
"""Compute mean and std deviation for centering, scaling.
Zero valued std components are reset to 1.0 to avoid NaNs when scaling.
"""
X = np.asarray(X)
Xr = np.rollaxis(X, axis)
if with_mean:
mean_ = Xr.mean(axis=0)
else:
mean_ = None
if with_std:
std_ = Xr.std(axis=0)
std_ = _handle_zeros_in_scale(std_)
else:
std_ = None
return mean_, std_
def _handle_zeros_in_scale(scale):
''' Makes sure that whenever scale is zero, we handle it correctly.
This happens in most scalers when we have constant features.'''
# if we are fitting on 1D arrays, scale might be a scalar
if np.isscalar(scale):
if scale == 0:
scale = 1.
elif isinstance(scale, np.ndarray):
scale[scale == 0.0] = 1.0
scale[~np.isfinite(scale)] = 1.0
return scale
def scale(X, axis=0, with_mean=True, with_std=True, copy=True):
"""Standardize a dataset along any axis
Center to the mean and component wise scale to unit variance.
Read more in the :ref:`User Guide <preprocessing_scaler>`.
Parameters
----------
X : array-like or CSR matrix.
The data to center and scale.
axis : int (0 by default)
axis used to compute the means and standard deviations along. If 0,
independently standardize each feature, otherwise (if 1) standardize
each sample.
with_mean : boolean, True by default
If True, center the data before scaling.
with_std : boolean, True by default
If True, scale the data to unit variance (or equivalently,
unit standard deviation).
copy : boolean, optional, default True
set to False to perform inplace row normalization and avoid a
copy (if the input is already a numpy array or a scipy.sparse
CSR matrix and if axis is 1).
Notes
-----
This implementation will refuse to center scipy.sparse matrices
since it would make them non-sparse and would potentially crash the
program with memory exhaustion problems.
Instead the caller is expected to either set explicitly
`with_mean=False` (in that case, only variance scaling will be
performed on the features of the CSR matrix) or to call `X.toarray()`
if he/she expects the materialized dense array to fit in memory.
To avoid memory copy the caller should pass a CSR matrix.
See also
--------
:class:`sklearn.preprocessing.StandardScaler` to perform centering and
scaling using the ``Transformer`` API (e.g. as part of a preprocessing
:class:`sklearn.pipeline.Pipeline`)
"""
X = check_array(X, accept_sparse='csr', copy=copy, ensure_2d=False,
warn_on_dtype=True, estimator='the scale function',
dtype=FLOAT_DTYPES)
if sparse.issparse(X):
if with_mean:
raise ValueError(
"Cannot center sparse matrices: pass `with_mean=False` instead"
" See docstring for motivation and alternatives.")
if axis != 0:
raise ValueError("Can only scale sparse matrix on axis=0, "
" got axis=%d" % axis)
if not sparse.isspmatrix_csr(X):
X = X.tocsr()
copy = False
if copy:
X = X.copy()
_, var = mean_variance_axis(X, axis=0)
var = _handle_zeros_in_scale(var)
inplace_column_scale(X, 1 / np.sqrt(var))
else:
X = np.asarray(X)
mean_, std_ = _mean_and_std(
X, axis, with_mean=with_mean, with_std=with_std)
if copy:
X = X.copy()
# Xr is a view on the original array that enables easy use of
# broadcasting on the axis in which we are interested in
Xr = np.rollaxis(X, axis)
if with_mean:
Xr -= mean_
mean_1 = Xr.mean(axis=0)
# Verify that mean_1 is 'close to zero'. If X contains very
# large values, mean_1 can also be very large, due to a lack of
# precision of mean_. In this case, a pre-scaling of the
# concerned feature is efficient, for instance by its mean or
# maximum.
if not np.allclose(mean_1, 0):
warnings.warn("Numerical issues were encountered "
"when centering the data "
"and might not be solved. Dataset may "
"contain too large values. You may need "
"to prescale your features.")
Xr -= mean_1
if with_std:
Xr /= std_
if with_mean:
mean_2 = Xr.mean(axis=0)
# If mean_2 is not 'close to zero', it comes from the fact that
# std_ is very small so that mean_2 = mean_1/std_ > 0, even if
# mean_1 was close to zero. The problem is thus essentially due
# to the lack of precision of mean_. A solution is then to
# substract the mean again:
if not np.allclose(mean_2, 0):
warnings.warn("Numerical issues were encountered "
"when scaling the data "
"and might not be solved. The standard "
"deviation of the data is probably "
"very close to 0. ")
Xr -= mean_2
return X
class MinMaxScaler(BaseEstimator, TransformerMixin):
"""Transforms features by scaling each feature to a given range.
This estimator scales and translates each feature individually such
that it is in the given range on the training set, i.e. between
zero and one.
The transformation is given by::
X_std = (X - X.min(axis=0)) / (X.max(axis=0) - X.min(axis=0))
X_scaled = X_std * (max - min) + min
where min, max = feature_range.
This transformation is often used as an alternative to zero mean,
unit variance scaling.
Read more in the :ref:`User Guide <preprocessing_scaler>`.
Parameters
----------
feature_range: tuple (min, max), default=(0, 1)
Desired range of transformed data.
copy : boolean, optional, default True
Set to False to perform inplace row normalization and avoid a
copy (if the input is already a numpy array).
Attributes
----------
min_ : ndarray, shape (n_features,)
Per feature adjustment for minimum.
scale_ : ndarray, shape (n_features,)
Per feature relative scaling of the data.
"""
def __init__(self, feature_range=(0, 1), copy=True):
self.feature_range = feature_range
self.copy = copy
def fit(self, X, y=None):
"""Compute the minimum and maximum to be used for later scaling.
Parameters
----------
X : array-like, shape [n_samples, n_features]
The data used to compute the per-feature minimum and maximum
used for later scaling along the features axis.
"""
X = check_array(X, copy=self.copy, ensure_2d=False, warn_on_dtype=True,
estimator=self, dtype=FLOAT_DTYPES)
feature_range = self.feature_range
if feature_range[0] >= feature_range[1]:
raise ValueError("Minimum of desired feature range must be smaller"
" than maximum. Got %s." % str(feature_range))
data_min = np.min(X, axis=0)
data_range = np.max(X, axis=0) - data_min
data_range = _handle_zeros_in_scale(data_range)
self.scale_ = (feature_range[1] - feature_range[0]) / data_range
self.min_ = feature_range[0] - data_min * self.scale_
self.data_range = data_range
self.data_min = data_min
return self
def transform(self, X):
"""Scaling features of X according to feature_range.
Parameters
----------
X : array-like with shape [n_samples, n_features]
Input data that will be transformed.
"""
check_is_fitted(self, 'scale_')
X = check_array(X, copy=self.copy, ensure_2d=False)
X *= self.scale_
X += self.min_
return X
def inverse_transform(self, X):
"""Undo the scaling of X according to feature_range.
Parameters
----------
X : array-like with shape [n_samples, n_features]
Input data that will be transformed.
"""
check_is_fitted(self, 'scale_')
X = check_array(X, copy=self.copy, ensure_2d=False)
X -= self.min_
X /= self.scale_
return X
def minmax_scale(X, feature_range=(0, 1), axis=0, copy=True):
"""Transforms features by scaling each feature to a given range.
This estimator scales and translates each feature individually such
that it is in the given range on the training set, i.e. between
zero and one.
The transformation is given by::
X_std = (X - X.min(axis=0)) / (X.max(axis=0) - X.min(axis=0))
X_scaled = X_std * (max - min) + min
where min, max = feature_range.
This transformation is often used as an alternative to zero mean,
unit variance scaling.
Read more in the :ref:`User Guide <preprocessing_scaler>`.
Parameters
----------
feature_range: tuple (min, max), default=(0, 1)
Desired range of transformed data.
axis : int (0 by default)
axis used to scale along. If 0, independently scale each feature,
otherwise (if 1) scale each sample.
copy : boolean, optional, default is True
Set to False to perform inplace scaling and avoid a copy (if the input
is already a numpy array).
"""
s = MinMaxScaler(feature_range=feature_range, copy=copy)
if axis == 0:
return s.fit_transform(X)
else:
return s.fit_transform(X.T).T
class StandardScaler(BaseEstimator, TransformerMixin):
"""Standardize features by removing the mean and scaling to unit variance
Centering and scaling happen independently on each feature by computing
the relevant statistics on the samples in the training set. Mean and
standard deviation are then stored to be used on later data using the
`transform` method.
Standardization of a dataset is a common requirement for many
machine learning estimators: they might behave badly if the
individual feature do not more or less look like standard normally
distributed data (e.g. Gaussian with 0 mean and unit variance).
For instance many elements used in the objective function of
a learning algorithm (such as the RBF kernel of Support Vector
Machines or the L1 and L2 regularizers of linear models) assume that
all features are centered around 0 and have variance in the same
order. If a feature has a variance that is orders of magnitude larger
that others, it might dominate the objective function and make the
estimator unable to learn from other features correctly as expected.
Read more in the :ref:`User Guide <preprocessing_scaler>`.
Parameters
----------
with_mean : boolean, True by default
If True, center the data before scaling.
This does not work (and will raise an exception) when attempted on
sparse matrices, because centering them entails building a dense
matrix which in common use cases is likely to be too large to fit in
memory.
with_std : boolean, True by default
If True, scale the data to unit variance (or equivalently,
unit standard deviation).
copy : boolean, optional, default True
If False, try to avoid a copy and do inplace scaling instead.
This is not guaranteed to always work inplace; e.g. if the data is
not a NumPy array or scipy.sparse CSR matrix, a copy may still be
returned.
Attributes
----------
mean_ : array of floats with shape [n_features]
The mean value for each feature in the training set.
std_ : array of floats with shape [n_features]
The standard deviation for each feature in the training set.
Set to one if the standard deviation is zero for a given feature.
See also
--------
:func:`sklearn.preprocessing.scale` to perform centering and
scaling without using the ``Transformer`` object oriented API
:class:`sklearn.decomposition.RandomizedPCA` with `whiten=True`
to further remove the linear correlation across features.
"""
def __init__(self, copy=True, with_mean=True, with_std=True):
self.with_mean = with_mean
self.with_std = with_std
self.copy = copy
def fit(self, X, y=None):
"""Compute the mean and std to be used for later scaling.
Parameters
----------
X : array-like or CSR matrix with shape [n_samples, n_features]
The data used to compute the mean and standard deviation
used for later scaling along the features axis.
"""
X = check_array(X, accept_sparse='csr', copy=self.copy,
ensure_2d=False, warn_on_dtype=True,
estimator=self, dtype=FLOAT_DTYPES)
if sparse.issparse(X):
if self.with_mean:
raise ValueError(
"Cannot center sparse matrices: pass `with_mean=False` "
"instead. See docstring for motivation and alternatives.")
self.mean_ = None
if self.with_std:
var = mean_variance_axis(X, axis=0)[1]
self.std_ = np.sqrt(var)
self.std_ = _handle_zeros_in_scale(self.std_)
else:
self.std_ = None
return self
else:
self.mean_, self.std_ = _mean_and_std(
X, axis=0, with_mean=self.with_mean, with_std=self.with_std)
return self
def transform(self, X, y=None, copy=None):
"""Perform standardization by centering and scaling
Parameters
----------
X : array-like with shape [n_samples, n_features]
The data used to scale along the features axis.
"""
check_is_fitted(self, 'std_')
copy = copy if copy is not None else self.copy
X = check_array(X, accept_sparse='csr', copy=copy,
ensure_2d=False, warn_on_dtype=True,
estimator=self, dtype=FLOAT_DTYPES)
if sparse.issparse(X):
if self.with_mean:
raise ValueError(
"Cannot center sparse matrices: pass `with_mean=False` "
"instead. See docstring for motivation and alternatives.")
if self.std_ is not None:
inplace_column_scale(X, 1 / self.std_)
else:
if self.with_mean:
X -= self.mean_
if self.with_std:
X /= self.std_
return X
def inverse_transform(self, X, copy=None):
"""Scale back the data to the original representation
Parameters
----------
X : array-like with shape [n_samples, n_features]
The data used to scale along the features axis.
"""
check_is_fitted(self, 'std_')
copy = copy if copy is not None else self.copy
if sparse.issparse(X):
if self.with_mean:
raise ValueError(
"Cannot uncenter sparse matrices: pass `with_mean=False` "
"instead See docstring for motivation and alternatives.")
if not sparse.isspmatrix_csr(X):
X = X.tocsr()
copy = False
if copy:
X = X.copy()
if self.std_ is not None:
inplace_column_scale(X, self.std_)
else:
X = np.asarray(X)
if copy:
X = X.copy()
if self.with_std:
X *= self.std_
if self.with_mean:
X += self.mean_
return X
class MaxAbsScaler(BaseEstimator, TransformerMixin):
"""Scale each feature by its maximum absolute value.
This estimator scales and translates each feature individually such
that the maximal absolute value of each feature in the
training set will be 1.0. It does not shift/center the data, and
thus does not destroy any sparsity.
This scaler can also be applied to sparse CSR or CSC matrices.
Parameters
----------
copy : boolean, optional, default is True
Set to False to perform inplace scaling and avoid a copy (if the input
is already a numpy array).
Attributes
----------
scale_ : ndarray, shape (n_features,)
Per feature relative scaling of the data.
"""
def __init__(self, copy=True):
self.copy = copy
def fit(self, X, y=None):
"""Compute the minimum and maximum to be used for later scaling.
Parameters
----------
X : array-like, shape [n_samples, n_features]
The data used to compute the per-feature minimum and maximum
used for later scaling along the features axis.
"""
X = check_array(X, accept_sparse=('csr', 'csc'), copy=self.copy,
ensure_2d=False, estimator=self, dtype=FLOAT_DTYPES)
if sparse.issparse(X):
mins, maxs = min_max_axis(X, axis=0)
scales = np.maximum(np.abs(mins), np.abs(maxs))
else:
scales = np.abs(X).max(axis=0)
scales = np.array(scales)
scales = scales.reshape(-1)
self.scale_ = _handle_zeros_in_scale(scales)
return self
def transform(self, X, y=None):
"""Scale the data
Parameters
----------
X : array-like or CSR matrix.
The data that should be scaled.
"""
check_is_fitted(self, 'scale_')
X = check_array(X, accept_sparse=('csr', 'csc'), copy=self.copy,
ensure_2d=False, estimator=self, dtype=FLOAT_DTYPES)
if sparse.issparse(X):
if X.shape[0] == 1:
inplace_row_scale(X, 1.0 / self.scale_)
else:
inplace_column_scale(X, 1.0 / self.scale_)
else:
X /= self.scale_
return X
def inverse_transform(self, X):
"""Scale back the data to the original representation
Parameters
----------
X : array-like or CSR matrix.
The data that should be transformed back.
"""
check_is_fitted(self, 'scale_')
X = check_array(X, accept_sparse=('csr', 'csc'), copy=self.copy,
ensure_2d=False, estimator=self, dtype=FLOAT_DTYPES)
if sparse.issparse(X):
if X.shape[0] == 1:
inplace_row_scale(X, self.scale_)
else:
inplace_column_scale(X, self.scale_)
else:
X *= self.scale_
return X
def maxabs_scale(X, axis=0, copy=True):
"""Scale each feature to the [-1, 1] range without breaking the sparsity.
This estimator scales each feature individually such
that the maximal absolute value of each feature in the
training set will be 1.0.
This scaler can also be applied to sparse CSR or CSC matrices.
Parameters
----------
axis : int (0 by default)
axis used to scale along. If 0, independently scale each feature,
otherwise (if 1) scale each sample.
copy : boolean, optional, default is True
Set to False to perform inplace scaling and avoid a copy (if the input
is already a numpy array).
"""
s = MaxAbsScaler(copy=copy)
if axis == 0:
return s.fit_transform(X)
else:
return s.fit_transform(X.T).T
class RobustScaler(BaseEstimator, TransformerMixin):
"""Scale features using statistics that are robust to outliers.
This Scaler removes the median and scales the data according to
the Interquartile Range (IQR). The IQR is the range between the 1st
quartile (25th quantile) and the 3rd quartile (75th quantile).
Centering and scaling happen independently on each feature (or each
sample, depending on the `axis` argument) by computing the relevant
statistics on the samples in the training set. Median and interquartile
range are then stored to be used on later data using the `transform`
method.
Standardization of a dataset is a common requirement for many
machine learning estimators. Typically this is done by removing the mean
and scaling to unit variance. However, outliers can often influence the
sample mean / variance in a negative way. In such cases, the median and
the interquartile range often give better results.
Read more in the :ref:`User Guide <preprocessing_scaler>`.
Parameters
----------
with_centering : boolean, True by default
If True, center the data before scaling.
This does not work (and will raise an exception) when attempted on
sparse matrices, because centering them entails building a dense
matrix which in common use cases is likely to be too large to fit in
memory.
with_scaling : boolean, True by default
If True, scale the data to interquartile range.
copy : boolean, optional, default is True
If False, try to avoid a copy and do inplace scaling instead.
This is not guaranteed to always work inplace; e.g. if the data is
not a NumPy array or scipy.sparse CSR matrix, a copy may still be
returned.
Attributes
----------
center_ : array of floats
The median value for each feature in the training set.
scale_ : array of floats
The (scaled) interquartile range for each feature in the training set.
See also
--------
:class:`sklearn.preprocessing.StandardScaler` to perform centering
and scaling using mean and variance.
:class:`sklearn.decomposition.RandomizedPCA` with `whiten=True`
to further remove the linear correlation across features.
Notes
-----
See examples/preprocessing/plot_robust_scaling.py for an example.
http://en.wikipedia.org/wiki/Median_(statistics)
http://en.wikipedia.org/wiki/Interquartile_range
"""
def __init__(self, with_centering=True, with_scaling=True, copy=True):
self.with_centering = with_centering
self.with_scaling = with_scaling
self.copy = copy
def _check_array(self, X, copy):
"""Makes sure centering is not enabled for sparse matrices."""
X = check_array(X, accept_sparse=('csr', 'csc'), copy=self.copy,
ensure_2d=False, estimator=self, dtype=FLOAT_DTYPES)
if sparse.issparse(X):
if self.with_centering:
raise ValueError(
"Cannot center sparse matrices: use `with_centering=False`"
" instead. See docstring for motivation and alternatives.")
return X
def fit(self, X, y=None):
"""Compute the median and quantiles to be used for scaling.
Parameters
----------
X : array-like with shape [n_samples, n_features]
The data used to compute the median and quantiles
used for later scaling along the features axis.
"""
if sparse.issparse(X):
raise TypeError("RobustScaler cannot be fitted on sparse inputs")
X = self._check_array(X, self.copy)
if self.with_centering:
self.center_ = np.median(X, axis=0)
if self.with_scaling:
q = np.percentile(X, (25, 75), axis=0)
self.scale_ = (q[1] - q[0])
self.scale_ = _handle_zeros_in_scale(self.scale_)
return self
def transform(self, X, y=None):
"""Center and scale the data
Parameters
----------
X : array-like or CSR matrix.
The data used to scale along the specified axis.
"""
if self.with_centering:
check_is_fitted(self, 'center_')
if self.with_scaling:
check_is_fitted(self, 'scale_')
X = self._check_array(X, self.copy)
if sparse.issparse(X):
if self.with_scaling:
if X.shape[0] == 1:
inplace_row_scale(X, 1.0 / self.scale_)
elif self.axis == 0:
inplace_column_scale(X, 1.0 / self.scale_)
else:
if self.with_centering:
X -= self.center_
if self.with_scaling:
X /= self.scale_
return X
def inverse_transform(self, X):
"""Scale back the data to the original representation
Parameters
----------
X : array-like or CSR matrix.
The data used to scale along the specified axis.
"""
if self.with_centering:
check_is_fitted(self, 'center_')
if self.with_scaling:
check_is_fitted(self, 'scale_')
X = self._check_array(X, self.copy)
if sparse.issparse(X):
if self.with_scaling:
if X.shape[0] == 1:
inplace_row_scale(X, self.scale_)
else:
inplace_column_scale(X, self.scale_)
else:
if self.with_scaling:
X *= self.scale_
if self.with_centering:
X += self.center_
return X
def robust_scale(X, axis=0, with_centering=True, with_scaling=True, copy=True):
"""Standardize a dataset along any axis
Center to the median and component wise scale
according to the interquartile range.
Read more in the :ref:`User Guide <preprocessing_scaler>`.
Parameters
----------
X : array-like.
The data to center and scale.
axis : int (0 by default)
axis used to compute the medians and IQR along. If 0,
independently scale each feature, otherwise (if 1) scale
each sample.
with_centering : boolean, True by default
If True, center the data before scaling.
with_scaling : boolean, True by default
If True, scale the data to unit variance (or equivalently,
unit standard deviation).
copy : boolean, optional, default is True
set to False to perform inplace row normalization and avoid a
copy (if the input is already a numpy array or a scipy.sparse
CSR matrix and if axis is 1).
Notes
-----
This implementation will refuse to center scipy.sparse matrices
since it would make them non-sparse and would potentially crash the
program with memory exhaustion problems.
Instead the caller is expected to either set explicitly
`with_centering=False` (in that case, only variance scaling will be
performed on the features of the CSR matrix) or to call `X.toarray()`
if he/she expects the materialized dense array to fit in memory.
To avoid memory copy the caller should pass a CSR matrix.
See also
--------
:class:`sklearn.preprocessing.RobustScaler` to perform centering and
scaling using the ``Transformer`` API (e.g. as part of a preprocessing
:class:`sklearn.pipeline.Pipeline`)
"""
s = RobustScaler(with_centering=with_centering, with_scaling=with_scaling,
copy=copy)
if axis == 0:
return s.fit_transform(X)
else:
return s.fit_transform(X.T).T
class PolynomialFeatures(BaseEstimator, TransformerMixin):
"""Generate polynomial and interaction features.
Generate a new feature matrix consisting of all polynomial combinations
of the features with degree less than or equal to the specified degree.
For example, if an input sample is two dimensional and of the form
[a, b], the degree-2 polynomial features are [1, a, b, a^2, ab, b^2].
Parameters
----------
degree : integer
The degree of the polynomial features. Default = 2.
interaction_only : boolean, default = False
If true, only interaction features are produced: features that are
products of at most ``degree`` *distinct* input features (so not
``x[1] ** 2``, ``x[0] * x[2] ** 3``, etc.).
include_bias : boolean
If True (default), then include a bias column, the feature in which
all polynomial powers are zero (i.e. a column of ones - acts as an
intercept term in a linear model).
Examples
--------
>>> X = np.arange(6).reshape(3, 2)
>>> X
array([[0, 1],
[2, 3],
[4, 5]])
>>> poly = PolynomialFeatures(2)
>>> poly.fit_transform(X)
array([[ 1, 0, 1, 0, 0, 1],
[ 1, 2, 3, 4, 6, 9],
[ 1, 4, 5, 16, 20, 25]])
>>> poly = PolynomialFeatures(interaction_only=True)
>>> poly.fit_transform(X)
array([[ 1, 0, 1, 0],
[ 1, 2, 3, 6],
[ 1, 4, 5, 20]])
Attributes
----------
powers_ : array, shape (n_input_features, n_output_features)
powers_[i, j] is the exponent of the jth input in the ith output.
n_input_features_ : int
The total number of input features.
n_output_features_ : int
The total number of polynomial output features. The number of output
features is computed by iterating over all suitably sized combinations
of input features.
Notes
-----
Be aware that the number of features in the output array scales
polynomially in the number of features of the input array, and
exponentially in the degree. High degrees can cause overfitting.
See :ref:`examples/linear_model/plot_polynomial_interpolation.py
<example_linear_model_plot_polynomial_interpolation.py>`
"""
def __init__(self, degree=2, interaction_only=False, include_bias=True):
self.degree = degree
self.interaction_only = interaction_only
self.include_bias = include_bias
@staticmethod
def _combinations(n_features, degree, interaction_only, include_bias):
comb = (combinations if interaction_only else combinations_w_r)
start = int(not include_bias)
return chain.from_iterable(comb(range(n_features), i)
for i in range(start, degree + 1))
@property
def powers_(self):
check_is_fitted(self, 'n_input_features_')
combinations = self._combinations(self.n_input_features_, self.degree,
self.interaction_only,
self.include_bias)
return np.vstack(np.bincount(c, minlength=self.n_input_features_)
for c in combinations)
def fit(self, X, y=None):
"""
Compute number of output features.
"""
n_samples, n_features = check_array(X).shape
combinations = self._combinations(n_features, self.degree,
self.interaction_only,
self.include_bias)
self.n_input_features_ = n_features
self.n_output_features_ = sum(1 for _ in combinations)
return self
def transform(self, X, y=None):
"""Transform data to polynomial features
Parameters
----------
X : array with shape [n_samples, n_features]
The data to transform, row by row.
Returns
-------
XP : np.ndarray shape [n_samples, NP]
The matrix of features, where NP is the number of polynomial
features generated from the combination of inputs.
"""
check_is_fitted(self, ['n_input_features_', 'n_output_features_'])
X = check_array(X)
n_samples, n_features = X.shape
if n_features != self.n_input_features_:
raise ValueError("X shape does not match training shape")
# allocate output data
XP = np.empty((n_samples, self.n_output_features_), dtype=X.dtype)
combinations = self._combinations(n_features, self.degree,
self.interaction_only,
self.include_bias)
for i, c in enumerate(combinations):
XP[:, i] = X[:, c].prod(1)
return XP
def normalize(X, norm='l2', axis=1, copy=True):
"""Scale input vectors individually to unit norm (vector length).
Read more in the :ref:`User Guide <preprocessing_normalization>`.
Parameters
----------
X : array or scipy.sparse matrix with shape [n_samples, n_features]
The data to normalize, element by element.
scipy.sparse matrices should be in CSR format to avoid an
un-necessary copy.
norm : 'l1', 'l2', or 'max', optional ('l2' by default)
The norm to use to normalize each non zero sample (or each non-zero
feature if axis is 0).
axis : 0 or 1, optional (1 by default)
axis used to normalize the data along. If 1, independently normalize
each sample, otherwise (if 0) normalize each feature.
copy : boolean, optional, default True
set to False to perform inplace row normalization and avoid a
copy (if the input is already a numpy array or a scipy.sparse
CSR matrix and if axis is 1).
See also
--------
:class:`sklearn.preprocessing.Normalizer` to perform normalization
using the ``Transformer`` API (e.g. as part of a preprocessing
:class:`sklearn.pipeline.Pipeline`)
"""
if norm not in ('l1', 'l2', 'max'):
raise ValueError("'%s' is not a supported norm" % norm)
if axis == 0:
sparse_format = 'csc'
elif axis == 1:
sparse_format = 'csr'
else:
raise ValueError("'%d' is not a supported axis" % axis)
X = check_array(X, sparse_format, copy=copy, warn_on_dtype=True,
estimator='the normalize function', dtype=FLOAT_DTYPES)
if axis == 0:
X = X.T
if sparse.issparse(X):
if norm == 'l1':
inplace_csr_row_normalize_l1(X)
elif norm == 'l2':
inplace_csr_row_normalize_l2(X)
elif norm == 'max':
_, norms = min_max_axis(X, 1)
norms = norms.repeat(np.diff(X.indptr))
mask = norms != 0
X.data[mask] /= norms[mask]
else:
if norm == 'l1':
norms = np.abs(X).sum(axis=1)
elif norm == 'l2':
norms = row_norms(X)
elif norm == 'max':
norms = np.max(X, axis=1)
norms = _handle_zeros_in_scale(norms)
X /= norms[:, np.newaxis]
if axis == 0:
X = X.T
return X
class Normalizer(BaseEstimator, TransformerMixin):
"""Normalize samples individually to unit norm.
Each sample (i.e. each row of the data matrix) with at least one
non zero component is rescaled independently of other samples so
that its norm (l1 or l2) equals one.
This transformer is able to work both with dense numpy arrays and
scipy.sparse matrix (use CSR format if you want to avoid the burden of
a copy / conversion).
Scaling inputs to unit norms is a common operation for text
classification or clustering for instance. For instance the dot
product of two l2-normalized TF-IDF vectors is the cosine similarity
of the vectors and is the base similarity metric for the Vector
Space Model commonly used by the Information Retrieval community.
Read more in the :ref:`User Guide <preprocessing_normalization>`.
Parameters
----------
norm : 'l1', 'l2', or 'max', optional ('l2' by default)
The norm to use to normalize each non zero sample.
copy : boolean, optional, default True
set to False to perform inplace row normalization and avoid a
copy (if the input is already a numpy array or a scipy.sparse
CSR matrix).
Notes
-----
This estimator is stateless (besides constructor parameters), the
fit method does nothing but is useful when used in a pipeline.
See also
--------
:func:`sklearn.preprocessing.normalize` equivalent function
without the object oriented API
"""
def __init__(self, norm='l2', copy=True):
self.norm = norm
self.copy = copy
def fit(self, X, y=None):
"""Do nothing and return the estimator unchanged
This method is just there to implement the usual API and hence
work in pipelines.
"""
X = check_array(X, accept_sparse='csr')
return self
def transform(self, X, y=None, copy=None):
"""Scale each non zero row of X to unit norm
Parameters
----------
X : array or scipy.sparse matrix with shape [n_samples, n_features]
The data to normalize, row by row. scipy.sparse matrices should be
in CSR format to avoid an un-necessary copy.
"""
copy = copy if copy is not None else self.copy
X = check_array(X, accept_sparse='csr')
return normalize(X, norm=self.norm, axis=1, copy=copy)
def binarize(X, threshold=0.0, copy=True):
"""Boolean thresholding of array-like or scipy.sparse matrix
Read more in the :ref:`User Guide <preprocessing_binarization>`.
Parameters
----------
X : array or scipy.sparse matrix with shape [n_samples, n_features]
The data to binarize, element by element.
scipy.sparse matrices should be in CSR or CSC format to avoid an
un-necessary copy.
threshold : float, optional (0.0 by default)
Feature values below or equal to this are replaced by 0, above it by 1.
Threshold may not be less than 0 for operations on sparse matrices.
copy : boolean, optional, default True
set to False to perform inplace binarization and avoid a copy
(if the input is already a numpy array or a scipy.sparse CSR / CSC
matrix and if axis is 1).
See also
--------
:class:`sklearn.preprocessing.Binarizer` to perform binarization
using the ``Transformer`` API (e.g. as part of a preprocessing
:class:`sklearn.pipeline.Pipeline`)
"""
X = check_array(X, accept_sparse=['csr', 'csc'], copy=copy)
if sparse.issparse(X):
if threshold < 0:
raise ValueError('Cannot binarize a sparse matrix with threshold '
'< 0')
cond = X.data > threshold
not_cond = np.logical_not(cond)
X.data[cond] = 1
X.data[not_cond] = 0
X.eliminate_zeros()
else:
cond = X > threshold
not_cond = np.logical_not(cond)
X[cond] = 1
X[not_cond] = 0
return X
class Binarizer(BaseEstimator, TransformerMixin):
"""Binarize data (set feature values to 0 or 1) according to a threshold
Values greater than the threshold map to 1, while values less than
or equal to the threshold map to 0. With the default threshold of 0,
only positive values map to 1.
Binarization is a common operation on text count data where the
analyst can decide to only consider the presence or absence of a
feature rather than a quantified number of occurrences for instance.
It can also be used as a pre-processing step for estimators that
consider boolean random variables (e.g. modelled using the Bernoulli
distribution in a Bayesian setting).
Read more in the :ref:`User Guide <preprocessing_binarization>`.
Parameters
----------
threshold : float, optional (0.0 by default)
Feature values below or equal to this are replaced by 0, above it by 1.
Threshold may not be less than 0 for operations on sparse matrices.
copy : boolean, optional, default True
set to False to perform inplace binarization and avoid a copy (if
the input is already a numpy array or a scipy.sparse CSR matrix).
Notes
-----
If the input is a sparse matrix, only the non-zero values are subject
to update by the Binarizer class.
This estimator is stateless (besides constructor parameters), the
fit method does nothing but is useful when used in a pipeline.
"""
def __init__(self, threshold=0.0, copy=True):
self.threshold = threshold
self.copy = copy
def fit(self, X, y=None):
"""Do nothing and return the estimator unchanged
This method is just there to implement the usual API and hence
work in pipelines.
"""
check_array(X, accept_sparse='csr')
return self
def transform(self, X, y=None, copy=None):
"""Binarize each element of X
Parameters
----------
X : array or scipy.sparse matrix with shape [n_samples, n_features]
The data to binarize, element by element.
scipy.sparse matrices should be in CSR format to avoid an
un-necessary copy.
"""
copy = copy if copy is not None else self.copy
return binarize(X, threshold=self.threshold, copy=copy)
class KernelCenterer(BaseEstimator, TransformerMixin):
"""Center a kernel matrix
Let K(x, z) be a kernel defined by phi(x)^T phi(z), where phi is a
function mapping x to a Hilbert space. KernelCenterer centers (i.e.,
normalize to have zero mean) the data without explicitly computing phi(x).
It is equivalent to centering phi(x) with
sklearn.preprocessing.StandardScaler(with_std=False).
Read more in the :ref:`User Guide <kernel_centering>`.
"""
def fit(self, K, y=None):
"""Fit KernelCenterer
Parameters
----------
K : numpy array of shape [n_samples, n_samples]
Kernel matrix.
Returns
-------
self : returns an instance of self.
"""
K = check_array(K)
n_samples = K.shape[0]
self.K_fit_rows_ = np.sum(K, axis=0) / n_samples
self.K_fit_all_ = self.K_fit_rows_.sum() / n_samples
return self
def transform(self, K, y=None, copy=True):
"""Center kernel matrix.
Parameters
----------
K : numpy array of shape [n_samples1, n_samples2]
Kernel matrix.
copy : boolean, optional, default True
Set to False to perform inplace computation.
Returns
-------
K_new : numpy array of shape [n_samples1, n_samples2]
"""
check_is_fitted(self, 'K_fit_all_')
K = check_array(K)
if copy:
K = K.copy()
K_pred_cols = (np.sum(K, axis=1) /
self.K_fit_rows_.shape[0])[:, np.newaxis]
K -= self.K_fit_rows_
K -= K_pred_cols
K += self.K_fit_all_
return K
def add_dummy_feature(X, value=1.0):
"""Augment dataset with an additional dummy feature.
This is useful for fitting an intercept term with implementations which
cannot otherwise fit it directly.
Parameters
----------
X : array or scipy.sparse matrix with shape [n_samples, n_features]
Data.
value : float
Value to use for the dummy feature.
Returns
-------
X : array or scipy.sparse matrix with shape [n_samples, n_features + 1]
Same data with dummy feature added as first column.
Examples
--------
>>> from sklearn.preprocessing import add_dummy_feature
>>> add_dummy_feature([[0, 1], [1, 0]])
array([[ 1., 0., 1.],
[ 1., 1., 0.]])
"""
X = check_array(X, accept_sparse=['csc', 'csr', 'coo'])
n_samples, n_features = X.shape
shape = (n_samples, n_features + 1)
if sparse.issparse(X):
if sparse.isspmatrix_coo(X):
# Shift columns to the right.
col = X.col + 1
# Column indices of dummy feature are 0 everywhere.
col = np.concatenate((np.zeros(n_samples), col))
# Row indices of dummy feature are 0, ..., n_samples-1.
row = np.concatenate((np.arange(n_samples), X.row))
# Prepend the dummy feature n_samples times.
data = np.concatenate((np.ones(n_samples) * value, X.data))
return sparse.coo_matrix((data, (row, col)), shape)
elif sparse.isspmatrix_csc(X):
# Shift index pointers since we need to add n_samples elements.
indptr = X.indptr + n_samples
# indptr[0] must be 0.
indptr = np.concatenate((np.array([0]), indptr))
# Row indices of dummy feature are 0, ..., n_samples-1.
indices = np.concatenate((np.arange(n_samples), X.indices))
# Prepend the dummy feature n_samples times.
data = np.concatenate((np.ones(n_samples) * value, X.data))
return sparse.csc_matrix((data, indices, indptr), shape)
else:
klass = X.__class__
return klass(add_dummy_feature(X.tocoo(), value))
else:
return np.hstack((np.ones((n_samples, 1)) * value, X))
def _transform_selected(X, transform, selected="all", copy=True):
"""Apply a transform function to portion of selected features
Parameters
----------
X : array-like or sparse matrix, shape=(n_samples, n_features)
Dense array or sparse matrix.
transform : callable
A callable transform(X) -> X_transformed
copy : boolean, optional
Copy X even if it could be avoided.
selected: "all" or array of indices or mask
Specify which features to apply the transform to.
Returns
-------
X : array or sparse matrix, shape=(n_samples, n_features_new)
"""
if selected == "all":
return transform(X)
X = check_array(X, accept_sparse='csc', copy=copy)
if len(selected) == 0:
return X
n_features = X.shape[1]
ind = np.arange(n_features)
sel = np.zeros(n_features, dtype=bool)
sel[np.asarray(selected)] = True
not_sel = np.logical_not(sel)
n_selected = np.sum(sel)
if n_selected == 0:
# No features selected.
return X
elif n_selected == n_features:
# All features selected.
return transform(X)
else:
X_sel = transform(X[:, ind[sel]])
X_not_sel = X[:, ind[not_sel]]
if sparse.issparse(X_sel) or sparse.issparse(X_not_sel):
return sparse.hstack((X_sel, X_not_sel))
else:
return np.hstack((X_sel, X_not_sel))
class OneHotEncoder(BaseEstimator, TransformerMixin):
"""Encode categorical integer features using a one-hot aka one-of-K scheme.
The input to this transformer should be a matrix of integers, denoting
the values taken on by categorical (discrete) features. The output will be
a sparse matrix where each column corresponds to one possible value of one
feature. It is assumed that input features take on values in the range
[0, n_values).
This encoding is needed for feeding categorical data to many scikit-learn
estimators, notably linear models and SVMs with the standard kernels.
Read more in the :ref:`User Guide <preprocessing_categorical_features>`.
Parameters
----------
n_values : 'auto', int or array of ints
Number of values per feature.
- 'auto' : determine value range from training data.
- int : maximum value for all features.
- array : maximum value per feature.
categorical_features: "all" or array of indices or mask
Specify what features are treated as categorical.
- 'all' (default): All features are treated as categorical.
- array of indices: Array of categorical feature indices.
- mask: Array of length n_features and with dtype=bool.
Non-categorical features are always stacked to the right of the matrix.
dtype : number type, default=np.float
Desired dtype of output.
sparse : boolean, default=True
Will return sparse matrix if set True else will return an array.
handle_unknown : str, 'error' or 'ignore'
Whether to raise an error or ignore if a unknown categorical feature is
present during transform.
Attributes
----------
active_features_ : array
Indices for active features, meaning values that actually occur
in the training set. Only available when n_values is ``'auto'``.
feature_indices_ : array of shape (n_features,)
Indices to feature ranges.
Feature ``i`` in the original data is mapped to features
from ``feature_indices_[i]`` to ``feature_indices_[i+1]``
(and then potentially masked by `active_features_` afterwards)
n_values_ : array of shape (n_features,)
Maximum number of values per feature.
Examples
--------
Given a dataset with three features and two samples, we let the encoder
find the maximum value per feature and transform the data to a binary
one-hot encoding.
>>> from sklearn.preprocessing import OneHotEncoder
>>> enc = OneHotEncoder()
>>> enc.fit([[0, 0, 3], [1, 1, 0], [0, 2, 1], \
[1, 0, 2]]) # doctest: +ELLIPSIS
OneHotEncoder(categorical_features='all', dtype=<... 'float'>,
handle_unknown='error', n_values='auto', sparse=True)
>>> enc.n_values_
array([2, 3, 4])
>>> enc.feature_indices_
array([0, 2, 5, 9])
>>> enc.transform([[0, 1, 1]]).toarray()
array([[ 1., 0., 0., 1., 0., 0., 1., 0., 0.]])
See also
--------
sklearn.feature_extraction.DictVectorizer : performs a one-hot encoding of
dictionary items (also handles string-valued features).
sklearn.feature_extraction.FeatureHasher : performs an approximate one-hot
encoding of dictionary items or strings.
"""
def __init__(self, n_values="auto", categorical_features="all",
dtype=np.float, sparse=True, handle_unknown='error'):
self.n_values = n_values
self.categorical_features = categorical_features
self.dtype = dtype
self.sparse = sparse
self.handle_unknown = handle_unknown
def fit(self, X, y=None):
"""Fit OneHotEncoder to X.
Parameters
----------
X : array-like, shape=(n_samples, n_feature)
Input array of type int.
Returns
-------
self
"""
self.fit_transform(X)
return self
def _fit_transform(self, X):
"""Assumes X contains only categorical features."""
X = check_array(X, dtype=np.int)
if np.any(X < 0):
raise ValueError("X needs to contain only non-negative integers.")
n_samples, n_features = X.shape
if self.n_values == 'auto':
n_values = np.max(X, axis=0) + 1
elif isinstance(self.n_values, numbers.Integral):
if (np.max(X, axis=0) >= self.n_values).any():
raise ValueError("Feature out of bounds for n_values=%d"
% self.n_values)
n_values = np.empty(n_features, dtype=np.int)
n_values.fill(self.n_values)
else:
try:
n_values = np.asarray(self.n_values, dtype=int)
except (ValueError, TypeError):
raise TypeError("Wrong type for parameter `n_values`. Expected"
" 'auto', int or array of ints, got %r"
% type(X))
if n_values.ndim < 1 or n_values.shape[0] != X.shape[1]:
raise ValueError("Shape mismatch: if n_values is an array,"
" it has to be of shape (n_features,).")
self.n_values_ = n_values
n_values = np.hstack([[0], n_values])
indices = np.cumsum(n_values)
self.feature_indices_ = indices
column_indices = (X + indices[:-1]).ravel()
row_indices = np.repeat(np.arange(n_samples, dtype=np.int32),
n_features)
data = np.ones(n_samples * n_features)
out = sparse.coo_matrix((data, (row_indices, column_indices)),
shape=(n_samples, indices[-1]),
dtype=self.dtype).tocsr()
if self.n_values == 'auto':
mask = np.array(out.sum(axis=0)).ravel() != 0
active_features = np.where(mask)[0]
out = out[:, active_features]
self.active_features_ = active_features
return out if self.sparse else out.toarray()
def fit_transform(self, X, y=None):
"""Fit OneHotEncoder to X, then transform X.
Equivalent to self.fit(X).transform(X), but more convenient and more
efficient. See fit for the parameters, transform for the return value.
"""
return _transform_selected(X, self._fit_transform,
self.categorical_features, copy=True)
def _transform(self, X):
"""Assumes X contains only categorical features."""
X = check_array(X, dtype=np.int)
if np.any(X < 0):
raise ValueError("X needs to contain only non-negative integers.")
n_samples, n_features = X.shape
indices = self.feature_indices_
if n_features != indices.shape[0] - 1:
raise ValueError("X has different shape than during fitting."
" Expected %d, got %d."
% (indices.shape[0] - 1, n_features))
# We use only those catgorical features of X that are known using fit.
# i.e lesser than n_values_ using mask.
# This means, if self.handle_unknown is "ignore", the row_indices and
# col_indices corresponding to the unknown categorical feature are
# ignored.
mask = (X < self.n_values_).ravel()
if np.any(~mask):
if self.handle_unknown not in ['error', 'ignore']:
raise ValueError("handle_unknown should be either error or "
"unknown got %s" % self.handle_unknown)
if self.handle_unknown == 'error':
raise ValueError("unknown categorical feature present %s "
"during transform." % X[~mask])
column_indices = (X + indices[:-1]).ravel()[mask]
row_indices = np.repeat(np.arange(n_samples, dtype=np.int32),
n_features)[mask]
data = np.ones(np.sum(mask))
out = sparse.coo_matrix((data, (row_indices, column_indices)),
shape=(n_samples, indices[-1]),
dtype=self.dtype).tocsr()
if self.n_values == 'auto':
out = out[:, self.active_features_]
return out if self.sparse else out.toarray()
def transform(self, X):
"""Transform X using one-hot encoding.
Parameters
----------
X : array-like, shape=(n_samples, n_features)
Input array of type int.
Returns
-------
X_out : sparse matrix if sparse=True else a 2-d array, dtype=int
Transformed input.
"""
return _transform_selected(X, self._transform,
self.categorical_features, copy=True)
| bsd-3-clause |
Carmezim/tensorflow | tensorflow/contrib/learn/python/learn/estimators/estimator.py | 5 | 55283 | # Copyright 2016 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Base Estimator class."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import abc
import copy
import os
import tempfile
import numpy as np
import six
from tensorflow.contrib import framework as contrib_framework
from tensorflow.contrib import layers
from tensorflow.contrib import metrics as metrics_lib
from tensorflow.contrib.framework import deprecated
from tensorflow.contrib.framework import deprecated_args
from tensorflow.contrib.framework import list_variables
from tensorflow.contrib.framework import load_variable
from tensorflow.contrib.framework.python.ops import variables as contrib_variables
from tensorflow.contrib.learn.python.learn import evaluable
from tensorflow.contrib.learn.python.learn import metric_spec
from tensorflow.contrib.learn.python.learn import monitors as monitor_lib
from tensorflow.contrib.learn.python.learn import trainable
from tensorflow.contrib.learn.python.learn.estimators import _sklearn as sklearn
from tensorflow.contrib.learn.python.learn.estimators import constants
from tensorflow.contrib.learn.python.learn.estimators import metric_key
from tensorflow.contrib.learn.python.learn.estimators import model_fn as model_fn_lib
from tensorflow.contrib.learn.python.learn.estimators import run_config
from tensorflow.contrib.learn.python.learn.estimators import tensor_signature
from tensorflow.contrib.learn.python.learn.estimators._sklearn import NotFittedError
from tensorflow.contrib.learn.python.learn.learn_io import data_feeder
from tensorflow.contrib.learn.python.learn.utils import export
from tensorflow.contrib.learn.python.learn.utils import saved_model_export_utils
from tensorflow.contrib.training.python.training import evaluation
from tensorflow.core.framework import summary_pb2
from tensorflow.core.protobuf import config_pb2
from tensorflow.python.client import session as tf_session
from tensorflow.python.framework import ops
from tensorflow.python.framework import random_seed
from tensorflow.python.framework import sparse_tensor
from tensorflow.python.ops import control_flow_ops
from tensorflow.python.ops import lookup_ops
from tensorflow.python.ops import resources
from tensorflow.python.ops import variables
from tensorflow.python.platform import gfile
from tensorflow.python.platform import tf_logging as logging
from tensorflow.python.saved_model import builder as saved_model_builder
from tensorflow.python.saved_model import tag_constants
from tensorflow.python.training import basic_session_run_hooks
from tensorflow.python.training import device_setter
from tensorflow.python.training import monitored_session
from tensorflow.python.training import saver
from tensorflow.python.training import summary_io
from tensorflow.python.util import compat
from tensorflow.python.util import tf_decorator
from tensorflow.python.util import tf_inspect
AS_ITERABLE_DATE = '2016-09-15'
AS_ITERABLE_INSTRUCTIONS = (
'The default behavior of predict() is changing. The default value for\n'
'as_iterable will change to True, and then the flag will be removed\n'
'altogether. The behavior of this flag is described below.')
SCIKIT_DECOUPLE_DATE = '2016-12-01'
SCIKIT_DECOUPLE_INSTRUCTIONS = (
'Estimator is decoupled from Scikit Learn interface by moving into\n'
'separate class SKCompat. Arguments x, y and batch_size are only\n'
'available in the SKCompat class, Estimator will only accept input_fn.\n'
'Example conversion:\n'
' est = Estimator(...) -> est = SKCompat(Estimator(...))')
def _verify_input_args(x, y, input_fn, feed_fn, batch_size):
"""Verifies validity of co-existance of input arguments."""
if input_fn is None:
if x is None:
raise ValueError('Either x or input_fn must be provided.')
if contrib_framework.is_tensor(x) or (y is not None and
contrib_framework.is_tensor(y)):
raise ValueError('Inputs cannot be tensors. Please provide input_fn.')
if feed_fn is not None:
raise ValueError('Can not provide both feed_fn and x or y.')
else:
if (x is not None) or (y is not None):
raise ValueError('Can not provide both input_fn and x or y.')
if batch_size is not None:
raise ValueError('Can not provide both input_fn and batch_size.')
def _get_input_fn(x, y, input_fn, feed_fn, batch_size, shuffle=False, epochs=1):
"""Make inputs into input and feed functions.
Args:
x: Numpy, Pandas or Dask matrix or iterable.
y: Numpy, Pandas or Dask matrix or iterable.
input_fn: Pre-defined input function for training data.
feed_fn: Pre-defined data feeder function.
batch_size: Size to split data into parts. Must be >= 1.
shuffle: Whether to shuffle the inputs.
epochs: Number of epochs to run.
Returns:
Data input and feeder function based on training data.
Raises:
ValueError: Only one of `(x & y)` or `input_fn` must be provided.
"""
_verify_input_args(x, y, input_fn, feed_fn, batch_size)
if input_fn is not None:
return input_fn, feed_fn
df = data_feeder.setup_train_data_feeder(
x,
y,
n_classes=None,
batch_size=batch_size,
shuffle=shuffle,
epochs=epochs)
return df.input_builder, df.get_feed_dict_fn()
def infer_real_valued_columns_from_input_fn(input_fn):
"""Creates `FeatureColumn` objects for inputs defined by `input_fn`.
This interprets all inputs as dense, fixed-length float values. This creates
a local graph in which it calls `input_fn` to build the tensors, then discards
it.
Args:
input_fn: Input function returning a tuple of:
features - Dictionary of string feature name to `Tensor` or `Tensor`.
labels - `Tensor` of label values.
Returns:
List of `FeatureColumn` objects.
"""
with ops.Graph().as_default():
features, _ = input_fn()
return layers.infer_real_valued_columns(features)
def infer_real_valued_columns_from_input(x):
"""Creates `FeatureColumn` objects for inputs defined by input `x`.
This interprets all inputs as dense, fixed-length float values.
Args:
x: Real-valued matrix of shape [n_samples, n_features...]. Can be
iterator that returns arrays of features.
Returns:
List of `FeatureColumn` objects.
"""
input_fn, _ = _get_input_fn(
x=x, y=None, input_fn=None, feed_fn=None, batch_size=None)
return infer_real_valued_columns_from_input_fn(input_fn)
def _model_fn_args(fn):
"""Get argument names for function-like object.
Args:
fn: Function, or function-like object (e.g., result of `functools.partial`).
Returns:
`tuple` of string argument names.
Raises:
ValueError: if partial function has positionally bound arguments
"""
_, fn = tf_decorator.unwrap(fn)
if hasattr(fn, 'func') and hasattr(fn, 'keywords') and hasattr(fn, 'args'):
# Handle functools.partial and similar objects.
return tuple([
arg for arg in tf_inspect.getargspec(fn.func).args[len(fn.args):]
if arg not in set(fn.keywords.keys())
])
# Handle function.
return tuple(tf_inspect.getargspec(fn).args)
def _get_replica_device_setter(config):
"""Creates a replica device setter if required.
Args:
config: A RunConfig instance.
Returns:
A replica device setter, or None.
"""
ps_ops = [
'Variable', 'VariableV2', 'AutoReloadVariable', 'MutableHashTable',
'MutableHashTableOfTensors', 'MutableDenseHashTable'
]
if config.task_type:
worker_device = '/job:%s/task:%d' % (config.task_type, config.task_id)
else:
worker_device = '/job:worker'
if config.num_ps_replicas > 0:
return device_setter.replica_device_setter(
ps_tasks=config.num_ps_replicas, worker_device=worker_device,
merge_devices=True, ps_ops=ps_ops, cluster=config.cluster_spec)
else:
return None
def _make_metrics_ops(metrics, features, labels, predictions):
"""Add metrics based on `features`, `labels`, and `predictions`.
`metrics` contains a specification for how to run metrics. It is a dict
mapping friendly names to either `MetricSpec` objects, or directly to a metric
function (assuming that `predictions` and `labels` are single tensors), or to
`(pred_name, metric)` `tuple`, which passes `predictions[pred_name]` and
`labels` to `metric` (assuming `labels` is a single tensor).
Users are encouraged to use `MetricSpec` objects, which are more flexible and
cleaner. They also lead to clearer errors.
Args:
metrics: A dict mapping names to metrics specification, for example
`MetricSpec` objects.
features: A dict of tensors returned from an input_fn as features/inputs.
labels: A single tensor or a dict of tensors returned from an input_fn as
labels.
predictions: A single tensor or a dict of tensors output from a model as
predictions.
Returns:
A dict mapping the friendly given in `metrics` to the result of calling the
given metric function.
Raises:
ValueError: If metrics specifications do not work with the type of
`features`, `labels`, or `predictions` provided. Mostly, a dict is given
but no pred_name specified.
"""
metrics = metrics or {}
# If labels is a dict with a single key, unpack into a single tensor.
labels_tensor_or_dict = labels
if isinstance(labels, dict) and len(labels) == 1:
labels_tensor_or_dict = labels[list(labels.keys())[0]]
result = {}
# Iterate in lexicographic order, so the graph is identical among runs.
for name, metric in sorted(six.iteritems(metrics)):
if isinstance(metric, metric_spec.MetricSpec):
result[name] = metric.create_metric_ops(features, labels, predictions)
continue
# TODO(b/31229024): Remove the rest of this loop
logging.warning('Please specify metrics using MetricSpec. Using bare '
'functions or (key, fn) tuples is deprecated and support '
'for it will be removed on Oct 1, 2016.')
if isinstance(name, tuple):
# Multi-head metrics.
if len(name) != 2:
raise ValueError('Invalid metric for {}. It returned a tuple with '
'len {}, expected 2.'.format(name, len(name)))
if not isinstance(predictions, dict):
raise ValueError(
'Metrics passed provide (name, prediction), '
'but predictions are not dict. '
'Metrics: %s, Predictions: %s.' % (metrics, predictions))
# Here are two options: labels are single Tensor or a dict.
if isinstance(labels, dict) and name[1] in labels:
# If labels are dict and the prediction name is in it, apply metric.
result[name[0]] = metric(predictions[name[1]], labels[name[1]])
else:
# Otherwise pass the labels to the metric.
result[name[0]] = metric(predictions[name[1]], labels_tensor_or_dict)
else:
# Single head metrics.
if isinstance(predictions, dict):
raise ValueError(
'Metrics passed provide only name, no prediction, '
'but predictions are dict. '
'Metrics: %s, Labels: %s.' % (metrics, labels_tensor_or_dict))
result[name] = metric(predictions, labels_tensor_or_dict)
return result
def _dict_to_str(dictionary):
"""Get a `str` representation of a `dict`.
Args:
dictionary: The `dict` to be represented as `str`.
Returns:
A `str` representing the `dictionary`.
"""
return ', '.join('%s = %s' % (k, v) for k, v in sorted(dictionary.items()))
def _write_dict_to_summary(output_dir,
dictionary,
current_global_step):
"""Writes a `dict` into summary file in given output directory.
Args:
output_dir: `str`, directory to write the summary file in.
dictionary: the `dict` to be written to summary file.
current_global_step: `int`, the current global step.
"""
logging.info('Saving dict for global step %d: %s', current_global_step,
_dict_to_str(dictionary))
summary_writer = summary_io.SummaryWriterCache.get(output_dir)
summary_proto = summary_pb2.Summary()
for key in dictionary:
if dictionary[key] is None:
continue
value = summary_proto.value.add()
value.tag = key
if (isinstance(dictionary[key], np.float32) or
isinstance(dictionary[key], float)):
value.simple_value = float(dictionary[key])
else:
logging.warn('Skipping summary for %s, must be a float or np.float32.',
key)
summary_writer.add_summary(summary_proto, current_global_step)
summary_writer.flush()
class BaseEstimator(
sklearn.BaseEstimator, evaluable.Evaluable, trainable.Trainable):
"""Abstract BaseEstimator class to train and evaluate TensorFlow models.
Users should not instantiate or subclass this class. Instead, use `Estimator`.
"""
__metaclass__ = abc.ABCMeta
# Note that for Google users, this is overriden with
# learn_runner.EstimatorConfig.
# TODO(wicke): Remove this once launcher takes over config functionality
_Config = run_config.RunConfig # pylint: disable=invalid-name
def __init__(self, model_dir=None, config=None):
"""Initializes a BaseEstimator instance.
Args:
model_dir: Directory to save model parameters, graph and etc. This can
also be used to load checkpoints from the directory into a estimator to
continue training a previously saved model. If `None`, the model_dir in
`config` will be used if set. If both are set, they must be same.
config: A RunConfig instance.
"""
# Create a run configuration.
if config is None:
self._config = BaseEstimator._Config()
logging.info('Using default config.')
else:
self._config = config
if self._config.session_config is None:
self._session_config = config_pb2.ConfigProto(allow_soft_placement=True)
else:
self._session_config = self._config.session_config
# Model directory.
if (model_dir is not None) and (self._config.model_dir is not None):
if model_dir != self._config.model_dir:
# TODO(b/9965722): remove this suppression after it is no longer
# necessary.
# pylint: disable=g-doc-exception
raise ValueError(
"model_dir are set both in constructor and RunConfig, but with "
"different values. In constructor: '{}', in RunConfig: "
"'{}' ".format(model_dir, self._config.model_dir))
self._model_dir = model_dir or self._config.model_dir
if self._model_dir is None:
self._model_dir = tempfile.mkdtemp()
logging.warning('Using temporary folder as model directory: %s',
self._model_dir)
if self._config.model_dir is None:
self._config = self._config.replace(model_dir=self._model_dir)
logging.info('Using config: %s', str(vars(self._config)))
# Set device function depending if there are replicas or not.
self._device_fn = _get_replica_device_setter(self._config)
# Features and labels TensorSignature objects.
# TODO(wicke): Rename these to something more descriptive
self._features_info = None
self._labels_info = None
self._graph = None
@property
def config(self):
# TODO(wicke): make RunConfig immutable, and then return it without a copy.
return copy.deepcopy(self._config)
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('y', None), ('batch_size', None)
)
def fit(self, x=None, y=None, input_fn=None, steps=None, batch_size=None,
monitors=None, max_steps=None):
# pylint: disable=g-doc-args,g-doc-return-or-yield
"""See `Trainable`.
Raises:
ValueError: If `x` or `y` are not `None` while `input_fn` is not `None`.
ValueError: If both `steps` and `max_steps` are not `None`.
"""
if (steps is not None) and (max_steps is not None):
raise ValueError('Can not provide both steps and max_steps.')
_verify_input_args(x, y, input_fn, None, batch_size)
if x is not None:
SKCompat(self).fit(x, y, batch_size, steps, max_steps, monitors)
return self
if max_steps is not None:
try:
start_step = load_variable(self._model_dir, ops.GraphKeys.GLOBAL_STEP)
if max_steps <= start_step:
logging.info('Skipping training since max_steps has already saved.')
return self
except: # pylint: disable=bare-except
pass
hooks = monitor_lib.replace_monitors_with_hooks(monitors, self)
if steps is not None or max_steps is not None:
hooks.append(basic_session_run_hooks.StopAtStepHook(steps, max_steps))
loss = self._train_model(input_fn=input_fn, hooks=hooks)
logging.info('Loss for final step: %s.', loss)
return self
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('y', None), ('batch_size', None)
)
def partial_fit(
self, x=None, y=None, input_fn=None, steps=1, batch_size=None,
monitors=None):
"""Incremental fit on a batch of samples.
This method is expected to be called several times consecutively
on different or the same chunks of the dataset. This either can
implement iterative training or out-of-core/online training.
This is especially useful when the whole dataset is too big to
fit in memory at the same time. Or when model is taking long time
to converge, and you want to split up training into subparts.
Args:
x: Matrix of shape [n_samples, n_features...]. Can be iterator that
returns arrays of features. The training input samples for fitting the
model. If set, `input_fn` must be `None`.
y: Vector or matrix [n_samples] or [n_samples, n_outputs]. Can be
iterator that returns array of labels. The training label values
(class labels in classification, real numbers in regression). If set,
`input_fn` must be `None`.
input_fn: Input function. If set, `x`, `y`, and `batch_size` must be
`None`.
steps: Number of steps for which to train model. If `None`, train forever.
batch_size: minibatch size to use on the input, defaults to first
dimension of `x`. Must be `None` if `input_fn` is provided.
monitors: List of `BaseMonitor` subclass instances. Used for callbacks
inside the training loop.
Returns:
`self`, for chaining.
Raises:
ValueError: If at least one of `x` and `y` is provided, and `input_fn` is
provided.
"""
logging.warning('The current implementation of partial_fit is not optimized'
' for use in a loop. Consider using fit() instead.')
return self.fit(x=x, y=y, input_fn=input_fn, steps=steps,
batch_size=batch_size, monitors=monitors)
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('y', None), ('batch_size', None)
)
def evaluate(self,
x=None,
y=None,
input_fn=None,
feed_fn=None,
batch_size=None,
steps=None,
metrics=None,
name=None,
checkpoint_path=None,
hooks=None,
log_progress=True):
# pylint: disable=g-doc-args,g-doc-return-or-yield
"""See `Evaluable`.
Raises:
ValueError: If at least one of `x` or `y` is provided, and at least one of
`input_fn` or `feed_fn` is provided.
Or if `metrics` is not `None` or `dict`.
"""
_verify_input_args(x, y, input_fn, feed_fn, batch_size)
if x is not None:
return SKCompat(self).score(x, y, batch_size, steps, metrics)
if metrics is not None and not isinstance(metrics, dict):
raise ValueError('Metrics argument should be None or dict. '
'Got %s.' % metrics)
eval_results, global_step = self._evaluate_model(
input_fn=input_fn,
feed_fn=feed_fn,
steps=steps,
metrics=metrics,
name=name,
checkpoint_path=checkpoint_path,
hooks=hooks,
log_progress=log_progress)
if eval_results is not None:
eval_results.update({'global_step': global_step})
return eval_results
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('batch_size', None), ('as_iterable', True)
)
def predict(
self, x=None, input_fn=None, batch_size=None, outputs=None,
as_iterable=True):
"""Returns predictions for given features.
Args:
x: Matrix of shape [n_samples, n_features...]. Can be iterator that
returns arrays of features. The training input samples for fitting the
model. If set, `input_fn` must be `None`.
input_fn: Input function. If set, `x` and 'batch_size' must be `None`.
batch_size: Override default batch size. If set, 'input_fn' must be
'None'.
outputs: list of `str`, name of the output to predict.
If `None`, returns all.
as_iterable: If True, return an iterable which keeps yielding predictions
for each example until inputs are exhausted. Note: The inputs must
terminate if you want the iterable to terminate (e.g. be sure to pass
num_epochs=1 if you are using something like read_batch_features).
Returns:
A numpy array of predicted classes or regression values if the
constructor's `model_fn` returns a `Tensor` for `predictions` or a `dict`
of numpy arrays if `model_fn` returns a `dict`. Returns an iterable of
predictions if as_iterable is True.
Raises:
ValueError: If x and input_fn are both provided or both `None`.
"""
_verify_input_args(x, None, input_fn, None, batch_size)
if x is not None and not as_iterable:
return SKCompat(self).predict(x, batch_size)
input_fn, feed_fn = _get_input_fn(x, None, input_fn, None, batch_size)
return self._infer_model(
input_fn=input_fn,
feed_fn=feed_fn,
outputs=outputs,
as_iterable=as_iterable)
def get_variable_value(self, name):
"""Returns value of the variable given by name.
Args:
name: string, name of the tensor.
Returns:
Numpy array - value of the tensor.
"""
return load_variable(self.model_dir, name)
def get_variable_names(self):
"""Returns list of all variable names in this model.
Returns:
List of names.
"""
return [name for name, _ in list_variables(self.model_dir)]
@property
def model_dir(self):
return self._model_dir
@deprecated('2017-03-25', 'Please use Estimator.export_savedmodel() instead.')
def export(self,
export_dir,
input_fn=export._default_input_fn, # pylint: disable=protected-access
input_feature_key=None,
use_deprecated_input_fn=True,
signature_fn=None,
prediction_key=None,
default_batch_size=1,
exports_to_keep=None,
checkpoint_path=None):
"""Exports inference graph into given dir.
Args:
export_dir: A string containing a directory to write the exported graph
and checkpoints.
input_fn: If `use_deprecated_input_fn` is true, then a function that given
`Tensor` of `Example` strings, parses it into features that are then
passed to the model. Otherwise, a function that takes no argument and
returns a tuple of (features, labels), where features is a dict of
string key to `Tensor` and labels is a `Tensor` that's currently not
used (and so can be `None`).
input_feature_key: Only used if `use_deprecated_input_fn` is false. String
key into the features dict returned by `input_fn` that corresponds to a
the raw `Example` strings `Tensor` that the exported model will take as
input. Can only be `None` if you're using a custom `signature_fn` that
does not use the first arg (examples).
use_deprecated_input_fn: Determines the signature format of `input_fn`.
signature_fn: Function that returns a default signature and a named
signature map, given `Tensor` of `Example` strings, `dict` of `Tensor`s
for features and `Tensor` or `dict` of `Tensor`s for predictions.
prediction_key: The key for a tensor in the `predictions` dict (output
from the `model_fn`) to use as the `predictions` input to the
`signature_fn`. Optional. If `None`, predictions will pass to
`signature_fn` without filtering.
default_batch_size: Default batch size of the `Example` placeholder.
exports_to_keep: Number of exports to keep.
checkpoint_path: the checkpoint path of the model to be exported. If it is
`None` (which is default), will use the latest checkpoint in
export_dir.
Returns:
The string path to the exported directory. NB: this functionality was
added ca. 2016/09/25; clients that depend on the return value may need
to handle the case where this function returns None because subclasses
are not returning a value.
"""
# pylint: disable=protected-access
return export._export_estimator(
estimator=self,
export_dir=export_dir,
signature_fn=signature_fn,
prediction_key=prediction_key,
input_fn=input_fn,
input_feature_key=input_feature_key,
use_deprecated_input_fn=use_deprecated_input_fn,
default_batch_size=default_batch_size,
exports_to_keep=exports_to_keep,
checkpoint_path=checkpoint_path)
@abc.abstractproperty
def _get_train_ops(self, features, labels):
"""Method that builds model graph and returns trainer ops.
Expected to be overridden by sub-classes that require custom support.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
Returns:
A `ModelFnOps` object.
"""
pass
@abc.abstractproperty
def _get_predict_ops(self, features):
"""Method that builds model graph and returns prediction ops.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
Returns:
A `ModelFnOps` object.
"""
pass
def _get_eval_ops(self, features, labels, metrics):
"""Method that builds model graph and returns evaluation ops.
Expected to be overriden by sub-classes that require custom support.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
metrics: Dict of metrics to run. If None, the default metric functions
are used; if {}, no metrics are used. Otherwise, `metrics` should map
friendly names for the metric to a `MetricSpec` object defining which
model outputs to evaluate against which labels with which metric
function. Metric ops should support streaming, e.g., returning
update_op and value tensors. See more details in
`../../../../metrics/python/metrics/ops/streaming_metrics.py` and
`../metric_spec.py`.
Returns:
A `ModelFnOps` object.
"""
raise NotImplementedError('_get_eval_ops not implemented in BaseEstimator')
@deprecated(
'2016-09-23',
'The signature of the input_fn accepted by export is changing to be '
'consistent with what\'s used by tf.Learn Estimator\'s train/evaluate, '
'which makes this function useless. This will be removed after the '
'deprecation date.')
def _get_feature_ops_from_example(self, examples_batch):
"""Returns feature parser for given example batch using features info.
This function requires `fit()` has been called.
Args:
examples_batch: batch of tf.Example
Returns:
features: `Tensor` or `dict` of `Tensor` objects.
Raises:
ValueError: If `_features_info` attribute is not available (usually
because `fit()` has not been called).
"""
if self._features_info is None:
raise ValueError('Features information missing, was fit() ever called?')
return tensor_signature.create_example_parser_from_signatures(
self._features_info, examples_batch)
def _check_inputs(self, features, labels):
if self._features_info is not None:
logging.debug('Given features: %s, required signatures: %s.',
str(features), str(self._features_info))
if not tensor_signature.tensors_compatible(features, self._features_info):
raise ValueError('Features are incompatible with given information. '
'Given features: %s, required signatures: %s.' %
(str(features), str(self._features_info)))
else:
self._features_info = tensor_signature.create_signatures(features)
logging.debug('Setting feature info to %s.', str(self._features_info))
if labels is not None:
if self._labels_info is not None:
logging.debug('Given labels: %s, required signatures: %s.',
str(labels), str(self._labels_info))
if not tensor_signature.tensors_compatible(labels, self._labels_info):
raise ValueError('Labels are incompatible with given information. '
'Given labels: %s, required signatures: %s.' %
(str(labels), str(self._labels_info)))
else:
self._labels_info = tensor_signature.create_signatures(labels)
logging.debug('Setting labels info to %s', str(self._labels_info))
def _extract_metric_update_ops(self, eval_dict):
"""Separate update operations from metric value operations."""
update_ops = []
value_ops = {}
for name, metric_ops in six.iteritems(eval_dict):
if isinstance(metric_ops, (list, tuple)):
if len(metric_ops) == 2:
value_ops[name] = metric_ops[0]
update_ops.append(metric_ops[1])
else:
logging.warning(
'Ignoring metric {}. It returned a list|tuple with len {}, '
'expected 2'.format(name, len(metric_ops)))
value_ops[name] = metric_ops
else:
value_ops[name] = metric_ops
if update_ops:
update_ops = control_flow_ops.group(*update_ops)
else:
update_ops = None
return update_ops, value_ops
def _evaluate_model(self,
input_fn,
steps,
feed_fn=None,
metrics=None,
name='',
checkpoint_path=None,
hooks=None,
log_progress=True):
# TODO(wicke): Remove this once Model and associated code are gone.
if (hasattr(self._config, 'execution_mode') and
self._config.execution_mode not in ('all', 'evaluate', 'eval_evalset')):
return None, None
# Check that model has been trained (if nothing has been set explicitly).
if not checkpoint_path:
latest_path = saver.latest_checkpoint(self._model_dir)
if not latest_path:
raise NotFittedError("Couldn't find trained model at %s."
% self._model_dir)
checkpoint_path = latest_path
# Setup output directory.
eval_dir = os.path.join(self._model_dir, 'eval' if not name else
'eval_' + name)
with ops.Graph().as_default() as g:
random_seed.set_random_seed(self._config.tf_random_seed)
global_step = contrib_framework.create_global_step(g)
features, labels = input_fn()
self._check_inputs(features, labels)
model_fn_results = self._get_eval_ops(features, labels, metrics)
eval_dict = model_fn_results.eval_metric_ops
update_op, eval_dict = self._extract_metric_update_ops(eval_dict)
# We need to copy the hook array as we modify it, thus [:].
hooks = hooks[:] if hooks else []
if feed_fn:
hooks.append(basic_session_run_hooks.FeedFnHook(feed_fn))
if steps:
hooks.append(
evaluation.StopAfterNEvalsHook(
steps, log_progress=log_progress))
global_step_key = 'global_step'
while global_step_key in eval_dict:
global_step_key = '_' + global_step_key
eval_dict[global_step_key] = global_step
eval_results = evaluation.evaluate_once(
checkpoint_path=checkpoint_path,
master=self._config.evaluation_master,
scaffold=model_fn_results.scaffold,
eval_ops=update_op,
final_ops=eval_dict,
hooks=hooks,
config=self._session_config)
current_global_step = eval_results[global_step_key]
_write_dict_to_summary(eval_dir, eval_results, current_global_step)
return eval_results, current_global_step
def _get_features_from_input_fn(self, input_fn):
result = input_fn()
if isinstance(result, (list, tuple)):
return result[0]
return result
def _infer_model(self,
input_fn,
feed_fn=None,
outputs=None,
as_iterable=True,
iterate_batches=False):
# Check that model has been trained.
checkpoint_path = saver.latest_checkpoint(self._model_dir)
if not checkpoint_path:
raise NotFittedError("Couldn't find trained model at %s."
% self._model_dir)
with ops.Graph().as_default() as g:
random_seed.set_random_seed(self._config.tf_random_seed)
contrib_framework.create_global_step(g)
features = self._get_features_from_input_fn(input_fn)
infer_ops = self._get_predict_ops(features)
predictions = self._filter_predictions(infer_ops.predictions, outputs)
mon_sess = monitored_session.MonitoredSession(
session_creator=monitored_session.ChiefSessionCreator(
checkpoint_filename_with_path=checkpoint_path,
scaffold=infer_ops.scaffold,
config=self._session_config))
if not as_iterable:
with mon_sess:
if not mon_sess.should_stop():
return mon_sess.run(predictions, feed_fn() if feed_fn else None)
else:
return self._predict_generator(mon_sess, predictions, feed_fn,
iterate_batches)
def _predict_generator(self, mon_sess, predictions, feed_fn, iterate_batches):
with mon_sess:
while not mon_sess.should_stop():
preds = mon_sess.run(predictions, feed_fn() if feed_fn else None)
if iterate_batches:
yield preds
elif not isinstance(predictions, dict):
for pred in preds:
yield pred
else:
first_tensor = list(preds.values())[0]
if isinstance(first_tensor, sparse_tensor.SparseTensorValue):
batch_length = first_tensor.dense_shape[0]
else:
batch_length = first_tensor.shape[0]
for i in range(batch_length):
yield {key: value[i] for key, value in six.iteritems(preds)}
if self._is_input_constant(feed_fn, mon_sess.graph):
return
def _is_input_constant(self, feed_fn, graph):
# If there are no queue_runners, the input `predictions` is a
# constant, and we should stop after the first epoch. If,
# instead, there are queue_runners, eventually they should throw
# an `OutOfRangeError`.
if graph.get_collection(ops.GraphKeys.QUEUE_RUNNERS):
return False
# data_feeder uses feed_fn to generate `OutOfRangeError`.
if feed_fn is not None:
return False
return True
def _filter_predictions(self, predictions, outputs):
if not outputs:
return predictions
if not isinstance(predictions, dict):
raise ValueError(
'outputs argument is not valid in case of non-dict predictions.')
existing_keys = predictions.keys()
predictions = {
key: value
for key, value in six.iteritems(predictions) if key in outputs
}
if not predictions:
raise ValueError('Expected to run at least one output from %s, '
'provided %s.' % (existing_keys, outputs))
return predictions
def _train_model(self, input_fn, hooks):
all_hooks = []
self._graph = ops.Graph()
with self._graph.as_default() as g, g.device(self._device_fn):
random_seed.set_random_seed(self._config.tf_random_seed)
global_step = contrib_framework.create_global_step(g)
features, labels = input_fn()
self._check_inputs(features, labels)
model_fn_ops = self._get_train_ops(features, labels)
ops.add_to_collection(ops.GraphKeys.LOSSES, model_fn_ops.loss)
all_hooks.extend([
basic_session_run_hooks.NanTensorHook(model_fn_ops.loss),
basic_session_run_hooks.LoggingTensorHook(
{
'loss': model_fn_ops.loss,
'step': global_step
},
every_n_iter=100)
])
all_hooks.extend(hooks)
scaffold = model_fn_ops.scaffold or monitored_session.Scaffold()
if not (scaffold.saver or ops.get_collection(ops.GraphKeys.SAVERS)):
ops.add_to_collection(
ops.GraphKeys.SAVERS,
saver.Saver(
sharded=True,
max_to_keep=self._config.keep_checkpoint_max,
defer_build=True,
save_relative_paths=True))
chief_hooks = []
if (self._config.save_checkpoints_secs or
self._config.save_checkpoints_steps):
saver_hook_exists = any([
isinstance(h, basic_session_run_hooks.CheckpointSaverHook)
for h in (all_hooks + model_fn_ops.training_hooks + chief_hooks +
model_fn_ops.training_chief_hooks)
])
if not saver_hook_exists:
chief_hooks = [
basic_session_run_hooks.CheckpointSaverHook(
self._model_dir,
save_secs=self._config.save_checkpoints_secs,
save_steps=self._config.save_checkpoints_steps,
scaffold=scaffold)
]
with monitored_session.MonitoredTrainingSession(
master=self._config.master,
is_chief=self._config.is_chief,
checkpoint_dir=self._model_dir,
scaffold=scaffold,
hooks=all_hooks + model_fn_ops.training_hooks,
chief_only_hooks=chief_hooks + model_fn_ops.training_chief_hooks,
save_checkpoint_secs=0, # Saving is handled by a hook.
save_summaries_steps=self._config.save_summary_steps,
config=self._session_config
) as mon_sess:
loss = None
while not mon_sess.should_stop():
_, loss = mon_sess.run([model_fn_ops.train_op, model_fn_ops.loss])
summary_io.SummaryWriterCache.clear()
return loss
def _identity_feature_engineering_fn(features, labels):
return features, labels
class Estimator(BaseEstimator):
"""Estimator class is the basic TensorFlow model trainer/evaluator.
"""
def __init__(self,
model_fn=None,
model_dir=None,
config=None,
params=None,
feature_engineering_fn=None):
"""Constructs an `Estimator` instance.
Args:
model_fn: Model function. Follows the signature:
* Args:
* `features`: single `Tensor` or `dict` of `Tensor`s
(depending on data passed to `fit`),
* `labels`: `Tensor` or `dict` of `Tensor`s (for multi-head
models). If mode is `ModeKeys.INFER`, `labels=None` will be
passed. If the `model_fn`'s signature does not accept
`mode`, the `model_fn` must still be able to handle
`labels=None`.
* `mode`: Optional. Specifies if this training, evaluation or
prediction. See `ModeKeys`.
* `params`: Optional `dict` of hyperparameters. Will receive what
is passed to Estimator in `params` parameter. This allows
to configure Estimators from hyper parameter tuning.
* `config`: Optional configuration object. Will receive what is passed
to Estimator in `config` parameter, or the default `config`.
Allows updating things in your model_fn based on configuration
such as `num_ps_replicas`.
* `model_dir`: Optional directory where model parameters, graph etc
are saved. Will receive what is passed to Estimator in
`model_dir` parameter, or the default `model_dir`. Allows
updating things in your model_fn that expect model_dir, such as
training hooks.
* Returns:
`ModelFnOps`
Also supports a legacy signature which returns tuple of:
* predictions: `Tensor`, `SparseTensor` or dictionary of same.
Can also be any type that is convertible to a `Tensor` or
`SparseTensor`, or dictionary of same.
* loss: Scalar loss `Tensor`.
* train_op: Training update `Tensor` or `Operation`.
Supports next three signatures for the function:
* `(features, labels) -> (predictions, loss, train_op)`
* `(features, labels, mode) -> (predictions, loss, train_op)`
* `(features, labels, mode, params) -> (predictions, loss, train_op)`
* `(features, labels, mode, params, config) ->
(predictions, loss, train_op)`
* `(features, labels, mode, params, config, model_dir) ->
(predictions, loss, train_op)`
model_dir: Directory to save model parameters, graph and etc. This can
also be used to load checkpoints from the directory into a estimator to
continue training a previously saved model.
config: Configuration object.
params: `dict` of hyper parameters that will be passed into `model_fn`.
Keys are names of parameters, values are basic python types.
feature_engineering_fn: Feature engineering function. Takes features and
labels which are the output of `input_fn` and
returns features and labels which will be fed
into `model_fn`. Please check `model_fn` for
a definition of features and labels.
Raises:
ValueError: parameters of `model_fn` don't match `params`.
"""
super(Estimator, self).__init__(model_dir=model_dir, config=config)
if model_fn is not None:
# Check number of arguments of the given function matches requirements.
model_fn_args = _model_fn_args(model_fn)
if params is not None and 'params' not in model_fn_args:
raise ValueError('Estimator\'s model_fn (%s) has less than 4 '
'arguments, but not None params (%s) are passed.' %
(model_fn, params))
if params is None and 'params' in model_fn_args:
logging.warning('Estimator\'s model_fn (%s) includes params '
'argument, but params are not passed to Estimator.',
model_fn)
self._model_fn = model_fn
self.params = params
self._feature_engineering_fn = (
feature_engineering_fn or _identity_feature_engineering_fn)
def _call_model_fn(self, features, labels, mode):
"""Calls model function with support of 2, 3 or 4 arguments.
Args:
features: features dict.
labels: labels dict.
mode: ModeKeys
Returns:
A `ModelFnOps` object. If model_fn returns a tuple, wraps them up in a
`ModelFnOps` object.
Raises:
ValueError: if model_fn returns invalid objects.
"""
features, labels = self._feature_engineering_fn(features, labels)
model_fn_args = _model_fn_args(self._model_fn)
kwargs = {}
if 'mode' in model_fn_args:
kwargs['mode'] = mode
if 'params' in model_fn_args:
kwargs['params'] = self.params
if 'config' in model_fn_args:
kwargs['config'] = self.config
if 'model_dir' in model_fn_args:
kwargs['model_dir'] = self.model_dir
model_fn_results = self._model_fn(features, labels, **kwargs)
if isinstance(model_fn_results, model_fn_lib.ModelFnOps):
return model_fn_results
# Here model_fn_results should be a tuple with 3 elements.
if len(model_fn_results) != 3:
raise ValueError('Unrecognized value returned by model_fn, '
'please return ModelFnOps.')
return model_fn_lib.ModelFnOps(
mode=mode,
predictions=model_fn_results[0],
loss=model_fn_results[1],
train_op=model_fn_results[2])
def _get_train_ops(self, features, labels):
"""Method that builds model graph and returns trainer ops.
Expected to be overriden by sub-classes that require custom support.
This implementation uses `model_fn` passed as parameter to constructor to
build model.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
Returns:
`ModelFnOps` object.
"""
return self._call_model_fn(features, labels, model_fn_lib.ModeKeys.TRAIN)
def _get_eval_ops(self, features, labels, metrics):
"""Method that builds model graph and returns evaluation ops.
Expected to be overriden by sub-classes that require custom support.
This implementation uses `model_fn` passed as parameter to constructor to
build model.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
metrics: Dict of metrics to run. If None, the default metric functions
are used; if {}, no metrics are used. Otherwise, `metrics` should map
friendly names for the metric to a `MetricSpec` object defining which
model outputs to evaluate against which labels with which metric
function. Metric ops should support streaming, e.g., returning
update_op and value tensors. See more details in
`../../../../metrics/python/metrics/ops/streaming_metrics.py` and
`../metric_spec.py`.
Returns:
`ModelFnOps` object.
Raises:
ValueError: if `metrics` don't match `labels`.
"""
model_fn_ops = self._call_model_fn(
features, labels, model_fn_lib.ModeKeys.EVAL)
features, labels = self._feature_engineering_fn(features, labels)
# Custom metrics should overwrite defaults.
if metrics:
model_fn_ops.eval_metric_ops.update(_make_metrics_ops(
metrics, features, labels, model_fn_ops.predictions))
if metric_key.MetricKey.LOSS not in model_fn_ops.eval_metric_ops:
model_fn_ops.eval_metric_ops[metric_key.MetricKey.LOSS] = (
metrics_lib.streaming_mean(model_fn_ops.loss))
return model_fn_ops
def _get_predict_ops(self, features):
"""Method that builds model graph and returns prediction ops.
Expected to be overriden by sub-classes that require custom support.
This implementation uses `model_fn` passed as parameter to constructor to
build model.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
Returns:
`ModelFnOps` object.
"""
labels = tensor_signature.create_placeholders_from_signatures(
self._labels_info)
return self._call_model_fn(features, labels, model_fn_lib.ModeKeys.INFER)
def export_savedmodel(
self, export_dir_base, serving_input_fn,
default_output_alternative_key=None,
assets_extra=None,
as_text=False,
checkpoint_path=None):
"""Exports inference graph as a SavedModel into given dir.
Args:
export_dir_base: A string containing a directory to write the exported
graph and checkpoints.
serving_input_fn: A function that takes no argument and
returns an `InputFnOps`.
default_output_alternative_key: the name of the head to serve when none is
specified. Not needed for single-headed models.
assets_extra: A dict specifying how to populate the assets.extra directory
within the exported SavedModel. Each key should give the destination
path (including the filename) relative to the assets.extra directory.
The corresponding value gives the full path of the source file to be
copied. For example, the simple case of copying a single file without
renaming it is specified as
`{'my_asset_file.txt': '/path/to/my_asset_file.txt'}`.
as_text: whether to write the SavedModel proto in text format.
checkpoint_path: The checkpoint path to export. If None (the default),
the most recent checkpoint found within the model directory is chosen.
Returns:
The string path to the exported directory.
Raises:
ValueError: if an unrecognized export_type is requested.
"""
if serving_input_fn is None:
raise ValueError('serving_input_fn must be defined.')
with ops.Graph().as_default() as g:
contrib_variables.create_global_step(g)
# Call the serving_input_fn and collect the input alternatives.
input_ops = serving_input_fn()
input_alternatives, features = (
saved_model_export_utils.get_input_alternatives(input_ops))
# TODO(b/34388557) This is a stopgap, pending recording model provenance.
# Record which features are expected at serving time. It is assumed that
# these are the features that were used in training.
for feature_key in input_ops.features.keys():
ops.add_to_collection(
constants.COLLECTION_DEF_KEY_FOR_INPUT_FEATURE_KEYS, feature_key)
# Call the model_fn and collect the output alternatives.
model_fn_ops = self._call_model_fn(features, None,
model_fn_lib.ModeKeys.INFER)
output_alternatives, actual_default_output_alternative_key = (
saved_model_export_utils.get_output_alternatives(
model_fn_ops, default_output_alternative_key))
# Build the SignatureDefs from all pairs of input and output alternatives
signature_def_map = saved_model_export_utils.build_all_signature_defs(
input_alternatives, output_alternatives,
actual_default_output_alternative_key)
if not checkpoint_path:
# Locate the latest checkpoint
checkpoint_path = saver.latest_checkpoint(self._model_dir)
if not checkpoint_path:
raise NotFittedError("Couldn't find trained model at %s."
% self._model_dir)
export_dir = saved_model_export_utils.get_timestamped_export_dir(
export_dir_base)
if (model_fn_ops.scaffold is not None and
model_fn_ops.scaffold.saver is not None):
saver_for_restore = model_fn_ops.scaffold.saver
else:
saver_for_restore = saver.Saver(sharded=True)
with tf_session.Session('') as session:
saver_for_restore.restore(session, checkpoint_path)
init_op = control_flow_ops.group(
variables.local_variables_initializer(),
resources.initialize_resources(resources.shared_resources()),
lookup_ops.tables_initializer())
# Perform the export
builder = saved_model_builder.SavedModelBuilder(export_dir)
builder.add_meta_graph_and_variables(
session, [tag_constants.SERVING],
signature_def_map=signature_def_map,
assets_collection=ops.get_collection(
ops.GraphKeys.ASSET_FILEPATHS),
legacy_init_op=init_op)
builder.save(as_text)
# Add the extra assets
if assets_extra:
assets_extra_path = os.path.join(compat.as_bytes(export_dir),
compat.as_bytes('assets.extra'))
for dest_relative, source in assets_extra.items():
dest_absolute = os.path.join(compat.as_bytes(assets_extra_path),
compat.as_bytes(dest_relative))
dest_path = os.path.dirname(dest_absolute)
gfile.MakeDirs(dest_path)
gfile.Copy(source, dest_absolute)
return export_dir
# For time of deprecation x,y from Estimator allow direct access.
# pylint: disable=protected-access
class SKCompat(sklearn.BaseEstimator):
"""Scikit learn wrapper for TensorFlow Learn Estimator."""
def __init__(self, estimator):
self._estimator = estimator
def fit(self, x, y, batch_size=128, steps=None, max_steps=None,
monitors=None):
input_fn, feed_fn = _get_input_fn(x, y, input_fn=None, feed_fn=None,
batch_size=batch_size, shuffle=True,
epochs=None)
all_monitors = []
if feed_fn:
all_monitors = [basic_session_run_hooks.FeedFnHook(feed_fn)]
if monitors:
all_monitors.extend(monitors)
self._estimator.fit(input_fn=input_fn,
steps=steps,
max_steps=max_steps,
monitors=all_monitors)
return self
def score(self, x, y, batch_size=128, steps=None, metrics=None):
input_fn, feed_fn = _get_input_fn(x, y, input_fn=None,
feed_fn=None, batch_size=batch_size,
shuffle=False, epochs=1)
if metrics is not None and not isinstance(metrics, dict):
raise ValueError('Metrics argument should be None or dict. '
'Got %s.' % metrics)
eval_results, global_step = self._estimator._evaluate_model(
input_fn=input_fn,
feed_fn=feed_fn,
steps=steps,
metrics=metrics,
name='score')
if eval_results is not None:
eval_results.update({'global_step': global_step})
return eval_results
def predict(self, x, batch_size=128, outputs=None):
input_fn, feed_fn = _get_input_fn(
x, None, input_fn=None, feed_fn=None, batch_size=batch_size,
shuffle=False, epochs=1)
results = list(
self._estimator._infer_model(
input_fn=input_fn,
feed_fn=feed_fn,
outputs=outputs,
as_iterable=True,
iterate_batches=True))
if not isinstance(results[0], dict):
return np.concatenate([output for output in results], axis=0)
return {
key: np.concatenate(
[output[key] for output in results], axis=0)
for key in results[0]
}
| apache-2.0 |
henridwyer/scikit-learn | examples/calibration/plot_calibration.py | 225 | 4795 | """
======================================
Probability calibration of classifiers
======================================
When performing classification you often want to predict not only
the class label, but also the associated probability. This probability
gives you some kind of confidence on the prediction. However, not all
classifiers provide well-calibrated probabilities, some being over-confident
while others being under-confident. Thus, a separate calibration of predicted
probabilities is often desirable as a postprocessing. This example illustrates
two different methods for this calibration and evaluates the quality of the
returned probabilities using Brier's score
(see http://en.wikipedia.org/wiki/Brier_score).
Compared are the estimated probability using a Gaussian naive Bayes classifier
without calibration, with a sigmoid calibration, and with a non-parametric
isotonic calibration. One can observe that only the non-parametric model is able
to provide a probability calibration that returns probabilities close to the
expected 0.5 for most of the samples belonging to the middle cluster with
heterogeneous labels. This results in a significantly improved Brier score.
"""
print(__doc__)
# Author: Mathieu Blondel <[email protected]>
# Alexandre Gramfort <[email protected]>
# Balazs Kegl <[email protected]>
# Jan Hendrik Metzen <[email protected]>
# License: BSD Style.
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import cm
from sklearn.datasets import make_blobs
from sklearn.naive_bayes import GaussianNB
from sklearn.metrics import brier_score_loss
from sklearn.calibration import CalibratedClassifierCV
from sklearn.cross_validation import train_test_split
n_samples = 50000
n_bins = 3 # use 3 bins for calibration_curve as we have 3 clusters here
# Generate 3 blobs with 2 classes where the second blob contains
# half positive samples and half negative samples. Probability in this
# blob is therefore 0.5.
centers = [(-5, -5), (0, 0), (5, 5)]
X, y = make_blobs(n_samples=n_samples, n_features=2, cluster_std=1.0,
centers=centers, shuffle=False, random_state=42)
y[:n_samples // 2] = 0
y[n_samples // 2:] = 1
sample_weight = np.random.RandomState(42).rand(y.shape[0])
# split train, test for calibration
X_train, X_test, y_train, y_test, sw_train, sw_test = \
train_test_split(X, y, sample_weight, test_size=0.9, random_state=42)
# Gaussian Naive-Bayes with no calibration
clf = GaussianNB()
clf.fit(X_train, y_train) # GaussianNB itself does not support sample-weights
prob_pos_clf = clf.predict_proba(X_test)[:, 1]
# Gaussian Naive-Bayes with isotonic calibration
clf_isotonic = CalibratedClassifierCV(clf, cv=2, method='isotonic')
clf_isotonic.fit(X_train, y_train, sw_train)
prob_pos_isotonic = clf_isotonic.predict_proba(X_test)[:, 1]
# Gaussian Naive-Bayes with sigmoid calibration
clf_sigmoid = CalibratedClassifierCV(clf, cv=2, method='sigmoid')
clf_sigmoid.fit(X_train, y_train, sw_train)
prob_pos_sigmoid = clf_sigmoid.predict_proba(X_test)[:, 1]
print("Brier scores: (the smaller the better)")
clf_score = brier_score_loss(y_test, prob_pos_clf, sw_test)
print("No calibration: %1.3f" % clf_score)
clf_isotonic_score = brier_score_loss(y_test, prob_pos_isotonic, sw_test)
print("With isotonic calibration: %1.3f" % clf_isotonic_score)
clf_sigmoid_score = brier_score_loss(y_test, prob_pos_sigmoid, sw_test)
print("With sigmoid calibration: %1.3f" % clf_sigmoid_score)
###############################################################################
# Plot the data and the predicted probabilities
plt.figure()
y_unique = np.unique(y)
colors = cm.rainbow(np.linspace(0.0, 1.0, y_unique.size))
for this_y, color in zip(y_unique, colors):
this_X = X_train[y_train == this_y]
this_sw = sw_train[y_train == this_y]
plt.scatter(this_X[:, 0], this_X[:, 1], s=this_sw * 50, c=color, alpha=0.5,
label="Class %s" % this_y)
plt.legend(loc="best")
plt.title("Data")
plt.figure()
order = np.lexsort((prob_pos_clf, ))
plt.plot(prob_pos_clf[order], 'r', label='No calibration (%1.3f)' % clf_score)
plt.plot(prob_pos_isotonic[order], 'g', linewidth=3,
label='Isotonic calibration (%1.3f)' % clf_isotonic_score)
plt.plot(prob_pos_sigmoid[order], 'b', linewidth=3,
label='Sigmoid calibration (%1.3f)' % clf_sigmoid_score)
plt.plot(np.linspace(0, y_test.size, 51)[1::2],
y_test[order].reshape(25, -1).mean(1),
'k', linewidth=3, label=r'Empirical')
plt.ylim([-0.05, 1.05])
plt.xlabel("Instances sorted according to predicted probability "
"(uncalibrated GNB)")
plt.ylabel("P(y=1)")
plt.legend(loc="upper left")
plt.title("Gaussian naive Bayes probabilities")
plt.show()
| bsd-3-clause |
grantvk/aima-python | submissions/Fritz/myNN.py | 13 | 4756 | from sklearn import datasets
from sklearn.neural_network import MLPClassifier
import traceback
from submissions.Fritz import medal_of_honor
class DataFrame:
data = []
feature_names = []
target = []
target_names = []
honordata = DataFrame()
honordata.data = []
honortarget = []
class DataFrame2:
data2 = []
feature_names2 = []
target2 = []
target_names2 = []
honortarget2 = []
honordata2 = DataFrame2()
honordata2.data = []
medalofhonor = medal_of_honor.get_awardees(test=True)
for issued in medalofhonor:
try:
date = int(issued['birth']["date"]["year"])
honortarget.append(date)
date2 = int(issued['awarded']["date"]["month"])
honortarget2.append(date2)
day = int(issued['awarded']['date']['day'])
month = int(issued['awarded']['date']['month'])
year = int(issued['awarded']['date']['year'])
dayBorn = int(issued['birth']['date']['day'])
monthBorn = int(issued['birth']['date']['month'])
yearBorn = int(issued['birth']['date']['year'])
honordata.data.append([day, month, year])
honordata2.data.append([dayBorn, monthBorn, yearBorn])
except:
traceback.print_exc()
honordata.feature_names = [
'day',
'month',
'year',
]
honordata2.feature_names = [
'dayBorn',
'monthBorn',
'yearBorn',
]
honordata.target = []
honordata2.target = []
def targetdata(HDate):
if (HDate > 1880 and HDate != -1):
return 1
return 0
def targetdata2(HDate2):
if (HDate2 > 10 and HDate2 != -1):
return 1
return 0
for issued in honortarget:
TD = targetdata(issued)
honordata.target.append(TD)
honordata.target_names = [
'Born before 1880',
'Born after 1880',
]
for issued2 in honortarget2:
TD2 = targetdata2(issued2)
honordata2.target.append(TD2)
honordata2.target_names = [
'Awarded on or before October',
'Awarded after October',
]
'''
Make a customn classifier,
'''
mlpc = MLPClassifier(
# hidden_layer_sizes = (100,),
# activation = 'relu',
solver='sgd', # 'adam',
# alpha = 0.0001,
# batch_size='auto',
learning_rate = 'adaptive', # 'constant',
# power_t = 0.5,
max_iter = 1000, # 200,
# shuffle = True,
# random_state = None,
# tol = 1e-4,
# verbose = False,
# warm_start = False,
# momentum = 0.9,
# nesterovs_momentum = True,
# early_stopping = False,
# validation_fraction = 0.1,
# beta_1 = 0.9,
# beta_2 = 0.999,
# epsilon = 1e-8,
)
'''
Scaling the data.
'''
dateScaled = DataFrame()
def setupScales(grid):
global min, max
min = list(grid[0])
max = list(grid[0])
for row in range(1, len(grid)):
for col in range(len(grid[row])):
cell = grid[row][col]
if cell < min[col]:
min[col] = cell
if cell > max[col]:
max[col] = cell
def scaleGrid(grid):
newGrid = []
for row in range(len(grid)):
newRow = []
for col in range(len(grid[row])):
try:
cell = grid[row][col]
scaled = (cell - min[col]) \
/ (max[col] - min[col])
newRow.append(scaled)
except:
pass
newGrid.append(newRow)
return newGrid
setupScales(honordata.data)
dateScaled.data = scaleGrid(honordata.data)
dateScaled.feature_names = honordata.feature_names
dateScaled.target = honordata.target
dateScaled.target_names = honordata.target_names
dateScaled2 = DataFrame2()
def setupScales2(grid):
global min, max
min = list(grid[0])
max = list(grid[0])
for row in range(1, len(grid)):
for col in range(len(grid[row])):
cell = grid[row][col]
if cell < min[col]:
min[col] = cell
if cell > max[col]:
max[col] = cell
def scaleGrid2(grid):
newGrid = []
for row in range(len(grid)):
newRow = []
for col in range(len(grid[row])):
try:
cell = grid[row][col]
scaled2 = (cell - min[col]) \
/ (max[col] - min[col])
newRow.append(scaled2)
except:
pass
newGrid.append(newRow)
return newGrid
setupScales(honordata2.data)
dateScaled2.data = scaleGrid2(honordata2.data)
dateScaled2.feature_names = honordata2.feature_names
dateScaled2.target = honordata2.target
dateScaled2.target_names = honordata2.target_names
Examples = {
'Default Date':{
'frame': honordata,
},
'DateSGD': {
'frame': honordata,
'mlpc': mlpc
},
'dateScaled2': {
'frame': dateScaled,
},
}
| mit |
procoder317/scikit-learn | examples/svm/plot_weighted_samples.py | 188 | 1943 | """
=====================
SVM: Weighted samples
=====================
Plot decision function of a weighted dataset, where the size of points
is proportional to its weight.
The sample weighting rescales the C parameter, which means that the classifier
puts more emphasis on getting these points right. The effect might often be
subtle.
To emphasize the effect here, we particularly weight outliers, making the
deformation of the decision boundary very visible.
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from sklearn import svm
def plot_decision_function(classifier, sample_weight, axis, title):
# plot the decision function
xx, yy = np.meshgrid(np.linspace(-4, 5, 500), np.linspace(-4, 5, 500))
Z = classifier.decision_function(np.c_[xx.ravel(), yy.ravel()])
Z = Z.reshape(xx.shape)
# plot the line, the points, and the nearest vectors to the plane
axis.contourf(xx, yy, Z, alpha=0.75, cmap=plt.cm.bone)
axis.scatter(X[:, 0], X[:, 1], c=Y, s=100 * sample_weight, alpha=0.9,
cmap=plt.cm.bone)
axis.axis('off')
axis.set_title(title)
# we create 20 points
np.random.seed(0)
X = np.r_[np.random.randn(10, 2) + [1, 1], np.random.randn(10, 2)]
Y = [1] * 10 + [-1] * 10
sample_weight_last_ten = abs(np.random.randn(len(X)))
sample_weight_constant = np.ones(len(X))
# and bigger weights to some outliers
sample_weight_last_ten[15:] *= 5
sample_weight_last_ten[9] *= 15
# for reference, first fit without class weights
# fit the model
clf_weights = svm.SVC()
clf_weights.fit(X, Y, sample_weight=sample_weight_last_ten)
clf_no_weights = svm.SVC()
clf_no_weights.fit(X, Y)
fig, axes = plt.subplots(1, 2, figsize=(14, 6))
plot_decision_function(clf_no_weights, sample_weight_constant, axes[0],
"Constant weights")
plot_decision_function(clf_weights, sample_weight_last_ten, axes[1],
"Modified weights")
plt.show()
| bsd-3-clause |
nesterione/scikit-learn | examples/ensemble/plot_random_forest_embedding.py | 286 | 3531 | """
=========================================================
Hashing feature transformation using Totally Random Trees
=========================================================
RandomTreesEmbedding provides a way to map data to a
very high-dimensional, sparse representation, which might
be beneficial for classification.
The mapping is completely unsupervised and very efficient.
This example visualizes the partitions given by several
trees and shows how the transformation can also be used for
non-linear dimensionality reduction or non-linear classification.
Points that are neighboring often share the same leaf of a tree and therefore
share large parts of their hashed representation. This allows to
separate two concentric circles simply based on the principal components of the
transformed data.
In high-dimensional spaces, linear classifiers often achieve
excellent accuracy. For sparse binary data, BernoulliNB
is particularly well-suited. The bottom row compares the
decision boundary obtained by BernoulliNB in the transformed
space with an ExtraTreesClassifier forests learned on the
original data.
"""
import numpy as np
import matplotlib.pyplot as plt
from sklearn.datasets import make_circles
from sklearn.ensemble import RandomTreesEmbedding, ExtraTreesClassifier
from sklearn.decomposition import TruncatedSVD
from sklearn.naive_bayes import BernoulliNB
# make a synthetic dataset
X, y = make_circles(factor=0.5, random_state=0, noise=0.05)
# use RandomTreesEmbedding to transform data
hasher = RandomTreesEmbedding(n_estimators=10, random_state=0, max_depth=3)
X_transformed = hasher.fit_transform(X)
# Visualize result using PCA
pca = TruncatedSVD(n_components=2)
X_reduced = pca.fit_transform(X_transformed)
# Learn a Naive Bayes classifier on the transformed data
nb = BernoulliNB()
nb.fit(X_transformed, y)
# Learn an ExtraTreesClassifier for comparison
trees = ExtraTreesClassifier(max_depth=3, n_estimators=10, random_state=0)
trees.fit(X, y)
# scatter plot of original and reduced data
fig = plt.figure(figsize=(9, 8))
ax = plt.subplot(221)
ax.scatter(X[:, 0], X[:, 1], c=y, s=50)
ax.set_title("Original Data (2d)")
ax.set_xticks(())
ax.set_yticks(())
ax = plt.subplot(222)
ax.scatter(X_reduced[:, 0], X_reduced[:, 1], c=y, s=50)
ax.set_title("PCA reduction (2d) of transformed data (%dd)" %
X_transformed.shape[1])
ax.set_xticks(())
ax.set_yticks(())
# Plot the decision in original space. For that, we will assign a color to each
# point in the mesh [x_min, m_max] x [y_min, y_max].
h = .01
x_min, x_max = X[:, 0].min() - .5, X[:, 0].max() + .5
y_min, y_max = X[:, 1].min() - .5, X[:, 1].max() + .5
xx, yy = np.meshgrid(np.arange(x_min, x_max, h), np.arange(y_min, y_max, h))
# transform grid using RandomTreesEmbedding
transformed_grid = hasher.transform(np.c_[xx.ravel(), yy.ravel()])
y_grid_pred = nb.predict_proba(transformed_grid)[:, 1]
ax = plt.subplot(223)
ax.set_title("Naive Bayes on Transformed data")
ax.pcolormesh(xx, yy, y_grid_pred.reshape(xx.shape))
ax.scatter(X[:, 0], X[:, 1], c=y, s=50)
ax.set_ylim(-1.4, 1.4)
ax.set_xlim(-1.4, 1.4)
ax.set_xticks(())
ax.set_yticks(())
# transform grid using ExtraTreesClassifier
y_grid_pred = trees.predict_proba(np.c_[xx.ravel(), yy.ravel()])[:, 1]
ax = plt.subplot(224)
ax.set_title("ExtraTrees predictions")
ax.pcolormesh(xx, yy, y_grid_pred.reshape(xx.shape))
ax.scatter(X[:, 0], X[:, 1], c=y, s=50)
ax.set_ylim(-1.4, 1.4)
ax.set_xlim(-1.4, 1.4)
ax.set_xticks(())
ax.set_yticks(())
plt.tight_layout()
plt.show()
| bsd-3-clause |
DailyActie/Surrogate-Model | 01-codes/scikit-learn-master/benchmarks/bench_tree.py | 1 | 3618 | """
To run this, you'll need to have installed.
* scikit-learn
Does two benchmarks
First, we fix a training set, increase the number of
samples to classify and plot number of classified samples as a
function of time.
In the second benchmark, we increase the number of dimensions of the
training set, classify a sample and plot the time taken as a function
of the number of dimensions.
"""
import gc
from datetime import datetime
import numpy as np
import pylab as pl
# to store the results
scikit_classifier_results = []
scikit_regressor_results = []
mu_second = 0.0 + 10 ** 6 # number of microseconds in a second
def bench_scikit_tree_classifier(X, Y):
"""Benchmark with scikit-learn decision tree classifier"""
from sklearn.tree import DecisionTreeClassifier
gc.collect()
# start time
tstart = datetime.now()
clf = DecisionTreeClassifier()
clf.fit(X, Y).predict(X)
delta = (datetime.now() - tstart)
# stop time
scikit_classifier_results.append(
delta.seconds + delta.microseconds / mu_second)
def bench_scikit_tree_regressor(X, Y):
"""Benchmark with scikit-learn decision tree regressor"""
from sklearn.tree import DecisionTreeRegressor
gc.collect()
# start time
tstart = datetime.now()
clf = DecisionTreeRegressor()
clf.fit(X, Y).predict(X)
delta = (datetime.now() - tstart)
# stop time
scikit_regressor_results.append(
delta.seconds + delta.microseconds / mu_second)
if __name__ == '__main__':
print('============================================')
print('Warning: this is going to take a looong time')
print('============================================')
n = 10
step = 10000
n_samples = 10000
dim = 10
n_classes = 10
for i in range(n):
print('============================================')
print('Entering iteration %s of %s' % (i, n))
print('============================================')
n_samples += step
X = np.random.randn(n_samples, dim)
Y = np.random.randint(0, n_classes, (n_samples,))
bench_scikit_tree_classifier(X, Y)
Y = np.random.randn(n_samples)
bench_scikit_tree_regressor(X, Y)
xx = range(0, n * step, step)
pl.figure('scikit-learn tree benchmark results')
pl.subplot(211)
pl.title('Learning with varying number of samples')
pl.plot(xx, scikit_classifier_results, 'g-', label='classification')
pl.plot(xx, scikit_regressor_results, 'r-', label='regression')
pl.legend(loc='upper left')
pl.xlabel('number of samples')
pl.ylabel('Time (s)')
scikit_classifier_results = []
scikit_regressor_results = []
n = 10
step = 500
start_dim = 500
n_classes = 10
dim = start_dim
for i in range(0, n):
print('============================================')
print('Entering iteration %s of %s' % (i, n))
print('============================================')
dim += step
X = np.random.randn(100, dim)
Y = np.random.randint(0, n_classes, (100,))
bench_scikit_tree_classifier(X, Y)
Y = np.random.randn(100)
bench_scikit_tree_regressor(X, Y)
xx = np.arange(start_dim, start_dim + n * step, step)
pl.subplot(212)
pl.title('Learning in high dimensional spaces')
pl.plot(xx, scikit_classifier_results, 'g-', label='classification')
pl.plot(xx, scikit_regressor_results, 'r-', label='regression')
pl.legend(loc='upper left')
pl.xlabel('number of dimensions')
pl.ylabel('Time (s)')
pl.axis('tight')
pl.show()
| mit |
ZENGXH/scikit-learn | sklearn/neighbors/regression.py | 106 | 10572 | """Nearest Neighbor Regression"""
# Authors: Jake Vanderplas <[email protected]>
# Fabian Pedregosa <[email protected]>
# Alexandre Gramfort <[email protected]>
# Sparseness support by Lars Buitinck <[email protected]>
# Multi-output support by Arnaud Joly <[email protected]>
#
# License: BSD 3 clause (C) INRIA, University of Amsterdam
import numpy as np
from .base import _get_weights, _check_weights, NeighborsBase, KNeighborsMixin
from .base import RadiusNeighborsMixin, SupervisedFloatMixin
from ..base import RegressorMixin
from ..utils import check_array
class KNeighborsRegressor(NeighborsBase, KNeighborsMixin,
SupervisedFloatMixin,
RegressorMixin):
"""Regression based on k-nearest neighbors.
The target is predicted by local interpolation of the targets
associated of the nearest neighbors in the training set.
Read more in the :ref:`User Guide <regression>`.
Parameters
----------
n_neighbors : int, optional (default = 5)
Number of neighbors to use by default for :meth:`k_neighbors` queries.
weights : str or callable
weight function used in prediction. Possible values:
- 'uniform' : uniform weights. All points in each neighborhood
are weighted equally.
- 'distance' : weight points by the inverse of their distance.
in this case, closer neighbors of a query point will have a
greater influence than neighbors which are further away.
- [callable] : a user-defined function which accepts an
array of distances, and returns an array of the same shape
containing the weights.
Uniform weights are used by default.
algorithm : {'auto', 'ball_tree', 'kd_tree', 'brute'}, optional
Algorithm used to compute the nearest neighbors:
- 'ball_tree' will use :class:`BallTree`
- 'kd_tree' will use :class:`KDtree`
- 'brute' will use a brute-force search.
- 'auto' will attempt to decide the most appropriate algorithm
based on the values passed to :meth:`fit` method.
Note: fitting on sparse input will override the setting of
this parameter, using brute force.
leaf_size : int, optional (default = 30)
Leaf size passed to BallTree or KDTree. This can affect the
speed of the construction and query, as well as the memory
required to store the tree. The optimal value depends on the
nature of the problem.
metric : string or DistanceMetric object (default='minkowski')
the distance metric to use for the tree. The default metric is
minkowski, and with p=2 is equivalent to the standard Euclidean
metric. See the documentation of the DistanceMetric class for a
list of available metrics.
p : integer, optional (default = 2)
Power parameter for the Minkowski metric. When p = 1, this is
equivalent to using manhattan_distance (l1), and euclidean_distance
(l2) for p = 2. For arbitrary p, minkowski_distance (l_p) is used.
metric_params: dict, optional (default = None)
additional keyword arguments for the metric function.
Examples
--------
>>> X = [[0], [1], [2], [3]]
>>> y = [0, 0, 1, 1]
>>> from sklearn.neighbors import KNeighborsRegressor
>>> neigh = KNeighborsRegressor(n_neighbors=2)
>>> neigh.fit(X, y) # doctest: +ELLIPSIS
KNeighborsRegressor(...)
>>> print(neigh.predict([[1.5]]))
[ 0.5]
See also
--------
NearestNeighbors
RadiusNeighborsRegressor
KNeighborsClassifier
RadiusNeighborsClassifier
Notes
-----
See :ref:`Nearest Neighbors <neighbors>` in the online documentation
for a discussion of the choice of ``algorithm`` and ``leaf_size``.
.. warning::
Regarding the Nearest Neighbors algorithms, if it is found that two
neighbors, neighbor `k+1` and `k`, have identical distances but
but different labels, the results will depend on the ordering of the
training data.
http://en.wikipedia.org/wiki/K-nearest_neighbor_algorithm
"""
def __init__(self, n_neighbors=5, weights='uniform',
algorithm='auto', leaf_size=30,
p=2, metric='minkowski', metric_params=None, **kwargs):
self._init_params(n_neighbors=n_neighbors,
algorithm=algorithm,
leaf_size=leaf_size, metric=metric, p=p,
metric_params=metric_params, **kwargs)
self.weights = _check_weights(weights)
def predict(self, X):
"""Predict the target for the provided data
Parameters
----------
X : array or matrix, shape = [n_samples, n_features]
Returns
-------
y : array of int, shape = [n_samples] or [n_samples, n_outputs]
Target values
"""
X = check_array(X, accept_sparse='csr')
neigh_dist, neigh_ind = self.kneighbors(X)
weights = _get_weights(neigh_dist, self.weights)
_y = self._y
if _y.ndim == 1:
_y = _y.reshape((-1, 1))
if weights is None:
y_pred = np.mean(_y[neigh_ind], axis=1)
else:
y_pred = np.empty((X.shape[0], _y.shape[1]), dtype=np.float)
denom = np.sum(weights, axis=1)
for j in range(_y.shape[1]):
num = np.sum(_y[neigh_ind, j] * weights, axis=1)
y_pred[:, j] = num / denom
if self._y.ndim == 1:
y_pred = y_pred.ravel()
return y_pred
class RadiusNeighborsRegressor(NeighborsBase, RadiusNeighborsMixin,
SupervisedFloatMixin,
RegressorMixin):
"""Regression based on neighbors within a fixed radius.
The target is predicted by local interpolation of the targets
associated of the nearest neighbors in the training set.
Read more in the :ref:`User Guide <regression>`.
Parameters
----------
radius : float, optional (default = 1.0)
Range of parameter space to use by default for :meth`radius_neighbors`
queries.
weights : str or callable
weight function used in prediction. Possible values:
- 'uniform' : uniform weights. All points in each neighborhood
are weighted equally.
- 'distance' : weight points by the inverse of their distance.
in this case, closer neighbors of a query point will have a
greater influence than neighbors which are further away.
- [callable] : a user-defined function which accepts an
array of distances, and returns an array of the same shape
containing the weights.
Uniform weights are used by default.
algorithm : {'auto', 'ball_tree', 'kd_tree', 'brute'}, optional
Algorithm used to compute the nearest neighbors:
- 'ball_tree' will use :class:`BallTree`
- 'kd_tree' will use :class:`KDtree`
- 'brute' will use a brute-force search.
- 'auto' will attempt to decide the most appropriate algorithm
based on the values passed to :meth:`fit` method.
Note: fitting on sparse input will override the setting of
this parameter, using brute force.
leaf_size : int, optional (default = 30)
Leaf size passed to BallTree or KDTree. This can affect the
speed of the construction and query, as well as the memory
required to store the tree. The optimal value depends on the
nature of the problem.
metric : string or DistanceMetric object (default='minkowski')
the distance metric to use for the tree. The default metric is
minkowski, and with p=2 is equivalent to the standard Euclidean
metric. See the documentation of the DistanceMetric class for a
list of available metrics.
p : integer, optional (default = 2)
Power parameter for the Minkowski metric. When p = 1, this is
equivalent to using manhattan_distance (l1), and euclidean_distance
(l2) for p = 2. For arbitrary p, minkowski_distance (l_p) is used.
metric_params: dict, optional (default = None)
additional keyword arguments for the metric function.
Examples
--------
>>> X = [[0], [1], [2], [3]]
>>> y = [0, 0, 1, 1]
>>> from sklearn.neighbors import RadiusNeighborsRegressor
>>> neigh = RadiusNeighborsRegressor(radius=1.0)
>>> neigh.fit(X, y) # doctest: +ELLIPSIS
RadiusNeighborsRegressor(...)
>>> print(neigh.predict([[1.5]]))
[ 0.5]
See also
--------
NearestNeighbors
KNeighborsRegressor
KNeighborsClassifier
RadiusNeighborsClassifier
Notes
-----
See :ref:`Nearest Neighbors <neighbors>` in the online documentation
for a discussion of the choice of ``algorithm`` and ``leaf_size``.
http://en.wikipedia.org/wiki/K-nearest_neighbor_algorithm
"""
def __init__(self, radius=1.0, weights='uniform',
algorithm='auto', leaf_size=30,
p=2, metric='minkowski', metric_params=None, **kwargs):
self._init_params(radius=radius,
algorithm=algorithm,
leaf_size=leaf_size,
p=p, metric=metric, metric_params=metric_params,
**kwargs)
self.weights = _check_weights(weights)
def predict(self, X):
"""Predict the target for the provided data
Parameters
----------
X : array or matrix, shape = [n_samples, n_features]
Returns
-------
y : array of int, shape = [n_samples] or [n_samples, n_outputs]
Target values
"""
X = check_array(X, accept_sparse='csr')
neigh_dist, neigh_ind = self.radius_neighbors(X)
weights = _get_weights(neigh_dist, self.weights)
_y = self._y
if _y.ndim == 1:
_y = _y.reshape((-1, 1))
if weights is None:
y_pred = np.array([np.mean(_y[ind, :], axis=0)
for ind in neigh_ind])
else:
y_pred = np.array([(np.average(_y[ind, :], axis=0,
weights=weights[i]))
for (i, ind) in enumerate(neigh_ind)])
if self._y.ndim == 1:
y_pred = y_pred.ravel()
return y_pred
| bsd-3-clause |
yunfeilu/scikit-learn | examples/manifold/plot_lle_digits.py | 59 | 8576 | """
=============================================================================
Manifold learning on handwritten digits: Locally Linear Embedding, Isomap...
=============================================================================
An illustration of various embeddings on the digits dataset.
The RandomTreesEmbedding, from the :mod:`sklearn.ensemble` module, is not
technically a manifold embedding method, as it learn a high-dimensional
representation on which we apply a dimensionality reduction method.
However, it is often useful to cast a dataset into a representation in
which the classes are linearly-separable.
t-SNE will be initialized with the embedding that is generated by PCA in
this example, which is not the default setting. It ensures global stability
of the embedding, i.e., the embedding does not depend on random
initialization.
"""
# Authors: Fabian Pedregosa <[email protected]>
# Olivier Grisel <[email protected]>
# Mathieu Blondel <[email protected]>
# Gael Varoquaux
# License: BSD 3 clause (C) INRIA 2011
print(__doc__)
from time import time
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import offsetbox
from sklearn import (manifold, datasets, decomposition, ensemble, lda,
random_projection)
digits = datasets.load_digits(n_class=6)
X = digits.data
y = digits.target
n_samples, n_features = X.shape
n_neighbors = 30
#----------------------------------------------------------------------
# Scale and visualize the embedding vectors
def plot_embedding(X, title=None):
x_min, x_max = np.min(X, 0), np.max(X, 0)
X = (X - x_min) / (x_max - x_min)
plt.figure()
ax = plt.subplot(111)
for i in range(X.shape[0]):
plt.text(X[i, 0], X[i, 1], str(digits.target[i]),
color=plt.cm.Set1(y[i] / 10.),
fontdict={'weight': 'bold', 'size': 9})
if hasattr(offsetbox, 'AnnotationBbox'):
# only print thumbnails with matplotlib > 1.0
shown_images = np.array([[1., 1.]]) # just something big
for i in range(digits.data.shape[0]):
dist = np.sum((X[i] - shown_images) ** 2, 1)
if np.min(dist) < 4e-3:
# don't show points that are too close
continue
shown_images = np.r_[shown_images, [X[i]]]
imagebox = offsetbox.AnnotationBbox(
offsetbox.OffsetImage(digits.images[i], cmap=plt.cm.gray_r),
X[i])
ax.add_artist(imagebox)
plt.xticks([]), plt.yticks([])
if title is not None:
plt.title(title)
#----------------------------------------------------------------------
# Plot images of the digits
n_img_per_row = 20
img = np.zeros((10 * n_img_per_row, 10 * n_img_per_row))
for i in range(n_img_per_row):
ix = 10 * i + 1
for j in range(n_img_per_row):
iy = 10 * j + 1
img[ix:ix + 8, iy:iy + 8] = X[i * n_img_per_row + j].reshape((8, 8))
plt.imshow(img, cmap=plt.cm.binary)
plt.xticks([])
plt.yticks([])
plt.title('A selection from the 64-dimensional digits dataset')
#----------------------------------------------------------------------
# Random 2D projection using a random unitary matrix
print("Computing random projection")
rp = random_projection.SparseRandomProjection(n_components=2, random_state=42)
X_projected = rp.fit_transform(X)
plot_embedding(X_projected, "Random Projection of the digits")
#----------------------------------------------------------------------
# Projection on to the first 2 principal components
print("Computing PCA projection")
t0 = time()
X_pca = decomposition.TruncatedSVD(n_components=2).fit_transform(X)
plot_embedding(X_pca,
"Principal Components projection of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# Projection on to the first 2 linear discriminant components
print("Computing Linear Discriminant Analysis projection")
X2 = X.copy()
X2.flat[::X.shape[1] + 1] += 0.01 # Make X invertible
t0 = time()
X_lda = discriminant_analysis.LinearDiscriminantAnalysis(n_components=2).fit_transform(X2, y)
plot_embedding(X_lda,
"Linear Discriminant projection of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# Isomap projection of the digits dataset
print("Computing Isomap embedding")
t0 = time()
X_iso = manifold.Isomap(n_neighbors, n_components=2).fit_transform(X)
print("Done.")
plot_embedding(X_iso,
"Isomap projection of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# Locally linear embedding of the digits dataset
print("Computing LLE embedding")
clf = manifold.LocallyLinearEmbedding(n_neighbors, n_components=2,
method='standard')
t0 = time()
X_lle = clf.fit_transform(X)
print("Done. Reconstruction error: %g" % clf.reconstruction_error_)
plot_embedding(X_lle,
"Locally Linear Embedding of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# Modified Locally linear embedding of the digits dataset
print("Computing modified LLE embedding")
clf = manifold.LocallyLinearEmbedding(n_neighbors, n_components=2,
method='modified')
t0 = time()
X_mlle = clf.fit_transform(X)
print("Done. Reconstruction error: %g" % clf.reconstruction_error_)
plot_embedding(X_mlle,
"Modified Locally Linear Embedding of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# HLLE embedding of the digits dataset
print("Computing Hessian LLE embedding")
clf = manifold.LocallyLinearEmbedding(n_neighbors, n_components=2,
method='hessian')
t0 = time()
X_hlle = clf.fit_transform(X)
print("Done. Reconstruction error: %g" % clf.reconstruction_error_)
plot_embedding(X_hlle,
"Hessian Locally Linear Embedding of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# LTSA embedding of the digits dataset
print("Computing LTSA embedding")
clf = manifold.LocallyLinearEmbedding(n_neighbors, n_components=2,
method='ltsa')
t0 = time()
X_ltsa = clf.fit_transform(X)
print("Done. Reconstruction error: %g" % clf.reconstruction_error_)
plot_embedding(X_ltsa,
"Local Tangent Space Alignment of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# MDS embedding of the digits dataset
print("Computing MDS embedding")
clf = manifold.MDS(n_components=2, n_init=1, max_iter=100)
t0 = time()
X_mds = clf.fit_transform(X)
print("Done. Stress: %f" % clf.stress_)
plot_embedding(X_mds,
"MDS embedding of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# Random Trees embedding of the digits dataset
print("Computing Totally Random Trees embedding")
hasher = ensemble.RandomTreesEmbedding(n_estimators=200, random_state=0,
max_depth=5)
t0 = time()
X_transformed = hasher.fit_transform(X)
pca = decomposition.TruncatedSVD(n_components=2)
X_reduced = pca.fit_transform(X_transformed)
plot_embedding(X_reduced,
"Random forest embedding of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# Spectral embedding of the digits dataset
print("Computing Spectral embedding")
embedder = manifold.SpectralEmbedding(n_components=2, random_state=0,
eigen_solver="arpack")
t0 = time()
X_se = embedder.fit_transform(X)
plot_embedding(X_se,
"Spectral embedding of the digits (time %.2fs)" %
(time() - t0))
#----------------------------------------------------------------------
# t-SNE embedding of the digits dataset
print("Computing t-SNE embedding")
tsne = manifold.TSNE(n_components=2, init='pca', random_state=0)
t0 = time()
X_tsne = tsne.fit_transform(X)
plot_embedding(X_tsne,
"t-SNE embedding of the digits (time %.2fs)" %
(time() - t0))
plt.show()
| bsd-3-clause |
DSLituiev/scikit-learn | examples/svm/plot_weighted_samples.py | 95 | 1943 | """
=====================
SVM: Weighted samples
=====================
Plot decision function of a weighted dataset, where the size of points
is proportional to its weight.
The sample weighting rescales the C parameter, which means that the classifier
puts more emphasis on getting these points right. The effect might often be
subtle.
To emphasize the effect here, we particularly weight outliers, making the
deformation of the decision boundary very visible.
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from sklearn import svm
def plot_decision_function(classifier, sample_weight, axis, title):
# plot the decision function
xx, yy = np.meshgrid(np.linspace(-4, 5, 500), np.linspace(-4, 5, 500))
Z = classifier.decision_function(np.c_[xx.ravel(), yy.ravel()])
Z = Z.reshape(xx.shape)
# plot the line, the points, and the nearest vectors to the plane
axis.contourf(xx, yy, Z, alpha=0.75, cmap=plt.cm.bone)
axis.scatter(X[:, 0], X[:, 1], c=y, s=100 * sample_weight, alpha=0.9,
cmap=plt.cm.bone)
axis.axis('off')
axis.set_title(title)
# we create 20 points
np.random.seed(0)
X = np.r_[np.random.randn(10, 2) + [1, 1], np.random.randn(10, 2)]
y = [1] * 10 + [-1] * 10
sample_weight_last_ten = abs(np.random.randn(len(X)))
sample_weight_constant = np.ones(len(X))
# and bigger weights to some outliers
sample_weight_last_ten[15:] *= 5
sample_weight_last_ten[9] *= 15
# for reference, first fit without class weights
# fit the model
clf_weights = svm.SVC()
clf_weights.fit(X, y, sample_weight=sample_weight_last_ten)
clf_no_weights = svm.SVC()
clf_no_weights.fit(X, y)
fig, axes = plt.subplots(1, 2, figsize=(14, 6))
plot_decision_function(clf_no_weights, sample_weight_constant, axes[0],
"Constant weights")
plot_decision_function(clf_weights, sample_weight_last_ten, axes[1],
"Modified weights")
plt.show()
| bsd-3-clause |
ClimbsRocks/scikit-learn | examples/ensemble/plot_forest_importances_faces.py | 403 | 1519 | """
=================================================
Pixel importances with a parallel forest of trees
=================================================
This example shows the use of forests of trees to evaluate the importance
of the pixels in an image classification task (faces). The hotter the pixel,
the more important.
The code below also illustrates how the construction and the computation
of the predictions can be parallelized within multiple jobs.
"""
print(__doc__)
from time import time
import matplotlib.pyplot as plt
from sklearn.datasets import fetch_olivetti_faces
from sklearn.ensemble import ExtraTreesClassifier
# Number of cores to use to perform parallel fitting of the forest model
n_jobs = 1
# Load the faces dataset
data = fetch_olivetti_faces()
X = data.images.reshape((len(data.images), -1))
y = data.target
mask = y < 5 # Limit to 5 classes
X = X[mask]
y = y[mask]
# Build a forest and compute the pixel importances
print("Fitting ExtraTreesClassifier on faces data with %d cores..." % n_jobs)
t0 = time()
forest = ExtraTreesClassifier(n_estimators=1000,
max_features=128,
n_jobs=n_jobs,
random_state=0)
forest.fit(X, y)
print("done in %0.3fs" % (time() - t0))
importances = forest.feature_importances_
importances = importances.reshape(data.images[0].shape)
# Plot pixel importances
plt.matshow(importances, cmap=plt.cm.hot)
plt.title("Pixel importances with forests of trees")
plt.show()
| bsd-3-clause |
chenyyx/scikit-learn-doc-zh | examples/en/cross_decomposition/plot_compare_cross_decomposition.py | 55 | 4953 | """
===================================
Compare cross decomposition methods
===================================
Simple usage of various cross decomposition algorithms:
- PLSCanonical
- PLSRegression, with multivariate response, a.k.a. PLS2
- PLSRegression, with univariate response, a.k.a. PLS1
- CCA
Given 2 multivariate covarying two-dimensional datasets, X, and Y,
PLS extracts the 'directions of covariance', i.e. the components of each
datasets that explain the most shared variance between both datasets.
This is apparent on the **scatterplot matrix** display: components 1 in
dataset X and dataset Y are maximally correlated (points lie around the
first diagonal). This is also true for components 2 in both dataset,
however, the correlation across datasets for different components is
weak: the point cloud is very spherical.
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from sklearn.cross_decomposition import PLSCanonical, PLSRegression, CCA
# #############################################################################
# Dataset based latent variables model
n = 500
# 2 latents vars:
l1 = np.random.normal(size=n)
l2 = np.random.normal(size=n)
latents = np.array([l1, l1, l2, l2]).T
X = latents + np.random.normal(size=4 * n).reshape((n, 4))
Y = latents + np.random.normal(size=4 * n).reshape((n, 4))
X_train = X[:n // 2]
Y_train = Y[:n // 2]
X_test = X[n // 2:]
Y_test = Y[n // 2:]
print("Corr(X)")
print(np.round(np.corrcoef(X.T), 2))
print("Corr(Y)")
print(np.round(np.corrcoef(Y.T), 2))
# #############################################################################
# Canonical (symmetric) PLS
# Transform data
# ~~~~~~~~~~~~~~
plsca = PLSCanonical(n_components=2)
plsca.fit(X_train, Y_train)
X_train_r, Y_train_r = plsca.transform(X_train, Y_train)
X_test_r, Y_test_r = plsca.transform(X_test, Y_test)
# Scatter plot of scores
# ~~~~~~~~~~~~~~~~~~~~~~
# 1) On diagonal plot X vs Y scores on each components
plt.figure(figsize=(12, 8))
plt.subplot(221)
plt.scatter(X_train_r[:, 0], Y_train_r[:, 0], label="train",
marker="o", c="b", s=25)
plt.scatter(X_test_r[:, 0], Y_test_r[:, 0], label="test",
marker="o", c="r", s=25)
plt.xlabel("x scores")
plt.ylabel("y scores")
plt.title('Comp. 1: X vs Y (test corr = %.2f)' %
np.corrcoef(X_test_r[:, 0], Y_test_r[:, 0])[0, 1])
plt.xticks(())
plt.yticks(())
plt.legend(loc="best")
plt.subplot(224)
plt.scatter(X_train_r[:, 1], Y_train_r[:, 1], label="train",
marker="o", c="b", s=25)
plt.scatter(X_test_r[:, 1], Y_test_r[:, 1], label="test",
marker="o", c="r", s=25)
plt.xlabel("x scores")
plt.ylabel("y scores")
plt.title('Comp. 2: X vs Y (test corr = %.2f)' %
np.corrcoef(X_test_r[:, 1], Y_test_r[:, 1])[0, 1])
plt.xticks(())
plt.yticks(())
plt.legend(loc="best")
# 2) Off diagonal plot components 1 vs 2 for X and Y
plt.subplot(222)
plt.scatter(X_train_r[:, 0], X_train_r[:, 1], label="train",
marker="*", c="b", s=50)
plt.scatter(X_test_r[:, 0], X_test_r[:, 1], label="test",
marker="*", c="r", s=50)
plt.xlabel("X comp. 1")
plt.ylabel("X comp. 2")
plt.title('X comp. 1 vs X comp. 2 (test corr = %.2f)'
% np.corrcoef(X_test_r[:, 0], X_test_r[:, 1])[0, 1])
plt.legend(loc="best")
plt.xticks(())
plt.yticks(())
plt.subplot(223)
plt.scatter(Y_train_r[:, 0], Y_train_r[:, 1], label="train",
marker="*", c="b", s=50)
plt.scatter(Y_test_r[:, 0], Y_test_r[:, 1], label="test",
marker="*", c="r", s=50)
plt.xlabel("Y comp. 1")
plt.ylabel("Y comp. 2")
plt.title('Y comp. 1 vs Y comp. 2 , (test corr = %.2f)'
% np.corrcoef(Y_test_r[:, 0], Y_test_r[:, 1])[0, 1])
plt.legend(loc="best")
plt.xticks(())
plt.yticks(())
plt.show()
# #############################################################################
# PLS regression, with multivariate response, a.k.a. PLS2
n = 1000
q = 3
p = 10
X = np.random.normal(size=n * p).reshape((n, p))
B = np.array([[1, 2] + [0] * (p - 2)] * q).T
# each Yj = 1*X1 + 2*X2 + noize
Y = np.dot(X, B) + np.random.normal(size=n * q).reshape((n, q)) + 5
pls2 = PLSRegression(n_components=3)
pls2.fit(X, Y)
print("True B (such that: Y = XB + Err)")
print(B)
# compare pls2.coef_ with B
print("Estimated B")
print(np.round(pls2.coef_, 1))
pls2.predict(X)
# PLS regression, with univariate response, a.k.a. PLS1
n = 1000
p = 10
X = np.random.normal(size=n * p).reshape((n, p))
y = X[:, 0] + 2 * X[:, 1] + np.random.normal(size=n * 1) + 5
pls1 = PLSRegression(n_components=3)
pls1.fit(X, y)
# note that the number of components exceeds 1 (the dimension of y)
print("Estimated betas")
print(np.round(pls1.coef_, 1))
# #############################################################################
# CCA (PLS mode B with symmetric deflation)
cca = CCA(n_components=2)
cca.fit(X_train, Y_train)
X_train_r, Y_train_r = cca.transform(X_train, Y_train)
X_test_r, Y_test_r = cca.transform(X_test, Y_test)
| gpl-3.0 |
ilo10/scikit-learn | sklearn/feature_extraction/tests/test_image.py | 205 | 10378 | # Authors: Emmanuelle Gouillart <[email protected]>
# Gael Varoquaux <[email protected]>
# License: BSD 3 clause
import numpy as np
import scipy as sp
from scipy import ndimage
from nose.tools import assert_equal, assert_true
from numpy.testing import assert_raises
from sklearn.feature_extraction.image import (
img_to_graph, grid_to_graph, extract_patches_2d,
reconstruct_from_patches_2d, PatchExtractor, extract_patches)
from sklearn.utils.graph import connected_components
def test_img_to_graph():
x, y = np.mgrid[:4, :4] - 10
grad_x = img_to_graph(x)
grad_y = img_to_graph(y)
assert_equal(grad_x.nnz, grad_y.nnz)
# Negative elements are the diagonal: the elements of the original
# image. Positive elements are the values of the gradient, they
# should all be equal on grad_x and grad_y
np.testing.assert_array_equal(grad_x.data[grad_x.data > 0],
grad_y.data[grad_y.data > 0])
def test_grid_to_graph():
#Checking that the function works with graphs containing no edges
size = 2
roi_size = 1
# Generating two convex parts with one vertex
# Thus, edges will be empty in _to_graph
mask = np.zeros((size, size), dtype=np.bool)
mask[0:roi_size, 0:roi_size] = True
mask[-roi_size:, -roi_size:] = True
mask = mask.reshape(size ** 2)
A = grid_to_graph(n_x=size, n_y=size, mask=mask, return_as=np.ndarray)
assert_true(connected_components(A)[0] == 2)
# Checking that the function works whatever the type of mask is
mask = np.ones((size, size), dtype=np.int16)
A = grid_to_graph(n_x=size, n_y=size, n_z=size, mask=mask)
assert_true(connected_components(A)[0] == 1)
# Checking dtype of the graph
mask = np.ones((size, size))
A = grid_to_graph(n_x=size, n_y=size, n_z=size, mask=mask, dtype=np.bool)
assert_true(A.dtype == np.bool)
A = grid_to_graph(n_x=size, n_y=size, n_z=size, mask=mask, dtype=np.int)
assert_true(A.dtype == np.int)
A = grid_to_graph(n_x=size, n_y=size, n_z=size, mask=mask, dtype=np.float)
assert_true(A.dtype == np.float)
def test_connect_regions():
lena = sp.misc.lena()
for thr in (50, 150):
mask = lena > thr
graph = img_to_graph(lena, mask)
assert_equal(ndimage.label(mask)[1], connected_components(graph)[0])
def test_connect_regions_with_grid():
lena = sp.misc.lena()
mask = lena > 50
graph = grid_to_graph(*lena.shape, mask=mask)
assert_equal(ndimage.label(mask)[1], connected_components(graph)[0])
mask = lena > 150
graph = grid_to_graph(*lena.shape, mask=mask, dtype=None)
assert_equal(ndimage.label(mask)[1], connected_components(graph)[0])
def _downsampled_lena():
lena = sp.misc.lena().astype(np.float32)
lena = (lena[::2, ::2] + lena[1::2, ::2] + lena[::2, 1::2]
+ lena[1::2, 1::2])
lena = (lena[::2, ::2] + lena[1::2, ::2] + lena[::2, 1::2]
+ lena[1::2, 1::2])
lena = lena.astype(np.float)
lena /= 16.0
return lena
def _orange_lena(lena=None):
lena = _downsampled_lena() if lena is None else lena
lena_color = np.zeros(lena.shape + (3,))
lena_color[:, :, 0] = 256 - lena
lena_color[:, :, 1] = 256 - lena / 2
lena_color[:, :, 2] = 256 - lena / 4
return lena_color
def _make_images(lena=None):
lena = _downsampled_lena() if lena is None else lena
# make a collection of lenas
images = np.zeros((3,) + lena.shape)
images[0] = lena
images[1] = lena + 1
images[2] = lena + 2
return images
downsampled_lena = _downsampled_lena()
orange_lena = _orange_lena(downsampled_lena)
lena_collection = _make_images(downsampled_lena)
def test_extract_patches_all():
lena = downsampled_lena
i_h, i_w = lena.shape
p_h, p_w = 16, 16
expected_n_patches = (i_h - p_h + 1) * (i_w - p_w + 1)
patches = extract_patches_2d(lena, (p_h, p_w))
assert_equal(patches.shape, (expected_n_patches, p_h, p_w))
def test_extract_patches_all_color():
lena = orange_lena
i_h, i_w = lena.shape[:2]
p_h, p_w = 16, 16
expected_n_patches = (i_h - p_h + 1) * (i_w - p_w + 1)
patches = extract_patches_2d(lena, (p_h, p_w))
assert_equal(patches.shape, (expected_n_patches, p_h, p_w, 3))
def test_extract_patches_all_rect():
lena = downsampled_lena
lena = lena[:, 32:97]
i_h, i_w = lena.shape
p_h, p_w = 16, 12
expected_n_patches = (i_h - p_h + 1) * (i_w - p_w + 1)
patches = extract_patches_2d(lena, (p_h, p_w))
assert_equal(patches.shape, (expected_n_patches, p_h, p_w))
def test_extract_patches_max_patches():
lena = downsampled_lena
i_h, i_w = lena.shape
p_h, p_w = 16, 16
patches = extract_patches_2d(lena, (p_h, p_w), max_patches=100)
assert_equal(patches.shape, (100, p_h, p_w))
expected_n_patches = int(0.5 * (i_h - p_h + 1) * (i_w - p_w + 1))
patches = extract_patches_2d(lena, (p_h, p_w), max_patches=0.5)
assert_equal(patches.shape, (expected_n_patches, p_h, p_w))
assert_raises(ValueError, extract_patches_2d, lena, (p_h, p_w),
max_patches=2.0)
assert_raises(ValueError, extract_patches_2d, lena, (p_h, p_w),
max_patches=-1.0)
def test_reconstruct_patches_perfect():
lena = downsampled_lena
p_h, p_w = 16, 16
patches = extract_patches_2d(lena, (p_h, p_w))
lena_reconstructed = reconstruct_from_patches_2d(patches, lena.shape)
np.testing.assert_array_equal(lena, lena_reconstructed)
def test_reconstruct_patches_perfect_color():
lena = orange_lena
p_h, p_w = 16, 16
patches = extract_patches_2d(lena, (p_h, p_w))
lena_reconstructed = reconstruct_from_patches_2d(patches, lena.shape)
np.testing.assert_array_equal(lena, lena_reconstructed)
def test_patch_extractor_fit():
lenas = lena_collection
extr = PatchExtractor(patch_size=(8, 8), max_patches=100, random_state=0)
assert_true(extr == extr.fit(lenas))
def test_patch_extractor_max_patches():
lenas = lena_collection
i_h, i_w = lenas.shape[1:3]
p_h, p_w = 8, 8
max_patches = 100
expected_n_patches = len(lenas) * max_patches
extr = PatchExtractor(patch_size=(p_h, p_w), max_patches=max_patches,
random_state=0)
patches = extr.transform(lenas)
assert_true(patches.shape == (expected_n_patches, p_h, p_w))
max_patches = 0.5
expected_n_patches = len(lenas) * int((i_h - p_h + 1) * (i_w - p_w + 1)
* max_patches)
extr = PatchExtractor(patch_size=(p_h, p_w), max_patches=max_patches,
random_state=0)
patches = extr.transform(lenas)
assert_true(patches.shape == (expected_n_patches, p_h, p_w))
def test_patch_extractor_max_patches_default():
lenas = lena_collection
extr = PatchExtractor(max_patches=100, random_state=0)
patches = extr.transform(lenas)
assert_equal(patches.shape, (len(lenas) * 100, 12, 12))
def test_patch_extractor_all_patches():
lenas = lena_collection
i_h, i_w = lenas.shape[1:3]
p_h, p_w = 8, 8
expected_n_patches = len(lenas) * (i_h - p_h + 1) * (i_w - p_w + 1)
extr = PatchExtractor(patch_size=(p_h, p_w), random_state=0)
patches = extr.transform(lenas)
assert_true(patches.shape == (expected_n_patches, p_h, p_w))
def test_patch_extractor_color():
lenas = _make_images(orange_lena)
i_h, i_w = lenas.shape[1:3]
p_h, p_w = 8, 8
expected_n_patches = len(lenas) * (i_h - p_h + 1) * (i_w - p_w + 1)
extr = PatchExtractor(patch_size=(p_h, p_w), random_state=0)
patches = extr.transform(lenas)
assert_true(patches.shape == (expected_n_patches, p_h, p_w, 3))
def test_extract_patches_strided():
image_shapes_1D = [(10,), (10,), (11,), (10,)]
patch_sizes_1D = [(1,), (2,), (3,), (8,)]
patch_steps_1D = [(1,), (1,), (4,), (2,)]
expected_views_1D = [(10,), (9,), (3,), (2,)]
last_patch_1D = [(10,), (8,), (8,), (2,)]
image_shapes_2D = [(10, 20), (10, 20), (10, 20), (11, 20)]
patch_sizes_2D = [(2, 2), (10, 10), (10, 11), (6, 6)]
patch_steps_2D = [(5, 5), (3, 10), (3, 4), (4, 2)]
expected_views_2D = [(2, 4), (1, 2), (1, 3), (2, 8)]
last_patch_2D = [(5, 15), (0, 10), (0, 8), (4, 14)]
image_shapes_3D = [(5, 4, 3), (3, 3, 3), (7, 8, 9), (7, 8, 9)]
patch_sizes_3D = [(2, 2, 3), (2, 2, 2), (1, 7, 3), (1, 3, 3)]
patch_steps_3D = [(1, 2, 10), (1, 1, 1), (2, 1, 3), (3, 3, 4)]
expected_views_3D = [(4, 2, 1), (2, 2, 2), (4, 2, 3), (3, 2, 2)]
last_patch_3D = [(3, 2, 0), (1, 1, 1), (6, 1, 6), (6, 3, 4)]
image_shapes = image_shapes_1D + image_shapes_2D + image_shapes_3D
patch_sizes = patch_sizes_1D + patch_sizes_2D + patch_sizes_3D
patch_steps = patch_steps_1D + patch_steps_2D + patch_steps_3D
expected_views = expected_views_1D + expected_views_2D + expected_views_3D
last_patches = last_patch_1D + last_patch_2D + last_patch_3D
for (image_shape, patch_size, patch_step, expected_view,
last_patch) in zip(image_shapes, patch_sizes, patch_steps,
expected_views, last_patches):
image = np.arange(np.prod(image_shape)).reshape(image_shape)
patches = extract_patches(image, patch_shape=patch_size,
extraction_step=patch_step)
ndim = len(image_shape)
assert_true(patches.shape[:ndim] == expected_view)
last_patch_slices = [slice(i, i + j, None) for i, j in
zip(last_patch, patch_size)]
assert_true((patches[[slice(-1, None, None)] * ndim] ==
image[last_patch_slices].squeeze()).all())
def test_extract_patches_square():
# test same patch size for all dimensions
lena = downsampled_lena
i_h, i_w = lena.shape
p = 8
expected_n_patches = ((i_h - p + 1), (i_w - p + 1))
patches = extract_patches(lena, patch_shape=p)
assert_true(patches.shape == (expected_n_patches[0], expected_n_patches[1],
p, p))
def test_width_patch():
# width and height of the patch should be less than the image
x = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
assert_raises(ValueError, extract_patches_2d, x, (4, 1))
assert_raises(ValueError, extract_patches_2d, x, (1, 4))
| bsd-3-clause |
rexshihaoren/scikit-learn | sklearn/pipeline.py | 162 | 21103 | """
The :mod:`sklearn.pipeline` module implements utilities to build a composite
estimator, as a chain of transforms and estimators.
"""
# Author: Edouard Duchesnay
# Gael Varoquaux
# Virgile Fritsch
# Alexandre Gramfort
# Lars Buitinck
# Licence: BSD
from collections import defaultdict
import numpy as np
from scipy import sparse
from .base import BaseEstimator, TransformerMixin
from .externals.joblib import Parallel, delayed
from .externals import six
from .utils import tosequence
from .utils.metaestimators import if_delegate_has_method
from .externals.six import iteritems
__all__ = ['Pipeline', 'FeatureUnion']
class Pipeline(BaseEstimator):
"""Pipeline of transforms with a final estimator.
Sequentially apply a list of transforms and a final estimator.
Intermediate steps of the pipeline must be 'transforms', that is, they
must implement fit and transform methods.
The final estimator only needs to implement fit.
The purpose of the pipeline is to assemble several steps that can be
cross-validated together while setting different parameters.
For this, it enables setting parameters of the various steps using their
names and the parameter name separated by a '__', as in the example below.
Read more in the :ref:`User Guide <pipeline>`.
Parameters
----------
steps : list
List of (name, transform) tuples (implementing fit/transform) that are
chained, in the order in which they are chained, with the last object
an estimator.
Attributes
----------
named_steps : dict
Read-only attribute to access any step parameter by user given name.
Keys are step names and values are steps parameters.
Examples
--------
>>> from sklearn import svm
>>> from sklearn.datasets import samples_generator
>>> from sklearn.feature_selection import SelectKBest
>>> from sklearn.feature_selection import f_regression
>>> from sklearn.pipeline import Pipeline
>>> # generate some data to play with
>>> X, y = samples_generator.make_classification(
... n_informative=5, n_redundant=0, random_state=42)
>>> # ANOVA SVM-C
>>> anova_filter = SelectKBest(f_regression, k=5)
>>> clf = svm.SVC(kernel='linear')
>>> anova_svm = Pipeline([('anova', anova_filter), ('svc', clf)])
>>> # You can set the parameters using the names issued
>>> # For instance, fit using a k of 10 in the SelectKBest
>>> # and a parameter 'C' of the svm
>>> anova_svm.set_params(anova__k=10, svc__C=.1).fit(X, y)
... # doctest: +ELLIPSIS
Pipeline(steps=[...])
>>> prediction = anova_svm.predict(X)
>>> anova_svm.score(X, y) # doctest: +ELLIPSIS
0.77...
>>> # getting the selected features chosen by anova_filter
>>> anova_svm.named_steps['anova'].get_support()
... # doctest: +NORMALIZE_WHITESPACE
array([ True, True, True, False, False, True, False, True, True, True,
False, False, True, False, True, False, False, False, False,
True], dtype=bool)
"""
# BaseEstimator interface
def __init__(self, steps):
names, estimators = zip(*steps)
if len(dict(steps)) != len(steps):
raise ValueError("Provided step names are not unique: %s" % (names,))
# shallow copy of steps
self.steps = tosequence(steps)
transforms = estimators[:-1]
estimator = estimators[-1]
for t in transforms:
if (not (hasattr(t, "fit") or hasattr(t, "fit_transform")) or not
hasattr(t, "transform")):
raise TypeError("All intermediate steps of the chain should "
"be transforms and implement fit and transform"
" '%s' (type %s) doesn't)" % (t, type(t)))
if not hasattr(estimator, "fit"):
raise TypeError("Last step of chain should implement fit "
"'%s' (type %s) doesn't)"
% (estimator, type(estimator)))
@property
def _estimator_type(self):
return self.steps[-1][1]._estimator_type
def get_params(self, deep=True):
if not deep:
return super(Pipeline, self).get_params(deep=False)
else:
out = self.named_steps
for name, step in six.iteritems(self.named_steps):
for key, value in six.iteritems(step.get_params(deep=True)):
out['%s__%s' % (name, key)] = value
out.update(super(Pipeline, self).get_params(deep=False))
return out
@property
def named_steps(self):
return dict(self.steps)
@property
def _final_estimator(self):
return self.steps[-1][1]
# Estimator interface
def _pre_transform(self, X, y=None, **fit_params):
fit_params_steps = dict((step, {}) for step, _ in self.steps)
for pname, pval in six.iteritems(fit_params):
step, param = pname.split('__', 1)
fit_params_steps[step][param] = pval
Xt = X
for name, transform in self.steps[:-1]:
if hasattr(transform, "fit_transform"):
Xt = transform.fit_transform(Xt, y, **fit_params_steps[name])
else:
Xt = transform.fit(Xt, y, **fit_params_steps[name]) \
.transform(Xt)
return Xt, fit_params_steps[self.steps[-1][0]]
def fit(self, X, y=None, **fit_params):
"""Fit all the transforms one after the other and transform the
data, then fit the transformed data using the final estimator.
Parameters
----------
X : iterable
Training data. Must fulfill input requirements of first step of the
pipeline.
y : iterable, default=None
Training targets. Must fulfill label requirements for all steps of
the pipeline.
"""
Xt, fit_params = self._pre_transform(X, y, **fit_params)
self.steps[-1][-1].fit(Xt, y, **fit_params)
return self
def fit_transform(self, X, y=None, **fit_params):
"""Fit all the transforms one after the other and transform the
data, then use fit_transform on transformed data using the final
estimator.
Parameters
----------
X : iterable
Training data. Must fulfill input requirements of first step of the
pipeline.
y : iterable, default=None
Training targets. Must fulfill label requirements for all steps of
the pipeline.
"""
Xt, fit_params = self._pre_transform(X, y, **fit_params)
if hasattr(self.steps[-1][-1], 'fit_transform'):
return self.steps[-1][-1].fit_transform(Xt, y, **fit_params)
else:
return self.steps[-1][-1].fit(Xt, y, **fit_params).transform(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def predict(self, X):
"""Applies transforms to the data, and the predict method of the
final estimator. Valid only if the final estimator implements
predict.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].predict(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def fit_predict(self, X, y=None, **fit_params):
"""Applies fit_predict of last step in pipeline after transforms.
Applies fit_transforms of a pipeline to the data, followed by the
fit_predict method of the final estimator in the pipeline. Valid
only if the final estimator implements fit_predict.
Parameters
----------
X : iterable
Training data. Must fulfill input requirements of first step of
the pipeline.
y : iterable, default=None
Training targets. Must fulfill label requirements for all steps
of the pipeline.
"""
Xt, fit_params = self._pre_transform(X, y, **fit_params)
return self.steps[-1][-1].fit_predict(Xt, y, **fit_params)
@if_delegate_has_method(delegate='_final_estimator')
def predict_proba(self, X):
"""Applies transforms to the data, and the predict_proba method of the
final estimator. Valid only if the final estimator implements
predict_proba.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].predict_proba(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def decision_function(self, X):
"""Applies transforms to the data, and the decision_function method of
the final estimator. Valid only if the final estimator implements
decision_function.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].decision_function(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def predict_log_proba(self, X):
"""Applies transforms to the data, and the predict_log_proba method of
the final estimator. Valid only if the final estimator implements
predict_log_proba.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].predict_log_proba(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def transform(self, X):
"""Applies transforms to the data, and the transform method of the
final estimator. Valid only if the final estimator implements
transform.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps:
Xt = transform.transform(Xt)
return Xt
@if_delegate_has_method(delegate='_final_estimator')
def inverse_transform(self, X):
"""Applies inverse transform to the data.
Starts with the last step of the pipeline and applies ``inverse_transform`` in
inverse order of the pipeline steps.
Valid only if all steps of the pipeline implement inverse_transform.
Parameters
----------
X : iterable
Data to inverse transform. Must fulfill output requirements of the
last step of the pipeline.
"""
if X.ndim == 1:
X = X[None, :]
Xt = X
for name, step in self.steps[::-1]:
Xt = step.inverse_transform(Xt)
return Xt
@if_delegate_has_method(delegate='_final_estimator')
def score(self, X, y=None):
"""Applies transforms to the data, and the score method of the
final estimator. Valid only if the final estimator implements
score.
Parameters
----------
X : iterable
Data to score. Must fulfill input requirements of first step of the
pipeline.
y : iterable, default=None
Targets used for scoring. Must fulfill label requirements for all steps of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].score(Xt, y)
@property
def classes_(self):
return self.steps[-1][-1].classes_
@property
def _pairwise(self):
# check if first estimator expects pairwise input
return getattr(self.steps[0][1], '_pairwise', False)
def _name_estimators(estimators):
"""Generate names for estimators."""
names = [type(estimator).__name__.lower() for estimator in estimators]
namecount = defaultdict(int)
for est, name in zip(estimators, names):
namecount[name] += 1
for k, v in list(six.iteritems(namecount)):
if v == 1:
del namecount[k]
for i in reversed(range(len(estimators))):
name = names[i]
if name in namecount:
names[i] += "-%d" % namecount[name]
namecount[name] -= 1
return list(zip(names, estimators))
def make_pipeline(*steps):
"""Construct a Pipeline from the given estimators.
This is a shorthand for the Pipeline constructor; it does not require, and
does not permit, naming the estimators. Instead, they will be given names
automatically based on their types.
Examples
--------
>>> from sklearn.naive_bayes import GaussianNB
>>> from sklearn.preprocessing import StandardScaler
>>> make_pipeline(StandardScaler(), GaussianNB()) # doctest: +NORMALIZE_WHITESPACE
Pipeline(steps=[('standardscaler',
StandardScaler(copy=True, with_mean=True, with_std=True)),
('gaussiannb', GaussianNB())])
Returns
-------
p : Pipeline
"""
return Pipeline(_name_estimators(steps))
def _fit_one_transformer(transformer, X, y):
return transformer.fit(X, y)
def _transform_one(transformer, name, X, transformer_weights):
if transformer_weights is not None and name in transformer_weights:
# if we have a weight for this transformer, muliply output
return transformer.transform(X) * transformer_weights[name]
return transformer.transform(X)
def _fit_transform_one(transformer, name, X, y, transformer_weights,
**fit_params):
if transformer_weights is not None and name in transformer_weights:
# if we have a weight for this transformer, muliply output
if hasattr(transformer, 'fit_transform'):
X_transformed = transformer.fit_transform(X, y, **fit_params)
return X_transformed * transformer_weights[name], transformer
else:
X_transformed = transformer.fit(X, y, **fit_params).transform(X)
return X_transformed * transformer_weights[name], transformer
if hasattr(transformer, 'fit_transform'):
X_transformed = transformer.fit_transform(X, y, **fit_params)
return X_transformed, transformer
else:
X_transformed = transformer.fit(X, y, **fit_params).transform(X)
return X_transformed, transformer
class FeatureUnion(BaseEstimator, TransformerMixin):
"""Concatenates results of multiple transformer objects.
This estimator applies a list of transformer objects in parallel to the
input data, then concatenates the results. This is useful to combine
several feature extraction mechanisms into a single transformer.
Read more in the :ref:`User Guide <feature_union>`.
Parameters
----------
transformer_list: list of (string, transformer) tuples
List of transformer objects to be applied to the data. The first
half of each tuple is the name of the transformer.
n_jobs: int, optional
Number of jobs to run in parallel (default 1).
transformer_weights: dict, optional
Multiplicative weights for features per transformer.
Keys are transformer names, values the weights.
"""
def __init__(self, transformer_list, n_jobs=1, transformer_weights=None):
self.transformer_list = transformer_list
self.n_jobs = n_jobs
self.transformer_weights = transformer_weights
def get_feature_names(self):
"""Get feature names from all transformers.
Returns
-------
feature_names : list of strings
Names of the features produced by transform.
"""
feature_names = []
for name, trans in self.transformer_list:
if not hasattr(trans, 'get_feature_names'):
raise AttributeError("Transformer %s does not provide"
" get_feature_names." % str(name))
feature_names.extend([name + "__" + f for f in
trans.get_feature_names()])
return feature_names
def fit(self, X, y=None):
"""Fit all transformers using X.
Parameters
----------
X : array-like or sparse matrix, shape (n_samples, n_features)
Input data, used to fit transformers.
"""
transformers = Parallel(n_jobs=self.n_jobs)(
delayed(_fit_one_transformer)(trans, X, y)
for name, trans in self.transformer_list)
self._update_transformer_list(transformers)
return self
def fit_transform(self, X, y=None, **fit_params):
"""Fit all transformers using X, transform the data and concatenate
results.
Parameters
----------
X : array-like or sparse matrix, shape (n_samples, n_features)
Input data to be transformed.
Returns
-------
X_t : array-like or sparse matrix, shape (n_samples, sum_n_components)
hstack of results of transformers. sum_n_components is the
sum of n_components (output dimension) over transformers.
"""
result = Parallel(n_jobs=self.n_jobs)(
delayed(_fit_transform_one)(trans, name, X, y,
self.transformer_weights, **fit_params)
for name, trans in self.transformer_list)
Xs, transformers = zip(*result)
self._update_transformer_list(transformers)
if any(sparse.issparse(f) for f in Xs):
Xs = sparse.hstack(Xs).tocsr()
else:
Xs = np.hstack(Xs)
return Xs
def transform(self, X):
"""Transform X separately by each transformer, concatenate results.
Parameters
----------
X : array-like or sparse matrix, shape (n_samples, n_features)
Input data to be transformed.
Returns
-------
X_t : array-like or sparse matrix, shape (n_samples, sum_n_components)
hstack of results of transformers. sum_n_components is the
sum of n_components (output dimension) over transformers.
"""
Xs = Parallel(n_jobs=self.n_jobs)(
delayed(_transform_one)(trans, name, X, self.transformer_weights)
for name, trans in self.transformer_list)
if any(sparse.issparse(f) for f in Xs):
Xs = sparse.hstack(Xs).tocsr()
else:
Xs = np.hstack(Xs)
return Xs
def get_params(self, deep=True):
if not deep:
return super(FeatureUnion, self).get_params(deep=False)
else:
out = dict(self.transformer_list)
for name, trans in self.transformer_list:
for key, value in iteritems(trans.get_params(deep=True)):
out['%s__%s' % (name, key)] = value
out.update(super(FeatureUnion, self).get_params(deep=False))
return out
def _update_transformer_list(self, transformers):
self.transformer_list[:] = [
(name, new)
for ((name, old), new) in zip(self.transformer_list, transformers)
]
# XXX it would be nice to have a keyword-only n_jobs argument to this function,
# but that's not allowed in Python 2.x.
def make_union(*transformers):
"""Construct a FeatureUnion from the given transformers.
This is a shorthand for the FeatureUnion constructor; it does not require,
and does not permit, naming the transformers. Instead, they will be given
names automatically based on their types. It also does not allow weighting.
Examples
--------
>>> from sklearn.decomposition import PCA, TruncatedSVD
>>> make_union(PCA(), TruncatedSVD()) # doctest: +NORMALIZE_WHITESPACE
FeatureUnion(n_jobs=1,
transformer_list=[('pca', PCA(copy=True, n_components=None,
whiten=False)),
('truncatedsvd',
TruncatedSVD(algorithm='randomized',
n_components=2, n_iter=5,
random_state=None, tol=0.0))],
transformer_weights=None)
Returns
-------
f : FeatureUnion
"""
return FeatureUnion(_name_estimators(transformers))
| bsd-3-clause |
georgetown-analytics/machine-learning | examples/FrancoMBM/Wine.py | 1 | 6158 |
# importing libraries
import sys
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import scipy as sp
import IPython
from IPython.display import display
import sklearn
from sklearn.model_selection import train_test_split
from sklearn.neighbors import KNeighborsClassifier
from sklearn.preprocessing import StandardScaler
from sklearn.preprocessing import MinMaxScaler
from sklearn.preprocessing import Normalizer
from sklearn import cross_validation
from sklearn.model_selection import cross_val_score
from sklearn.metrics import classification_report
# importing datasets
raw_df_red = pd.read_csv(r"C:\Users\franc\Desktop\SecondDesk\DataScienceCertificate\Classes\Assingments\MachineLearning\Homework\winequality-red.csv", sep =';')
raw_df_white = pd.read_csv(r"C:\Users\franc\Desktop\SecondDesk\DataScienceCertificate\Classes\Assingments\MachineLearning\Homework\winequality-white.csv", sep =';')
# exploring datasets
raw_df_red.describe()
raw_df_white.describe()
raw_df_white.info()
#-------------------------------white whine selection--------------------------
X = raw_df_white.iloc[:,:-1].values # independent variables X
y = raw_df_white['quality'].values # dependent Variables y
X_train_white, X_test_white, y_train_white, y_test_white = cross_validation.train_test_split(X, y, test_size = 0.2, random_state = 0)
# visual data exploration
X_train = raw_df_white.iloc[:,:-1]
y_train = raw_df_white['quality']
pd.plotting.scatter_matrix(X_train, c = y_train, figsize = (30, 30), marker ='o', hist_kwds = {'bins': 20},
s = 60, alpha = 0.7)
#before scaling
plt.boxplot(X_train_white, manage_xticks = False)
plt.yscale("symlog")
plt.xlabel("Features")
plt.ylabel("Target Variable")
plt.show()
scaler = StandardScaler()
#scaler = MinMaxScaler()
#scaler = Normalizer()
X_train_white = scaler.fit(X_train_white).transform(X_train_white)
X_test_white = scaler.fit(X_test_white).transform(X_test_white)
# after scaling
plt.boxplot(X_train_white, manage_xticks = False)
plt.yscale("symlog")
plt.xlabel("Features")
plt.ylabel("Target Variable")
plt.show()
# performing PCA
from sklearn.decomposition import PCA
pca = PCA(n_components = None) # input a number for feature extraction
X_train_white = pca.fit_transform(X_train_white)
X_test_white = pca.transform(X_test_white)
explained_var = pca.explained_variance_ratio_
print (explained_var)
#-----------------KNN--------------------------------------
knn = KNeighborsClassifier(n_neighbors = 10, metric = 'manhattan', weights = 'distance', algorithm = 'auto')
knn.fit(X_train_white, y_train_white)
predicted_knn = knn.predict(X_test_white)
# print("Predictions: {}".format(predicted_knn))
scores = cross_val_score(knn, X = X_train_white, y = y_train_white)
print ("Cross Validation Scores: {}".format(scores))
report = classification_report(y_test_white, predicted_knn)
print (report)
# Finding the best parameters for knn:
from sklearn.model_selection import GridSearchCV
from sklearn.model_selection import RandomizedSearchCV
params2 = [{'n_neighbors': [1,10,50,100], 'algorithm': ['auto','ball_tree','kd_tree' ],
'weights': ['uniform', 'distance'], 'metric': ['minkowski', 'manhattan']}]
grid_search = GridSearchCV(estimator = knn, param_grid = params2, scoring = 'accuracy', cv = 5, n_jobs = 1)
grid_search = grid_search.fit(X_train_white, y_train_white)
accuracy = grid_search.best_score_
best_params = grid_search.best_params_
print(accuracy)
print(best_params)
train_accuracy = []
test_accuracy = []
neighbors = range(1,100,10)
algorithms = ['auto', 'ball_tree', 'kd_tree']
weights = ['uniform', 'distance']
for i in neighbors:
knn = KNeighborsClassifier(n_neighbors = i, metric = 'manhattan', weights = 'distance', algorithm = 'auto')
knn.fit(X_train_white, y_train_white)
train_accuracy.append(knn.score(X_train_white, y_train_white))
test_accuracy.append(knn.score(X_test_white, y_test_white))
plt.plot(neighbors, train_accuracy, label = 'Train set accuracy')
plt.plot(neighbors, test_accuracy, label = 'Test set accuracy')
plt.ylabel("Accuracy")
plt.xlabel("Number of neighbors")
plt.legend()
plt.show()
#------------------------------- Kernel SVC:----------------------------------
from sklearn.svm import SVC
svm = SVC(C = 1000, kernel = 'rbf', gamma = 1)
svm.fit(X_train_white, y_train_white)
predicted = svm.predict(X_test_white)
#print("Predictions: {}".format(predicted))scores = cross_val_score(svm, X = X_train_white, y = y_train_white)
report = classification_report(y_test_white, predicted)
print (report)
# print ("Cross Validation Scores: {}".format(scores))
# -----------Finding the best parameters for SVC----------
params = [{'C': [1, 10, 100, 1000], 'kernel': ['rbf'], 'gamma': [1, 0.1, 0.01, 0.001]}]
grid_search = GridSearchCV(estimator = svm, param_grid = params, scoring = 'accuracy', cv = 5, n_jobs =1)
grid_search = grid_search.fit(X_train_white, y_train_white)
accuracySVC = grid_search.best_score_
best_paramsSVC = grid_search.best_params_
print (accuracySVC)
print (best_paramsSVC)
train_accuracy = []
test_accuracy = []
Ci = [10, 100, 1000]
for i in Ci:
svm = SVC(C = i, kernel = 'rbf', gamma = 1) # try rbf, linear and poly
svm.fit(X_train_white, y_train_white)
train_accuracy.append(svm.score(X_train_white, y_train_white))
test_accuracy.append(svm.score(X_test_white, y_test_white))
plt.plot(Ci, train_accuracy, label = 'Train set accuracy')
plt.plot(Ci, test_accuracy, label = 'Test set accuracy')
plt.ylabel("Accuracy")
plt.xlabel("C")
plt.legend()
plt.show()
####---------XGBoost-----------------
from xgboost.sklearn import XGBClassifier
from xgboost.sklearn import XGBRegressor
xclas = XGBClassifier() # for classifier
xclas.fit(X_train_white, y_train_white)
y_pred = xclas.predict(X_test_white)
cross_val_score(xclas, X_train_white, y_train_white)
from sklearn.metrics import confusion_matrix
cm = confusion_matrix(y_test_white, y_pred)
print (cm)
| mit |
shyamalschandra/scikit-learn | sklearn/datasets/species_distributions.py | 64 | 7917 | """
=============================
Species distribution dataset
=============================
This dataset represents the geographic distribution of species.
The dataset is provided by Phillips et. al. (2006).
The two species are:
- `"Bradypus variegatus"
<http://www.iucnredlist.org/apps/redlist/details/3038/0>`_ ,
the Brown-throated Sloth.
- `"Microryzomys minutus"
<http://www.iucnredlist.org/apps/redlist/details/13408/0>`_ ,
also known as the Forest Small Rice Rat, a rodent that lives in Peru,
Colombia, Ecuador, Peru, and Venezuela.
References:
* `"Maximum entropy modeling of species geographic distributions"
<http://www.cs.princeton.edu/~schapire/papers/ecolmod.pdf>`_
S. J. Phillips, R. P. Anderson, R. E. Schapire - Ecological Modelling,
190:231-259, 2006.
Notes:
* See examples/applications/plot_species_distribution_modeling.py
for an example of using this dataset
"""
# Authors: Peter Prettenhofer <[email protected]>
# Jake Vanderplas <[email protected]>
#
# License: BSD 3 clause
from io import BytesIO
from os import makedirs
from os.path import exists
try:
# Python 2
from urllib2 import urlopen
PY2 = True
except ImportError:
# Python 3
from urllib.request import urlopen
PY2 = False
import numpy as np
from sklearn.datasets.base import get_data_home, Bunch
from sklearn.datasets.base import _pkl_filepath
from sklearn.externals import joblib
DIRECTORY_URL = "http://www.cs.princeton.edu/~schapire/maxent/datasets/"
SAMPLES_URL = DIRECTORY_URL + "samples.zip"
COVERAGES_URL = DIRECTORY_URL + "coverages.zip"
DATA_ARCHIVE_NAME = "species_coverage.pkz"
def _load_coverage(F, header_length=6, dtype=np.int16):
"""Load a coverage file from an open file object.
This will return a numpy array of the given dtype
"""
header = [F.readline() for i in range(header_length)]
make_tuple = lambda t: (t.split()[0], float(t.split()[1]))
header = dict([make_tuple(line) for line in header])
M = np.loadtxt(F, dtype=dtype)
nodata = int(header[b'NODATA_value'])
if nodata != -9999:
M[nodata] = -9999
return M
def _load_csv(F):
"""Load csv file.
Parameters
----------
F : file object
CSV file open in byte mode.
Returns
-------
rec : np.ndarray
record array representing the data
"""
if PY2:
# Numpy recarray wants Python 2 str but not unicode
names = F.readline().strip().split(',')
else:
# Numpy recarray wants Python 3 str but not bytes...
names = F.readline().decode('ascii').strip().split(',')
rec = np.loadtxt(F, skiprows=0, delimiter=',', dtype='a22,f4,f4')
rec.dtype.names = names
return rec
def construct_grids(batch):
"""Construct the map grid from the batch object
Parameters
----------
batch : Batch object
The object returned by :func:`fetch_species_distributions`
Returns
-------
(xgrid, ygrid) : 1-D arrays
The grid corresponding to the values in batch.coverages
"""
# x,y coordinates for corner cells
xmin = batch.x_left_lower_corner + batch.grid_size
xmax = xmin + (batch.Nx * batch.grid_size)
ymin = batch.y_left_lower_corner + batch.grid_size
ymax = ymin + (batch.Ny * batch.grid_size)
# x coordinates of the grid cells
xgrid = np.arange(xmin, xmax, batch.grid_size)
# y coordinates of the grid cells
ygrid = np.arange(ymin, ymax, batch.grid_size)
return (xgrid, ygrid)
def fetch_species_distributions(data_home=None,
download_if_missing=True):
"""Loader for species distribution dataset from Phillips et. al. (2006)
Read more in the :ref:`User Guide <datasets>`.
Parameters
----------
data_home : optional, default: None
Specify another download and cache folder for the datasets. By default
all scikit learn data is stored in '~/scikit_learn_data' subfolders.
download_if_missing: optional, True by default
If False, raise a IOError if the data is not locally available
instead of trying to download the data from the source site.
Returns
--------
The data is returned as a Bunch object with the following attributes:
coverages : array, shape = [14, 1592, 1212]
These represent the 14 features measured at each point of the map grid.
The latitude/longitude values for the grid are discussed below.
Missing data is represented by the value -9999.
train : record array, shape = (1623,)
The training points for the data. Each point has three fields:
- train['species'] is the species name
- train['dd long'] is the longitude, in degrees
- train['dd lat'] is the latitude, in degrees
test : record array, shape = (619,)
The test points for the data. Same format as the training data.
Nx, Ny : integers
The number of longitudes (x) and latitudes (y) in the grid
x_left_lower_corner, y_left_lower_corner : floats
The (x,y) position of the lower-left corner, in degrees
grid_size : float
The spacing between points of the grid, in degrees
Notes
------
This dataset represents the geographic distribution of species.
The dataset is provided by Phillips et. al. (2006).
The two species are:
- `"Bradypus variegatus"
<http://www.iucnredlist.org/apps/redlist/details/3038/0>`_ ,
the Brown-throated Sloth.
- `"Microryzomys minutus"
<http://www.iucnredlist.org/apps/redlist/details/13408/0>`_ ,
also known as the Forest Small Rice Rat, a rodent that lives in Peru,
Colombia, Ecuador, Peru, and Venezuela.
References
----------
* `"Maximum entropy modeling of species geographic distributions"
<http://www.cs.princeton.edu/~schapire/papers/ecolmod.pdf>`_
S. J. Phillips, R. P. Anderson, R. E. Schapire - Ecological Modelling,
190:231-259, 2006.
Notes
-----
* See examples/applications/plot_species_distribution_modeling.py
for an example of using this dataset with scikit-learn
"""
data_home = get_data_home(data_home)
if not exists(data_home):
makedirs(data_home)
# Define parameters for the data files. These should not be changed
# unless the data model changes. They will be saved in the npz file
# with the downloaded data.
extra_params = dict(x_left_lower_corner=-94.8,
Nx=1212,
y_left_lower_corner=-56.05,
Ny=1592,
grid_size=0.05)
dtype = np.int16
archive_path = _pkl_filepath(data_home, DATA_ARCHIVE_NAME)
if not exists(archive_path):
print('Downloading species data from %s to %s' % (SAMPLES_URL,
data_home))
X = np.load(BytesIO(urlopen(SAMPLES_URL).read()))
for f in X.files:
fhandle = BytesIO(X[f])
if 'train' in f:
train = _load_csv(fhandle)
if 'test' in f:
test = _load_csv(fhandle)
print('Downloading coverage data from %s to %s' % (COVERAGES_URL,
data_home))
X = np.load(BytesIO(urlopen(COVERAGES_URL).read()))
coverages = []
for f in X.files:
fhandle = BytesIO(X[f])
print(' - converting', f)
coverages.append(_load_coverage(fhandle))
coverages = np.asarray(coverages, dtype=dtype)
bunch = Bunch(coverages=coverages,
test=test,
train=train,
**extra_params)
joblib.dump(bunch, archive_path, compress=9)
else:
bunch = joblib.load(archive_path)
return bunch
| bsd-3-clause |
jpautom/scikit-learn | sklearn/datasets/tests/test_samples_generator.py | 181 | 15664 | from __future__ import division
from collections import defaultdict
from functools import partial
import numpy as np
import scipy.sparse as sp
from sklearn.externals.six.moves import zip
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import assert_less
from sklearn.utils.testing import assert_raises
from sklearn.datasets import make_classification
from sklearn.datasets import make_multilabel_classification
from sklearn.datasets import make_hastie_10_2
from sklearn.datasets import make_regression
from sklearn.datasets import make_blobs
from sklearn.datasets import make_friedman1
from sklearn.datasets import make_friedman2
from sklearn.datasets import make_friedman3
from sklearn.datasets import make_low_rank_matrix
from sklearn.datasets import make_sparse_coded_signal
from sklearn.datasets import make_sparse_uncorrelated
from sklearn.datasets import make_spd_matrix
from sklearn.datasets import make_swiss_roll
from sklearn.datasets import make_s_curve
from sklearn.datasets import make_biclusters
from sklearn.datasets import make_checkerboard
from sklearn.utils.validation import assert_all_finite
def test_make_classification():
X, y = make_classification(n_samples=100, n_features=20, n_informative=5,
n_redundant=1, n_repeated=1, n_classes=3,
n_clusters_per_class=1, hypercube=False,
shift=None, scale=None, weights=[0.1, 0.25],
random_state=0)
assert_equal(X.shape, (100, 20), "X shape mismatch")
assert_equal(y.shape, (100,), "y shape mismatch")
assert_equal(np.unique(y).shape, (3,), "Unexpected number of classes")
assert_equal(sum(y == 0), 10, "Unexpected number of samples in class #0")
assert_equal(sum(y == 1), 25, "Unexpected number of samples in class #1")
assert_equal(sum(y == 2), 65, "Unexpected number of samples in class #2")
def test_make_classification_informative_features():
"""Test the construction of informative features in make_classification
Also tests `n_clusters_per_class`, `n_classes`, `hypercube` and
fully-specified `weights`.
"""
# Create very separate clusters; check that vertices are unique and
# correspond to classes
class_sep = 1e6
make = partial(make_classification, class_sep=class_sep, n_redundant=0,
n_repeated=0, flip_y=0, shift=0, scale=1, shuffle=False)
for n_informative, weights, n_clusters_per_class in [(2, [1], 1),
(2, [1/3] * 3, 1),
(2, [1/4] * 4, 1),
(2, [1/2] * 2, 2),
(2, [3/4, 1/4], 2),
(10, [1/3] * 3, 10)
]:
n_classes = len(weights)
n_clusters = n_classes * n_clusters_per_class
n_samples = n_clusters * 50
for hypercube in (False, True):
X, y = make(n_samples=n_samples, n_classes=n_classes,
weights=weights, n_features=n_informative,
n_informative=n_informative,
n_clusters_per_class=n_clusters_per_class,
hypercube=hypercube, random_state=0)
assert_equal(X.shape, (n_samples, n_informative))
assert_equal(y.shape, (n_samples,))
# Cluster by sign, viewed as strings to allow uniquing
signs = np.sign(X)
signs = signs.view(dtype='|S{0}'.format(signs.strides[0]))
unique_signs, cluster_index = np.unique(signs,
return_inverse=True)
assert_equal(len(unique_signs), n_clusters,
"Wrong number of clusters, or not in distinct "
"quadrants")
clusters_by_class = defaultdict(set)
for cluster, cls in zip(cluster_index, y):
clusters_by_class[cls].add(cluster)
for clusters in clusters_by_class.values():
assert_equal(len(clusters), n_clusters_per_class,
"Wrong number of clusters per class")
assert_equal(len(clusters_by_class), n_classes,
"Wrong number of classes")
assert_array_almost_equal(np.bincount(y) / len(y) // weights,
[1] * n_classes,
err_msg="Wrong number of samples "
"per class")
# Ensure on vertices of hypercube
for cluster in range(len(unique_signs)):
centroid = X[cluster_index == cluster].mean(axis=0)
if hypercube:
assert_array_almost_equal(np.abs(centroid),
[class_sep] * n_informative,
decimal=0,
err_msg="Clusters are not "
"centered on hypercube "
"vertices")
else:
assert_raises(AssertionError,
assert_array_almost_equal,
np.abs(centroid),
[class_sep] * n_informative,
decimal=0,
err_msg="Clusters should not be cenetered "
"on hypercube vertices")
assert_raises(ValueError, make, n_features=2, n_informative=2, n_classes=5,
n_clusters_per_class=1)
assert_raises(ValueError, make, n_features=2, n_informative=2, n_classes=3,
n_clusters_per_class=2)
def test_make_multilabel_classification_return_sequences():
for allow_unlabeled, min_length in zip((True, False), (0, 1)):
X, Y = make_multilabel_classification(n_samples=100, n_features=20,
n_classes=3, random_state=0,
return_indicator=False,
allow_unlabeled=allow_unlabeled)
assert_equal(X.shape, (100, 20), "X shape mismatch")
if not allow_unlabeled:
assert_equal(max([max(y) for y in Y]), 2)
assert_equal(min([len(y) for y in Y]), min_length)
assert_true(max([len(y) for y in Y]) <= 3)
def test_make_multilabel_classification_return_indicator():
for allow_unlabeled, min_length in zip((True, False), (0, 1)):
X, Y = make_multilabel_classification(n_samples=25, n_features=20,
n_classes=3, random_state=0,
allow_unlabeled=allow_unlabeled)
assert_equal(X.shape, (25, 20), "X shape mismatch")
assert_equal(Y.shape, (25, 3), "Y shape mismatch")
assert_true(np.all(np.sum(Y, axis=0) > min_length))
# Also test return_distributions and return_indicator with True
X2, Y2, p_c, p_w_c = make_multilabel_classification(
n_samples=25, n_features=20, n_classes=3, random_state=0,
allow_unlabeled=allow_unlabeled, return_distributions=True)
assert_array_equal(X, X2)
assert_array_equal(Y, Y2)
assert_equal(p_c.shape, (3,))
assert_almost_equal(p_c.sum(), 1)
assert_equal(p_w_c.shape, (20, 3))
assert_almost_equal(p_w_c.sum(axis=0), [1] * 3)
def test_make_multilabel_classification_return_indicator_sparse():
for allow_unlabeled, min_length in zip((True, False), (0, 1)):
X, Y = make_multilabel_classification(n_samples=25, n_features=20,
n_classes=3, random_state=0,
return_indicator='sparse',
allow_unlabeled=allow_unlabeled)
assert_equal(X.shape, (25, 20), "X shape mismatch")
assert_equal(Y.shape, (25, 3), "Y shape mismatch")
assert_true(sp.issparse(Y))
def test_make_hastie_10_2():
X, y = make_hastie_10_2(n_samples=100, random_state=0)
assert_equal(X.shape, (100, 10), "X shape mismatch")
assert_equal(y.shape, (100,), "y shape mismatch")
assert_equal(np.unique(y).shape, (2,), "Unexpected number of classes")
def test_make_regression():
X, y, c = make_regression(n_samples=100, n_features=10, n_informative=3,
effective_rank=5, coef=True, bias=0.0,
noise=1.0, random_state=0)
assert_equal(X.shape, (100, 10), "X shape mismatch")
assert_equal(y.shape, (100,), "y shape mismatch")
assert_equal(c.shape, (10,), "coef shape mismatch")
assert_equal(sum(c != 0.0), 3, "Unexpected number of informative features")
# Test that y ~= np.dot(X, c) + bias + N(0, 1.0).
assert_almost_equal(np.std(y - np.dot(X, c)), 1.0, decimal=1)
# Test with small number of features.
X, y = make_regression(n_samples=100, n_features=1) # n_informative=3
assert_equal(X.shape, (100, 1))
def test_make_regression_multitarget():
X, y, c = make_regression(n_samples=100, n_features=10, n_informative=3,
n_targets=3, coef=True, noise=1., random_state=0)
assert_equal(X.shape, (100, 10), "X shape mismatch")
assert_equal(y.shape, (100, 3), "y shape mismatch")
assert_equal(c.shape, (10, 3), "coef shape mismatch")
assert_array_equal(sum(c != 0.0), 3,
"Unexpected number of informative features")
# Test that y ~= np.dot(X, c) + bias + N(0, 1.0)
assert_almost_equal(np.std(y - np.dot(X, c)), 1.0, decimal=1)
def test_make_blobs():
cluster_stds = np.array([0.05, 0.2, 0.4])
cluster_centers = np.array([[0.0, 0.0], [1.0, 1.0], [0.0, 1.0]])
X, y = make_blobs(random_state=0, n_samples=50, n_features=2,
centers=cluster_centers, cluster_std=cluster_stds)
assert_equal(X.shape, (50, 2), "X shape mismatch")
assert_equal(y.shape, (50,), "y shape mismatch")
assert_equal(np.unique(y).shape, (3,), "Unexpected number of blobs")
for i, (ctr, std) in enumerate(zip(cluster_centers, cluster_stds)):
assert_almost_equal((X[y == i] - ctr).std(), std, 1, "Unexpected std")
def test_make_friedman1():
X, y = make_friedman1(n_samples=5, n_features=10, noise=0.0,
random_state=0)
assert_equal(X.shape, (5, 10), "X shape mismatch")
assert_equal(y.shape, (5,), "y shape mismatch")
assert_array_almost_equal(y,
10 * np.sin(np.pi * X[:, 0] * X[:, 1])
+ 20 * (X[:, 2] - 0.5) ** 2
+ 10 * X[:, 3] + 5 * X[:, 4])
def test_make_friedman2():
X, y = make_friedman2(n_samples=5, noise=0.0, random_state=0)
assert_equal(X.shape, (5, 4), "X shape mismatch")
assert_equal(y.shape, (5,), "y shape mismatch")
assert_array_almost_equal(y,
(X[:, 0] ** 2
+ (X[:, 1] * X[:, 2] - 1
/ (X[:, 1] * X[:, 3])) ** 2) ** 0.5)
def test_make_friedman3():
X, y = make_friedman3(n_samples=5, noise=0.0, random_state=0)
assert_equal(X.shape, (5, 4), "X shape mismatch")
assert_equal(y.shape, (5,), "y shape mismatch")
assert_array_almost_equal(y, np.arctan((X[:, 1] * X[:, 2]
- 1 / (X[:, 1] * X[:, 3]))
/ X[:, 0]))
def test_make_low_rank_matrix():
X = make_low_rank_matrix(n_samples=50, n_features=25, effective_rank=5,
tail_strength=0.01, random_state=0)
assert_equal(X.shape, (50, 25), "X shape mismatch")
from numpy.linalg import svd
u, s, v = svd(X)
assert_less(sum(s) - 5, 0.1, "X rank is not approximately 5")
def test_make_sparse_coded_signal():
Y, D, X = make_sparse_coded_signal(n_samples=5, n_components=8,
n_features=10, n_nonzero_coefs=3,
random_state=0)
assert_equal(Y.shape, (10, 5), "Y shape mismatch")
assert_equal(D.shape, (10, 8), "D shape mismatch")
assert_equal(X.shape, (8, 5), "X shape mismatch")
for col in X.T:
assert_equal(len(np.flatnonzero(col)), 3, 'Non-zero coefs mismatch')
assert_array_almost_equal(np.dot(D, X), Y)
assert_array_almost_equal(np.sqrt((D ** 2).sum(axis=0)),
np.ones(D.shape[1]))
def test_make_sparse_uncorrelated():
X, y = make_sparse_uncorrelated(n_samples=5, n_features=10, random_state=0)
assert_equal(X.shape, (5, 10), "X shape mismatch")
assert_equal(y.shape, (5,), "y shape mismatch")
def test_make_spd_matrix():
X = make_spd_matrix(n_dim=5, random_state=0)
assert_equal(X.shape, (5, 5), "X shape mismatch")
assert_array_almost_equal(X, X.T)
from numpy.linalg import eig
eigenvalues, _ = eig(X)
assert_array_equal(eigenvalues > 0, np.array([True] * 5),
"X is not positive-definite")
def test_make_swiss_roll():
X, t = make_swiss_roll(n_samples=5, noise=0.0, random_state=0)
assert_equal(X.shape, (5, 3), "X shape mismatch")
assert_equal(t.shape, (5,), "t shape mismatch")
assert_array_almost_equal(X[:, 0], t * np.cos(t))
assert_array_almost_equal(X[:, 2], t * np.sin(t))
def test_make_s_curve():
X, t = make_s_curve(n_samples=5, noise=0.0, random_state=0)
assert_equal(X.shape, (5, 3), "X shape mismatch")
assert_equal(t.shape, (5,), "t shape mismatch")
assert_array_almost_equal(X[:, 0], np.sin(t))
assert_array_almost_equal(X[:, 2], np.sign(t) * (np.cos(t) - 1))
def test_make_biclusters():
X, rows, cols = make_biclusters(
shape=(100, 100), n_clusters=4, shuffle=True, random_state=0)
assert_equal(X.shape, (100, 100), "X shape mismatch")
assert_equal(rows.shape, (4, 100), "rows shape mismatch")
assert_equal(cols.shape, (4, 100,), "columns shape mismatch")
assert_all_finite(X)
assert_all_finite(rows)
assert_all_finite(cols)
X2, _, _ = make_biclusters(shape=(100, 100), n_clusters=4,
shuffle=True, random_state=0)
assert_array_almost_equal(X, X2)
def test_make_checkerboard():
X, rows, cols = make_checkerboard(
shape=(100, 100), n_clusters=(20, 5),
shuffle=True, random_state=0)
assert_equal(X.shape, (100, 100), "X shape mismatch")
assert_equal(rows.shape, (100, 100), "rows shape mismatch")
assert_equal(cols.shape, (100, 100,), "columns shape mismatch")
X, rows, cols = make_checkerboard(
shape=(100, 100), n_clusters=2, shuffle=True, random_state=0)
assert_all_finite(X)
assert_all_finite(rows)
assert_all_finite(cols)
X1, _, _ = make_checkerboard(shape=(100, 100), n_clusters=2,
shuffle=True, random_state=0)
X2, _, _ = make_checkerboard(shape=(100, 100), n_clusters=2,
shuffle=True, random_state=0)
assert_array_equal(X1, X2)
| bsd-3-clause |
equialgo/scikit-learn | examples/cluster/plot_adjusted_for_chance_measures.py | 105 | 4300 | """
==========================================================
Adjustment for chance in clustering performance evaluation
==========================================================
The following plots demonstrate the impact of the number of clusters and
number of samples on various clustering performance evaluation metrics.
Non-adjusted measures such as the V-Measure show a dependency between
the number of clusters and the number of samples: the mean V-Measure
of random labeling increases significantly as the number of clusters is
closer to the total number of samples used to compute the measure.
Adjusted for chance measure such as ARI display some random variations
centered around a mean score of 0.0 for any number of samples and
clusters.
Only adjusted measures can hence safely be used as a consensus index
to evaluate the average stability of clustering algorithms for a given
value of k on various overlapping sub-samples of the dataset.
"""
print(__doc__)
# Author: Olivier Grisel <[email protected]>
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from time import time
from sklearn import metrics
def uniform_labelings_scores(score_func, n_samples, n_clusters_range,
fixed_n_classes=None, n_runs=5, seed=42):
"""Compute score for 2 random uniform cluster labelings.
Both random labelings have the same number of clusters for each value
possible value in ``n_clusters_range``.
When fixed_n_classes is not None the first labeling is considered a ground
truth class assignment with fixed number of classes.
"""
random_labels = np.random.RandomState(seed).randint
scores = np.zeros((len(n_clusters_range), n_runs))
if fixed_n_classes is not None:
labels_a = random_labels(low=0, high=fixed_n_classes, size=n_samples)
for i, k in enumerate(n_clusters_range):
for j in range(n_runs):
if fixed_n_classes is None:
labels_a = random_labels(low=0, high=k, size=n_samples)
labels_b = random_labels(low=0, high=k, size=n_samples)
scores[i, j] = score_func(labels_a, labels_b)
return scores
score_funcs = [
metrics.adjusted_rand_score,
metrics.v_measure_score,
metrics.adjusted_mutual_info_score,
metrics.mutual_info_score,
]
# 2 independent random clusterings with equal cluster number
n_samples = 100
n_clusters_range = np.linspace(2, n_samples, 10).astype(np.int)
plt.figure(1)
plots = []
names = []
for score_func in score_funcs:
print("Computing %s for %d values of n_clusters and n_samples=%d"
% (score_func.__name__, len(n_clusters_range), n_samples))
t0 = time()
scores = uniform_labelings_scores(score_func, n_samples, n_clusters_range)
print("done in %0.3fs" % (time() - t0))
plots.append(plt.errorbar(
n_clusters_range, np.median(scores, axis=1), scores.std(axis=1))[0])
names.append(score_func.__name__)
plt.title("Clustering measures for 2 random uniform labelings\n"
"with equal number of clusters")
plt.xlabel('Number of clusters (Number of samples is fixed to %d)' % n_samples)
plt.ylabel('Score value')
plt.legend(plots, names)
plt.ylim(ymin=-0.05, ymax=1.05)
# Random labeling with varying n_clusters against ground class labels
# with fixed number of clusters
n_samples = 1000
n_clusters_range = np.linspace(2, 100, 10).astype(np.int)
n_classes = 10
plt.figure(2)
plots = []
names = []
for score_func in score_funcs:
print("Computing %s for %d values of n_clusters and n_samples=%d"
% (score_func.__name__, len(n_clusters_range), n_samples))
t0 = time()
scores = uniform_labelings_scores(score_func, n_samples, n_clusters_range,
fixed_n_classes=n_classes)
print("done in %0.3fs" % (time() - t0))
plots.append(plt.errorbar(
n_clusters_range, scores.mean(axis=1), scores.std(axis=1))[0])
names.append(score_func.__name__)
plt.title("Clustering measures for random uniform labeling\n"
"against reference assignment with %d classes" % n_classes)
plt.xlabel('Number of clusters (Number of samples is fixed to %d)' % n_samples)
plt.ylabel('Score value')
plt.ylim(ymin=-0.05, ymax=1.05)
plt.legend(plots, names)
plt.show()
| bsd-3-clause |
siutanwong/scikit-learn | sklearn/ensemble/tests/test_forest.py | 48 | 35412 | """
Testing for the forest module (sklearn.ensemble.forest).
"""
# Authors: Gilles Louppe,
# Brian Holt,
# Andreas Mueller,
# Arnaud Joly
# License: BSD 3 clause
import pickle
from collections import defaultdict
from itertools import product
import numpy as np
from scipy.sparse import csr_matrix, csc_matrix, coo_matrix
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_false, assert_true
from sklearn.utils.testing import assert_less, assert_greater
from sklearn.utils.testing import assert_greater_equal
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_warns
from sklearn.utils.testing import ignore_warnings
from sklearn import datasets
from sklearn.decomposition import TruncatedSVD
from sklearn.ensemble import ExtraTreesClassifier
from sklearn.ensemble import ExtraTreesRegressor
from sklearn.ensemble import RandomForestClassifier
from sklearn.ensemble import RandomForestRegressor
from sklearn.ensemble import RandomTreesEmbedding
from sklearn.grid_search import GridSearchCV
from sklearn.svm import LinearSVC
from sklearn.utils.validation import check_random_state
from sklearn.tree.tree import SPARSE_SPLITTERS
# toy sample
X = [[-2, -1], [-1, -1], [-1, -2], [1, 1], [1, 2], [2, 1]]
y = [-1, -1, -1, 1, 1, 1]
T = [[-1, -1], [2, 2], [3, 2]]
true_result = [-1, 1, 1]
# also load the iris dataset
# and randomly permute it
iris = datasets.load_iris()
rng = check_random_state(0)
perm = rng.permutation(iris.target.size)
iris.data = iris.data[perm]
iris.target = iris.target[perm]
# also load the boston dataset
# and randomly permute it
boston = datasets.load_boston()
perm = rng.permutation(boston.target.size)
boston.data = boston.data[perm]
boston.target = boston.target[perm]
FOREST_CLASSIFIERS = {
"ExtraTreesClassifier": ExtraTreesClassifier,
"RandomForestClassifier": RandomForestClassifier,
}
FOREST_REGRESSORS = {
"ExtraTreesRegressor": ExtraTreesRegressor,
"RandomForestRegressor": RandomForestRegressor,
}
FOREST_TRANSFORMERS = {
"RandomTreesEmbedding": RandomTreesEmbedding,
}
FOREST_ESTIMATORS = dict()
FOREST_ESTIMATORS.update(FOREST_CLASSIFIERS)
FOREST_ESTIMATORS.update(FOREST_REGRESSORS)
FOREST_ESTIMATORS.update(FOREST_TRANSFORMERS)
def check_classification_toy(name):
"""Check classification on a toy dataset."""
ForestClassifier = FOREST_CLASSIFIERS[name]
clf = ForestClassifier(n_estimators=10, random_state=1)
clf.fit(X, y)
assert_array_equal(clf.predict(T), true_result)
assert_equal(10, len(clf))
clf = ForestClassifier(n_estimators=10, max_features=1, random_state=1)
clf.fit(X, y)
assert_array_equal(clf.predict(T), true_result)
assert_equal(10, len(clf))
# also test apply
leaf_indices = clf.apply(X)
assert_equal(leaf_indices.shape, (len(X), clf.n_estimators))
def test_classification_toy():
for name in FOREST_CLASSIFIERS:
yield check_classification_toy, name
def check_iris_criterion(name, criterion):
# Check consistency on dataset iris.
ForestClassifier = FOREST_CLASSIFIERS[name]
clf = ForestClassifier(n_estimators=10, criterion=criterion,
random_state=1)
clf.fit(iris.data, iris.target)
score = clf.score(iris.data, iris.target)
assert_greater(score, 0.9, "Failed with criterion %s and score = %f"
% (criterion, score))
clf = ForestClassifier(n_estimators=10, criterion=criterion,
max_features=2, random_state=1)
clf.fit(iris.data, iris.target)
score = clf.score(iris.data, iris.target)
assert_greater(score, 0.5, "Failed with criterion %s and score = %f"
% (criterion, score))
def test_iris():
for name, criterion in product(FOREST_CLASSIFIERS, ("gini", "entropy")):
yield check_iris_criterion, name, criterion
def check_boston_criterion(name, criterion):
# Check consistency on dataset boston house prices.
ForestRegressor = FOREST_REGRESSORS[name]
clf = ForestRegressor(n_estimators=5, criterion=criterion, random_state=1)
clf.fit(boston.data, boston.target)
score = clf.score(boston.data, boston.target)
assert_greater(score, 0.95, "Failed with max_features=None, criterion %s "
"and score = %f" % (criterion, score))
clf = ForestRegressor(n_estimators=5, criterion=criterion,
max_features=6, random_state=1)
clf.fit(boston.data, boston.target)
score = clf.score(boston.data, boston.target)
assert_greater(score, 0.95, "Failed with max_features=6, criterion %s "
"and score = %f" % (criterion, score))
def test_boston():
for name, criterion in product(FOREST_REGRESSORS, ("mse", )):
yield check_boston_criterion, name, criterion
def check_regressor_attributes(name):
# Regression models should not have a classes_ attribute.
r = FOREST_REGRESSORS[name](random_state=0)
assert_false(hasattr(r, "classes_"))
assert_false(hasattr(r, "n_classes_"))
r.fit([[1, 2, 3], [4, 5, 6]], [1, 2])
assert_false(hasattr(r, "classes_"))
assert_false(hasattr(r, "n_classes_"))
def test_regressor_attributes():
for name in FOREST_REGRESSORS:
yield check_regressor_attributes, name
def check_probability(name):
# Predict probabilities.
ForestClassifier = FOREST_CLASSIFIERS[name]
with np.errstate(divide="ignore"):
clf = ForestClassifier(n_estimators=10, random_state=1, max_features=1,
max_depth=1)
clf.fit(iris.data, iris.target)
assert_array_almost_equal(np.sum(clf.predict_proba(iris.data), axis=1),
np.ones(iris.data.shape[0]))
assert_array_almost_equal(clf.predict_proba(iris.data),
np.exp(clf.predict_log_proba(iris.data)))
def test_probability():
for name in FOREST_CLASSIFIERS:
yield check_probability, name
def check_importances(name, X, y):
# Check variable importances.
ForestClassifier = FOREST_CLASSIFIERS[name]
for n_jobs in [1, 2]:
clf = ForestClassifier(n_estimators=10, n_jobs=n_jobs)
clf.fit(X, y)
importances = clf.feature_importances_
n_important = np.sum(importances > 0.1)
assert_equal(importances.shape[0], 10)
assert_equal(n_important, 3)
X_new = clf.transform(X, threshold="mean")
assert_less(0 < X_new.shape[1], X.shape[1])
# Check with sample weights
sample_weight = np.ones(y.shape)
sample_weight[y == 1] *= 100
clf = ForestClassifier(n_estimators=50, n_jobs=n_jobs, random_state=0)
clf.fit(X, y, sample_weight=sample_weight)
importances = clf.feature_importances_
assert_true(np.all(importances >= 0.0))
clf = ForestClassifier(n_estimators=50, n_jobs=n_jobs, random_state=0)
clf.fit(X, y, sample_weight=3 * sample_weight)
importances_bis = clf.feature_importances_
assert_almost_equal(importances, importances_bis)
def test_importances():
X, y = datasets.make_classification(n_samples=1000, n_features=10,
n_informative=3, n_redundant=0,
n_repeated=0, shuffle=False,
random_state=0)
for name in FOREST_CLASSIFIERS:
yield check_importances, name, X, y
def check_unfitted_feature_importances(name):
assert_raises(ValueError, getattr, FOREST_ESTIMATORS[name](random_state=0),
"feature_importances_")
def test_unfitted_feature_importances():
for name in FOREST_ESTIMATORS:
yield check_unfitted_feature_importances, name
def check_oob_score(name, X, y, n_estimators=20):
# Check that oob prediction is a good estimation of the generalization
# error.
# Proper behavior
est = FOREST_ESTIMATORS[name](oob_score=True, random_state=0,
n_estimators=n_estimators, bootstrap=True)
n_samples = X.shape[0]
est.fit(X[:n_samples // 2, :], y[:n_samples // 2])
test_score = est.score(X[n_samples // 2:, :], y[n_samples // 2:])
if name in FOREST_CLASSIFIERS:
assert_less(abs(test_score - est.oob_score_), 0.1)
else:
assert_greater(test_score, est.oob_score_)
assert_greater(est.oob_score_, .8)
# Check warning if not enough estimators
with np.errstate(divide="ignore", invalid="ignore"):
est = FOREST_ESTIMATORS[name](oob_score=True, random_state=0,
n_estimators=1, bootstrap=True)
assert_warns(UserWarning, est.fit, X, y)
def test_oob_score():
for name in FOREST_CLASSIFIERS:
yield check_oob_score, name, iris.data, iris.target
# csc matrix
yield check_oob_score, name, csc_matrix(iris.data), iris.target
# non-contiguous targets in classification
yield check_oob_score, name, iris.data, iris.target * 2 + 1
for name in FOREST_REGRESSORS:
yield check_oob_score, name, boston.data, boston.target, 50
# csc matrix
yield check_oob_score, name, csc_matrix(boston.data), boston.target, 50
def check_oob_score_raise_error(name):
ForestEstimator = FOREST_ESTIMATORS[name]
if name in FOREST_TRANSFORMERS:
for oob_score in [True, False]:
assert_raises(TypeError, ForestEstimator, oob_score=oob_score)
assert_raises(NotImplementedError, ForestEstimator()._set_oob_score,
X, y)
else:
# Unfitted / no bootstrap / no oob_score
for oob_score, bootstrap in [(True, False), (False, True),
(False, False)]:
est = ForestEstimator(oob_score=oob_score, bootstrap=bootstrap,
random_state=0)
assert_false(hasattr(est, "oob_score_"))
# No bootstrap
assert_raises(ValueError, ForestEstimator(oob_score=True,
bootstrap=False).fit, X, y)
def test_oob_score_raise_error():
for name in FOREST_ESTIMATORS:
yield check_oob_score_raise_error, name
def check_gridsearch(name):
forest = FOREST_CLASSIFIERS[name]()
clf = GridSearchCV(forest, {'n_estimators': (1, 2), 'max_depth': (1, 2)})
clf.fit(iris.data, iris.target)
def test_gridsearch():
# Check that base trees can be grid-searched.
for name in FOREST_CLASSIFIERS:
yield check_gridsearch, name
def check_parallel(name, X, y):
"""Check parallel computations in classification"""
ForestEstimator = FOREST_ESTIMATORS[name]
forest = ForestEstimator(n_estimators=10, n_jobs=3, random_state=0)
forest.fit(X, y)
assert_equal(len(forest), 10)
forest.set_params(n_jobs=1)
y1 = forest.predict(X)
forest.set_params(n_jobs=2)
y2 = forest.predict(X)
assert_array_almost_equal(y1, y2, 3)
def test_parallel():
for name in FOREST_CLASSIFIERS:
yield check_parallel, name, iris.data, iris.target
for name in FOREST_REGRESSORS:
yield check_parallel, name, boston.data, boston.target
def check_pickle(name, X, y):
# Check pickability.
ForestEstimator = FOREST_ESTIMATORS[name]
obj = ForestEstimator(random_state=0)
obj.fit(X, y)
score = obj.score(X, y)
pickle_object = pickle.dumps(obj)
obj2 = pickle.loads(pickle_object)
assert_equal(type(obj2), obj.__class__)
score2 = obj2.score(X, y)
assert_equal(score, score2)
def test_pickle():
for name in FOREST_CLASSIFIERS:
yield check_pickle, name, iris.data[::2], iris.target[::2]
for name in FOREST_REGRESSORS:
yield check_pickle, name, boston.data[::2], boston.target[::2]
def check_multioutput(name):
# Check estimators on multi-output problems.
X_train = [[-2, -1], [-1, -1], [-1, -2], [1, 1], [1, 2], [2, 1], [-2, 1],
[-1, 1], [-1, 2], [2, -1], [1, -1], [1, -2]]
y_train = [[-1, 0], [-1, 0], [-1, 0], [1, 1], [1, 1], [1, 1], [-1, 2],
[-1, 2], [-1, 2], [1, 3], [1, 3], [1, 3]]
X_test = [[-1, -1], [1, 1], [-1, 1], [1, -1]]
y_test = [[-1, 0], [1, 1], [-1, 2], [1, 3]]
est = FOREST_ESTIMATORS[name](random_state=0, bootstrap=False)
y_pred = est.fit(X_train, y_train).predict(X_test)
assert_array_almost_equal(y_pred, y_test)
if name in FOREST_CLASSIFIERS:
with np.errstate(divide="ignore"):
proba = est.predict_proba(X_test)
assert_equal(len(proba), 2)
assert_equal(proba[0].shape, (4, 2))
assert_equal(proba[1].shape, (4, 4))
log_proba = est.predict_log_proba(X_test)
assert_equal(len(log_proba), 2)
assert_equal(log_proba[0].shape, (4, 2))
assert_equal(log_proba[1].shape, (4, 4))
def test_multioutput():
for name in FOREST_CLASSIFIERS:
yield check_multioutput, name
for name in FOREST_REGRESSORS:
yield check_multioutput, name
def check_classes_shape(name):
# Test that n_classes_ and classes_ have proper shape.
ForestClassifier = FOREST_CLASSIFIERS[name]
# Classification, single output
clf = ForestClassifier(random_state=0).fit(X, y)
assert_equal(clf.n_classes_, 2)
assert_array_equal(clf.classes_, [-1, 1])
# Classification, multi-output
_y = np.vstack((y, np.array(y) * 2)).T
clf = ForestClassifier(random_state=0).fit(X, _y)
assert_array_equal(clf.n_classes_, [2, 2])
assert_array_equal(clf.classes_, [[-1, 1], [-2, 2]])
def test_classes_shape():
for name in FOREST_CLASSIFIERS:
yield check_classes_shape, name
def test_random_trees_dense_type():
# Test that the `sparse_output` parameter of RandomTreesEmbedding
# works by returning a dense array.
# Create the RTE with sparse=False
hasher = RandomTreesEmbedding(n_estimators=10, sparse_output=False)
X, y = datasets.make_circles(factor=0.5)
X_transformed = hasher.fit_transform(X)
# Assert that type is ndarray, not scipy.sparse.csr.csr_matrix
assert_equal(type(X_transformed), np.ndarray)
def test_random_trees_dense_equal():
# Test that the `sparse_output` parameter of RandomTreesEmbedding
# works by returning the same array for both argument values.
# Create the RTEs
hasher_dense = RandomTreesEmbedding(n_estimators=10, sparse_output=False,
random_state=0)
hasher_sparse = RandomTreesEmbedding(n_estimators=10, sparse_output=True,
random_state=0)
X, y = datasets.make_circles(factor=0.5)
X_transformed_dense = hasher_dense.fit_transform(X)
X_transformed_sparse = hasher_sparse.fit_transform(X)
# Assert that dense and sparse hashers have same array.
assert_array_equal(X_transformed_sparse.toarray(), X_transformed_dense)
def test_random_hasher():
# test random forest hashing on circles dataset
# make sure that it is linearly separable.
# even after projected to two SVD dimensions
# Note: Not all random_states produce perfect results.
hasher = RandomTreesEmbedding(n_estimators=30, random_state=1)
X, y = datasets.make_circles(factor=0.5)
X_transformed = hasher.fit_transform(X)
# test fit and transform:
hasher = RandomTreesEmbedding(n_estimators=30, random_state=1)
assert_array_equal(hasher.fit(X).transform(X).toarray(),
X_transformed.toarray())
# one leaf active per data point per forest
assert_equal(X_transformed.shape[0], X.shape[0])
assert_array_equal(X_transformed.sum(axis=1), hasher.n_estimators)
svd = TruncatedSVD(n_components=2)
X_reduced = svd.fit_transform(X_transformed)
linear_clf = LinearSVC()
linear_clf.fit(X_reduced, y)
assert_equal(linear_clf.score(X_reduced, y), 1.)
def test_random_hasher_sparse_data():
X, y = datasets.make_multilabel_classification(return_indicator=True,
random_state=0)
hasher = RandomTreesEmbedding(n_estimators=30, random_state=1)
X_transformed = hasher.fit_transform(X)
X_transformed_sparse = hasher.fit_transform(csc_matrix(X))
assert_array_equal(X_transformed_sparse.toarray(), X_transformed.toarray())
def test_parallel_train():
rng = check_random_state(12321)
n_samples, n_features = 80, 30
X_train = rng.randn(n_samples, n_features)
y_train = rng.randint(0, 2, n_samples)
clfs = [
RandomForestClassifier(n_estimators=20, n_jobs=n_jobs,
random_state=12345).fit(X_train, y_train)
for n_jobs in [1, 2, 3, 8, 16, 32]
]
X_test = rng.randn(n_samples, n_features)
probas = [clf.predict_proba(X_test) for clf in clfs]
for proba1, proba2 in zip(probas, probas[1:]):
assert_array_almost_equal(proba1, proba2)
def test_distribution():
rng = check_random_state(12321)
# Single variable with 4 values
X = rng.randint(0, 4, size=(1000, 1))
y = rng.rand(1000)
n_trees = 500
clf = ExtraTreesRegressor(n_estimators=n_trees, random_state=42).fit(X, y)
uniques = defaultdict(int)
for tree in clf.estimators_:
tree = "".join(("%d,%d/" % (f, int(t)) if f >= 0 else "-")
for f, t in zip(tree.tree_.feature,
tree.tree_.threshold))
uniques[tree] += 1
uniques = sorted([(1. * count / n_trees, tree)
for tree, count in uniques.items()])
# On a single variable problem where X_0 has 4 equiprobable values, there
# are 5 ways to build a random tree. The more compact (0,1/0,0/--0,2/--) of
# them has probability 1/3 while the 4 others have probability 1/6.
assert_equal(len(uniques), 5)
assert_greater(0.20, uniques[0][0]) # Rough approximation of 1/6.
assert_greater(0.20, uniques[1][0])
assert_greater(0.20, uniques[2][0])
assert_greater(0.20, uniques[3][0])
assert_greater(uniques[4][0], 0.3)
assert_equal(uniques[4][1], "0,1/0,0/--0,2/--")
# Two variables, one with 2 values, one with 3 values
X = np.empty((1000, 2))
X[:, 0] = np.random.randint(0, 2, 1000)
X[:, 1] = np.random.randint(0, 3, 1000)
y = rng.rand(1000)
clf = ExtraTreesRegressor(n_estimators=100, max_features=1,
random_state=1).fit(X, y)
uniques = defaultdict(int)
for tree in clf.estimators_:
tree = "".join(("%d,%d/" % (f, int(t)) if f >= 0 else "-")
for f, t in zip(tree.tree_.feature,
tree.tree_.threshold))
uniques[tree] += 1
uniques = [(count, tree) for tree, count in uniques.items()]
assert_equal(len(uniques), 8)
def check_max_leaf_nodes_max_depth(name, X, y):
# Test precedence of max_leaf_nodes over max_depth.
ForestEstimator = FOREST_ESTIMATORS[name]
est = ForestEstimator(max_depth=1, max_leaf_nodes=4,
n_estimators=1).fit(X, y)
assert_greater(est.estimators_[0].tree_.max_depth, 1)
est = ForestEstimator(max_depth=1, n_estimators=1).fit(X, y)
assert_equal(est.estimators_[0].tree_.max_depth, 1)
def test_max_leaf_nodes_max_depth():
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
for name in FOREST_ESTIMATORS:
yield check_max_leaf_nodes_max_depth, name, X, y
def check_min_samples_leaf(name, X, y):
# Test if leaves contain more than leaf_count training examples
ForestEstimator = FOREST_ESTIMATORS[name]
# test both DepthFirstTreeBuilder and BestFirstTreeBuilder
# by setting max_leaf_nodes
for max_leaf_nodes in (None, 1000):
est = ForestEstimator(min_samples_leaf=5,
max_leaf_nodes=max_leaf_nodes,
random_state=0)
est.fit(X, y)
out = est.estimators_[0].tree_.apply(X)
node_counts = np.bincount(out)
# drop inner nodes
leaf_count = node_counts[node_counts != 0]
assert_greater(np.min(leaf_count), 4,
"Failed with {0}".format(name))
def test_min_samples_leaf():
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
X = X.astype(np.float32)
for name in FOREST_ESTIMATORS:
yield check_min_samples_leaf, name, X, y
def check_min_weight_fraction_leaf(name, X, y):
# Test if leaves contain at least min_weight_fraction_leaf of the
# training set
ForestEstimator = FOREST_ESTIMATORS[name]
rng = np.random.RandomState(0)
weights = rng.rand(X.shape[0])
total_weight = np.sum(weights)
# test both DepthFirstTreeBuilder and BestFirstTreeBuilder
# by setting max_leaf_nodes
for max_leaf_nodes in (None, 1000):
for frac in np.linspace(0, 0.5, 6):
est = ForestEstimator(min_weight_fraction_leaf=frac,
max_leaf_nodes=max_leaf_nodes,
random_state=0)
if isinstance(est, (RandomForestClassifier,
RandomForestRegressor)):
est.bootstrap = False
est.fit(X, y, sample_weight=weights)
out = est.estimators_[0].tree_.apply(X)
node_weights = np.bincount(out, weights=weights)
# drop inner nodes
leaf_weights = node_weights[node_weights != 0]
assert_greater_equal(
np.min(leaf_weights),
total_weight * est.min_weight_fraction_leaf,
"Failed with {0} "
"min_weight_fraction_leaf={1}".format(
name, est.min_weight_fraction_leaf))
def test_min_weight_fraction_leaf():
X, y = datasets.make_hastie_10_2(n_samples=100, random_state=1)
X = X.astype(np.float32)
for name in FOREST_ESTIMATORS:
yield check_min_weight_fraction_leaf, name, X, y
def check_sparse_input(name, X, X_sparse, y):
ForestEstimator = FOREST_ESTIMATORS[name]
dense = ForestEstimator(random_state=0, max_depth=2).fit(X, y)
sparse = ForestEstimator(random_state=0, max_depth=2).fit(X_sparse, y)
assert_array_almost_equal(sparse.apply(X), dense.apply(X))
if name in FOREST_CLASSIFIERS or name in FOREST_REGRESSORS:
assert_array_almost_equal(sparse.predict(X), dense.predict(X))
assert_array_almost_equal(sparse.feature_importances_,
dense.feature_importances_)
if name in FOREST_CLASSIFIERS:
assert_array_almost_equal(sparse.predict_proba(X),
dense.predict_proba(X))
assert_array_almost_equal(sparse.predict_log_proba(X),
dense.predict_log_proba(X))
if name in FOREST_TRANSFORMERS:
assert_array_almost_equal(sparse.transform(X).toarray(),
dense.transform(X).toarray())
assert_array_almost_equal(sparse.fit_transform(X).toarray(),
dense.fit_transform(X).toarray())
def test_sparse_input():
X, y = datasets.make_multilabel_classification(return_indicator=True,
random_state=0,
n_samples=40)
for name, sparse_matrix in product(FOREST_ESTIMATORS,
(csr_matrix, csc_matrix, coo_matrix)):
yield check_sparse_input, name, X, sparse_matrix(X), y
def check_memory_layout(name, dtype):
# Check that it works no matter the memory layout
est = FOREST_ESTIMATORS[name](random_state=0, bootstrap=False)
# Nothing
X = np.asarray(iris.data, dtype=dtype)
y = iris.target
assert_array_equal(est.fit(X, y).predict(X), y)
# C-order
X = np.asarray(iris.data, order="C", dtype=dtype)
y = iris.target
assert_array_equal(est.fit(X, y).predict(X), y)
# F-order
X = np.asarray(iris.data, order="F", dtype=dtype)
y = iris.target
assert_array_equal(est.fit(X, y).predict(X), y)
# Contiguous
X = np.ascontiguousarray(iris.data, dtype=dtype)
y = iris.target
assert_array_equal(est.fit(X, y).predict(X), y)
if est.base_estimator.splitter in SPARSE_SPLITTERS:
# csr matrix
X = csr_matrix(iris.data, dtype=dtype)
y = iris.target
assert_array_equal(est.fit(X, y).predict(X), y)
# csc_matrix
X = csc_matrix(iris.data, dtype=dtype)
y = iris.target
assert_array_equal(est.fit(X, y).predict(X), y)
# coo_matrix
X = coo_matrix(iris.data, dtype=dtype)
y = iris.target
assert_array_equal(est.fit(X, y).predict(X), y)
# Strided
X = np.asarray(iris.data[::3], dtype=dtype)
y = iris.target[::3]
assert_array_equal(est.fit(X, y).predict(X), y)
def test_memory_layout():
for name, dtype in product(FOREST_CLASSIFIERS, [np.float64, np.float32]):
yield check_memory_layout, name, dtype
for name, dtype in product(FOREST_REGRESSORS, [np.float64, np.float32]):
yield check_memory_layout, name, dtype
def check_1d_input(name, X, X_2d, y):
ForestEstimator = FOREST_ESTIMATORS[name]
assert_raises(ValueError, ForestEstimator(random_state=0).fit, X, y)
est = ForestEstimator(random_state=0)
est.fit(X_2d, y)
if name in FOREST_CLASSIFIERS or name in FOREST_REGRESSORS:
assert_raises(ValueError, est.predict, X)
def test_1d_input():
X = iris.data[:, 0].ravel()
X_2d = iris.data[:, 0].reshape((-1, 1))
y = iris.target
for name in FOREST_ESTIMATORS:
yield check_1d_input, name, X, X_2d, y
def check_class_weights(name):
# Check class_weights resemble sample_weights behavior.
ForestClassifier = FOREST_CLASSIFIERS[name]
# Iris is balanced, so no effect expected for using 'balanced' weights
clf1 = ForestClassifier(random_state=0)
clf1.fit(iris.data, iris.target)
clf2 = ForestClassifier(class_weight='balanced', random_state=0)
clf2.fit(iris.data, iris.target)
assert_almost_equal(clf1.feature_importances_, clf2.feature_importances_)
# Make a multi-output problem with three copies of Iris
iris_multi = np.vstack((iris.target, iris.target, iris.target)).T
# Create user-defined weights that should balance over the outputs
clf3 = ForestClassifier(class_weight=[{0: 2., 1: 2., 2: 1.},
{0: 2., 1: 1., 2: 2.},
{0: 1., 1: 2., 2: 2.}],
random_state=0)
clf3.fit(iris.data, iris_multi)
assert_almost_equal(clf2.feature_importances_, clf3.feature_importances_)
# Check against multi-output "balanced" which should also have no effect
clf4 = ForestClassifier(class_weight='balanced', random_state=0)
clf4.fit(iris.data, iris_multi)
assert_almost_equal(clf3.feature_importances_, clf4.feature_importances_)
# Inflate importance of class 1, check against user-defined weights
sample_weight = np.ones(iris.target.shape)
sample_weight[iris.target == 1] *= 100
class_weight = {0: 1., 1: 100., 2: 1.}
clf1 = ForestClassifier(random_state=0)
clf1.fit(iris.data, iris.target, sample_weight)
clf2 = ForestClassifier(class_weight=class_weight, random_state=0)
clf2.fit(iris.data, iris.target)
assert_almost_equal(clf1.feature_importances_, clf2.feature_importances_)
# Check that sample_weight and class_weight are multiplicative
clf1 = ForestClassifier(random_state=0)
clf1.fit(iris.data, iris.target, sample_weight ** 2)
clf2 = ForestClassifier(class_weight=class_weight, random_state=0)
clf2.fit(iris.data, iris.target, sample_weight)
assert_almost_equal(clf1.feature_importances_, clf2.feature_importances_)
def test_class_weights():
for name in FOREST_CLASSIFIERS:
yield check_class_weights, name
def check_class_weight_balanced_and_bootstrap_multi_output(name):
# Test class_weight works for multi-output"""
ForestClassifier = FOREST_CLASSIFIERS[name]
_y = np.vstack((y, np.array(y) * 2)).T
clf = ForestClassifier(class_weight='balanced', random_state=0)
clf.fit(X, _y)
clf = ForestClassifier(class_weight=[{-1: 0.5, 1: 1.}, {-2: 1., 2: 1.}],
random_state=0)
clf.fit(X, _y)
# smoke test for subsample and balanced subsample
clf = ForestClassifier(class_weight='balanced_subsample', random_state=0)
clf.fit(X, _y)
clf = ForestClassifier(class_weight='subsample', random_state=0)
ignore_warnings(clf.fit)(X, _y)
def test_class_weight_balanced_and_bootstrap_multi_output():
for name in FOREST_CLASSIFIERS:
yield check_class_weight_balanced_and_bootstrap_multi_output, name
def check_class_weight_errors(name):
# Test if class_weight raises errors and warnings when expected.
ForestClassifier = FOREST_CLASSIFIERS[name]
_y = np.vstack((y, np.array(y) * 2)).T
# Invalid preset string
clf = ForestClassifier(class_weight='the larch', random_state=0)
assert_raises(ValueError, clf.fit, X, y)
assert_raises(ValueError, clf.fit, X, _y)
# Warning warm_start with preset
clf = ForestClassifier(class_weight='auto', warm_start=True,
random_state=0)
assert_warns(UserWarning, clf.fit, X, y)
assert_warns(UserWarning, clf.fit, X, _y)
# Not a list or preset for multi-output
clf = ForestClassifier(class_weight=1, random_state=0)
assert_raises(ValueError, clf.fit, X, _y)
# Incorrect length list for multi-output
clf = ForestClassifier(class_weight=[{-1: 0.5, 1: 1.}], random_state=0)
assert_raises(ValueError, clf.fit, X, _y)
def test_class_weight_errors():
for name in FOREST_CLASSIFIERS:
yield check_class_weight_errors, name
def check_warm_start(name, random_state=42):
# Test if fitting incrementally with warm start gives a forest of the
# right size and the same results as a normal fit.
X, y = datasets.make_hastie_10_2(n_samples=20, random_state=1)
ForestEstimator = FOREST_ESTIMATORS[name]
clf_ws = None
for n_estimators in [5, 10]:
if clf_ws is None:
clf_ws = ForestEstimator(n_estimators=n_estimators,
random_state=random_state,
warm_start=True)
else:
clf_ws.set_params(n_estimators=n_estimators)
clf_ws.fit(X, y)
assert_equal(len(clf_ws), n_estimators)
clf_no_ws = ForestEstimator(n_estimators=10, random_state=random_state,
warm_start=False)
clf_no_ws.fit(X, y)
assert_equal(set([tree.random_state for tree in clf_ws]),
set([tree.random_state for tree in clf_no_ws]))
assert_array_equal(clf_ws.apply(X), clf_no_ws.apply(X),
err_msg="Failed with {0}".format(name))
def test_warm_start():
for name in FOREST_ESTIMATORS:
yield check_warm_start, name
def check_warm_start_clear(name):
# Test if fit clears state and grows a new forest when warm_start==False.
X, y = datasets.make_hastie_10_2(n_samples=20, random_state=1)
ForestEstimator = FOREST_ESTIMATORS[name]
clf = ForestEstimator(n_estimators=5, max_depth=1, warm_start=False,
random_state=1)
clf.fit(X, y)
clf_2 = ForestEstimator(n_estimators=5, max_depth=1, warm_start=True,
random_state=2)
clf_2.fit(X, y) # inits state
clf_2.set_params(warm_start=False, random_state=1)
clf_2.fit(X, y) # clears old state and equals clf
assert_array_almost_equal(clf_2.apply(X), clf.apply(X))
def test_warm_start_clear():
for name in FOREST_ESTIMATORS:
yield check_warm_start_clear, name
def check_warm_start_smaller_n_estimators(name):
# Test if warm start second fit with smaller n_estimators raises error.
X, y = datasets.make_hastie_10_2(n_samples=20, random_state=1)
ForestEstimator = FOREST_ESTIMATORS[name]
clf = ForestEstimator(n_estimators=5, max_depth=1, warm_start=True)
clf.fit(X, y)
clf.set_params(n_estimators=4)
assert_raises(ValueError, clf.fit, X, y)
def test_warm_start_smaller_n_estimators():
for name in FOREST_ESTIMATORS:
yield check_warm_start_smaller_n_estimators, name
def check_warm_start_equal_n_estimators(name):
# Test if warm start with equal n_estimators does nothing and returns the
# same forest and raises a warning.
X, y = datasets.make_hastie_10_2(n_samples=20, random_state=1)
ForestEstimator = FOREST_ESTIMATORS[name]
clf = ForestEstimator(n_estimators=5, max_depth=3, warm_start=True,
random_state=1)
clf.fit(X, y)
clf_2 = ForestEstimator(n_estimators=5, max_depth=3, warm_start=True,
random_state=1)
clf_2.fit(X, y)
# Now clf_2 equals clf.
clf_2.set_params(random_state=2)
assert_warns(UserWarning, clf_2.fit, X, y)
# If we had fit the trees again we would have got a different forest as we
# changed the random state.
assert_array_equal(clf.apply(X), clf_2.apply(X))
def test_warm_start_equal_n_estimators():
for name in FOREST_ESTIMATORS:
yield check_warm_start_equal_n_estimators, name
def check_warm_start_oob(name):
# Test that the warm start computes oob score when asked.
X, y = datasets.make_hastie_10_2(n_samples=20, random_state=1)
ForestEstimator = FOREST_ESTIMATORS[name]
# Use 15 estimators to avoid 'some inputs do not have OOB scores' warning.
clf = ForestEstimator(n_estimators=15, max_depth=3, warm_start=False,
random_state=1, bootstrap=True, oob_score=True)
clf.fit(X, y)
clf_2 = ForestEstimator(n_estimators=5, max_depth=3, warm_start=False,
random_state=1, bootstrap=True, oob_score=False)
clf_2.fit(X, y)
clf_2.set_params(warm_start=True, oob_score=True, n_estimators=15)
clf_2.fit(X, y)
assert_true(hasattr(clf_2, 'oob_score_'))
assert_equal(clf.oob_score_, clf_2.oob_score_)
# Test that oob_score is computed even if we don't need to train
# additional trees.
clf_3 = ForestEstimator(n_estimators=15, max_depth=3, warm_start=True,
random_state=1, bootstrap=True, oob_score=False)
clf_3.fit(X, y)
assert_true(not(hasattr(clf_3, 'oob_score_')))
clf_3.set_params(oob_score=True)
ignore_warnings(clf_3.fit)(X, y)
assert_equal(clf.oob_score_, clf_3.oob_score_)
def test_warm_start_oob():
for name in FOREST_CLASSIFIERS:
yield check_warm_start_oob, name
for name in FOREST_REGRESSORS:
yield check_warm_start_oob, name
def test_dtype_convert():
classifier = RandomForestClassifier()
CLASSES = 15
X = np.eye(CLASSES)
y = [ch for ch in 'ABCDEFGHIJKLMNOPQRSTU'[:CLASSES]]
result = classifier.fit(X, y).predict(X)
assert_array_equal(result, y) | bsd-3-clause |
alexsavio/scikit-learn | sklearn/learning_curve.py | 7 | 15161 | """Utilities to evaluate models with respect to a variable
"""
# Author: Alexander Fabisch <[email protected]>
#
# License: BSD 3 clause
import warnings
import numpy as np
from .base import is_classifier, clone
from .cross_validation import check_cv
from .externals.joblib import Parallel, delayed
from .cross_validation import _safe_split, _score, _fit_and_score
from .metrics.scorer import check_scoring
from .utils import indexable
from .utils.fixes import astype
warnings.warn("This module was deprecated in version 0.18 in favor of the "
"model_selection module into which all the functions are moved."
" This module will be removed in 0.20",
DeprecationWarning)
__all__ = ['learning_curve', 'validation_curve']
def learning_curve(estimator, X, y, train_sizes=np.linspace(0.1, 1.0, 5),
cv=None, scoring=None, exploit_incremental_learning=False,
n_jobs=1, pre_dispatch="all", verbose=0,
error_score='raise'):
"""Learning curve.
Determines cross-validated training and test scores for different training
set sizes.
A cross-validation generator splits the whole dataset k times in training
and test data. Subsets of the training set with varying sizes will be used
to train the estimator and a score for each training subset size and the
test set will be computed. Afterwards, the scores will be averaged over
all k runs for each training subset size.
Read more in the :ref:`User Guide <learning_curves>`.
Parameters
----------
estimator : object type that implements the "fit" and "predict" methods
An object of that type which is cloned for each validation.
X : array-like, shape (n_samples, n_features)
Training vector, where n_samples is the number of samples and
n_features is the number of features.
y : array-like, shape (n_samples) or (n_samples, n_features), optional
Target relative to X for classification or regression;
None for unsupervised learning.
train_sizes : array-like, shape (n_ticks,), dtype float or int
Relative or absolute numbers of training examples that will be used to
generate the learning curve. If the dtype is float, it is regarded as a
fraction of the maximum size of the training set (that is determined
by the selected validation method), i.e. it has to be within (0, 1].
Otherwise it is interpreted as absolute sizes of the training sets.
Note that for classification the number of samples usually have to
be big enough to contain at least one sample from each class.
(default: np.linspace(0.1, 1.0, 5))
cv : int, cross-validation generator or an iterable, optional
Determines the cross-validation splitting strategy.
Possible inputs for cv are:
- None, to use the default 3-fold cross-validation,
- integer, to specify the number of folds.
- An object to be used as a cross-validation generator.
- An iterable yielding train/test splits.
For integer/None inputs, if the estimator is a classifier and ``y`` is
either binary or multiclass,
:class:`sklearn.model_selection.StratifiedKFold` is used. In all
other cases, :class:`sklearn.model_selection.KFold` is used.
Refer :ref:`User Guide <cross_validation>` for the various
cross-validation strategies that can be used here.
scoring : string, callable or None, optional, default: None
A string (see model evaluation documentation) or
a scorer callable object / function with signature
``scorer(estimator, X, y)``.
exploit_incremental_learning : boolean, optional, default: False
If the estimator supports incremental learning, this will be
used to speed up fitting for different training set sizes.
n_jobs : integer, optional
Number of jobs to run in parallel (default 1).
pre_dispatch : integer or string, optional
Number of predispatched jobs for parallel execution (default is
all). The option can reduce the allocated memory. The string can
be an expression like '2*n_jobs'.
verbose : integer, optional
Controls the verbosity: the higher, the more messages.
error_score : 'raise' (default) or numeric
Value to assign to the score if an error occurs in estimator fitting.
If set to 'raise', the error is raised. If a numeric value is given,
FitFailedWarning is raised. This parameter does not affect the refit
step, which will always raise the error.
Returns
-------
train_sizes_abs : array, shape = (n_unique_ticks,), dtype int
Numbers of training examples that has been used to generate the
learning curve. Note that the number of ticks might be less
than n_ticks because duplicate entries will be removed.
train_scores : array, shape (n_ticks, n_cv_folds)
Scores on training sets.
test_scores : array, shape (n_ticks, n_cv_folds)
Scores on test set.
Notes
-----
See :ref:`examples/model_selection/plot_learning_curve.py
<sphx_glr_auto_examples_model_selection_plot_learning_curve.py>`
"""
if exploit_incremental_learning and not hasattr(estimator, "partial_fit"):
raise ValueError("An estimator must support the partial_fit interface "
"to exploit incremental learning")
X, y = indexable(X, y)
# Make a list since we will be iterating multiple times over the folds
cv = list(check_cv(cv, X, y, classifier=is_classifier(estimator)))
scorer = check_scoring(estimator, scoring=scoring)
# HACK as long as boolean indices are allowed in cv generators
if cv[0][0].dtype == bool:
new_cv = []
for i in range(len(cv)):
new_cv.append((np.nonzero(cv[i][0])[0], np.nonzero(cv[i][1])[0]))
cv = new_cv
n_max_training_samples = len(cv[0][0])
# Because the lengths of folds can be significantly different, it is
# not guaranteed that we use all of the available training data when we
# use the first 'n_max_training_samples' samples.
train_sizes_abs = _translate_train_sizes(train_sizes,
n_max_training_samples)
n_unique_ticks = train_sizes_abs.shape[0]
if verbose > 0:
print("[learning_curve] Training set sizes: " + str(train_sizes_abs))
parallel = Parallel(n_jobs=n_jobs, pre_dispatch=pre_dispatch,
verbose=verbose)
if exploit_incremental_learning:
classes = np.unique(y) if is_classifier(estimator) else None
out = parallel(delayed(_incremental_fit_estimator)(
clone(estimator), X, y, classes, train, test, train_sizes_abs,
scorer, verbose) for train, test in cv)
else:
out = parallel(delayed(_fit_and_score)(
clone(estimator), X, y, scorer, train[:n_train_samples], test,
verbose, parameters=None, fit_params=None, return_train_score=True,
error_score=error_score)
for train, test in cv for n_train_samples in train_sizes_abs)
out = np.array(out)[:, :2]
n_cv_folds = out.shape[0] // n_unique_ticks
out = out.reshape(n_cv_folds, n_unique_ticks, 2)
out = np.asarray(out).transpose((2, 1, 0))
return train_sizes_abs, out[0], out[1]
def _translate_train_sizes(train_sizes, n_max_training_samples):
"""Determine absolute sizes of training subsets and validate 'train_sizes'.
Examples:
_translate_train_sizes([0.5, 1.0], 10) -> [5, 10]
_translate_train_sizes([5, 10], 10) -> [5, 10]
Parameters
----------
train_sizes : array-like, shape (n_ticks,), dtype float or int
Numbers of training examples that will be used to generate the
learning curve. If the dtype is float, it is regarded as a
fraction of 'n_max_training_samples', i.e. it has to be within (0, 1].
n_max_training_samples : int
Maximum number of training samples (upper bound of 'train_sizes').
Returns
-------
train_sizes_abs : array, shape (n_unique_ticks,), dtype int
Numbers of training examples that will be used to generate the
learning curve. Note that the number of ticks might be less
than n_ticks because duplicate entries will be removed.
"""
train_sizes_abs = np.asarray(train_sizes)
n_ticks = train_sizes_abs.shape[0]
n_min_required_samples = np.min(train_sizes_abs)
n_max_required_samples = np.max(train_sizes_abs)
if np.issubdtype(train_sizes_abs.dtype, np.float):
if n_min_required_samples <= 0.0 or n_max_required_samples > 1.0:
raise ValueError("train_sizes has been interpreted as fractions "
"of the maximum number of training samples and "
"must be within (0, 1], but is within [%f, %f]."
% (n_min_required_samples,
n_max_required_samples))
train_sizes_abs = astype(train_sizes_abs * n_max_training_samples,
dtype=np.int, copy=False)
train_sizes_abs = np.clip(train_sizes_abs, 1,
n_max_training_samples)
else:
if (n_min_required_samples <= 0 or
n_max_required_samples > n_max_training_samples):
raise ValueError("train_sizes has been interpreted as absolute "
"numbers of training samples and must be within "
"(0, %d], but is within [%d, %d]."
% (n_max_training_samples,
n_min_required_samples,
n_max_required_samples))
train_sizes_abs = np.unique(train_sizes_abs)
if n_ticks > train_sizes_abs.shape[0]:
warnings.warn("Removed duplicate entries from 'train_sizes'. Number "
"of ticks will be less than the size of "
"'train_sizes' %d instead of %d)."
% (train_sizes_abs.shape[0], n_ticks), RuntimeWarning)
return train_sizes_abs
def _incremental_fit_estimator(estimator, X, y, classes, train, test,
train_sizes, scorer, verbose):
"""Train estimator on training subsets incrementally and compute scores."""
train_scores, test_scores = [], []
partitions = zip(train_sizes, np.split(train, train_sizes)[:-1])
for n_train_samples, partial_train in partitions:
train_subset = train[:n_train_samples]
X_train, y_train = _safe_split(estimator, X, y, train_subset)
X_partial_train, y_partial_train = _safe_split(estimator, X, y,
partial_train)
X_test, y_test = _safe_split(estimator, X, y, test, train_subset)
if y_partial_train is None:
estimator.partial_fit(X_partial_train, classes=classes)
else:
estimator.partial_fit(X_partial_train, y_partial_train,
classes=classes)
train_scores.append(_score(estimator, X_train, y_train, scorer))
test_scores.append(_score(estimator, X_test, y_test, scorer))
return np.array((train_scores, test_scores)).T
def validation_curve(estimator, X, y, param_name, param_range, cv=None,
scoring=None, n_jobs=1, pre_dispatch="all", verbose=0):
"""Validation curve.
Determine training and test scores for varying parameter values.
Compute scores for an estimator with different values of a specified
parameter. This is similar to grid search with one parameter. However, this
will also compute training scores and is merely a utility for plotting the
results.
Read more in the :ref:`User Guide <validation_curve>`.
Parameters
----------
estimator : object type that implements the "fit" and "predict" methods
An object of that type which is cloned for each validation.
X : array-like, shape (n_samples, n_features)
Training vector, where n_samples is the number of samples and
n_features is the number of features.
y : array-like, shape (n_samples) or (n_samples, n_features), optional
Target relative to X for classification or regression;
None for unsupervised learning.
param_name : string
Name of the parameter that will be varied.
param_range : array-like, shape (n_values,)
The values of the parameter that will be evaluated.
cv : int, cross-validation generator or an iterable, optional
Determines the cross-validation splitting strategy.
Possible inputs for cv are:
- None, to use the default 3-fold cross-validation,
- integer, to specify the number of folds.
- An object to be used as a cross-validation generator.
- An iterable yielding train/test splits.
For integer/None inputs, if the estimator is a classifier and ``y`` is
either binary or multiclass,
:class:`sklearn.model_selection.StratifiedKFold` is used. In all
other cases, :class:`sklearn.model_selection.KFold` is used.
Refer :ref:`User Guide <cross_validation>` for the various
cross-validation strategies that can be used here.
scoring : string, callable or None, optional, default: None
A string (see model evaluation documentation) or
a scorer callable object / function with signature
``scorer(estimator, X, y)``.
n_jobs : integer, optional
Number of jobs to run in parallel (default 1).
pre_dispatch : integer or string, optional
Number of predispatched jobs for parallel execution (default is
all). The option can reduce the allocated memory. The string can
be an expression like '2*n_jobs'.
verbose : integer, optional
Controls the verbosity: the higher, the more messages.
Returns
-------
train_scores : array, shape (n_ticks, n_cv_folds)
Scores on training sets.
test_scores : array, shape (n_ticks, n_cv_folds)
Scores on test set.
Notes
-----
See
:ref:`examples/model_selection/plot_validation_curve.py
<sphx_glr_auto_examples_model_selection_plot_validation_curve.py>`
"""
X, y = indexable(X, y)
cv = check_cv(cv, X, y, classifier=is_classifier(estimator))
scorer = check_scoring(estimator, scoring=scoring)
parallel = Parallel(n_jobs=n_jobs, pre_dispatch=pre_dispatch,
verbose=verbose)
out = parallel(delayed(_fit_and_score)(
estimator, X, y, scorer, train, test, verbose,
parameters={param_name: v}, fit_params=None, return_train_score=True)
for train, test in cv for v in param_range)
out = np.asarray(out)[:, :2]
n_params = len(param_range)
n_cv_folds = out.shape[0] // n_params
out = out.reshape(n_cv_folds, n_params, 2).transpose((2, 1, 0))
return out[0], out[1]
| bsd-3-clause |
PatrickChrist/scikit-learn | examples/tree/plot_tree_regression_multioutput.py | 206 | 1800 | """
===================================================================
Multi-output Decision Tree Regression
===================================================================
An example to illustrate multi-output regression with decision tree.
The :ref:`decision trees <tree>`
is used to predict simultaneously the noisy x and y observations of a circle
given a single underlying feature. As a result, it learns local linear
regressions approximating the circle.
We can see that if the maximum depth of the tree (controlled by the
`max_depth` parameter) is set too high, the decision trees learn too fine
details of the training data and learn from the noise, i.e. they overfit.
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from sklearn.tree import DecisionTreeRegressor
# Create a random dataset
rng = np.random.RandomState(1)
X = np.sort(200 * rng.rand(100, 1) - 100, axis=0)
y = np.array([np.pi * np.sin(X).ravel(), np.pi * np.cos(X).ravel()]).T
y[::5, :] += (0.5 - rng.rand(20, 2))
# Fit regression model
regr_1 = DecisionTreeRegressor(max_depth=2)
regr_2 = DecisionTreeRegressor(max_depth=5)
regr_3 = DecisionTreeRegressor(max_depth=8)
regr_1.fit(X, y)
regr_2.fit(X, y)
regr_3.fit(X, y)
# Predict
X_test = np.arange(-100.0, 100.0, 0.01)[:, np.newaxis]
y_1 = regr_1.predict(X_test)
y_2 = regr_2.predict(X_test)
y_3 = regr_3.predict(X_test)
# Plot the results
plt.figure()
plt.scatter(y[:, 0], y[:, 1], c="k", label="data")
plt.scatter(y_1[:, 0], y_1[:, 1], c="g", label="max_depth=2")
plt.scatter(y_2[:, 0], y_2[:, 1], c="r", label="max_depth=5")
plt.scatter(y_3[:, 0], y_3[:, 1], c="b", label="max_depth=8")
plt.xlim([-6, 6])
plt.ylim([-6, 6])
plt.xlabel("data")
plt.ylabel("target")
plt.title("Multi-output Decision Tree Regression")
plt.legend()
plt.show()
| bsd-3-clause |
elkingtonmcb/scikit-learn | examples/ensemble/plot_ensemble_oob.py | 259 | 3265 | """
=============================
OOB Errors for Random Forests
=============================
The ``RandomForestClassifier`` is trained using *bootstrap aggregation*, where
each new tree is fit from a bootstrap sample of the training observations
:math:`z_i = (x_i, y_i)`. The *out-of-bag* (OOB) error is the average error for
each :math:`z_i` calculated using predictions from the trees that do not
contain :math:`z_i` in their respective bootstrap sample. This allows the
``RandomForestClassifier`` to be fit and validated whilst being trained [1].
The example below demonstrates how the OOB error can be measured at the
addition of each new tree during training. The resulting plot allows a
practitioner to approximate a suitable value of ``n_estimators`` at which the
error stabilizes.
.. [1] T. Hastie, R. Tibshirani and J. Friedman, "Elements of Statistical
Learning Ed. 2", p592-593, Springer, 2009.
"""
import matplotlib.pyplot as plt
from collections import OrderedDict
from sklearn.datasets import make_classification
from sklearn.ensemble import RandomForestClassifier, ExtraTreesClassifier
# Author: Kian Ho <[email protected]>
# Gilles Louppe <[email protected]>
# Andreas Mueller <[email protected]>
#
# License: BSD 3 Clause
print(__doc__)
RANDOM_STATE = 123
# Generate a binary classification dataset.
X, y = make_classification(n_samples=500, n_features=25,
n_clusters_per_class=1, n_informative=15,
random_state=RANDOM_STATE)
# NOTE: Setting the `warm_start` construction parameter to `True` disables
# support for paralellised ensembles but is necessary for tracking the OOB
# error trajectory during training.
ensemble_clfs = [
("RandomForestClassifier, max_features='sqrt'",
RandomForestClassifier(warm_start=True, oob_score=True,
max_features="sqrt",
random_state=RANDOM_STATE)),
("RandomForestClassifier, max_features='log2'",
RandomForestClassifier(warm_start=True, max_features='log2',
oob_score=True,
random_state=RANDOM_STATE)),
("RandomForestClassifier, max_features=None",
RandomForestClassifier(warm_start=True, max_features=None,
oob_score=True,
random_state=RANDOM_STATE))
]
# Map a classifier name to a list of (<n_estimators>, <error rate>) pairs.
error_rate = OrderedDict((label, []) for label, _ in ensemble_clfs)
# Range of `n_estimators` values to explore.
min_estimators = 15
max_estimators = 175
for label, clf in ensemble_clfs:
for i in range(min_estimators, max_estimators + 1):
clf.set_params(n_estimators=i)
clf.fit(X, y)
# Record the OOB error for each `n_estimators=i` setting.
oob_error = 1 - clf.oob_score_
error_rate[label].append((i, oob_error))
# Generate the "OOB error rate" vs. "n_estimators" plot.
for label, clf_err in error_rate.items():
xs, ys = zip(*clf_err)
plt.plot(xs, ys, label=label)
plt.xlim(min_estimators, max_estimators)
plt.xlabel("n_estimators")
plt.ylabel("OOB error rate")
plt.legend(loc="upper right")
plt.show()
| bsd-3-clause |
tmhm/scikit-learn | examples/cluster/plot_cluster_comparison.py | 246 | 4684 | """
=========================================================
Comparing different clustering algorithms on toy datasets
=========================================================
This example aims at showing characteristics of different
clustering algorithms on datasets that are "interesting"
but still in 2D. The last dataset is an example of a 'null'
situation for clustering: the data is homogeneous, and
there is no good clustering.
While these examples give some intuition about the algorithms,
this intuition might not apply to very high dimensional data.
The results could be improved by tweaking the parameters for
each clustering strategy, for instance setting the number of
clusters for the methods that needs this parameter
specified. Note that affinity propagation has a tendency to
create many clusters. Thus in this example its two parameters
(damping and per-point preference) were set to to mitigate this
behavior.
"""
print(__doc__)
import time
import numpy as np
import matplotlib.pyplot as plt
from sklearn import cluster, datasets
from sklearn.neighbors import kneighbors_graph
from sklearn.preprocessing import StandardScaler
np.random.seed(0)
# Generate datasets. We choose the size big enough to see the scalability
# of the algorithms, but not too big to avoid too long running times
n_samples = 1500
noisy_circles = datasets.make_circles(n_samples=n_samples, factor=.5,
noise=.05)
noisy_moons = datasets.make_moons(n_samples=n_samples, noise=.05)
blobs = datasets.make_blobs(n_samples=n_samples, random_state=8)
no_structure = np.random.rand(n_samples, 2), None
colors = np.array([x for x in 'bgrcmykbgrcmykbgrcmykbgrcmyk'])
colors = np.hstack([colors] * 20)
clustering_names = [
'MiniBatchKMeans', 'AffinityPropagation', 'MeanShift',
'SpectralClustering', 'Ward', 'AgglomerativeClustering',
'DBSCAN', 'Birch']
plt.figure(figsize=(len(clustering_names) * 2 + 3, 9.5))
plt.subplots_adjust(left=.02, right=.98, bottom=.001, top=.96, wspace=.05,
hspace=.01)
plot_num = 1
datasets = [noisy_circles, noisy_moons, blobs, no_structure]
for i_dataset, dataset in enumerate(datasets):
X, y = dataset
# normalize dataset for easier parameter selection
X = StandardScaler().fit_transform(X)
# estimate bandwidth for mean shift
bandwidth = cluster.estimate_bandwidth(X, quantile=0.3)
# connectivity matrix for structured Ward
connectivity = kneighbors_graph(X, n_neighbors=10, include_self=False)
# make connectivity symmetric
connectivity = 0.5 * (connectivity + connectivity.T)
# create clustering estimators
ms = cluster.MeanShift(bandwidth=bandwidth, bin_seeding=True)
two_means = cluster.MiniBatchKMeans(n_clusters=2)
ward = cluster.AgglomerativeClustering(n_clusters=2, linkage='ward',
connectivity=connectivity)
spectral = cluster.SpectralClustering(n_clusters=2,
eigen_solver='arpack',
affinity="nearest_neighbors")
dbscan = cluster.DBSCAN(eps=.2)
affinity_propagation = cluster.AffinityPropagation(damping=.9,
preference=-200)
average_linkage = cluster.AgglomerativeClustering(
linkage="average", affinity="cityblock", n_clusters=2,
connectivity=connectivity)
birch = cluster.Birch(n_clusters=2)
clustering_algorithms = [
two_means, affinity_propagation, ms, spectral, ward, average_linkage,
dbscan, birch]
for name, algorithm in zip(clustering_names, clustering_algorithms):
# predict cluster memberships
t0 = time.time()
algorithm.fit(X)
t1 = time.time()
if hasattr(algorithm, 'labels_'):
y_pred = algorithm.labels_.astype(np.int)
else:
y_pred = algorithm.predict(X)
# plot
plt.subplot(4, len(clustering_algorithms), plot_num)
if i_dataset == 0:
plt.title(name, size=18)
plt.scatter(X[:, 0], X[:, 1], color=colors[y_pred].tolist(), s=10)
if hasattr(algorithm, 'cluster_centers_'):
centers = algorithm.cluster_centers_
center_colors = colors[:len(centers)]
plt.scatter(centers[:, 0], centers[:, 1], s=100, c=center_colors)
plt.xlim(-2, 2)
plt.ylim(-2, 2)
plt.xticks(())
plt.yticks(())
plt.text(.99, .01, ('%.2fs' % (t1 - t0)).lstrip('0'),
transform=plt.gca().transAxes, size=15,
horizontalalignment='right')
plot_num += 1
plt.show()
| bsd-3-clause |
bthirion/scikit-learn | sklearn/metrics/scorer.py | 33 | 17925 | """
The :mod:`sklearn.metrics.scorer` submodule implements a flexible
interface for model selection and evaluation using
arbitrary score functions.
A scorer object is a callable that can be passed to
:class:`sklearn.model_selection.GridSearchCV` or
:func:`sklearn.model_selection.cross_val_score` as the ``scoring``
parameter, to specify how a model should be evaluated.
The signature of the call is ``(estimator, X, y)`` where ``estimator``
is the model to be evaluated, ``X`` is the test data and ``y`` is the
ground truth labeling (or ``None`` in the case of unsupervised models).
"""
# Authors: Andreas Mueller <[email protected]>
# Lars Buitinck
# Arnaud Joly <[email protected]>
# License: Simplified BSD
from abc import ABCMeta, abstractmethod
import warnings
import numpy as np
from . import (r2_score, median_absolute_error, mean_absolute_error,
mean_squared_error, mean_squared_log_error, accuracy_score,
f1_score, roc_auc_score, average_precision_score,
precision_score, recall_score, log_loss)
from .cluster import adjusted_rand_score
from .cluster import homogeneity_score
from .cluster import completeness_score
from .cluster import v_measure_score
from .cluster import mutual_info_score
from .cluster import adjusted_mutual_info_score
from .cluster import normalized_mutual_info_score
from .cluster import fowlkes_mallows_score
from ..utils.multiclass import type_of_target
from ..externals import six
from ..base import is_regressor
class _BaseScorer(six.with_metaclass(ABCMeta, object)):
def __init__(self, score_func, sign, kwargs):
self._kwargs = kwargs
self._score_func = score_func
self._sign = sign
# XXX After removing the deprecated scorers (v0.20) remove the
# XXX deprecation_msg property again and remove __call__'s body again
self._deprecation_msg = None
@abstractmethod
def __call__(self, estimator, X, y, sample_weight=None):
if self._deprecation_msg is not None:
warnings.warn(self._deprecation_msg,
category=DeprecationWarning,
stacklevel=2)
def __repr__(self):
kwargs_string = "".join([", %s=%s" % (str(k), str(v))
for k, v in self._kwargs.items()])
return ("make_scorer(%s%s%s%s)"
% (self._score_func.__name__,
"" if self._sign > 0 else ", greater_is_better=False",
self._factory_args(), kwargs_string))
def _factory_args(self):
"""Return non-default make_scorer arguments for repr."""
return ""
class _PredictScorer(_BaseScorer):
def __call__(self, estimator, X, y_true, sample_weight=None):
"""Evaluate predicted target values for X relative to y_true.
Parameters
----------
estimator : object
Trained estimator to use for scoring. Must have a predict_proba
method; the output of that is used to compute the score.
X : array-like or sparse matrix
Test data that will be fed to estimator.predict.
y_true : array-like
Gold standard target values for X.
sample_weight : array-like, optional (default=None)
Sample weights.
Returns
-------
score : float
Score function applied to prediction of estimator on X.
"""
super(_PredictScorer, self).__call__(estimator, X, y_true,
sample_weight=sample_weight)
y_pred = estimator.predict(X)
if sample_weight is not None:
return self._sign * self._score_func(y_true, y_pred,
sample_weight=sample_weight,
**self._kwargs)
else:
return self._sign * self._score_func(y_true, y_pred,
**self._kwargs)
class _ProbaScorer(_BaseScorer):
def __call__(self, clf, X, y, sample_weight=None):
"""Evaluate predicted probabilities for X relative to y_true.
Parameters
----------
clf : object
Trained classifier to use for scoring. Must have a predict_proba
method; the output of that is used to compute the score.
X : array-like or sparse matrix
Test data that will be fed to clf.predict_proba.
y : array-like
Gold standard target values for X. These must be class labels,
not probabilities.
sample_weight : array-like, optional (default=None)
Sample weights.
Returns
-------
score : float
Score function applied to prediction of estimator on X.
"""
super(_ProbaScorer, self).__call__(clf, X, y,
sample_weight=sample_weight)
y_pred = clf.predict_proba(X)
if sample_weight is not None:
return self._sign * self._score_func(y, y_pred,
sample_weight=sample_weight,
**self._kwargs)
else:
return self._sign * self._score_func(y, y_pred, **self._kwargs)
def _factory_args(self):
return ", needs_proba=True"
class _ThresholdScorer(_BaseScorer):
def __call__(self, clf, X, y, sample_weight=None):
"""Evaluate decision function output for X relative to y_true.
Parameters
----------
clf : object
Trained classifier to use for scoring. Must have either a
decision_function method or a predict_proba method; the output of
that is used to compute the score.
X : array-like or sparse matrix
Test data that will be fed to clf.decision_function or
clf.predict_proba.
y : array-like
Gold standard target values for X. These must be class labels,
not decision function values.
sample_weight : array-like, optional (default=None)
Sample weights.
Returns
-------
score : float
Score function applied to prediction of estimator on X.
"""
super(_ThresholdScorer, self).__call__(clf, X, y,
sample_weight=sample_weight)
y_type = type_of_target(y)
if y_type not in ("binary", "multilabel-indicator"):
raise ValueError("{0} format is not supported".format(y_type))
if is_regressor(clf):
y_pred = clf.predict(X)
else:
try:
y_pred = clf.decision_function(X)
# For multi-output multi-class estimator
if isinstance(y_pred, list):
y_pred = np.vstack(p for p in y_pred).T
except (NotImplementedError, AttributeError):
y_pred = clf.predict_proba(X)
if y_type == "binary":
y_pred = y_pred[:, 1]
elif isinstance(y_pred, list):
y_pred = np.vstack([p[:, -1] for p in y_pred]).T
if sample_weight is not None:
return self._sign * self._score_func(y, y_pred,
sample_weight=sample_weight,
**self._kwargs)
else:
return self._sign * self._score_func(y, y_pred, **self._kwargs)
def _factory_args(self):
return ", needs_threshold=True"
def get_scorer(scoring):
if isinstance(scoring, six.string_types):
try:
scorer = SCORERS[scoring]
except KeyError:
scorers = [scorer for scorer in SCORERS
if SCORERS[scorer]._deprecation_msg is None]
raise ValueError('%r is not a valid scoring value. '
'Valid options are %s'
% (scoring, sorted(scorers)))
else:
scorer = scoring
return scorer
def _passthrough_scorer(estimator, *args, **kwargs):
"""Function that wraps estimator.score"""
return estimator.score(*args, **kwargs)
def check_scoring(estimator, scoring=None, allow_none=False):
"""Determine scorer from user options.
A TypeError will be thrown if the estimator cannot be scored.
Parameters
----------
estimator : estimator object implementing 'fit'
The object to use to fit the data.
scoring : string, callable or None, optional, default: None
A string (see model evaluation documentation) or
a scorer callable object / function with signature
``scorer(estimator, X, y)``.
allow_none : boolean, optional, default: False
If no scoring is specified and the estimator has no score function, we
can either return None or raise an exception.
Returns
-------
scoring : callable
A scorer callable object / function with signature
``scorer(estimator, X, y)``.
"""
has_scoring = scoring is not None
if not hasattr(estimator, 'fit'):
raise TypeError("estimator should be an estimator implementing "
"'fit' method, %r was passed" % estimator)
if isinstance(scoring, six.string_types):
return get_scorer(scoring)
elif has_scoring:
# Heuristic to ensure user has not passed a metric
module = getattr(scoring, '__module__', None)
if hasattr(module, 'startswith') and \
module.startswith('sklearn.metrics.') and \
not module.startswith('sklearn.metrics.scorer') and \
not module.startswith('sklearn.metrics.tests.'):
raise ValueError('scoring value %r looks like it is a metric '
'function rather than a scorer. A scorer should '
'require an estimator as its first parameter. '
'Please use `make_scorer` to convert a metric '
'to a scorer.' % scoring)
return get_scorer(scoring)
elif hasattr(estimator, 'score'):
return _passthrough_scorer
elif allow_none:
return None
else:
raise TypeError(
"If no scoring is specified, the estimator passed should "
"have a 'score' method. The estimator %r does not." % estimator)
def make_scorer(score_func, greater_is_better=True, needs_proba=False,
needs_threshold=False, **kwargs):
"""Make a scorer from a performance metric or loss function.
This factory function wraps scoring functions for use in GridSearchCV
and cross_val_score. It takes a score function, such as ``accuracy_score``,
``mean_squared_error``, ``adjusted_rand_index`` or ``average_precision``
and returns a callable that scores an estimator's output.
Read more in the :ref:`User Guide <scoring>`.
Parameters
----------
score_func : callable,
Score function (or loss function) with signature
``score_func(y, y_pred, **kwargs)``.
greater_is_better : boolean, default=True
Whether score_func is a score function (default), meaning high is good,
or a loss function, meaning low is good. In the latter case, the
scorer object will sign-flip the outcome of the score_func.
needs_proba : boolean, default=False
Whether score_func requires predict_proba to get probability estimates
out of a classifier.
needs_threshold : boolean, default=False
Whether score_func takes a continuous decision certainty.
This only works for binary classification using estimators that
have either a decision_function or predict_proba method.
For example ``average_precision`` or the area under the roc curve
can not be computed using discrete predictions alone.
**kwargs : additional arguments
Additional parameters to be passed to score_func.
Returns
-------
scorer : callable
Callable object that returns a scalar score; greater is better.
Examples
--------
>>> from sklearn.metrics import fbeta_score, make_scorer
>>> ftwo_scorer = make_scorer(fbeta_score, beta=2)
>>> ftwo_scorer
make_scorer(fbeta_score, beta=2)
>>> from sklearn.model_selection import GridSearchCV
>>> from sklearn.svm import LinearSVC
>>> grid = GridSearchCV(LinearSVC(), param_grid={'C': [1, 10]},
... scoring=ftwo_scorer)
"""
sign = 1 if greater_is_better else -1
if needs_proba and needs_threshold:
raise ValueError("Set either needs_proba or needs_threshold to True,"
" but not both.")
if needs_proba:
cls = _ProbaScorer
elif needs_threshold:
cls = _ThresholdScorer
else:
cls = _PredictScorer
return cls(score_func, sign, kwargs)
# Standard regression scores
r2_scorer = make_scorer(r2_score)
neg_mean_squared_error_scorer = make_scorer(mean_squared_error,
greater_is_better=False)
deprecation_msg = ('Scoring method mean_squared_error was renamed to '
'neg_mean_squared_error in version 0.18 and will '
'be removed in 0.20.')
mean_squared_error_scorer = make_scorer(mean_squared_error,
greater_is_better=False)
mean_squared_error_scorer._deprecation_msg = deprecation_msg
neg_mean_squared_log_error_scorer = make_scorer(mean_squared_log_error,
greater_is_better=False)
neg_mean_absolute_error_scorer = make_scorer(mean_absolute_error,
greater_is_better=False)
deprecation_msg = ('Scoring method mean_absolute_error was renamed to '
'neg_mean_absolute_error in version 0.18 and will '
'be removed in 0.20.')
mean_absolute_error_scorer = make_scorer(mean_absolute_error,
greater_is_better=False)
mean_absolute_error_scorer._deprecation_msg = deprecation_msg
neg_median_absolute_error_scorer = make_scorer(median_absolute_error,
greater_is_better=False)
deprecation_msg = ('Scoring method median_absolute_error was renamed to '
'neg_median_absolute_error in version 0.18 and will '
'be removed in 0.20.')
median_absolute_error_scorer = make_scorer(median_absolute_error,
greater_is_better=False)
median_absolute_error_scorer._deprecation_msg = deprecation_msg
# Standard Classification Scores
accuracy_scorer = make_scorer(accuracy_score)
f1_scorer = make_scorer(f1_score)
# Score functions that need decision values
roc_auc_scorer = make_scorer(roc_auc_score, greater_is_better=True,
needs_threshold=True)
average_precision_scorer = make_scorer(average_precision_score,
needs_threshold=True)
precision_scorer = make_scorer(precision_score)
recall_scorer = make_scorer(recall_score)
# Score function for probabilistic classification
neg_log_loss_scorer = make_scorer(log_loss, greater_is_better=False,
needs_proba=True)
deprecation_msg = ('Scoring method log_loss was renamed to '
'neg_log_loss in version 0.18 and will be removed in 0.20.')
log_loss_scorer = make_scorer(log_loss, greater_is_better=False,
needs_proba=True)
log_loss_scorer._deprecation_msg = deprecation_msg
# Clustering scores
adjusted_rand_scorer = make_scorer(adjusted_rand_score)
homogeneity_scorer = make_scorer(homogeneity_score)
completeness_scorer = make_scorer(completeness_score)
v_measure_scorer = make_scorer(v_measure_score)
mutual_info_scorer = make_scorer(mutual_info_score)
adjusted_mutual_info_scorer = make_scorer(adjusted_mutual_info_score)
normalized_mutual_info_scorer = make_scorer(normalized_mutual_info_score)
fowlkes_mallows_scorer = make_scorer(fowlkes_mallows_score)
SCORERS = dict(r2=r2_scorer,
neg_median_absolute_error=neg_median_absolute_error_scorer,
neg_mean_absolute_error=neg_mean_absolute_error_scorer,
neg_mean_squared_error=neg_mean_squared_error_scorer,
neg_mean_squared_log_error=neg_mean_squared_log_error_scorer,
median_absolute_error=median_absolute_error_scorer,
mean_absolute_error=mean_absolute_error_scorer,
mean_squared_error=mean_squared_error_scorer,
accuracy=accuracy_scorer, roc_auc=roc_auc_scorer,
average_precision=average_precision_scorer,
log_loss=log_loss_scorer,
neg_log_loss=neg_log_loss_scorer,
# Cluster metrics that use supervised evaluation
adjusted_rand_score=adjusted_rand_scorer,
homogeneity_score=homogeneity_scorer,
completeness_score=completeness_scorer,
v_measure_score=v_measure_scorer,
mutual_info_score=mutual_info_scorer,
adjusted_mutual_info_score=adjusted_mutual_info_scorer,
normalized_mutual_info_score=normalized_mutual_info_scorer,
fowlkes_mallows_score=fowlkes_mallows_scorer)
for name, metric in [('precision', precision_score),
('recall', recall_score), ('f1', f1_score)]:
SCORERS[name] = make_scorer(metric)
for average in ['macro', 'micro', 'samples', 'weighted']:
qualified_name = '{0}_{1}'.format(name, average)
SCORERS[qualified_name] = make_scorer(metric, pos_label=None,
average=average)
| bsd-3-clause |
wzbozon/scikit-learn | benchmarks/bench_glmnet.py | 297 | 3848 | """
To run this, you'll need to have installed.
* glmnet-python
* scikit-learn (of course)
Does two benchmarks
First, we fix a training set and increase the number of
samples. Then we plot the computation time as function of
the number of samples.
In the second benchmark, we increase the number of dimensions of the
training set. Then we plot the computation time as function of
the number of dimensions.
In both cases, only 10% of the features are informative.
"""
import numpy as np
import gc
from time import time
from sklearn.datasets.samples_generator import make_regression
alpha = 0.1
# alpha = 0.01
def rmse(a, b):
return np.sqrt(np.mean((a - b) ** 2))
def bench(factory, X, Y, X_test, Y_test, ref_coef):
gc.collect()
# start time
tstart = time()
clf = factory(alpha=alpha).fit(X, Y)
delta = (time() - tstart)
# stop time
print("duration: %0.3fs" % delta)
print("rmse: %f" % rmse(Y_test, clf.predict(X_test)))
print("mean coef abs diff: %f" % abs(ref_coef - clf.coef_.ravel()).mean())
return delta
if __name__ == '__main__':
from glmnet.elastic_net import Lasso as GlmnetLasso
from sklearn.linear_model import Lasso as ScikitLasso
# Delayed import of pylab
import pylab as pl
scikit_results = []
glmnet_results = []
n = 20
step = 500
n_features = 1000
n_informative = n_features / 10
n_test_samples = 1000
for i in range(1, n + 1):
print('==================')
print('Iteration %s of %s' % (i, n))
print('==================')
X, Y, coef_ = make_regression(
n_samples=(i * step) + n_test_samples, n_features=n_features,
noise=0.1, n_informative=n_informative, coef=True)
X_test = X[-n_test_samples:]
Y_test = Y[-n_test_samples:]
X = X[:(i * step)]
Y = Y[:(i * step)]
print("benchmarking scikit-learn: ")
scikit_results.append(bench(ScikitLasso, X, Y, X_test, Y_test, coef_))
print("benchmarking glmnet: ")
glmnet_results.append(bench(GlmnetLasso, X, Y, X_test, Y_test, coef_))
pl.clf()
xx = range(0, n * step, step)
pl.title('Lasso regression on sample dataset (%d features)' % n_features)
pl.plot(xx, scikit_results, 'b-', label='scikit-learn')
pl.plot(xx, glmnet_results, 'r-', label='glmnet')
pl.legend()
pl.xlabel('number of samples to classify')
pl.ylabel('Time (s)')
pl.show()
# now do a benchmark where the number of points is fixed
# and the variable is the number of features
scikit_results = []
glmnet_results = []
n = 20
step = 100
n_samples = 500
for i in range(1, n + 1):
print('==================')
print('Iteration %02d of %02d' % (i, n))
print('==================')
n_features = i * step
n_informative = n_features / 10
X, Y, coef_ = make_regression(
n_samples=(i * step) + n_test_samples, n_features=n_features,
noise=0.1, n_informative=n_informative, coef=True)
X_test = X[-n_test_samples:]
Y_test = Y[-n_test_samples:]
X = X[:n_samples]
Y = Y[:n_samples]
print("benchmarking scikit-learn: ")
scikit_results.append(bench(ScikitLasso, X, Y, X_test, Y_test, coef_))
print("benchmarking glmnet: ")
glmnet_results.append(bench(GlmnetLasso, X, Y, X_test, Y_test, coef_))
xx = np.arange(100, 100 + n * step, step)
pl.figure('scikit-learn vs. glmnet benchmark results')
pl.title('Regression in high dimensional spaces (%d samples)' % n_samples)
pl.plot(xx, scikit_results, 'b-', label='scikit-learn')
pl.plot(xx, glmnet_results, 'r-', label='glmnet')
pl.legend()
pl.xlabel('number of features')
pl.ylabel('Time (s)')
pl.axis('tight')
pl.show()
| bsd-3-clause |
imaculate/scikit-learn | sklearn/preprocessing/label.py | 28 | 26883 | # Authors: Alexandre Gramfort <[email protected]>
# Mathieu Blondel <[email protected]>
# Olivier Grisel <[email protected]>
# Andreas Mueller <[email protected]>
# Joel Nothman <[email protected]>
# Hamzeh Alsalhi <[email protected]>
# License: BSD 3 clause
from collections import defaultdict
import itertools
import array
import numpy as np
import scipy.sparse as sp
from ..base import BaseEstimator, TransformerMixin
from ..utils.fixes import np_version
from ..utils.fixes import sparse_min_max
from ..utils.fixes import astype
from ..utils.fixes import in1d
from ..utils import column_or_1d
from ..utils.validation import check_array
from ..utils.validation import check_is_fitted
from ..utils.validation import _num_samples
from ..utils.multiclass import unique_labels
from ..utils.multiclass import type_of_target
from ..externals import six
zip = six.moves.zip
map = six.moves.map
__all__ = [
'label_binarize',
'LabelBinarizer',
'LabelEncoder',
'MultiLabelBinarizer',
]
def _check_numpy_unicode_bug(labels):
"""Check that user is not subject to an old numpy bug
Fixed in master before 1.7.0:
https://github.com/numpy/numpy/pull/243
"""
if np_version[:3] < (1, 7, 0) and labels.dtype.kind == 'U':
raise RuntimeError("NumPy < 1.7.0 does not implement searchsorted"
" on unicode data correctly. Please upgrade"
" NumPy to use LabelEncoder with unicode inputs.")
class LabelEncoder(BaseEstimator, TransformerMixin):
"""Encode labels with value between 0 and n_classes-1.
Read more in the :ref:`User Guide <preprocessing_targets>`.
Attributes
----------
classes_ : array of shape (n_class,)
Holds the label for each class.
Examples
--------
`LabelEncoder` can be used to normalize labels.
>>> from sklearn import preprocessing
>>> le = preprocessing.LabelEncoder()
>>> le.fit([1, 2, 2, 6])
LabelEncoder()
>>> le.classes_
array([1, 2, 6])
>>> le.transform([1, 1, 2, 6]) #doctest: +ELLIPSIS
array([0, 0, 1, 2]...)
>>> le.inverse_transform([0, 0, 1, 2])
array([1, 1, 2, 6])
It can also be used to transform non-numerical labels (as long as they are
hashable and comparable) to numerical labels.
>>> le = preprocessing.LabelEncoder()
>>> le.fit(["paris", "paris", "tokyo", "amsterdam"])
LabelEncoder()
>>> list(le.classes_)
['amsterdam', 'paris', 'tokyo']
>>> le.transform(["tokyo", "tokyo", "paris"]) #doctest: +ELLIPSIS
array([2, 2, 1]...)
>>> list(le.inverse_transform([2, 2, 1]))
['tokyo', 'tokyo', 'paris']
"""
def fit(self, y):
"""Fit label encoder
Parameters
----------
y : array-like of shape (n_samples,)
Target values.
Returns
-------
self : returns an instance of self.
"""
y = column_or_1d(y, warn=True)
_check_numpy_unicode_bug(y)
self.classes_ = np.unique(y)
return self
def fit_transform(self, y):
"""Fit label encoder and return encoded labels
Parameters
----------
y : array-like of shape [n_samples]
Target values.
Returns
-------
y : array-like of shape [n_samples]
"""
y = column_or_1d(y, warn=True)
_check_numpy_unicode_bug(y)
self.classes_, y = np.unique(y, return_inverse=True)
return y
def transform(self, y):
"""Transform labels to normalized encoding.
Parameters
----------
y : array-like of shape [n_samples]
Target values.
Returns
-------
y : array-like of shape [n_samples]
"""
check_is_fitted(self, 'classes_')
y = column_or_1d(y, warn=True)
classes = np.unique(y)
_check_numpy_unicode_bug(classes)
if len(np.intersect1d(classes, self.classes_)) < len(classes):
diff = np.setdiff1d(classes, self.classes_)
raise ValueError("y contains new labels: %s" % str(diff))
return np.searchsorted(self.classes_, y)
def inverse_transform(self, y):
"""Transform labels back to original encoding.
Parameters
----------
y : numpy array of shape [n_samples]
Target values.
Returns
-------
y : numpy array of shape [n_samples]
"""
check_is_fitted(self, 'classes_')
diff = np.setdiff1d(y, np.arange(len(self.classes_)))
if diff:
raise ValueError("y contains new labels: %s" % str(diff))
y = np.asarray(y)
return self.classes_[y]
class LabelBinarizer(BaseEstimator, TransformerMixin):
"""Binarize labels in a one-vs-all fashion
Several regression and binary classification algorithms are
available in the scikit. A simple way to extend these algorithms
to the multi-class classification case is to use the so-called
one-vs-all scheme.
At learning time, this simply consists in learning one regressor
or binary classifier per class. In doing so, one needs to convert
multi-class labels to binary labels (belong or does not belong
to the class). LabelBinarizer makes this process easy with the
transform method.
At prediction time, one assigns the class for which the corresponding
model gave the greatest confidence. LabelBinarizer makes this easy
with the inverse_transform method.
Read more in the :ref:`User Guide <preprocessing_targets>`.
Parameters
----------
neg_label : int (default: 0)
Value with which negative labels must be encoded.
pos_label : int (default: 1)
Value with which positive labels must be encoded.
sparse_output : boolean (default: False)
True if the returned array from transform is desired to be in sparse
CSR format.
Attributes
----------
classes_ : array of shape [n_class]
Holds the label for each class.
y_type_ : str,
Represents the type of the target data as evaluated by
utils.multiclass.type_of_target. Possible type are 'continuous',
'continuous-multioutput', 'binary', 'multiclass',
'multiclass-multioutput', 'multilabel-indicator', and 'unknown'.
sparse_input_ : boolean,
True if the input data to transform is given as a sparse matrix, False
otherwise.
Examples
--------
>>> from sklearn import preprocessing
>>> lb = preprocessing.LabelBinarizer()
>>> lb.fit([1, 2, 6, 4, 2])
LabelBinarizer(neg_label=0, pos_label=1, sparse_output=False)
>>> lb.classes_
array([1, 2, 4, 6])
>>> lb.transform([1, 6])
array([[1, 0, 0, 0],
[0, 0, 0, 1]])
Binary targets transform to a column vector
>>> lb = preprocessing.LabelBinarizer()
>>> lb.fit_transform(['yes', 'no', 'no', 'yes'])
array([[1],
[0],
[0],
[1]])
Passing a 2D matrix for multilabel classification
>>> import numpy as np
>>> lb.fit(np.array([[0, 1, 1], [1, 0, 0]]))
LabelBinarizer(neg_label=0, pos_label=1, sparse_output=False)
>>> lb.classes_
array([0, 1, 2])
>>> lb.transform([0, 1, 2, 1])
array([[1, 0, 0],
[0, 1, 0],
[0, 0, 1],
[0, 1, 0]])
See also
--------
label_binarize : function to perform the transform operation of
LabelBinarizer with fixed classes.
"""
def __init__(self, neg_label=0, pos_label=1, sparse_output=False):
if neg_label >= pos_label:
raise ValueError("neg_label={0} must be strictly less than "
"pos_label={1}.".format(neg_label, pos_label))
if sparse_output and (pos_label == 0 or neg_label != 0):
raise ValueError("Sparse binarization is only supported with non "
"zero pos_label and zero neg_label, got "
"pos_label={0} and neg_label={1}"
"".format(pos_label, neg_label))
self.neg_label = neg_label
self.pos_label = pos_label
self.sparse_output = sparse_output
def fit(self, y):
"""Fit label binarizer
Parameters
----------
y : numpy array of shape (n_samples,) or (n_samples, n_classes)
Target values. The 2-d matrix should only contain 0 and 1,
represents multilabel classification.
Returns
-------
self : returns an instance of self.
"""
self.y_type_ = type_of_target(y)
if 'multioutput' in self.y_type_:
raise ValueError("Multioutput target data is not supported with "
"label binarization")
if _num_samples(y) == 0:
raise ValueError('y has 0 samples: %r' % y)
self.sparse_input_ = sp.issparse(y)
self.classes_ = unique_labels(y)
return self
def transform(self, y):
"""Transform multi-class labels to binary labels
The output of transform is sometimes referred to by some authors as the
1-of-K coding scheme.
Parameters
----------
y : numpy array or sparse matrix of shape (n_samples,) or
(n_samples, n_classes) Target values. The 2-d matrix should only
contain 0 and 1, represents multilabel classification. Sparse
matrix can be CSR, CSC, COO, DOK, or LIL.
Returns
-------
Y : numpy array or CSR matrix of shape [n_samples, n_classes]
Shape will be [n_samples, 1] for binary problems.
"""
check_is_fitted(self, 'classes_')
y_is_multilabel = type_of_target(y).startswith('multilabel')
if y_is_multilabel and not self.y_type_.startswith('multilabel'):
raise ValueError("The object was not fitted with multilabel"
" input.")
return label_binarize(y, self.classes_,
pos_label=self.pos_label,
neg_label=self.neg_label,
sparse_output=self.sparse_output)
def inverse_transform(self, Y, threshold=None):
"""Transform binary labels back to multi-class labels
Parameters
----------
Y : numpy array or sparse matrix with shape [n_samples, n_classes]
Target values. All sparse matrices are converted to CSR before
inverse transformation.
threshold : float or None
Threshold used in the binary and multi-label cases.
Use 0 when:
- Y contains the output of decision_function (classifier)
Use 0.5 when:
- Y contains the output of predict_proba
If None, the threshold is assumed to be half way between
neg_label and pos_label.
Returns
-------
y : numpy array or CSR matrix of shape [n_samples] Target values.
Notes
-----
In the case when the binary labels are fractional
(probabilistic), inverse_transform chooses the class with the
greatest value. Typically, this allows to use the output of a
linear model's decision_function method directly as the input
of inverse_transform.
"""
check_is_fitted(self, 'classes_')
if threshold is None:
threshold = (self.pos_label + self.neg_label) / 2.
if self.y_type_ == "multiclass":
y_inv = _inverse_binarize_multiclass(Y, self.classes_)
else:
y_inv = _inverse_binarize_thresholding(Y, self.y_type_,
self.classes_, threshold)
if self.sparse_input_:
y_inv = sp.csr_matrix(y_inv)
elif sp.issparse(y_inv):
y_inv = y_inv.toarray()
return y_inv
def label_binarize(y, classes, neg_label=0, pos_label=1, sparse_output=False):
"""Binarize labels in a one-vs-all fashion
Several regression and binary classification algorithms are
available in the scikit. A simple way to extend these algorithms
to the multi-class classification case is to use the so-called
one-vs-all scheme.
This function makes it possible to compute this transformation for a
fixed set of class labels known ahead of time.
Parameters
----------
y : array-like
Sequence of integer labels or multilabel data to encode.
classes : array-like of shape [n_classes]
Uniquely holds the label for each class.
neg_label : int (default: 0)
Value with which negative labels must be encoded.
pos_label : int (default: 1)
Value with which positive labels must be encoded.
sparse_output : boolean (default: False),
Set to true if output binary array is desired in CSR sparse format
Returns
-------
Y : numpy array or CSR matrix of shape [n_samples, n_classes]
Shape will be [n_samples, 1] for binary problems.
Examples
--------
>>> from sklearn.preprocessing import label_binarize
>>> label_binarize([1, 6], classes=[1, 2, 4, 6])
array([[1, 0, 0, 0],
[0, 0, 0, 1]])
The class ordering is preserved:
>>> label_binarize([1, 6], classes=[1, 6, 4, 2])
array([[1, 0, 0, 0],
[0, 1, 0, 0]])
Binary targets transform to a column vector
>>> label_binarize(['yes', 'no', 'no', 'yes'], classes=['no', 'yes'])
array([[1],
[0],
[0],
[1]])
See also
--------
LabelBinarizer : class used to wrap the functionality of label_binarize and
allow for fitting to classes independently of the transform operation
"""
if not isinstance(y, list):
# XXX Workaround that will be removed when list of list format is
# dropped
y = check_array(y, accept_sparse='csr', ensure_2d=False, dtype=None)
else:
if _num_samples(y) == 0:
raise ValueError('y has 0 samples: %r' % y)
if neg_label >= pos_label:
raise ValueError("neg_label={0} must be strictly less than "
"pos_label={1}.".format(neg_label, pos_label))
if (sparse_output and (pos_label == 0 or neg_label != 0)):
raise ValueError("Sparse binarization is only supported with non "
"zero pos_label and zero neg_label, got "
"pos_label={0} and neg_label={1}"
"".format(pos_label, neg_label))
# To account for pos_label == 0 in the dense case
pos_switch = pos_label == 0
if pos_switch:
pos_label = -neg_label
y_type = type_of_target(y)
if 'multioutput' in y_type:
raise ValueError("Multioutput target data is not supported with label "
"binarization")
if y_type == 'unknown':
raise ValueError("The type of target data is not known")
n_samples = y.shape[0] if sp.issparse(y) else len(y)
n_classes = len(classes)
classes = np.asarray(classes)
if y_type == "binary":
if n_classes == 1:
if sparse_output:
return sp.csr_matrix((n_samples, 1), dtype=int)
else:
Y = np.zeros((len(y), 1), dtype=np.int)
Y += neg_label
return Y
elif len(classes) >= 3:
y_type = "multiclass"
sorted_class = np.sort(classes)
if (y_type == "multilabel-indicator" and classes.size != y.shape[1]):
raise ValueError("classes {0} missmatch with the labels {1}"
"found in the data".format(classes, unique_labels(y)))
if y_type in ("binary", "multiclass"):
y = column_or_1d(y)
# pick out the known labels from y
y_in_classes = in1d(y, classes)
y_seen = y[y_in_classes]
indices = np.searchsorted(sorted_class, y_seen)
indptr = np.hstack((0, np.cumsum(y_in_classes)))
data = np.empty_like(indices)
data.fill(pos_label)
Y = sp.csr_matrix((data, indices, indptr),
shape=(n_samples, n_classes))
elif y_type == "multilabel-indicator":
Y = sp.csr_matrix(y)
if pos_label != 1:
data = np.empty_like(Y.data)
data.fill(pos_label)
Y.data = data
else:
raise ValueError("%s target data is not supported with label "
"binarization" % y_type)
if not sparse_output:
Y = Y.toarray()
Y = astype(Y, int, copy=False)
if neg_label != 0:
Y[Y == 0] = neg_label
if pos_switch:
Y[Y == pos_label] = 0
else:
Y.data = astype(Y.data, int, copy=False)
# preserve label ordering
if np.any(classes != sorted_class):
indices = np.searchsorted(sorted_class, classes)
Y = Y[:, indices]
if y_type == "binary":
if sparse_output:
Y = Y.getcol(-1)
else:
Y = Y[:, -1].reshape((-1, 1))
return Y
def _inverse_binarize_multiclass(y, classes):
"""Inverse label binarization transformation for multiclass.
Multiclass uses the maximal score instead of a threshold.
"""
classes = np.asarray(classes)
if sp.issparse(y):
# Find the argmax for each row in y where y is a CSR matrix
y = y.tocsr()
n_samples, n_outputs = y.shape
outputs = np.arange(n_outputs)
row_max = sparse_min_max(y, 1)[1]
row_nnz = np.diff(y.indptr)
y_data_repeated_max = np.repeat(row_max, row_nnz)
# picks out all indices obtaining the maximum per row
y_i_all_argmax = np.flatnonzero(y_data_repeated_max == y.data)
# For corner case where last row has a max of 0
if row_max[-1] == 0:
y_i_all_argmax = np.append(y_i_all_argmax, [len(y.data)])
# Gets the index of the first argmax in each row from y_i_all_argmax
index_first_argmax = np.searchsorted(y_i_all_argmax, y.indptr[:-1])
# first argmax of each row
y_ind_ext = np.append(y.indices, [0])
y_i_argmax = y_ind_ext[y_i_all_argmax[index_first_argmax]]
# Handle rows of all 0
y_i_argmax[np.where(row_nnz == 0)[0]] = 0
# Handles rows with max of 0 that contain negative numbers
samples = np.arange(n_samples)[(row_nnz > 0) &
(row_max.ravel() == 0)]
for i in samples:
ind = y.indices[y.indptr[i]:y.indptr[i + 1]]
y_i_argmax[i] = classes[np.setdiff1d(outputs, ind)][0]
return classes[y_i_argmax]
else:
return classes.take(y.argmax(axis=1), mode="clip")
def _inverse_binarize_thresholding(y, output_type, classes, threshold):
"""Inverse label binarization transformation using thresholding."""
if output_type == "binary" and y.ndim == 2 and y.shape[1] > 2:
raise ValueError("output_type='binary', but y.shape = {0}".
format(y.shape))
if output_type != "binary" and y.shape[1] != len(classes):
raise ValueError("The number of class is not equal to the number of "
"dimension of y.")
classes = np.asarray(classes)
# Perform thresholding
if sp.issparse(y):
if threshold > 0:
if y.format not in ('csr', 'csc'):
y = y.tocsr()
y.data = np.array(y.data > threshold, dtype=np.int)
y.eliminate_zeros()
else:
y = np.array(y.toarray() > threshold, dtype=np.int)
else:
y = np.array(y > threshold, dtype=np.int)
# Inverse transform data
if output_type == "binary":
if sp.issparse(y):
y = y.toarray()
if y.ndim == 2 and y.shape[1] == 2:
return classes[y[:, 1]]
else:
if len(classes) == 1:
return np.repeat(classes[0], len(y))
else:
return classes[y.ravel()]
elif output_type == "multilabel-indicator":
return y
else:
raise ValueError("{0} format is not supported".format(output_type))
class MultiLabelBinarizer(BaseEstimator, TransformerMixin):
"""Transform between iterable of iterables and a multilabel format
Although a list of sets or tuples is a very intuitive format for multilabel
data, it is unwieldy to process. This transformer converts between this
intuitive format and the supported multilabel format: a (samples x classes)
binary matrix indicating the presence of a class label.
Parameters
----------
classes : array-like of shape [n_classes] (optional)
Indicates an ordering for the class labels
sparse_output : boolean (default: False),
Set to true if output binary array is desired in CSR sparse format
Attributes
----------
classes_ : array of labels
A copy of the `classes` parameter where provided,
or otherwise, the sorted set of classes found when fitting.
Examples
--------
>>> mlb = MultiLabelBinarizer()
>>> mlb.fit_transform([(1, 2), (3,)])
array([[1, 1, 0],
[0, 0, 1]])
>>> mlb.classes_
array([1, 2, 3])
>>> mlb.fit_transform([set(['sci-fi', 'thriller']), set(['comedy'])])
array([[0, 1, 1],
[1, 0, 0]])
>>> list(mlb.classes_)
['comedy', 'sci-fi', 'thriller']
"""
def __init__(self, classes=None, sparse_output=False):
self.classes = classes
self.sparse_output = sparse_output
def fit(self, y):
"""Fit the label sets binarizer, storing `classes_`
Parameters
----------
y : iterable of iterables
A set of labels (any orderable and hashable object) for each
sample. If the `classes` parameter is set, `y` will not be
iterated.
Returns
-------
self : returns this MultiLabelBinarizer instance
"""
if self.classes is None:
classes = sorted(set(itertools.chain.from_iterable(y)))
else:
classes = self.classes
dtype = np.int if all(isinstance(c, int) for c in classes) else object
self.classes_ = np.empty(len(classes), dtype=dtype)
self.classes_[:] = classes
return self
def fit_transform(self, y):
"""Fit the label sets binarizer and transform the given label sets
Parameters
----------
y : iterable of iterables
A set of labels (any orderable and hashable object) for each
sample. If the `classes` parameter is set, `y` will not be
iterated.
Returns
-------
y_indicator : array or CSR matrix, shape (n_samples, n_classes)
A matrix such that `y_indicator[i, j] = 1` iff `classes_[j]` is in
`y[i]`, and 0 otherwise.
"""
if self.classes is not None:
return self.fit(y).transform(y)
# Automatically increment on new class
class_mapping = defaultdict(int)
class_mapping.default_factory = class_mapping.__len__
yt = self._transform(y, class_mapping)
# sort classes and reorder columns
tmp = sorted(class_mapping, key=class_mapping.get)
# (make safe for tuples)
dtype = np.int if all(isinstance(c, int) for c in tmp) else object
class_mapping = np.empty(len(tmp), dtype=dtype)
class_mapping[:] = tmp
self.classes_, inverse = np.unique(class_mapping, return_inverse=True)
yt.indices = np.take(inverse, yt.indices)
if not self.sparse_output:
yt = yt.toarray()
return yt
def transform(self, y):
"""Transform the given label sets
Parameters
----------
y : iterable of iterables
A set of labels (any orderable and hashable object) for each
sample. If the `classes` parameter is set, `y` will not be
iterated.
Returns
-------
y_indicator : array or CSR matrix, shape (n_samples, n_classes)
A matrix such that `y_indicator[i, j] = 1` iff `classes_[j]` is in
`y[i]`, and 0 otherwise.
"""
check_is_fitted(self, 'classes_')
class_to_index = dict(zip(self.classes_, range(len(self.classes_))))
yt = self._transform(y, class_to_index)
if not self.sparse_output:
yt = yt.toarray()
return yt
def _transform(self, y, class_mapping):
"""Transforms the label sets with a given mapping
Parameters
----------
y : iterable of iterables
class_mapping : Mapping
Maps from label to column index in label indicator matrix
Returns
-------
y_indicator : sparse CSR matrix, shape (n_samples, n_classes)
Label indicator matrix
"""
indices = array.array('i')
indptr = array.array('i', [0])
for labels in y:
indices.extend(set(class_mapping[label] for label in labels))
indptr.append(len(indices))
data = np.ones(len(indices), dtype=int)
return sp.csr_matrix((data, indices, indptr),
shape=(len(indptr) - 1, len(class_mapping)))
def inverse_transform(self, yt):
"""Transform the given indicator matrix into label sets
Parameters
----------
yt : array or sparse matrix of shape (n_samples, n_classes)
A matrix containing only 1s ands 0s.
Returns
-------
y : list of tuples
The set of labels for each sample such that `y[i]` consists of
`classes_[j]` for each `yt[i, j] == 1`.
"""
check_is_fitted(self, 'classes_')
if yt.shape[1] != len(self.classes_):
raise ValueError('Expected indicator for {0} classes, but got {1}'
.format(len(self.classes_), yt.shape[1]))
if sp.issparse(yt):
yt = yt.tocsr()
if len(yt.data) != 0 and len(np.setdiff1d(yt.data, [0, 1])) > 0:
raise ValueError('Expected only 0s and 1s in label indicator.')
return [tuple(self.classes_.take(yt.indices[start:end]))
for start, end in zip(yt.indptr[:-1], yt.indptr[1:])]
else:
unexpected = np.setdiff1d(yt, [0, 1])
if len(unexpected) > 0:
raise ValueError('Expected only 0s and 1s in label indicator. '
'Also got {0}'.format(unexpected))
return [tuple(self.classes_.compress(indicators)) for indicators
in yt]
| bsd-3-clause |
pompiduskus/scikit-learn | sklearn/mixture/tests/test_dpgmm.py | 261 | 4490 | import unittest
import sys
import numpy as np
from sklearn.mixture import DPGMM, VBGMM
from sklearn.mixture.dpgmm import log_normalize
from sklearn.datasets import make_blobs
from sklearn.utils.testing import assert_array_less, assert_equal
from sklearn.mixture.tests.test_gmm import GMMTester
from sklearn.externals.six.moves import cStringIO as StringIO
np.seterr(all='warn')
def test_class_weights():
# check that the class weights are updated
# simple 3 cluster dataset
X, y = make_blobs(random_state=1)
for Model in [DPGMM, VBGMM]:
dpgmm = Model(n_components=10, random_state=1, alpha=20, n_iter=50)
dpgmm.fit(X)
# get indices of components that are used:
indices = np.unique(dpgmm.predict(X))
active = np.zeros(10, dtype=np.bool)
active[indices] = True
# used components are important
assert_array_less(.1, dpgmm.weights_[active])
# others are not
assert_array_less(dpgmm.weights_[~active], .05)
def test_verbose_boolean():
# checks that the output for the verbose output is the same
# for the flag values '1' and 'True'
# simple 3 cluster dataset
X, y = make_blobs(random_state=1)
for Model in [DPGMM, VBGMM]:
dpgmm_bool = Model(n_components=10, random_state=1, alpha=20,
n_iter=50, verbose=True)
dpgmm_int = Model(n_components=10, random_state=1, alpha=20,
n_iter=50, verbose=1)
old_stdout = sys.stdout
sys.stdout = StringIO()
try:
# generate output with the boolean flag
dpgmm_bool.fit(X)
verbose_output = sys.stdout
verbose_output.seek(0)
bool_output = verbose_output.readline()
# generate output with the int flag
dpgmm_int.fit(X)
verbose_output = sys.stdout
verbose_output.seek(0)
int_output = verbose_output.readline()
assert_equal(bool_output, int_output)
finally:
sys.stdout = old_stdout
def test_verbose_first_level():
# simple 3 cluster dataset
X, y = make_blobs(random_state=1)
for Model in [DPGMM, VBGMM]:
dpgmm = Model(n_components=10, random_state=1, alpha=20, n_iter=50,
verbose=1)
old_stdout = sys.stdout
sys.stdout = StringIO()
try:
dpgmm.fit(X)
finally:
sys.stdout = old_stdout
def test_verbose_second_level():
# simple 3 cluster dataset
X, y = make_blobs(random_state=1)
for Model in [DPGMM, VBGMM]:
dpgmm = Model(n_components=10, random_state=1, alpha=20, n_iter=50,
verbose=2)
old_stdout = sys.stdout
sys.stdout = StringIO()
try:
dpgmm.fit(X)
finally:
sys.stdout = old_stdout
def test_log_normalize():
v = np.array([0.1, 0.8, 0.01, 0.09])
a = np.log(2 * v)
assert np.allclose(v, log_normalize(a), rtol=0.01)
def do_model(self, **kwds):
return VBGMM(verbose=False, **kwds)
class DPGMMTester(GMMTester):
model = DPGMM
do_test_eval = False
def score(self, g, train_obs):
_, z = g.score_samples(train_obs)
return g.lower_bound(train_obs, z)
class TestDPGMMWithSphericalCovars(unittest.TestCase, DPGMMTester):
covariance_type = 'spherical'
setUp = GMMTester._setUp
class TestDPGMMWithDiagCovars(unittest.TestCase, DPGMMTester):
covariance_type = 'diag'
setUp = GMMTester._setUp
class TestDPGMMWithTiedCovars(unittest.TestCase, DPGMMTester):
covariance_type = 'tied'
setUp = GMMTester._setUp
class TestDPGMMWithFullCovars(unittest.TestCase, DPGMMTester):
covariance_type = 'full'
setUp = GMMTester._setUp
class VBGMMTester(GMMTester):
model = do_model
do_test_eval = False
def score(self, g, train_obs):
_, z = g.score_samples(train_obs)
return g.lower_bound(train_obs, z)
class TestVBGMMWithSphericalCovars(unittest.TestCase, VBGMMTester):
covariance_type = 'spherical'
setUp = GMMTester._setUp
class TestVBGMMWithDiagCovars(unittest.TestCase, VBGMMTester):
covariance_type = 'diag'
setUp = GMMTester._setUp
class TestVBGMMWithTiedCovars(unittest.TestCase, VBGMMTester):
covariance_type = 'tied'
setUp = GMMTester._setUp
class TestVBGMMWithFullCovars(unittest.TestCase, VBGMMTester):
covariance_type = 'full'
setUp = GMMTester._setUp
| bsd-3-clause |
mjgrav2001/scikit-learn | examples/cluster/plot_feature_agglomeration_vs_univariate_selection.py | 218 | 3893 | """
==============================================
Feature agglomeration vs. univariate selection
==============================================
This example compares 2 dimensionality reduction strategies:
- univariate feature selection with Anova
- feature agglomeration with Ward hierarchical clustering
Both methods are compared in a regression problem using
a BayesianRidge as supervised estimator.
"""
# Author: Alexandre Gramfort <[email protected]>
# License: BSD 3 clause
print(__doc__)
import shutil
import tempfile
import numpy as np
import matplotlib.pyplot as plt
from scipy import linalg, ndimage
from sklearn.feature_extraction.image import grid_to_graph
from sklearn import feature_selection
from sklearn.cluster import FeatureAgglomeration
from sklearn.linear_model import BayesianRidge
from sklearn.pipeline import Pipeline
from sklearn.grid_search import GridSearchCV
from sklearn.externals.joblib import Memory
from sklearn.cross_validation import KFold
###############################################################################
# Generate data
n_samples = 200
size = 40 # image size
roi_size = 15
snr = 5.
np.random.seed(0)
mask = np.ones([size, size], dtype=np.bool)
coef = np.zeros((size, size))
coef[0:roi_size, 0:roi_size] = -1.
coef[-roi_size:, -roi_size:] = 1.
X = np.random.randn(n_samples, size ** 2)
for x in X: # smooth data
x[:] = ndimage.gaussian_filter(x.reshape(size, size), sigma=1.0).ravel()
X -= X.mean(axis=0)
X /= X.std(axis=0)
y = np.dot(X, coef.ravel())
noise = np.random.randn(y.shape[0])
noise_coef = (linalg.norm(y, 2) / np.exp(snr / 20.)) / linalg.norm(noise, 2)
y += noise_coef * noise # add noise
###############################################################################
# Compute the coefs of a Bayesian Ridge with GridSearch
cv = KFold(len(y), 2) # cross-validation generator for model selection
ridge = BayesianRidge()
cachedir = tempfile.mkdtemp()
mem = Memory(cachedir=cachedir, verbose=1)
# Ward agglomeration followed by BayesianRidge
connectivity = grid_to_graph(n_x=size, n_y=size)
ward = FeatureAgglomeration(n_clusters=10, connectivity=connectivity,
memory=mem)
clf = Pipeline([('ward', ward), ('ridge', ridge)])
# Select the optimal number of parcels with grid search
clf = GridSearchCV(clf, {'ward__n_clusters': [10, 20, 30]}, n_jobs=1, cv=cv)
clf.fit(X, y) # set the best parameters
coef_ = clf.best_estimator_.steps[-1][1].coef_
coef_ = clf.best_estimator_.steps[0][1].inverse_transform(coef_)
coef_agglomeration_ = coef_.reshape(size, size)
# Anova univariate feature selection followed by BayesianRidge
f_regression = mem.cache(feature_selection.f_regression) # caching function
anova = feature_selection.SelectPercentile(f_regression)
clf = Pipeline([('anova', anova), ('ridge', ridge)])
# Select the optimal percentage of features with grid search
clf = GridSearchCV(clf, {'anova__percentile': [5, 10, 20]}, cv=cv)
clf.fit(X, y) # set the best parameters
coef_ = clf.best_estimator_.steps[-1][1].coef_
coef_ = clf.best_estimator_.steps[0][1].inverse_transform(coef_)
coef_selection_ = coef_.reshape(size, size)
###############################################################################
# Inverse the transformation to plot the results on an image
plt.close('all')
plt.figure(figsize=(7.3, 2.7))
plt.subplot(1, 3, 1)
plt.imshow(coef, interpolation="nearest", cmap=plt.cm.RdBu_r)
plt.title("True weights")
plt.subplot(1, 3, 2)
plt.imshow(coef_selection_, interpolation="nearest", cmap=plt.cm.RdBu_r)
plt.title("Feature Selection")
plt.subplot(1, 3, 3)
plt.imshow(coef_agglomeration_, interpolation="nearest", cmap=plt.cm.RdBu_r)
plt.title("Feature Agglomeration")
plt.subplots_adjust(0.04, 0.0, 0.98, 0.94, 0.16, 0.26)
plt.show()
# Attempt to remove the temporary cachedir, but don't worry if it fails
shutil.rmtree(cachedir, ignore_errors=True)
| bsd-3-clause |
untom/scikit-learn | examples/linear_model/plot_sgd_loss_functions.py | 249 | 1095 | """
==========================
SGD: convex loss functions
==========================
A plot that compares the various convex loss functions supported by
:class:`sklearn.linear_model.SGDClassifier` .
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
def modified_huber_loss(y_true, y_pred):
z = y_pred * y_true
loss = -4 * z
loss[z >= -1] = (1 - z[z >= -1]) ** 2
loss[z >= 1.] = 0
return loss
xmin, xmax = -4, 4
xx = np.linspace(xmin, xmax, 100)
plt.plot([xmin, 0, 0, xmax], [1, 1, 0, 0], 'k-',
label="Zero-one loss")
plt.plot(xx, np.where(xx < 1, 1 - xx, 0), 'g-',
label="Hinge loss")
plt.plot(xx, -np.minimum(xx, 0), 'm-',
label="Perceptron loss")
plt.plot(xx, np.log2(1 + np.exp(-xx)), 'r-',
label="Log loss")
plt.plot(xx, np.where(xx < 1, 1 - xx, 0) ** 2, 'b-',
label="Squared hinge loss")
plt.plot(xx, modified_huber_loss(xx, 1), 'y--',
label="Modified Huber loss")
plt.ylim((0, 8))
plt.legend(loc="upper right")
plt.xlabel(r"Decision function $f(x)$")
plt.ylabel("$L(y, f(x))$")
plt.show()
| bsd-3-clause |
tomlof/scikit-learn | sklearn/datasets/twenty_newsgroups.py | 31 | 13747 | """Caching loader for the 20 newsgroups text classification dataset
The description of the dataset is available on the official website at:
http://people.csail.mit.edu/jrennie/20Newsgroups/
Quoting the introduction:
The 20 Newsgroups data set is a collection of approximately 20,000
newsgroup documents, partitioned (nearly) evenly across 20 different
newsgroups. To the best of my knowledge, it was originally collected
by Ken Lang, probably for his Newsweeder: Learning to filter netnews
paper, though he does not explicitly mention this collection. The 20
newsgroups collection has become a popular data set for experiments
in text applications of machine learning techniques, such as text
classification and text clustering.
This dataset loader will download the recommended "by date" variant of the
dataset and which features a point in time split between the train and
test sets. The compressed dataset size is around 14 Mb compressed. Once
uncompressed the train set is 52 MB and the test set is 34 MB.
The data is downloaded, extracted and cached in the '~/scikit_learn_data'
folder.
The `fetch_20newsgroups` function will not vectorize the data into numpy
arrays but the dataset lists the filenames of the posts and their categories
as target labels.
The `fetch_20newsgroups_vectorized` function will in addition do a simple
tf-idf vectorization step.
"""
# Copyright (c) 2011 Olivier Grisel <[email protected]>
# License: BSD 3 clause
import os
import logging
import tarfile
import pickle
import shutil
import re
import codecs
import numpy as np
import scipy.sparse as sp
from .base import get_data_home
from .base import Bunch
from .base import load_files
from .base import _pkl_filepath
from ..utils import check_random_state
from ..feature_extraction.text import CountVectorizer
from ..preprocessing import normalize
from ..externals import joblib, six
if six.PY3:
from urllib.request import urlopen
else:
from urllib2 import urlopen
logger = logging.getLogger(__name__)
URL = ("http://people.csail.mit.edu/jrennie/"
"20Newsgroups/20news-bydate.tar.gz")
ARCHIVE_NAME = "20news-bydate.tar.gz"
CACHE_NAME = "20news-bydate.pkz"
TRAIN_FOLDER = "20news-bydate-train"
TEST_FOLDER = "20news-bydate-test"
def download_20newsgroups(target_dir, cache_path):
"""Download the 20 newsgroups data and stored it as a zipped pickle."""
archive_path = os.path.join(target_dir, ARCHIVE_NAME)
train_path = os.path.join(target_dir, TRAIN_FOLDER)
test_path = os.path.join(target_dir, TEST_FOLDER)
if not os.path.exists(target_dir):
os.makedirs(target_dir)
if os.path.exists(archive_path):
# Download is not complete as the .tar.gz file is removed after
# download.
logger.warning("Download was incomplete, downloading again.")
os.remove(archive_path)
logger.warning("Downloading dataset from %s (14 MB)", URL)
opener = urlopen(URL)
with open(archive_path, 'wb') as f:
f.write(opener.read())
logger.info("Decompressing %s", archive_path)
tarfile.open(archive_path, "r:gz").extractall(path=target_dir)
os.remove(archive_path)
# Store a zipped pickle
cache = dict(train=load_files(train_path, encoding='latin1'),
test=load_files(test_path, encoding='latin1'))
compressed_content = codecs.encode(pickle.dumps(cache), 'zlib_codec')
with open(cache_path, 'wb') as f:
f.write(compressed_content)
shutil.rmtree(target_dir)
return cache
def strip_newsgroup_header(text):
"""
Given text in "news" format, strip the headers, by removing everything
before the first blank line.
"""
_before, _blankline, after = text.partition('\n\n')
return after
_QUOTE_RE = re.compile(r'(writes in|writes:|wrote:|says:|said:'
r'|^In article|^Quoted from|^\||^>)')
def strip_newsgroup_quoting(text):
"""
Given text in "news" format, strip lines beginning with the quote
characters > or |, plus lines that often introduce a quoted section
(for example, because they contain the string 'writes:'.)
"""
good_lines = [line for line in text.split('\n')
if not _QUOTE_RE.search(line)]
return '\n'.join(good_lines)
def strip_newsgroup_footer(text):
"""
Given text in "news" format, attempt to remove a signature block.
As a rough heuristic, we assume that signatures are set apart by either
a blank line or a line made of hyphens, and that it is the last such line
in the file (disregarding blank lines at the end).
"""
lines = text.strip().split('\n')
for line_num in range(len(lines) - 1, -1, -1):
line = lines[line_num]
if line.strip().strip('-') == '':
break
if line_num > 0:
return '\n'.join(lines[:line_num])
else:
return text
def fetch_20newsgroups(data_home=None, subset='train', categories=None,
shuffle=True, random_state=42,
remove=(),
download_if_missing=True):
"""Load the filenames and data from the 20 newsgroups dataset.
Read more in the :ref:`User Guide <20newsgroups>`.
Parameters
----------
subset : 'train' or 'test', 'all', optional
Select the dataset to load: 'train' for the training set, 'test'
for the test set, 'all' for both, with shuffled ordering.
data_home : optional, default: None
Specify a download and cache folder for the datasets. If None,
all scikit-learn data is stored in '~/scikit_learn_data' subfolders.
categories : None or collection of string or unicode
If None (default), load all the categories.
If not None, list of category names to load (other categories
ignored).
shuffle : bool, optional
Whether or not to shuffle the data: might be important for models that
make the assumption that the samples are independent and identically
distributed (i.i.d.), such as stochastic gradient descent.
random_state : numpy random number generator or seed integer
Used to shuffle the dataset.
download_if_missing : optional, True by default
If False, raise an IOError if the data is not locally available
instead of trying to download the data from the source site.
remove : tuple
May contain any subset of ('headers', 'footers', 'quotes'). Each of
these are kinds of text that will be detected and removed from the
newsgroup posts, preventing classifiers from overfitting on
metadata.
'headers' removes newsgroup headers, 'footers' removes blocks at the
ends of posts that look like signatures, and 'quotes' removes lines
that appear to be quoting another post.
'headers' follows an exact standard; the other filters are not always
correct.
"""
data_home = get_data_home(data_home=data_home)
cache_path = _pkl_filepath(data_home, CACHE_NAME)
twenty_home = os.path.join(data_home, "20news_home")
cache = None
if os.path.exists(cache_path):
try:
with open(cache_path, 'rb') as f:
compressed_content = f.read()
uncompressed_content = codecs.decode(
compressed_content, 'zlib_codec')
cache = pickle.loads(uncompressed_content)
except Exception as e:
print(80 * '_')
print('Cache loading failed')
print(80 * '_')
print(e)
if cache is None:
if download_if_missing:
logger.info("Downloading 20news dataset. "
"This may take a few minutes.")
cache = download_20newsgroups(target_dir=twenty_home,
cache_path=cache_path)
else:
raise IOError('20Newsgroups dataset not found')
if subset in ('train', 'test'):
data = cache[subset]
elif subset == 'all':
data_lst = list()
target = list()
filenames = list()
for subset in ('train', 'test'):
data = cache[subset]
data_lst.extend(data.data)
target.extend(data.target)
filenames.extend(data.filenames)
data.data = data_lst
data.target = np.array(target)
data.filenames = np.array(filenames)
else:
raise ValueError(
"subset can only be 'train', 'test' or 'all', got '%s'" % subset)
data.description = 'the 20 newsgroups by date dataset'
if 'headers' in remove:
data.data = [strip_newsgroup_header(text) for text in data.data]
if 'footers' in remove:
data.data = [strip_newsgroup_footer(text) for text in data.data]
if 'quotes' in remove:
data.data = [strip_newsgroup_quoting(text) for text in data.data]
if categories is not None:
labels = [(data.target_names.index(cat), cat) for cat in categories]
# Sort the categories to have the ordering of the labels
labels.sort()
labels, categories = zip(*labels)
mask = np.in1d(data.target, labels)
data.filenames = data.filenames[mask]
data.target = data.target[mask]
# searchsorted to have continuous labels
data.target = np.searchsorted(labels, data.target)
data.target_names = list(categories)
# Use an object array to shuffle: avoids memory copy
data_lst = np.array(data.data, dtype=object)
data_lst = data_lst[mask]
data.data = data_lst.tolist()
if shuffle:
random_state = check_random_state(random_state)
indices = np.arange(data.target.shape[0])
random_state.shuffle(indices)
data.filenames = data.filenames[indices]
data.target = data.target[indices]
# Use an object array to shuffle: avoids memory copy
data_lst = np.array(data.data, dtype=object)
data_lst = data_lst[indices]
data.data = data_lst.tolist()
return data
def fetch_20newsgroups_vectorized(subset="train", remove=(), data_home=None):
"""Load the 20 newsgroups dataset and transform it into tf-idf vectors.
This is a convenience function; the tf-idf transformation is done using the
default settings for `sklearn.feature_extraction.text.Vectorizer`. For more
advanced usage (stopword filtering, n-gram extraction, etc.), combine
fetch_20newsgroups with a custom `Vectorizer` or `CountVectorizer`.
Read more in the :ref:`User Guide <20newsgroups>`.
Parameters
----------
subset : 'train' or 'test', 'all', optional
Select the dataset to load: 'train' for the training set, 'test'
for the test set, 'all' for both, with shuffled ordering.
data_home : optional, default: None
Specify an download and cache folder for the datasets. If None,
all scikit-learn data is stored in '~/scikit_learn_data' subfolders.
remove : tuple
May contain any subset of ('headers', 'footers', 'quotes'). Each of
these are kinds of text that will be detected and removed from the
newsgroup posts, preventing classifiers from overfitting on
metadata.
'headers' removes newsgroup headers, 'footers' removes blocks at the
ends of posts that look like signatures, and 'quotes' removes lines
that appear to be quoting another post.
Returns
-------
bunch : Bunch object
bunch.data: sparse matrix, shape [n_samples, n_features]
bunch.target: array, shape [n_samples]
bunch.target_names: list, length [n_classes]
"""
data_home = get_data_home(data_home=data_home)
filebase = '20newsgroup_vectorized'
if remove:
filebase += 'remove-' + ('-'.join(remove))
target_file = _pkl_filepath(data_home, filebase + ".pkl")
# we shuffle but use a fixed seed for the memoization
data_train = fetch_20newsgroups(data_home=data_home,
subset='train',
categories=None,
shuffle=True,
random_state=12,
remove=remove)
data_test = fetch_20newsgroups(data_home=data_home,
subset='test',
categories=None,
shuffle=True,
random_state=12,
remove=remove)
if os.path.exists(target_file):
X_train, X_test = joblib.load(target_file)
else:
vectorizer = CountVectorizer(dtype=np.int16)
X_train = vectorizer.fit_transform(data_train.data).tocsr()
X_test = vectorizer.transform(data_test.data).tocsr()
joblib.dump((X_train, X_test), target_file, compress=9)
# the data is stored as int16 for compactness
# but normalize needs floats
X_train = X_train.astype(np.float64)
X_test = X_test.astype(np.float64)
normalize(X_train, copy=False)
normalize(X_test, copy=False)
target_names = data_train.target_names
if subset == "train":
data = X_train
target = data_train.target
elif subset == "test":
data = X_test
target = data_test.target
elif subset == "all":
data = sp.vstack((X_train, X_test)).tocsr()
target = np.concatenate((data_train.target, data_test.target))
else:
raise ValueError("%r is not a valid subset: should be one of "
"['train', 'test', 'all']" % subset)
return Bunch(data=data, target=target, target_names=target_names)
| bsd-3-clause |
mjudsp/Tsallis | sklearn/gaussian_process/tests/test_gpr.py | 23 | 11915 | """Testing for Gaussian process regression """
# Author: Jan Hendrik Metzen <[email protected]>
# Licence: BSD 3 clause
import numpy as np
from scipy.optimize import approx_fprime
from sklearn.gaussian_process import GaussianProcessRegressor
from sklearn.gaussian_process.kernels \
import RBF, ConstantKernel as C, WhiteKernel
from sklearn.utils.testing \
import (assert_true, assert_greater, assert_array_less,
assert_almost_equal, assert_equal)
def f(x):
return x * np.sin(x)
X = np.atleast_2d([1., 3., 5., 6., 7., 8.]).T
X2 = np.atleast_2d([2., 4., 5.5, 6.5, 7.5]).T
y = f(X).ravel()
fixed_kernel = RBF(length_scale=1.0, length_scale_bounds="fixed")
kernels = [RBF(length_scale=1.0), fixed_kernel,
RBF(length_scale=1.0, length_scale_bounds=(1e-3, 1e3)),
C(1.0, (1e-2, 1e2)) *
RBF(length_scale=1.0, length_scale_bounds=(1e-3, 1e3)),
C(1.0, (1e-2, 1e2)) *
RBF(length_scale=1.0, length_scale_bounds=(1e-3, 1e3)) +
C(1e-5, (1e-5, 1e2)),
C(0.1, (1e-2, 1e2)) *
RBF(length_scale=1.0, length_scale_bounds=(1e-3, 1e3)) +
C(1e-5, (1e-5, 1e2))]
def test_gpr_interpolation():
"""Test the interpolating property for different kernels."""
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
y_pred, y_cov = gpr.predict(X, return_cov=True)
assert_true(np.allclose(y_pred, y))
assert_true(np.allclose(np.diag(y_cov), 0.))
def test_lml_improving():
""" Test that hyperparameter-tuning improves log-marginal likelihood. """
for kernel in kernels:
if kernel == fixed_kernel:
continue
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
assert_greater(gpr.log_marginal_likelihood(gpr.kernel_.theta),
gpr.log_marginal_likelihood(kernel.theta))
def test_lml_precomputed():
""" Test that lml of optimized kernel is stored correctly. """
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
assert_equal(gpr.log_marginal_likelihood(gpr.kernel_.theta),
gpr.log_marginal_likelihood())
def test_converged_to_local_maximum():
""" Test that we are in local maximum after hyperparameter-optimization."""
for kernel in kernels:
if kernel == fixed_kernel:
continue
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
lml, lml_gradient = \
gpr.log_marginal_likelihood(gpr.kernel_.theta, True)
assert_true(np.all((np.abs(lml_gradient) < 1e-4) |
(gpr.kernel_.theta == gpr.kernel_.bounds[:, 0]) |
(gpr.kernel_.theta == gpr.kernel_.bounds[:, 1])))
def test_solution_inside_bounds():
""" Test that hyperparameter-optimization remains in bounds"""
for kernel in kernels:
if kernel == fixed_kernel:
continue
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
bounds = gpr.kernel_.bounds
max_ = np.finfo(gpr.kernel_.theta.dtype).max
tiny = 1e-10
bounds[~np.isfinite(bounds[:, 1]), 1] = max_
assert_array_less(bounds[:, 0], gpr.kernel_.theta + tiny)
assert_array_less(gpr.kernel_.theta, bounds[:, 1] + tiny)
def test_lml_gradient():
""" Compare analytic and numeric gradient of log marginal likelihood. """
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
lml, lml_gradient = gpr.log_marginal_likelihood(kernel.theta, True)
lml_gradient_approx = \
approx_fprime(kernel.theta,
lambda theta: gpr.log_marginal_likelihood(theta,
False),
1e-10)
assert_almost_equal(lml_gradient, lml_gradient_approx, 3)
def test_prior():
""" Test that GP prior has mean 0 and identical variances."""
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel)
y_mean, y_cov = gpr.predict(X, return_cov=True)
assert_almost_equal(y_mean, 0, 5)
if len(gpr.kernel.theta) > 1:
# XXX: quite hacky, works only for current kernels
assert_almost_equal(np.diag(y_cov), np.exp(kernel.theta[0]), 5)
else:
assert_almost_equal(np.diag(y_cov), 1, 5)
def test_sample_statistics():
""" Test that statistics of samples drawn from GP are correct."""
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
y_mean, y_cov = gpr.predict(X2, return_cov=True)
samples = gpr.sample_y(X2, 300000)
# More digits accuracy would require many more samples
assert_almost_equal(y_mean, np.mean(samples, 1), 1)
assert_almost_equal(np.diag(y_cov) / np.diag(y_cov).max(),
np.var(samples, 1) / np.diag(y_cov).max(), 1)
def test_no_optimizer():
""" Test that kernel parameters are unmodified when optimizer is None."""
kernel = RBF(1.0)
gpr = GaussianProcessRegressor(kernel=kernel, optimizer=None).fit(X, y)
assert_equal(np.exp(gpr.kernel_.theta), 1.0)
def test_predict_cov_vs_std():
""" Test that predicted std.-dev. is consistent with cov's diagonal."""
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
y_mean, y_cov = gpr.predict(X2, return_cov=True)
y_mean, y_std = gpr.predict(X2, return_std=True)
assert_almost_equal(np.sqrt(np.diag(y_cov)), y_std)
def test_anisotropic_kernel():
""" Test that GPR can identify meaningful anisotropic length-scales. """
# We learn a function which varies in one dimension ten-times slower
# than in the other. The corresponding length-scales should differ by at
# least a factor 5
rng = np.random.RandomState(0)
X = rng.uniform(-1, 1, (50, 2))
y = X[:, 0] + 0.1 * X[:, 1]
kernel = RBF([1.0, 1.0])
gpr = GaussianProcessRegressor(kernel=kernel).fit(X, y)
assert_greater(np.exp(gpr.kernel_.theta[1]),
np.exp(gpr.kernel_.theta[0]) * 5)
def test_random_starts():
"""
Test that an increasing number of random-starts of GP fitting only
increases the log marginal likelihood of the chosen theta.
"""
n_samples, n_features = 25, 2
np.random.seed(0)
rng = np.random.RandomState(0)
X = rng.randn(n_samples, n_features) * 2 - 1
y = np.sin(X).sum(axis=1) + np.sin(3 * X).sum(axis=1) \
+ rng.normal(scale=0.1, size=n_samples)
kernel = C(1.0, (1e-2, 1e2)) \
* RBF(length_scale=[1.0] * n_features,
length_scale_bounds=[(1e-4, 1e+2)] * n_features) \
+ WhiteKernel(noise_level=1e-5, noise_level_bounds=(1e-5, 1e1))
last_lml = -np.inf
for n_restarts_optimizer in range(5):
gp = GaussianProcessRegressor(
kernel=kernel, n_restarts_optimizer=n_restarts_optimizer,
random_state=0,).fit(X, y)
lml = gp.log_marginal_likelihood(gp.kernel_.theta)
assert_greater(lml, last_lml - np.finfo(np.float32).eps)
last_lml = lml
def test_y_normalization():
""" Test normalization of the target values in GP
Fitting non-normalizing GP on normalized y and fitting normalizing GP
on unnormalized y should yield identical results
"""
y_mean = y.mean(0)
y_norm = y - y_mean
for kernel in kernels:
# Fit non-normalizing GP on normalized y
gpr = GaussianProcessRegressor(kernel=kernel)
gpr.fit(X, y_norm)
# Fit normalizing GP on unnormalized y
gpr_norm = GaussianProcessRegressor(kernel=kernel, normalize_y=True)
gpr_norm.fit(X, y)
# Compare predicted mean, std-devs and covariances
y_pred, y_pred_std = gpr.predict(X2, return_std=True)
y_pred = y_mean + y_pred
y_pred_norm, y_pred_std_norm = gpr_norm.predict(X2, return_std=True)
assert_almost_equal(y_pred, y_pred_norm)
assert_almost_equal(y_pred_std, y_pred_std_norm)
_, y_cov = gpr.predict(X2, return_cov=True)
_, y_cov_norm = gpr_norm.predict(X2, return_cov=True)
assert_almost_equal(y_cov, y_cov_norm)
def test_y_multioutput():
""" Test that GPR can deal with multi-dimensional target values"""
y_2d = np.vstack((y, y * 2)).T
# Test for fixed kernel that first dimension of 2d GP equals the output
# of 1d GP and that second dimension is twice as large
kernel = RBF(length_scale=1.0)
gpr = GaussianProcessRegressor(kernel=kernel, optimizer=None,
normalize_y=False)
gpr.fit(X, y)
gpr_2d = GaussianProcessRegressor(kernel=kernel, optimizer=None,
normalize_y=False)
gpr_2d.fit(X, y_2d)
y_pred_1d, y_std_1d = gpr.predict(X2, return_std=True)
y_pred_2d, y_std_2d = gpr_2d.predict(X2, return_std=True)
_, y_cov_1d = gpr.predict(X2, return_cov=True)
_, y_cov_2d = gpr_2d.predict(X2, return_cov=True)
assert_almost_equal(y_pred_1d, y_pred_2d[:, 0])
assert_almost_equal(y_pred_1d, y_pred_2d[:, 1] / 2)
# Standard deviation and covariance do not depend on output
assert_almost_equal(y_std_1d, y_std_2d)
assert_almost_equal(y_cov_1d, y_cov_2d)
y_sample_1d = gpr.sample_y(X2, n_samples=10)
y_sample_2d = gpr_2d.sample_y(X2, n_samples=10)
assert_almost_equal(y_sample_1d, y_sample_2d[:, 0])
# Test hyperparameter optimization
for kernel in kernels:
gpr = GaussianProcessRegressor(kernel=kernel, normalize_y=True)
gpr.fit(X, y)
gpr_2d = GaussianProcessRegressor(kernel=kernel, normalize_y=True)
gpr_2d.fit(X, np.vstack((y, y)).T)
assert_almost_equal(gpr.kernel_.theta, gpr_2d.kernel_.theta, 4)
def test_custom_optimizer():
""" Test that GPR can use externally defined optimizers. """
# Define a dummy optimizer that simply tests 50 random hyperparameters
def optimizer(obj_func, initial_theta, bounds):
rng = np.random.RandomState(0)
theta_opt, func_min = \
initial_theta, obj_func(initial_theta, eval_gradient=False)
for _ in range(50):
theta = np.atleast_1d(rng.uniform(np.maximum(-2, bounds[:, 0]),
np.minimum(1, bounds[:, 1])))
f = obj_func(theta, eval_gradient=False)
if f < func_min:
theta_opt, func_min = theta, f
return theta_opt, func_min
for kernel in kernels:
if kernel == fixed_kernel:
continue
gpr = GaussianProcessRegressor(kernel=kernel, optimizer=optimizer)
gpr.fit(X, y)
# Checks that optimizer improved marginal likelihood
assert_greater(gpr.log_marginal_likelihood(gpr.kernel_.theta),
gpr.log_marginal_likelihood(gpr.kernel.theta))
def test_duplicate_input():
""" Test GPR can handle two different output-values for the same input. """
for kernel in kernels:
gpr_equal_inputs = \
GaussianProcessRegressor(kernel=kernel, alpha=1e-2)
gpr_similar_inputs = \
GaussianProcessRegressor(kernel=kernel, alpha=1e-2)
X_ = np.vstack((X, X[0]))
y_ = np.hstack((y, y[0] + 1))
gpr_equal_inputs.fit(X_, y_)
X_ = np.vstack((X, X[0] + 1e-15))
y_ = np.hstack((y, y[0] + 1))
gpr_similar_inputs.fit(X_, y_)
X_test = np.linspace(0, 10, 100)[:, None]
y_pred_equal, y_std_equal = \
gpr_equal_inputs.predict(X_test, return_std=True)
y_pred_similar, y_std_similar = \
gpr_similar_inputs.predict(X_test, return_std=True)
assert_almost_equal(y_pred_equal, y_pred_similar)
assert_almost_equal(y_std_equal, y_std_similar)
| bsd-3-clause |
macks22/scikit-learn | examples/linear_model/plot_sgd_loss_functions.py | 249 | 1095 | """
==========================
SGD: convex loss functions
==========================
A plot that compares the various convex loss functions supported by
:class:`sklearn.linear_model.SGDClassifier` .
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
def modified_huber_loss(y_true, y_pred):
z = y_pred * y_true
loss = -4 * z
loss[z >= -1] = (1 - z[z >= -1]) ** 2
loss[z >= 1.] = 0
return loss
xmin, xmax = -4, 4
xx = np.linspace(xmin, xmax, 100)
plt.plot([xmin, 0, 0, xmax], [1, 1, 0, 0], 'k-',
label="Zero-one loss")
plt.plot(xx, np.where(xx < 1, 1 - xx, 0), 'g-',
label="Hinge loss")
plt.plot(xx, -np.minimum(xx, 0), 'm-',
label="Perceptron loss")
plt.plot(xx, np.log2(1 + np.exp(-xx)), 'r-',
label="Log loss")
plt.plot(xx, np.where(xx < 1, 1 - xx, 0) ** 2, 'b-',
label="Squared hinge loss")
plt.plot(xx, modified_huber_loss(xx, 1), 'y--',
label="Modified Huber loss")
plt.ylim((0, 8))
plt.legend(loc="upper right")
plt.xlabel(r"Decision function $f(x)$")
plt.ylabel("$L(y, f(x))$")
plt.show()
| bsd-3-clause |
tomasreimers/tensorflow-emscripten | tensorflow/contrib/learn/python/learn/estimators/estimator.py | 5 | 55320 | # Copyright 2016 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Base Estimator class."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import abc
import copy
import inspect
import os
import tempfile
import numpy as np
import six
from tensorflow.contrib import framework as contrib_framework
from tensorflow.contrib import layers
from tensorflow.contrib import metrics as metrics_lib
from tensorflow.contrib.framework import deprecated
from tensorflow.contrib.framework import deprecated_arg_values
from tensorflow.contrib.framework import deprecated_args
from tensorflow.contrib.framework import list_variables
from tensorflow.contrib.framework import load_variable
from tensorflow.contrib.framework.python.framework import experimental
from tensorflow.contrib.framework.python.ops import variables as contrib_variables
from tensorflow.contrib.learn.python.learn import evaluable
from tensorflow.contrib.learn.python.learn import metric_spec
from tensorflow.contrib.learn.python.learn import monitors as monitor_lib
from tensorflow.contrib.learn.python.learn import trainable
from tensorflow.contrib.learn.python.learn.estimators import _sklearn as sklearn
from tensorflow.contrib.learn.python.learn.estimators import metric_key
from tensorflow.contrib.learn.python.learn.estimators import model_fn as model_fn_lib
from tensorflow.contrib.learn.python.learn.estimators import run_config
from tensorflow.contrib.learn.python.learn.estimators import tensor_signature
from tensorflow.contrib.learn.python.learn.estimators._sklearn import NotFittedError
from tensorflow.contrib.learn.python.learn.learn_io import data_feeder
from tensorflow.contrib.learn.python.learn.utils import export
from tensorflow.contrib.learn.python.learn.utils import saved_model_export_utils
from tensorflow.contrib.training.python.training import evaluation
from tensorflow.core.framework import summary_pb2
from tensorflow.python.client import session as tf_session
from tensorflow.python.framework import ops
from tensorflow.python.framework import random_seed
from tensorflow.python.framework import sparse_tensor
from tensorflow.python.ops import control_flow_ops
from tensorflow.python.ops import data_flow_ops
from tensorflow.python.ops import variables
from tensorflow.python.platform import gfile
from tensorflow.python.platform import tf_logging as logging
from tensorflow.python.saved_model import builder as saved_model_builder
from tensorflow.python.saved_model import tag_constants
from tensorflow.python.training import basic_session_run_hooks
from tensorflow.python.training import device_setter
from tensorflow.python.training import monitored_session
from tensorflow.python.training import saver
from tensorflow.python.training import session_run_hook
from tensorflow.python.training import summary_io
from tensorflow.python.util import compat
AS_ITERABLE_DATE = '2016-09-15'
AS_ITERABLE_INSTRUCTIONS = (
'The default behavior of predict() is changing. The default value for\n'
'as_iterable will change to True, and then the flag will be removed\n'
'altogether. The behavior of this flag is described below.')
SCIKIT_DECOUPLE_DATE = '2016-12-01'
SCIKIT_DECOUPLE_INSTRUCTIONS = (
'Estimator is decoupled from Scikit Learn interface by moving into\n'
'separate class SKCompat. Arguments x, y and batch_size are only\n'
'available in the SKCompat class, Estimator will only accept input_fn.\n'
'Example conversion:\n'
' est = Estimator(...) -> est = SKCompat(Estimator(...))')
def _verify_input_args(x, y, input_fn, feed_fn, batch_size):
"""Verifies validity of co-existance of input arguments."""
if input_fn is None:
if x is None:
raise ValueError('Either x or input_fn must be provided.')
if contrib_framework.is_tensor(x) or (y is not None and
contrib_framework.is_tensor(y)):
raise ValueError('Inputs cannot be tensors. Please provide input_fn.')
if feed_fn is not None:
raise ValueError('Can not provide both feed_fn and x or y.')
else:
if (x is not None) or (y is not None):
raise ValueError('Can not provide both input_fn and x or y.')
if batch_size is not None:
raise ValueError('Can not provide both input_fn and batch_size.')
def _get_input_fn(x, y, input_fn, feed_fn, batch_size, shuffle=False, epochs=1):
"""Make inputs into input and feed functions.
Args:
x: Numpy, Pandas or Dask matrix or iterable.
y: Numpy, Pandas or Dask matrix or iterable.
input_fn: Pre-defined input function for training data.
feed_fn: Pre-defined data feeder function.
batch_size: Size to split data into parts. Must be >= 1.
shuffle: Whether to shuffle the inputs.
epochs: Number of epochs to run.
Returns:
Data input and feeder function based on training data.
Raises:
ValueError: Only one of `(x & y)` or `input_fn` must be provided.
"""
_verify_input_args(x, y, input_fn, feed_fn, batch_size)
if input_fn is not None:
return input_fn, feed_fn
df = data_feeder.setup_train_data_feeder(
x,
y,
n_classes=None,
batch_size=batch_size,
shuffle=shuffle,
epochs=epochs)
return df.input_builder, df.get_feed_dict_fn()
def infer_real_valued_columns_from_input_fn(input_fn):
"""Creates `FeatureColumn` objects for inputs defined by `input_fn`.
This interprets all inputs as dense, fixed-length float values. This creates
a local graph in which it calls `input_fn` to build the tensors, then discards
it.
Args:
input_fn: Input function returning a tuple of:
features - Dictionary of string feature name to `Tensor` or `Tensor`.
labels - `Tensor` of label values.
Returns:
List of `FeatureColumn` objects.
"""
with ops.Graph().as_default():
features, _ = input_fn()
return layers.infer_real_valued_columns(features)
def infer_real_valued_columns_from_input(x):
"""Creates `FeatureColumn` objects for inputs defined by input `x`.
This interprets all inputs as dense, fixed-length float values.
Args:
x: Real-valued matrix of shape [n_samples, n_features...]. Can be
iterator that returns arrays of features.
Returns:
List of `FeatureColumn` objects.
"""
input_fn, _ = _get_input_fn(
x=x, y=None, input_fn=None, feed_fn=None, batch_size=None)
return infer_real_valued_columns_from_input_fn(input_fn)
def _get_arguments(func):
"""Returns list of arguments this function has."""
if hasattr(func, '__code__'):
# Regular function.
return inspect.getargspec(func).args
elif hasattr(func, '__call__'):
# Callable object.
return _get_arguments(func.__call__)
elif hasattr(func, 'func'):
# Partial function.
return _get_arguments(func.func)
def _get_replica_device_setter(config):
"""Creates a replica device setter if required.
Args:
config: A RunConfig instance.
Returns:
A replica device setter, or None.
"""
ps_ops = [
'Variable', 'VariableV2', 'AutoReloadVariable', 'MutableHashTable',
'MutableHashTableOfTensors', 'MutableDenseHashTable'
]
if config.task_type:
worker_device = '/job:%s/task:%d' % (config.task_type, config.task_id)
else:
worker_device = '/job:worker'
if config.num_ps_replicas > 0:
return device_setter.replica_device_setter(
ps_tasks=config.num_ps_replicas, worker_device=worker_device,
merge_devices=True, ps_ops=ps_ops, cluster=config.cluster_spec)
else:
return None
def _make_metrics_ops(metrics, features, labels, predictions):
"""Add metrics based on `features`, `labels`, and `predictions`.
`metrics` contains a specification for how to run metrics. It is a dict
mapping friendly names to either `MetricSpec` objects, or directly to a metric
function (assuming that `predictions` and `labels` are single tensors), or to
`(pred_name, metric)` `tuple`, which passes `predictions[pred_name]` and
`labels` to `metric` (assuming `labels` is a single tensor).
Users are encouraged to use `MetricSpec` objects, which are more flexible and
cleaner. They also lead to clearer errors.
Args:
metrics: A dict mapping names to metrics specification, for example
`MetricSpec` objects.
features: A dict of tensors returned from an input_fn as features/inputs.
labels: A single tensor or a dict of tensors returned from an input_fn as
labels.
predictions: A single tensor or a dict of tensors output from a model as
predictions.
Returns:
A dict mapping the friendly given in `metrics` to the result of calling the
given metric function.
Raises:
ValueError: If metrics specifications do not work with the type of
`features`, `labels`, or `predictions` provided. Mostly, a dict is given
but no pred_name specified.
"""
metrics = metrics or {}
# If labels is a dict with a single key, unpack into a single tensor.
labels_tensor_or_dict = labels
if isinstance(labels, dict) and len(labels) == 1:
labels_tensor_or_dict = labels[list(labels.keys())[0]]
result = {}
# Iterate in lexicographic order, so the graph is identical among runs.
for name, metric in sorted(six.iteritems(metrics)):
if isinstance(metric, metric_spec.MetricSpec):
result[name] = metric.create_metric_ops(features, labels, predictions)
continue
# TODO(b/31229024): Remove the rest of this loop
logging.warning('Please specify metrics using MetricSpec. Using bare '
'functions or (key, fn) tuples is deprecated and support '
'for it will be removed on Oct 1, 2016.')
if isinstance(name, tuple):
# Multi-head metrics.
if len(name) != 2:
raise ValueError('Invalid metric for {}. It returned a tuple with '
'len {}, expected 2.'.format(name, len(name)))
if not isinstance(predictions, dict):
raise ValueError(
'Metrics passed provide (name, prediction), '
'but predictions are not dict. '
'Metrics: %s, Predictions: %s.' % (metrics, predictions))
# Here are two options: labels are single Tensor or a dict.
if isinstance(labels, dict) and name[1] in labels:
# If labels are dict and the prediction name is in it, apply metric.
result[name[0]] = metric(predictions[name[1]], labels[name[1]])
else:
# Otherwise pass the labels to the metric.
result[name[0]] = metric(predictions[name[1]], labels_tensor_or_dict)
else:
# Single head metrics.
if isinstance(predictions, dict):
raise ValueError(
'Metrics passed provide only name, no prediction, '
'but predictions are dict. '
'Metrics: %s, Labels: %s.' % (metrics, labels_tensor_or_dict))
result[name] = metric(predictions, labels_tensor_or_dict)
return result
def _dict_to_str(dictionary):
"""Get a `str` representation of a `dict`.
Args:
dictionary: The `dict` to be represented as `str`.
Returns:
A `str` representing the `dictionary`.
"""
return ', '.join('%s = %s' % (k, v) for k, v in sorted(dictionary.items()))
def _write_dict_to_summary(output_dir,
dictionary,
current_global_step):
"""Writes a `dict` into summary file in given output directory.
Args:
output_dir: `str`, directory to write the summary file in.
dictionary: the `dict` to be written to summary file.
current_global_step: `int`, the current global step.
"""
logging.info('Saving dict for global step %d: %s', current_global_step,
_dict_to_str(dictionary))
summary_writer = summary_io.SummaryWriterCache.get(output_dir)
summary_proto = summary_pb2.Summary()
for key in dictionary:
if dictionary[key] is None:
continue
value = summary_proto.value.add()
value.tag = key
if (isinstance(dictionary[key], np.float32) or
isinstance(dictionary[key], float)):
value.simple_value = float(dictionary[key])
else:
logging.warn('Skipping summary for %s, must be a float or np.float32.',
key)
summary_writer.add_summary(summary_proto, current_global_step)
summary_writer.flush()
class BaseEstimator(
sklearn.BaseEstimator, evaluable.Evaluable, trainable.Trainable):
"""Abstract BaseEstimator class to train and evaluate TensorFlow models.
Concrete implementation of this class should provide the following functions:
* _get_train_ops
* _get_eval_ops
* _get_predict_ops
`Estimator` implemented below is a good example of how to use this class.
"""
__metaclass__ = abc.ABCMeta
# Note that for Google users, this is overriden with
# learn_runner.EstimatorConfig.
# TODO(wicke): Remove this once launcher takes over config functionality
_Config = run_config.RunConfig # pylint: disable=invalid-name
def __init__(self, model_dir=None, config=None):
"""Initializes a BaseEstimator instance.
Args:
model_dir: Directory to save model parameters, graph and etc. This can
also be used to load checkpoints from the directory into a estimator to
continue training a previously saved model.
config: A RunConfig instance.
"""
# Model directory.
self._model_dir = model_dir
if self._model_dir is None:
self._model_dir = tempfile.mkdtemp()
logging.warning('Using temporary folder as model directory: %s',
self._model_dir)
# Create a run configuration.
if config is None:
self._config = BaseEstimator._Config()
logging.info('Using default config.')
else:
self._config = config
logging.info('Using config: %s', str(vars(self._config)))
# Set device function depending if there are replicas or not.
self._device_fn = _get_replica_device_setter(self._config)
# Features and labels TensorSignature objects.
# TODO(wicke): Rename these to something more descriptive
self._features_info = None
self._labels_info = None
self._graph = None
@property
def config(self):
# TODO(wicke): make RunConfig immutable, and then return it without a copy.
return copy.deepcopy(self._config)
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('y', None), ('batch_size', None)
)
def fit(self, x=None, y=None, input_fn=None, steps=None, batch_size=None,
monitors=None, max_steps=None):
# pylint: disable=g-doc-args,g-doc-return-or-yield
"""See `Trainable`.
Raises:
ValueError: If `x` or `y` are not `None` while `input_fn` is not `None`.
ValueError: If both `steps` and `max_steps` are not `None`.
"""
if (steps is not None) and (max_steps is not None):
raise ValueError('Can not provide both steps and max_steps.')
_verify_input_args(x, y, input_fn, None, batch_size)
if x is not None:
SKCompat(self).fit(x, y, batch_size, steps, max_steps, monitors)
return self
if max_steps is not None:
try:
start_step = load_variable(self._model_dir, ops.GraphKeys.GLOBAL_STEP)
if max_steps <= start_step:
logging.info('Skipping training since max_steps has already saved.')
return self
except: # pylint: disable=bare-except
pass
hooks = monitor_lib.replace_monitors_with_hooks(monitors, self)
if steps is not None or max_steps is not None:
hooks.append(basic_session_run_hooks.StopAtStepHook(steps, max_steps))
loss = self._train_model(input_fn=input_fn, hooks=hooks)
logging.info('Loss for final step: %s.', loss)
return self
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('y', None), ('batch_size', None)
)
def partial_fit(
self, x=None, y=None, input_fn=None, steps=1, batch_size=None,
monitors=None):
"""Incremental fit on a batch of samples.
This method is expected to be called several times consecutively
on different or the same chunks of the dataset. This either can
implement iterative training or out-of-core/online training.
This is especially useful when the whole dataset is too big to
fit in memory at the same time. Or when model is taking long time
to converge, and you want to split up training into subparts.
Args:
x: Matrix of shape [n_samples, n_features...]. Can be iterator that
returns arrays of features. The training input samples for fitting the
model. If set, `input_fn` must be `None`.
y: Vector or matrix [n_samples] or [n_samples, n_outputs]. Can be
iterator that returns array of labels. The training label values
(class labels in classification, real numbers in regression). If set,
`input_fn` must be `None`.
input_fn: Input function. If set, `x`, `y`, and `batch_size` must be
`None`.
steps: Number of steps for which to train model. If `None`, train forever.
batch_size: minibatch size to use on the input, defaults to first
dimension of `x`. Must be `None` if `input_fn` is provided.
monitors: List of `BaseMonitor` subclass instances. Used for callbacks
inside the training loop.
Returns:
`self`, for chaining.
Raises:
ValueError: If at least one of `x` and `y` is provided, and `input_fn` is
provided.
"""
logging.warning('The current implementation of partial_fit is not optimized'
' for use in a loop. Consider using fit() instead.')
return self.fit(x=x, y=y, input_fn=input_fn, steps=steps,
batch_size=batch_size, monitors=monitors)
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('y', None), ('batch_size', None)
)
def evaluate(self,
x=None,
y=None,
input_fn=None,
feed_fn=None,
batch_size=None,
steps=None,
metrics=None,
name=None,
checkpoint_path=None,
hooks=None,
log_progress=True):
# pylint: disable=g-doc-args,g-doc-return-or-yield
"""See `Evaluable`.
Raises:
ValueError: If at least one of `x` or `y` is provided, and at least one of
`input_fn` or `feed_fn` is provided.
Or if `metrics` is not `None` or `dict`.
"""
_verify_input_args(x, y, input_fn, feed_fn, batch_size)
if x is not None:
return SKCompat(self).score(x, y, batch_size, steps, metrics)
if metrics is not None and not isinstance(metrics, dict):
raise ValueError('Metrics argument should be None or dict. '
'Got %s.' % metrics)
eval_results, global_step = self._evaluate_model(
input_fn=input_fn,
feed_fn=feed_fn,
steps=steps,
metrics=metrics,
name=name,
checkpoint_path=checkpoint_path,
hooks=hooks,
log_progress=log_progress)
if eval_results is not None:
eval_results.update({'global_step': global_step})
return eval_results
@deprecated_args(
SCIKIT_DECOUPLE_DATE, SCIKIT_DECOUPLE_INSTRUCTIONS, ('x', None),
('batch_size', None), ('as_iterable', True)
)
def predict(
self, x=None, input_fn=None, batch_size=None, outputs=None,
as_iterable=True):
"""Returns predictions for given features.
Args:
x: Matrix of shape [n_samples, n_features...]. Can be iterator that
returns arrays of features. The training input samples for fitting the
model. If set, `input_fn` must be `None`.
input_fn: Input function. If set, `x` and 'batch_size' must be `None`.
batch_size: Override default batch size. If set, 'input_fn' must be
'None'.
outputs: list of `str`, name of the output to predict.
If `None`, returns all.
as_iterable: If True, return an iterable which keeps yielding predictions
for each example until inputs are exhausted. Note: The inputs must
terminate if you want the iterable to terminate (e.g. be sure to pass
num_epochs=1 if you are using something like read_batch_features).
Returns:
A numpy array of predicted classes or regression values if the
constructor's `model_fn` returns a `Tensor` for `predictions` or a `dict`
of numpy arrays if `model_fn` returns a `dict`. Returns an iterable of
predictions if as_iterable is True.
Raises:
ValueError: If x and input_fn are both provided or both `None`.
"""
_verify_input_args(x, None, input_fn, None, batch_size)
if x is not None and not as_iterable:
return SKCompat(self).predict(x, batch_size)
input_fn, feed_fn = _get_input_fn(x, None, input_fn, None, batch_size)
return self._infer_model(
input_fn=input_fn,
feed_fn=feed_fn,
outputs=outputs,
as_iterable=as_iterable)
def get_variable_value(self, name):
"""Returns value of the variable given by name.
Args:
name: string, name of the tensor.
Returns:
Numpy array - value of the tensor.
"""
return load_variable(self.model_dir, name)
def get_variable_names(self):
"""Returns list of all variable names in this model.
Returns:
List of names.
"""
return [name for name, _ in list_variables(self.model_dir)]
@property
def model_dir(self):
return self._model_dir
@deprecated_arg_values(
'2016-09-23',
'The signature of the input_fn accepted by export is changing to be '
'consistent with what\'s used by tf.Learn Estimator\'s train/evaluate. '
'input_fn (and in most cases, input_feature_key) will become required '
'args, and use_deprecated_input_fn will default to False and be removed '
'altogether.',
use_deprecated_input_fn=True,
input_fn=None)
def export(self,
export_dir,
input_fn=export._default_input_fn, # pylint: disable=protected-access
input_feature_key=None,
use_deprecated_input_fn=True,
signature_fn=None,
prediction_key=None,
default_batch_size=1,
exports_to_keep=None):
"""Exports inference graph into given dir.
Args:
export_dir: A string containing a directory to write the exported graph
and checkpoints.
input_fn: If `use_deprecated_input_fn` is true, then a function that given
`Tensor` of `Example` strings, parses it into features that are then
passed to the model. Otherwise, a function that takes no argument and
returns a tuple of (features, labels), where features is a dict of
string key to `Tensor` and labels is a `Tensor` that's currently not
used (and so can be `None`).
input_feature_key: Only used if `use_deprecated_input_fn` is false. String
key into the features dict returned by `input_fn` that corresponds to a
the raw `Example` strings `Tensor` that the exported model will take as
input. Can only be `None` if you're using a custom `signature_fn` that
does not use the first arg (examples).
use_deprecated_input_fn: Determines the signature format of `input_fn`.
signature_fn: Function that returns a default signature and a named
signature map, given `Tensor` of `Example` strings, `dict` of `Tensor`s
for features and `Tensor` or `dict` of `Tensor`s for predictions.
prediction_key: The key for a tensor in the `predictions` dict (output
from the `model_fn`) to use as the `predictions` input to the
`signature_fn`. Optional. If `None`, predictions will pass to
`signature_fn` without filtering.
default_batch_size: Default batch size of the `Example` placeholder.
exports_to_keep: Number of exports to keep.
Returns:
The string path to the exported directory. NB: this functionality was
added ca. 2016/09/25; clients that depend on the return value may need
to handle the case where this function returns None because subclasses
are not returning a value.
"""
# pylint: disable=protected-access
return export._export_estimator(
estimator=self,
export_dir=export_dir,
signature_fn=signature_fn,
prediction_key=prediction_key,
input_fn=input_fn,
input_feature_key=input_feature_key,
use_deprecated_input_fn=use_deprecated_input_fn,
default_batch_size=default_batch_size,
exports_to_keep=exports_to_keep)
@abc.abstractproperty
def _get_train_ops(self, features, labels):
"""Method that builds model graph and returns trainer ops.
Expected to be overridden by sub-classes that require custom support.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
Returns:
A `ModelFnOps` object.
"""
pass
@abc.abstractproperty
def _get_predict_ops(self, features):
"""Method that builds model graph and returns prediction ops.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
Returns:
A `ModelFnOps` object.
"""
pass
def _get_eval_ops(self, features, labels, metrics):
"""Method that builds model graph and returns evaluation ops.
Expected to be overriden by sub-classes that require custom support.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
metrics: Dict of metrics to run. If None, the default metric functions
are used; if {}, no metrics are used. Otherwise, `metrics` should map
friendly names for the metric to a `MetricSpec` object defining which
model outputs to evaluate against which labels with which metric
function. Metric ops should support streaming, e.g., returning
update_op and value tensors. See more details in
`../../../../metrics/python/metrics/ops/streaming_metrics.py` and
`../metric_spec.py`.
Returns:
A `ModelFnOps` object.
"""
raise NotImplementedError('_get_eval_ops not implemented in BaseEstimator')
@deprecated(
'2016-09-23',
'The signature of the input_fn accepted by export is changing to be '
'consistent with what\'s used by tf.Learn Estimator\'s train/evaluate, '
'which makes this function useless. This will be removed after the '
'deprecation date.')
def _get_feature_ops_from_example(self, examples_batch):
"""Returns feature parser for given example batch using features info.
This function requires `fit()` has been called.
Args:
examples_batch: batch of tf.Example
Returns:
features: `Tensor` or `dict` of `Tensor` objects.
Raises:
ValueError: If `_features_info` attribute is not available (usually
because `fit()` has not been called).
"""
if self._features_info is None:
raise ValueError('Features information missing, was fit() ever called?')
return tensor_signature.create_example_parser_from_signatures(
self._features_info, examples_batch)
def _check_inputs(self, features, labels):
if self._features_info is not None:
logging.debug('Given features: %s, required signatures: %s.',
str(features), str(self._features_info))
if not tensor_signature.tensors_compatible(features, self._features_info):
raise ValueError('Features are incompatible with given information. '
'Given features: %s, required signatures: %s.' %
(str(features), str(self._features_info)))
else:
self._features_info = tensor_signature.create_signatures(features)
logging.debug('Setting feature info to %s.', str(self._features_info))
if labels is not None:
if self._labels_info is not None:
logging.debug('Given labels: %s, required signatures: %s.',
str(labels), str(self._labels_info))
if not tensor_signature.tensors_compatible(labels, self._labels_info):
raise ValueError('Labels are incompatible with given information. '
'Given labels: %s, required signatures: %s.' %
(str(labels), str(self._labels_info)))
else:
self._labels_info = tensor_signature.create_signatures(labels)
logging.debug('Setting labels info to %s', str(self._labels_info))
def _extract_metric_update_ops(self, eval_dict):
"""Separate update operations from metric value operations."""
update_ops = []
value_ops = {}
for name, metric_ops in six.iteritems(eval_dict):
if isinstance(metric_ops, (list, tuple)):
if len(metric_ops) == 2:
value_ops[name] = metric_ops[0]
update_ops.append(metric_ops[1])
else:
logging.warning(
'Ignoring metric {}. It returned a list|tuple with len {}, '
'expected 2'.format(name, len(metric_ops)))
value_ops[name] = metric_ops
else:
value_ops[name] = metric_ops
if update_ops:
update_ops = control_flow_ops.group(*update_ops)
else:
update_ops = None
return update_ops, value_ops
def _evaluate_model(self,
input_fn,
steps,
feed_fn=None,
metrics=None,
name='',
checkpoint_path=None,
hooks=None,
log_progress=True):
# TODO(wicke): Remove this once Model and associated code are gone.
if (hasattr(self._config, 'execution_mode') and
self._config.execution_mode not in ('all', 'evaluate', 'eval_evalset')):
return None, None
# Check that model has been trained (if nothing has been set explicitly).
if not checkpoint_path:
latest_path = saver.latest_checkpoint(self._model_dir)
if not latest_path:
raise NotFittedError("Couldn't find trained model at %s."
% self._model_dir)
checkpoint_path = latest_path
# Setup output directory.
eval_dir = os.path.join(self._model_dir, 'eval' if not name else
'eval_' + name)
with ops.Graph().as_default() as g:
random_seed.set_random_seed(self._config.tf_random_seed)
global_step = contrib_framework.create_global_step(g)
features, labels = input_fn()
self._check_inputs(features, labels)
# The default return type of _get_eval_ops is ModelFnOps. But there are
# some subclasses of tf.contrib.learn.Estimator which override this
# method and use the legacy signature, namely _get_eval_ops returns an
# `eval_dict` dictionary of Tensors. The following else-statement code
# covers these cases, but will soon be deleted after the subclasses are
# updated.
# TODO(b/32664904): Update subclasses and delete the else-statement.
eval_ops = self._get_eval_ops(features, labels, metrics)
if isinstance(eval_ops, model_fn_lib.ModelFnOps): # Default signature
eval_dict = eval_ops.eval_metric_ops
else: # Legacy signature
eval_dict = eval_ops
update_op, eval_dict = self._extract_metric_update_ops(eval_dict)
hooks = hooks or []
if feed_fn:
hooks.append(_FeedFnHook(feed_fn))
if steps:
hooks.append(
evaluation.StopAfterNEvalsHook(
steps, log_progress=log_progress))
global_step_key = 'global_step'
while global_step_key in eval_dict:
global_step_key = '_' + global_step_key
eval_dict[global_step_key] = global_step
eval_results = evaluation.evaluate_once(
checkpoint_path=checkpoint_path,
master=self._config.evaluation_master,
eval_ops=update_op,
final_ops=eval_dict,
hooks=hooks)
current_global_step = eval_results[global_step_key]
_write_dict_to_summary(eval_dir, eval_results, current_global_step)
return eval_results, current_global_step
def _get_features_from_input_fn(self, input_fn):
result = input_fn()
if isinstance(result, (list, tuple)):
return result[0]
return result
def _infer_model(self,
input_fn,
feed_fn=None,
outputs=None,
as_iterable=True,
iterate_batches=False):
# Check that model has been trained.
checkpoint_path = saver.latest_checkpoint(self._model_dir)
if not checkpoint_path:
raise NotFittedError("Couldn't find trained model at %s."
% self._model_dir)
with ops.Graph().as_default() as g:
random_seed.set_random_seed(self._config.tf_random_seed)
contrib_framework.create_global_step(g)
features = self._get_features_from_input_fn(input_fn)
infer_ops = self._call_legacy_get_predict_ops(features)
predictions = self._filter_predictions(infer_ops.predictions, outputs)
mon_sess = monitored_session.MonitoredSession(
session_creator=monitored_session.ChiefSessionCreator(
checkpoint_filename_with_path=checkpoint_path))
if not as_iterable:
with mon_sess:
if not mon_sess.should_stop():
return mon_sess.run(predictions, feed_fn() if feed_fn else None)
else:
return self._predict_generator(mon_sess, predictions, feed_fn,
iterate_batches)
def _predict_generator(self, mon_sess, predictions, feed_fn, iterate_batches):
with mon_sess:
while not mon_sess.should_stop():
preds = mon_sess.run(predictions, feed_fn() if feed_fn else None)
if iterate_batches:
yield preds
elif not isinstance(predictions, dict):
for pred in preds:
yield pred
else:
first_tensor = list(preds.values())[0]
if isinstance(first_tensor, sparse_tensor.SparseTensorValue):
batch_length = first_tensor.dense_shape[0]
else:
batch_length = first_tensor.shape[0]
for i in range(batch_length):
yield {key: value[i] for key, value in six.iteritems(preds)}
if self._is_input_constant(feed_fn, mon_sess.graph):
return
def _is_input_constant(self, feed_fn, graph):
# If there are no queue_runners, the input `predictions` is a
# constant, and we should stop after the first epoch. If,
# instead, there are queue_runners, eventually they should throw
# an `OutOfRangeError`.
if graph.get_collection(ops.GraphKeys.QUEUE_RUNNERS):
return False
# data_feeder uses feed_fn to generate `OutOfRangeError`.
if feed_fn is not None:
return False
return True
def _filter_predictions(self, predictions, outputs):
if not outputs:
return predictions
if not isinstance(predictions, dict):
raise ValueError(
'outputs argument is not valid in case of non-dict predictions.')
existing_keys = predictions.keys()
predictions = {
key: value
for key, value in six.iteritems(predictions) if key in outputs
}
if not predictions:
raise ValueError('Expected to run at least one output from %s, '
'provided %s.' % (existing_keys, outputs))
return predictions
def _train_model(self, input_fn, hooks):
all_hooks = []
self._graph = ops.Graph()
with self._graph.as_default() as g, g.device(self._device_fn):
random_seed.set_random_seed(self._config.tf_random_seed)
global_step = contrib_framework.create_global_step(g)
features, labels = input_fn()
self._check_inputs(features, labels)
model_fn_ops = self._call_legacy_get_train_ops(features, labels)
ops.add_to_collection(ops.GraphKeys.LOSSES, model_fn_ops.loss)
all_hooks.extend([
basic_session_run_hooks.NanTensorHook(model_fn_ops.loss),
basic_session_run_hooks.LoggingTensorHook(
{
'loss': model_fn_ops.loss,
'step': global_step
},
every_n_iter=100)
])
all_hooks.extend(hooks)
scaffold = model_fn_ops.training_scaffold or monitored_session.Scaffold()
if not (scaffold.saver or ops.get_collection(ops.GraphKeys.SAVERS)):
ops.add_to_collection(
ops.GraphKeys.SAVERS,
saver.Saver(
sharded=True,
max_to_keep=self._config.keep_checkpoint_max,
defer_build=True))
chief_hooks = []
if (self._config.save_checkpoints_secs or
self._config.save_checkpoints_steps):
saver_hook_exists = any([
isinstance(h, basic_session_run_hooks.CheckpointSaverHook)
for h in (all_hooks + model_fn_ops.training_hooks + chief_hooks +
model_fn_ops.training_chief_hooks)
])
if not saver_hook_exists:
chief_hooks = [
basic_session_run_hooks.CheckpointSaverHook(
self._model_dir,
save_secs=self._config.save_checkpoints_secs,
save_steps=self._config.save_checkpoints_steps,
scaffold=scaffold)
]
with monitored_session.MonitoredTrainingSession(
master=self._config.master,
is_chief=self._config.is_chief,
checkpoint_dir=self._model_dir,
scaffold=scaffold,
hooks=all_hooks + model_fn_ops.training_hooks,
chief_only_hooks=chief_hooks + model_fn_ops.training_chief_hooks,
save_checkpoint_secs=0, # Saving is handled by a hook.
save_summaries_steps=self._config.save_summary_steps,
config=self.config.tf_config) as mon_sess:
loss = None
while not mon_sess.should_stop():
_, loss = mon_sess.run([model_fn_ops.train_op, model_fn_ops.loss])
summary_io.SummaryWriterCache.clear()
return loss
def _call_legacy_get_predict_ops(self, features):
# The default return type of _get_predict_ops is ModelFnOps. But there are
# some subclasses of tf.contrib.learn.Estimator which override this
# method and use the legacy signature, namely _get_predict_ops returns a
# `predictions` Tensor or dict or Tensors. The following else-statement
# code covers these cases, but will soon be deleted after the subclasses
# are updated.
# TODO(b/32664904): Update subclasses and delete the else-statement.
infer_ops = self._get_predict_ops(features)
if isinstance(infer_ops, model_fn_lib.ModelFnOps): # Default signature
return infer_ops
return model_fn_lib.ModelFnOps(
mode=model_fn_lib.ModeKeys.INFER, predictions=infer_ops)
def _call_legacy_get_train_ops(self, features, labels):
train_ops = self._get_train_ops(features, labels)
if isinstance(train_ops, model_fn_lib.ModelFnOps): # Default signature
return train_ops
return model_fn_lib.ModelFnOps(
mode=model_fn_lib.ModeKeys.TRAIN,
predictions=None,
loss=train_ops[1],
train_op=train_ops[0])
def _identity_feature_engineering_fn(features, labels):
return features, labels
class Estimator(BaseEstimator):
"""Estimator class is the basic TensorFlow model trainer/evaluator.
"""
def __init__(self,
model_fn=None,
model_dir=None,
config=None,
params=None,
feature_engineering_fn=None):
"""Constructs an `Estimator` instance.
Args:
model_fn: Model function. Follows the signature:
* Args:
* `features`: single `Tensor` or `dict` of `Tensor`s
(depending on data passed to `fit`),
* `labels`: `Tensor` or `dict` of `Tensor`s (for multi-head
models). If mode is `ModeKeys.INFER`, `labels=None` will be
passed. If the `model_fn`'s signature does not accept
`mode`, the `model_fn` must still be able to handle
`labels=None`.
* `mode`: Optional. Specifies if this training, evaluation or
prediction. See `ModeKeys`.
* `params`: Optional `dict` of hyperparameters. Will receive what
is passed to Estimator in `params` parameter. This allows
to configure Estimators from hyper parameter tuning.
* `config`: Optional configuration object. Will receive what is passed
to Estimator in `config` parameter, or the default `config`.
Allows updating things in your model_fn based on configuration
such as `num_ps_replicas`.
* `model_dir`: Optional directory where model parameters, graph etc
are saved. Will receive what is passed to Estimator in
`model_dir` parameter, or the default `model_dir`. Allows
updating things in your model_fn that expect model_dir, such as
training hooks.
* Returns:
`ModelFnOps`
Also supports a legacy signature which returns tuple of:
* predictions: `Tensor`, `SparseTensor` or dictionary of same.
Can also be any type that is convertible to a `Tensor` or
`SparseTensor`, or dictionary of same.
* loss: Scalar loss `Tensor`.
* train_op: Training update `Tensor` or `Operation`.
Supports next three signatures for the function:
* `(features, labels) -> (predictions, loss, train_op)`
* `(features, labels, mode) -> (predictions, loss, train_op)`
* `(features, labels, mode, params) -> (predictions, loss, train_op)`
* `(features, labels, mode, params, config) ->
(predictions, loss, train_op)`
* `(features, labels, mode, params, config, model_dir) ->
(predictions, loss, train_op)`
model_dir: Directory to save model parameters, graph and etc. This can
also be used to load checkpoints from the directory into a estimator to
continue training a previously saved model.
config: Configuration object.
params: `dict` of hyper parameters that will be passed into `model_fn`.
Keys are names of parameters, values are basic python types.
feature_engineering_fn: Feature engineering function. Takes features and
labels which are the output of `input_fn` and
returns features and labels which will be fed
into `model_fn`. Please check `model_fn` for
a definition of features and labels.
Raises:
ValueError: parameters of `model_fn` don't match `params`.
"""
super(Estimator, self).__init__(model_dir=model_dir, config=config)
if model_fn is not None:
# Check number of arguments of the given function matches requirements.
model_fn_args = _get_arguments(model_fn)
if params is not None and 'params' not in model_fn_args:
raise ValueError('Estimator\'s model_fn (%s) has less than 4 '
'arguments, but not None params (%s) are passed.' %
(model_fn, params))
if params is None and 'params' in model_fn_args:
logging.warning('Estimator\'s model_fn (%s) includes params '
'argument, but params are not passed to Estimator.',
model_fn)
self._model_fn = model_fn
self.params = params
self._feature_engineering_fn = (
feature_engineering_fn or _identity_feature_engineering_fn)
def _call_model_fn(self, features, labels, mode):
"""Calls model function with support of 2, 3 or 4 arguments.
Args:
features: features dict.
labels: labels dict.
mode: ModeKeys
Returns:
A `ModelFnOps` object. If model_fn returns a tuple, wraps them up in a
`ModelFnOps` object.
Raises:
ValueError: if model_fn returns invalid objects.
"""
features, labels = self._feature_engineering_fn(features, labels)
model_fn_args = _get_arguments(self._model_fn)
kwargs = {}
if 'mode' in model_fn_args:
kwargs['mode'] = mode
if 'params' in model_fn_args:
kwargs['params'] = self.params
if 'config' in model_fn_args:
kwargs['config'] = self.config
if 'model_dir' in model_fn_args:
kwargs['model_dir'] = self.model_dir
model_fn_results = self._model_fn(features, labels, **kwargs)
if isinstance(model_fn_results, model_fn_lib.ModelFnOps):
return model_fn_results
# Here model_fn_ops should be a tuple with 3 elements.
if len(model_fn_results) != 3:
raise ValueError('Unrecognized value returned by model_fn, '
'please return ModelFnOps.')
return model_fn_lib.ModelFnOps(
mode=mode,
predictions=model_fn_results[0],
loss=model_fn_results[1],
train_op=model_fn_results[2])
def _get_train_ops(self, features, labels):
"""Method that builds model graph and returns trainer ops.
Expected to be overriden by sub-classes that require custom support.
This implementation uses `model_fn` passed as parameter to constructor to
build model.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
Returns:
`ModelFnOps` object.
"""
return self._call_model_fn(features, labels, model_fn_lib.ModeKeys.TRAIN)
def _get_eval_ops(self, features, labels, metrics):
"""Method that builds model graph and returns evaluation ops.
Expected to be overriden by sub-classes that require custom support.
This implementation uses `model_fn` passed as parameter to constructor to
build model.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
labels: `Tensor` or `dict` of `Tensor` objects.
metrics: Dict of metrics to run. If None, the default metric functions
are used; if {}, no metrics are used. Otherwise, `metrics` should map
friendly names for the metric to a `MetricSpec` object defining which
model outputs to evaluate against which labels with which metric
function. Metric ops should support streaming, e.g., returning
update_op and value tensors. See more details in
`../../../../metrics/python/metrics/ops/streaming_metrics.py` and
`../metric_spec.py`.
Returns:
`ModelFnOps` object.
Raises:
ValueError: if `metrics` don't match `labels`.
"""
model_fn_ops = self._call_model_fn(
features, labels, model_fn_lib.ModeKeys.EVAL)
# Custom metrics should overwrite defaults.
if metrics:
model_fn_ops.eval_metric_ops.update(_make_metrics_ops(
metrics, features, labels, model_fn_ops.predictions))
if metric_key.MetricKey.LOSS not in model_fn_ops.eval_metric_ops:
model_fn_ops.eval_metric_ops[metric_key.MetricKey.LOSS] = (
metrics_lib.streaming_mean(model_fn_ops.loss))
return model_fn_ops
def _get_predict_ops(self, features):
"""Method that builds model graph and returns prediction ops.
Expected to be overriden by sub-classes that require custom support.
This implementation uses `model_fn` passed as parameter to constructor to
build model.
Args:
features: `Tensor` or `dict` of `Tensor` objects.
Returns:
`ModelFnOps` object.
"""
labels = tensor_signature.create_placeholders_from_signatures(
self._labels_info)
return self._call_model_fn(features, labels, model_fn_lib.ModeKeys.INFER)
@experimental
def export_savedmodel(
self, export_dir_base, input_fn,
default_output_alternative_key=None,
assets_extra=None,
as_text=False,
exports_to_keep=None):
"""Exports inference graph as a SavedModel into given dir.
Args:
export_dir_base: A string containing a directory to write the exported
graph and checkpoints.
input_fn: A function that takes no argument and
returns an `InputFnOps`.
default_output_alternative_key: the name of the head to serve when none is
specified.
assets_extra: A dict specifying how to populate the assets.extra directory
within the exported SavedModel. Each key should give the destination
path (including the filename) relative to the assets.extra directory.
The corresponding value gives the full path of the source file to be
copied. For example, the simple case of copying a single file without
renaming it is specified as
`{'my_asset_file.txt': '/path/to/my_asset_file.txt'}`.
as_text: whether to write the SavedModel proto in text format.
exports_to_keep: Number of exports to keep.
Returns:
The string path to the exported directory.
Raises:
ValueError: if an unrecognized export_type is requested.
"""
if input_fn is None:
raise ValueError('input_fn must be defined.')
with ops.Graph().as_default() as g:
contrib_variables.create_global_step(g)
# Call the input_fn and collect the input alternatives.
input_ops = input_fn()
input_alternatives, features = (
saved_model_export_utils.get_input_alternatives(input_ops))
# Call the model_fn and collect the output alternatives.
model_fn_ops = self._call_model_fn(features, None,
model_fn_lib.ModeKeys.INFER)
output_alternatives, actual_default_output_alternative_key = (
saved_model_export_utils.get_output_alternatives(
model_fn_ops, default_output_alternative_key))
# Build the SignatureDefs from all pairs of input and output signatures
signature_def_map = saved_model_export_utils.build_all_signature_defs(
input_alternatives, output_alternatives,
actual_default_output_alternative_key)
# Locate the latest checkpoint
# TODO(soergel): does it help that we know we have one from this step?
checkpoint_path = saver.latest_checkpoint(self._model_dir)
if not checkpoint_path:
raise NotFittedError("Couldn't find trained model at %s."
% self._model_dir)
export_dir = saved_model_export_utils.get_timestamped_export_dir(
export_dir_base)
with tf_session.Session('') as session:
variables.initialize_local_variables()
data_flow_ops.tables_initializer()
saver_for_restore = saver.Saver(
variables.global_variables(),
sharded=True)
saver_for_restore.restore(session, checkpoint_path)
init_op = control_flow_ops.group(
variables.local_variables_initializer(),
data_flow_ops.tables_initializer())
# Perform the export
builder = saved_model_builder.SavedModelBuilder(export_dir)
builder.add_meta_graph_and_variables(
session, [tag_constants.SERVING],
signature_def_map=signature_def_map,
assets_collection=ops.get_collection(
ops.GraphKeys.ASSET_FILEPATHS),
legacy_init_op=init_op)
builder.save(as_text)
# Add the extra assets
if assets_extra:
assets_extra_path = os.path.join(compat.as_bytes(export_dir),
compat.as_bytes('assets.extra'))
for dest_relative, source in assets_extra.items():
dest_absolute = os.path.join(compat.as_bytes(assets_extra_path),
compat.as_bytes(dest_relative))
dest_path = os.path.dirname(dest_absolute)
gfile.MakeDirs(dest_path)
gfile.Copy(source, dest_absolute)
return export_dir
class _FeedFnHook(session_run_hook.SessionRunHook):
"""Runs feed_fn and sets the feed_dict accordingly."""
def __init__(self, feed_fn):
self.feed_fn = feed_fn
def before_run(self, run_context): # pylint: disable=unused-argument
return session_run_hook.SessionRunArgs(
fetches=None, feed_dict=self.feed_fn())
# For time of deprecation x,y from Estimator allow direct access.
# pylint: disable=protected-access
class SKCompat(sklearn.BaseEstimator):
"""Scikit learn wrapper for TensorFlow Learn Estimator."""
def __init__(self, estimator):
self._estimator = estimator
def fit(self, x, y, batch_size=128, steps=None, max_steps=None,
monitors=None):
input_fn, feed_fn = _get_input_fn(x, y, input_fn=None, feed_fn=None,
batch_size=batch_size, shuffle=True,
epochs=None)
all_monitors = []
if feed_fn:
all_monitors = [_FeedFnHook(feed_fn)]
if monitors:
all_monitors.extend(monitors)
self._estimator.fit(input_fn=input_fn,
steps=steps,
max_steps=max_steps,
monitors=all_monitors)
return self
def score(self, x, y, batch_size=128, steps=None, metrics=None):
input_fn, feed_fn = _get_input_fn(x, y, input_fn=None,
feed_fn=None, batch_size=batch_size,
shuffle=False, epochs=1)
if metrics is not None and not isinstance(metrics, dict):
raise ValueError('Metrics argument should be None or dict. '
'Got %s.' % metrics)
eval_results, global_step = self._estimator._evaluate_model(
input_fn=input_fn,
feed_fn=feed_fn,
steps=steps,
metrics=metrics,
name='score')
if eval_results is not None:
eval_results.update({'global_step': global_step})
return eval_results
def predict(self, x, batch_size=128, outputs=None):
input_fn, feed_fn = _get_input_fn(
x, None, input_fn=None, feed_fn=None, batch_size=batch_size,
shuffle=False, epochs=1)
results = list(
self._estimator._infer_model(
input_fn=input_fn,
feed_fn=feed_fn,
outputs=outputs,
as_iterable=True,
iterate_batches=True))
if not isinstance(results[0], dict):
return np.concatenate([output for output in results], axis=0)
return {
key: np.concatenate(
[output[key] for output in results], axis=0)
for key in results[0]
}
| apache-2.0 |
mxjl620/scikit-learn | sklearn/cluster/tests/test_spectral.py | 262 | 7954 | """Testing for Spectral Clustering methods"""
from sklearn.externals.six.moves import cPickle
dumps, loads = cPickle.dumps, cPickle.loads
import numpy as np
from scipy import sparse
from sklearn.utils import check_random_state
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_greater
from sklearn.utils.testing import assert_warns_message
from sklearn.cluster import SpectralClustering, spectral_clustering
from sklearn.cluster.spectral import spectral_embedding
from sklearn.cluster.spectral import discretize
from sklearn.metrics import pairwise_distances
from sklearn.metrics import adjusted_rand_score
from sklearn.metrics.pairwise import kernel_metrics, rbf_kernel
from sklearn.datasets.samples_generator import make_blobs
def test_spectral_clustering():
S = np.array([[1.0, 1.0, 1.0, 0.2, 0.0, 0.0, 0.0],
[1.0, 1.0, 1.0, 0.2, 0.0, 0.0, 0.0],
[1.0, 1.0, 1.0, 0.2, 0.0, 0.0, 0.0],
[0.2, 0.2, 0.2, 1.0, 1.0, 1.0, 1.0],
[0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0],
[0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0],
[0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0]])
for eigen_solver in ('arpack', 'lobpcg'):
for assign_labels in ('kmeans', 'discretize'):
for mat in (S, sparse.csr_matrix(S)):
model = SpectralClustering(random_state=0, n_clusters=2,
affinity='precomputed',
eigen_solver=eigen_solver,
assign_labels=assign_labels
).fit(mat)
labels = model.labels_
if labels[0] == 0:
labels = 1 - labels
assert_array_equal(labels, [1, 1, 1, 0, 0, 0, 0])
model_copy = loads(dumps(model))
assert_equal(model_copy.n_clusters, model.n_clusters)
assert_equal(model_copy.eigen_solver, model.eigen_solver)
assert_array_equal(model_copy.labels_, model.labels_)
def test_spectral_amg_mode():
# Test the amg mode of SpectralClustering
centers = np.array([
[0., 0., 0.],
[10., 10., 10.],
[20., 20., 20.],
])
X, true_labels = make_blobs(n_samples=100, centers=centers,
cluster_std=1., random_state=42)
D = pairwise_distances(X) # Distance matrix
S = np.max(D) - D # Similarity matrix
S = sparse.coo_matrix(S)
try:
from pyamg import smoothed_aggregation_solver
amg_loaded = True
except ImportError:
amg_loaded = False
if amg_loaded:
labels = spectral_clustering(S, n_clusters=len(centers),
random_state=0, eigen_solver="amg")
# We don't care too much that it's good, just that it *worked*.
# There does have to be some lower limit on the performance though.
assert_greater(np.mean(labels == true_labels), .3)
else:
assert_raises(ValueError, spectral_embedding, S,
n_components=len(centers),
random_state=0, eigen_solver="amg")
def test_spectral_unknown_mode():
# Test that SpectralClustering fails with an unknown mode set.
centers = np.array([
[0., 0., 0.],
[10., 10., 10.],
[20., 20., 20.],
])
X, true_labels = make_blobs(n_samples=100, centers=centers,
cluster_std=1., random_state=42)
D = pairwise_distances(X) # Distance matrix
S = np.max(D) - D # Similarity matrix
S = sparse.coo_matrix(S)
assert_raises(ValueError, spectral_clustering, S, n_clusters=2,
random_state=0, eigen_solver="<unknown>")
def test_spectral_unknown_assign_labels():
# Test that SpectralClustering fails with an unknown assign_labels set.
centers = np.array([
[0., 0., 0.],
[10., 10., 10.],
[20., 20., 20.],
])
X, true_labels = make_blobs(n_samples=100, centers=centers,
cluster_std=1., random_state=42)
D = pairwise_distances(X) # Distance matrix
S = np.max(D) - D # Similarity matrix
S = sparse.coo_matrix(S)
assert_raises(ValueError, spectral_clustering, S, n_clusters=2,
random_state=0, assign_labels="<unknown>")
def test_spectral_clustering_sparse():
X, y = make_blobs(n_samples=20, random_state=0,
centers=[[1, 1], [-1, -1]], cluster_std=0.01)
S = rbf_kernel(X, gamma=1)
S = np.maximum(S - 1e-4, 0)
S = sparse.coo_matrix(S)
labels = SpectralClustering(random_state=0, n_clusters=2,
affinity='precomputed').fit(S).labels_
assert_equal(adjusted_rand_score(y, labels), 1)
def test_affinities():
# Note: in the following, random_state has been selected to have
# a dataset that yields a stable eigen decomposition both when built
# on OSX and Linux
X, y = make_blobs(n_samples=20, random_state=0,
centers=[[1, 1], [-1, -1]], cluster_std=0.01
)
# nearest neighbors affinity
sp = SpectralClustering(n_clusters=2, affinity='nearest_neighbors',
random_state=0)
assert_warns_message(UserWarning, 'not fully connected', sp.fit, X)
assert_equal(adjusted_rand_score(y, sp.labels_), 1)
sp = SpectralClustering(n_clusters=2, gamma=2, random_state=0)
labels = sp.fit(X).labels_
assert_equal(adjusted_rand_score(y, labels), 1)
X = check_random_state(10).rand(10, 5) * 10
kernels_available = kernel_metrics()
for kern in kernels_available:
# Additive chi^2 gives a negative similarity matrix which
# doesn't make sense for spectral clustering
if kern != 'additive_chi2':
sp = SpectralClustering(n_clusters=2, affinity=kern,
random_state=0)
labels = sp.fit(X).labels_
assert_equal((X.shape[0],), labels.shape)
sp = SpectralClustering(n_clusters=2, affinity=lambda x, y: 1,
random_state=0)
labels = sp.fit(X).labels_
assert_equal((X.shape[0],), labels.shape)
def histogram(x, y, **kwargs):
# Histogram kernel implemented as a callable.
assert_equal(kwargs, {}) # no kernel_params that we didn't ask for
return np.minimum(x, y).sum()
sp = SpectralClustering(n_clusters=2, affinity=histogram, random_state=0)
labels = sp.fit(X).labels_
assert_equal((X.shape[0],), labels.shape)
# raise error on unknown affinity
sp = SpectralClustering(n_clusters=2, affinity='<unknown>')
assert_raises(ValueError, sp.fit, X)
def test_discretize(seed=8):
# Test the discretize using a noise assignment matrix
random_state = np.random.RandomState(seed)
for n_samples in [50, 100, 150, 500]:
for n_class in range(2, 10):
# random class labels
y_true = random_state.random_integers(0, n_class, n_samples)
y_true = np.array(y_true, np.float)
# noise class assignment matrix
y_indicator = sparse.coo_matrix((np.ones(n_samples),
(np.arange(n_samples),
y_true)),
shape=(n_samples,
n_class + 1))
y_true_noisy = (y_indicator.toarray()
+ 0.1 * random_state.randn(n_samples,
n_class + 1))
y_pred = discretize(y_true_noisy, random_state)
assert_greater(adjusted_rand_score(y_true, y_pred), 0.8)
| bsd-3-clause |
waterponey/scikit-learn | sklearn/datasets/species_distributions.py | 13 | 7866 | """
=============================
Species distribution dataset
=============================
This dataset represents the geographic distribution of species.
The dataset is provided by Phillips et. al. (2006).
The two species are:
- `"Bradypus variegatus"
<http://www.iucnredlist.org/details/3038/0>`_ ,
the Brown-throated Sloth.
- `"Microryzomys minutus"
<http://www.iucnredlist.org/details/13408/0>`_ ,
also known as the Forest Small Rice Rat, a rodent that lives in Peru,
Colombia, Ecuador, Peru, and Venezuela.
References:
* `"Maximum entropy modeling of species geographic distributions"
<http://www.cs.princeton.edu/~schapire/papers/ecolmod.pdf>`_
S. J. Phillips, R. P. Anderson, R. E. Schapire - Ecological Modelling,
190:231-259, 2006.
Notes:
* See examples/applications/plot_species_distribution_modeling.py
for an example of using this dataset
"""
# Authors: Peter Prettenhofer <[email protected]>
# Jake Vanderplas <[email protected]>
#
# License: BSD 3 clause
from io import BytesIO
from os import makedirs
from os.path import exists
try:
# Python 2
from urllib2 import urlopen
PY2 = True
except ImportError:
# Python 3
from urllib.request import urlopen
PY2 = False
import numpy as np
from sklearn.datasets.base import get_data_home, Bunch
from sklearn.datasets.base import _pkl_filepath
from sklearn.externals import joblib
DIRECTORY_URL = "http://www.cs.princeton.edu/~schapire/maxent/datasets/"
SAMPLES_URL = DIRECTORY_URL + "samples.zip"
COVERAGES_URL = DIRECTORY_URL + "coverages.zip"
DATA_ARCHIVE_NAME = "species_coverage.pkz"
def _load_coverage(F, header_length=6, dtype=np.int16):
"""Load a coverage file from an open file object.
This will return a numpy array of the given dtype
"""
header = [F.readline() for i in range(header_length)]
make_tuple = lambda t: (t.split()[0], float(t.split()[1]))
header = dict([make_tuple(line) for line in header])
M = np.loadtxt(F, dtype=dtype)
nodata = int(header[b'NODATA_value'])
if nodata != -9999:
M[nodata] = -9999
return M
def _load_csv(F):
"""Load csv file.
Parameters
----------
F : file object
CSV file open in byte mode.
Returns
-------
rec : np.ndarray
record array representing the data
"""
if PY2:
# Numpy recarray wants Python 2 str but not unicode
names = F.readline().strip().split(',')
else:
# Numpy recarray wants Python 3 str but not bytes...
names = F.readline().decode('ascii').strip().split(',')
rec = np.loadtxt(F, skiprows=0, delimiter=',', dtype='a22,f4,f4')
rec.dtype.names = names
return rec
def construct_grids(batch):
"""Construct the map grid from the batch object
Parameters
----------
batch : Batch object
The object returned by :func:`fetch_species_distributions`
Returns
-------
(xgrid, ygrid) : 1-D arrays
The grid corresponding to the values in batch.coverages
"""
# x,y coordinates for corner cells
xmin = batch.x_left_lower_corner + batch.grid_size
xmax = xmin + (batch.Nx * batch.grid_size)
ymin = batch.y_left_lower_corner + batch.grid_size
ymax = ymin + (batch.Ny * batch.grid_size)
# x coordinates of the grid cells
xgrid = np.arange(xmin, xmax, batch.grid_size)
# y coordinates of the grid cells
ygrid = np.arange(ymin, ymax, batch.grid_size)
return (xgrid, ygrid)
def fetch_species_distributions(data_home=None,
download_if_missing=True):
"""Loader for species distribution dataset from Phillips et. al. (2006)
Read more in the :ref:`User Guide <datasets>`.
Parameters
----------
data_home : optional, default: None
Specify another download and cache folder for the datasets. By default
all scikit learn data is stored in '~/scikit_learn_data' subfolders.
download_if_missing : optional, True by default
If False, raise a IOError if the data is not locally available
instead of trying to download the data from the source site.
Returns
--------
The data is returned as a Bunch object with the following attributes:
coverages : array, shape = [14, 1592, 1212]
These represent the 14 features measured at each point of the map grid.
The latitude/longitude values for the grid are discussed below.
Missing data is represented by the value -9999.
train : record array, shape = (1623,)
The training points for the data. Each point has three fields:
- train['species'] is the species name
- train['dd long'] is the longitude, in degrees
- train['dd lat'] is the latitude, in degrees
test : record array, shape = (619,)
The test points for the data. Same format as the training data.
Nx, Ny : integers
The number of longitudes (x) and latitudes (y) in the grid
x_left_lower_corner, y_left_lower_corner : floats
The (x,y) position of the lower-left corner, in degrees
grid_size : float
The spacing between points of the grid, in degrees
Notes
------
This dataset represents the geographic distribution of species.
The dataset is provided by Phillips et. al. (2006).
The two species are:
- `"Bradypus variegatus"
<http://www.iucnredlist.org/details/3038/0>`_ ,
the Brown-throated Sloth.
- `"Microryzomys minutus"
<http://www.iucnredlist.org/details/13408/0>`_ ,
also known as the Forest Small Rice Rat, a rodent that lives in Peru,
Colombia, Ecuador, Peru, and Venezuela.
References
----------
* `"Maximum entropy modeling of species geographic distributions"
<http://www.cs.princeton.edu/~schapire/papers/ecolmod.pdf>`_
S. J. Phillips, R. P. Anderson, R. E. Schapire - Ecological Modelling,
190:231-259, 2006.
Notes
-----
* See examples/applications/plot_species_distribution_modeling.py
for an example of using this dataset with scikit-learn
"""
data_home = get_data_home(data_home)
if not exists(data_home):
makedirs(data_home)
# Define parameters for the data files. These should not be changed
# unless the data model changes. They will be saved in the npz file
# with the downloaded data.
extra_params = dict(x_left_lower_corner=-94.8,
Nx=1212,
y_left_lower_corner=-56.05,
Ny=1592,
grid_size=0.05)
dtype = np.int16
archive_path = _pkl_filepath(data_home, DATA_ARCHIVE_NAME)
if not exists(archive_path):
print('Downloading species data from %s to %s' % (SAMPLES_URL,
data_home))
X = np.load(BytesIO(urlopen(SAMPLES_URL).read()))
for f in X.files:
fhandle = BytesIO(X[f])
if 'train' in f:
train = _load_csv(fhandle)
if 'test' in f:
test = _load_csv(fhandle)
print('Downloading coverage data from %s to %s' % (COVERAGES_URL,
data_home))
X = np.load(BytesIO(urlopen(COVERAGES_URL).read()))
coverages = []
for f in X.files:
fhandle = BytesIO(X[f])
print(' - converting', f)
coverages.append(_load_coverage(fhandle))
coverages = np.asarray(coverages, dtype=dtype)
bunch = Bunch(coverages=coverages,
test=test,
train=train,
**extra_params)
joblib.dump(bunch, archive_path, compress=9)
else:
bunch = joblib.load(archive_path)
return bunch
| bsd-3-clause |
howthebodyworks/mlmistrels | src/encoder.py | 1 | 3657 | #!/bin/local/bin/python3
# A utility, script, or potentially one day class to convert audio waveforms in to windowed, reduced descriptors, for some machine learning algorithm to go nuts on later
# Authors: James Nichols, Darwin Vickers
# Includes a test of converting then reversing the predictor to see how things sound. Uses Librosa extensively.
import librosa
import matplotlib.pyplot as plt
#import seaborn as sns
import numpy as np
from util import compress
from reconstruct import reconstruct
def randomise_phase(D):
""" A function that takes reals of any and randomises all the phases,
it does so by randomly modifying the angle of a complex number """
# Create a univariate matrix, use the euler identity to make
# uniformly distributed complex numbers of arg 1
rands = np.exp(np.vectorize(complex)(0, 2.0 * np.pi * np.random.random(D.shape)))
return D * rands
class Encode(object):
def __init__(self, win_len = 2048):
self.win_len = win_len
def encode(self, sound):
return sound
def decode(self, A):
return A
class SparseEncode(Encode):
""" An encoder that uses sparse tensor representation of the spectrogram """
def __init__(self, win_len = 2048, n_decomp = 4):
import sklearn.decomposition
self.win_len = win_len
self.n_decomp = n_decomp
self.T = sklearn.decomposition.MiniBatchDictionaryLearning(n_components=self.n_decomp)
def encode(self, sound):
D = librosa.stft(sound, n_fft=self.win_len)
self.comps, A = librosa.decompose.decompose(np.abs(D), transformer=self.T, sort=True)
return A
def decode(self, A):
return librosa.istft(randomise_phase(self.comps.dot(A)))
class BinEncode(Encode):
def __init__(self, win_len = 2048, n_bins = 32):
self.win_len = win_len
self.n_bins = 32
self.bin_size = self.win_len // (2 * self.n_bins)
def encode(self, sound):
D = librosa.stft(sound, n_fft=self.win_len)
# Make the time series of predictors
A = np.zeros([self.n_bins+1, D.shape[1]], dtype=np.complex)
# Try bin-power
for t in range(D.shape[1]):
# Consider the 0 Hz component separately (Maybe get rid of this...?)
A[0, t] = D[0, t]
# Simple mean of the complex numbers n the bin...
A[1:,t] = np.array([np.mean(D[b_start:b_start+self.bin_size,t])*self.bin_size for b_start in range(1, D.shape[0], self.bin_size)])
return A
def decode(self, A):
D = np.zeros((self.win_len//2+1, A.shape[1]), dtype=np.complex)
for t in range(A.shape[1]):
# Simple covering of the bin with mean of the bin
D[0, t] = A[0, t]
D[1:, t] = np.repeat(A[1:, t], self.bin_size)
# The center frequency is given the average
#D_r[0, t] = TS[0, t]
#D_r[1+bin_size//2:D_r.shape[0]:bin_size, t] = TS[1:, t]
# Random frequency in bin is given the average
return librosa.istft(randomise_phase(D))
class PeaksEncode(Encode):
hop_length = 0
sound_length = 0
def __init__(self, win_len = 2048):
self.win_len = win_len
self.hop_length = win_len/4
self.sr=22050
def encode(self, sound):
H_pitch, H_pitch_mag = lr.piptrack(audio, sr = self.sr, n_fft = self.win_len, hop_length = self.hop_length)
features = compress(H_pitch, H_pitch_mag, n_peaks = 16)
return features
def decode(self, A):
reconstruct(A, n_fft = self.win_length, sr = self.sr, hop_length = self.hop_length)
return A | gpl-3.0 |
IndraVikas/scikit-learn | examples/linear_model/plot_lasso_model_selection.py | 311 | 5431 | """
===================================================
Lasso model selection: Cross-Validation / AIC / BIC
===================================================
Use the Akaike information criterion (AIC), the Bayes Information
criterion (BIC) and cross-validation to select an optimal value
of the regularization parameter alpha of the :ref:`lasso` estimator.
Results obtained with LassoLarsIC are based on AIC/BIC criteria.
Information-criterion based model selection is very fast, but it
relies on a proper estimation of degrees of freedom, are
derived for large samples (asymptotic results) and assume the model
is correct, i.e. that the data are actually generated by this model.
They also tend to break when the problem is badly conditioned
(more features than samples).
For cross-validation, we use 20-fold with 2 algorithms to compute the
Lasso path: coordinate descent, as implemented by the LassoCV class, and
Lars (least angle regression) as implemented by the LassoLarsCV class.
Both algorithms give roughly the same results. They differ with regards
to their execution speed and sources of numerical errors.
Lars computes a path solution only for each kink in the path. As a
result, it is very efficient when there are only of few kinks, which is
the case if there are few features or samples. Also, it is able to
compute the full path without setting any meta parameter. On the
opposite, coordinate descent compute the path points on a pre-specified
grid (here we use the default). Thus it is more efficient if the number
of grid points is smaller than the number of kinks in the path. Such a
strategy can be interesting if the number of features is really large
and there are enough samples to select a large amount. In terms of
numerical errors, for heavily correlated variables, Lars will accumulate
more errors, while the coordinate descent algorithm will only sample the
path on a grid.
Note how the optimal value of alpha varies for each fold. This
illustrates why nested-cross validation is necessary when trying to
evaluate the performance of a method for which a parameter is chosen by
cross-validation: this choice of parameter may not be optimal for unseen
data.
"""
print(__doc__)
# Author: Olivier Grisel, Gael Varoquaux, Alexandre Gramfort
# License: BSD 3 clause
import time
import numpy as np
import matplotlib.pyplot as plt
from sklearn.linear_model import LassoCV, LassoLarsCV, LassoLarsIC
from sklearn import datasets
diabetes = datasets.load_diabetes()
X = diabetes.data
y = diabetes.target
rng = np.random.RandomState(42)
X = np.c_[X, rng.randn(X.shape[0], 14)] # add some bad features
# normalize data as done by Lars to allow for comparison
X /= np.sqrt(np.sum(X ** 2, axis=0))
##############################################################################
# LassoLarsIC: least angle regression with BIC/AIC criterion
model_bic = LassoLarsIC(criterion='bic')
t1 = time.time()
model_bic.fit(X, y)
t_bic = time.time() - t1
alpha_bic_ = model_bic.alpha_
model_aic = LassoLarsIC(criterion='aic')
model_aic.fit(X, y)
alpha_aic_ = model_aic.alpha_
def plot_ic_criterion(model, name, color):
alpha_ = model.alpha_
alphas_ = model.alphas_
criterion_ = model.criterion_
plt.plot(-np.log10(alphas_), criterion_, '--', color=color,
linewidth=3, label='%s criterion' % name)
plt.axvline(-np.log10(alpha_), color=color, linewidth=3,
label='alpha: %s estimate' % name)
plt.xlabel('-log(alpha)')
plt.ylabel('criterion')
plt.figure()
plot_ic_criterion(model_aic, 'AIC', 'b')
plot_ic_criterion(model_bic, 'BIC', 'r')
plt.legend()
plt.title('Information-criterion for model selection (training time %.3fs)'
% t_bic)
##############################################################################
# LassoCV: coordinate descent
# Compute paths
print("Computing regularization path using the coordinate descent lasso...")
t1 = time.time()
model = LassoCV(cv=20).fit(X, y)
t_lasso_cv = time.time() - t1
# Display results
m_log_alphas = -np.log10(model.alphas_)
plt.figure()
ymin, ymax = 2300, 3800
plt.plot(m_log_alphas, model.mse_path_, ':')
plt.plot(m_log_alphas, model.mse_path_.mean(axis=-1), 'k',
label='Average across the folds', linewidth=2)
plt.axvline(-np.log10(model.alpha_), linestyle='--', color='k',
label='alpha: CV estimate')
plt.legend()
plt.xlabel('-log(alpha)')
plt.ylabel('Mean square error')
plt.title('Mean square error on each fold: coordinate descent '
'(train time: %.2fs)' % t_lasso_cv)
plt.axis('tight')
plt.ylim(ymin, ymax)
##############################################################################
# LassoLarsCV: least angle regression
# Compute paths
print("Computing regularization path using the Lars lasso...")
t1 = time.time()
model = LassoLarsCV(cv=20).fit(X, y)
t_lasso_lars_cv = time.time() - t1
# Display results
m_log_alphas = -np.log10(model.cv_alphas_)
plt.figure()
plt.plot(m_log_alphas, model.cv_mse_path_, ':')
plt.plot(m_log_alphas, model.cv_mse_path_.mean(axis=-1), 'k',
label='Average across the folds', linewidth=2)
plt.axvline(-np.log10(model.alpha_), linestyle='--', color='k',
label='alpha CV')
plt.legend()
plt.xlabel('-log(alpha)')
plt.ylabel('Mean square error')
plt.title('Mean square error on each fold: Lars (train time: %.2fs)'
% t_lasso_lars_cv)
plt.axis('tight')
plt.ylim(ymin, ymax)
plt.show()
| bsd-3-clause |
SeldonIO/seldon-server | python/seldon/sklearn_estimator.py | 3 | 2924 | from sklearn.feature_extraction import DictVectorizer
from seldon.pipeline.pandas_pipelines import BasePandasEstimator
from collections import OrderedDict
import io
from sklearn.utils import check_X_y
from sklearn.utils import check_array
from sklearn.base import BaseEstimator,ClassifierMixin
import pandas as pd
class SKLearnClassifier(BasePandasEstimator,BaseEstimator,ClassifierMixin):
"""
Wrapper for XGBoost classifier with pandas support
XGBoost specific arguments follow https://github.com/dmlc/xgboost/blob/master/python-package/xgboost/sklearn.py
clf : sklearn estimator
sklearn estimator to run
target : str
Target column
target_readable : str
More descriptive version of target variable
included : list str, optional
columns to include
excluded : list str, optional
columns to exclude
id_map : dict (int,str), optional
map of class ids to high level names
sk_args : str, optional
extra args for sklearn classifier
"""
def __init__(self, clf=None,target=None, target_readable=None,included=None,excluded=None,id_map={},vectorizer=None,**sk_args):
super(SKLearnClassifier, self).__init__(target,target_readable,included,excluded,id_map)
self.vectorizer = vectorizer
self.clf = clf
self.sk_args = sk_args
def fit(self,X,y=None):
"""
Fit an sklearn classifier to data
Parameters
----------
X : pandas dataframe or array-like
training samples
y : array like, required for array-like X and not used presently for pandas dataframe
class labels
Returns
-------
self: object
"""
if isinstance(X,pd.DataFrame):
df = X
(X,y,self.vectorizer) = self.convert_numpy(df)
else:
check_X_y(X,y)
self.clf.fit(X,y)
return self
def predict_proba(self,X):
"""
Returns class probability estimates for the given test data.
X : pandas dataframe or array-like
Test samples
Returns
-------
proba : array-like, shape = (n_samples, n_outputs)
Class probability estimates.
"""
if isinstance(X,pd.DataFrame):
df = X
(X,_,_) = self.convert_numpy(df)
else:
check_array(X)
return self.clf.predict_proba(X)
def predict(self,X):
"""
Returns class predictions
X : pandas dataframe or array-like
Test samples
Returns
-------
proba : array-like, shape = (n_samples, n_outputs)
Class predictions
"""
if isinstance(X,pd.DataFrame):
df = X
(X,_,_) = self.convert_numpy(df)
else:
check_array(X)
return self.clf.predict(X)
| apache-2.0 |
alexeyum/scikit-learn | sklearn/feature_selection/tests/test_feature_select.py | 43 | 24671 | """
Todo: cross-check the F-value with stats model
"""
from __future__ import division
import itertools
import warnings
import numpy as np
from scipy import stats, sparse
from numpy.testing import run_module_suite
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_not_in
from sklearn.utils.testing import assert_less
from sklearn.utils.testing import assert_warns
from sklearn.utils.testing import ignore_warnings
from sklearn.utils.testing import assert_warns_message
from sklearn.utils.testing import assert_greater
from sklearn.utils.testing import assert_greater_equal
from sklearn.utils import safe_mask
from sklearn.datasets.samples_generator import (make_classification,
make_regression)
from sklearn.feature_selection import (
chi2, f_classif, f_oneway, f_regression, mutual_info_classif,
mutual_info_regression, SelectPercentile, SelectKBest, SelectFpr,
SelectFdr, SelectFwe, GenericUnivariateSelect)
##############################################################################
# Test the score functions
def test_f_oneway_vs_scipy_stats():
# Test that our f_oneway gives the same result as scipy.stats
rng = np.random.RandomState(0)
X1 = rng.randn(10, 3)
X2 = 1 + rng.randn(10, 3)
f, pv = stats.f_oneway(X1, X2)
f2, pv2 = f_oneway(X1, X2)
assert_true(np.allclose(f, f2))
assert_true(np.allclose(pv, pv2))
def test_f_oneway_ints():
# Smoke test f_oneway on integers: that it does raise casting errors
# with recent numpys
rng = np.random.RandomState(0)
X = rng.randint(10, size=(10, 10))
y = np.arange(10)
fint, pint = f_oneway(X, y)
# test that is gives the same result as with float
f, p = f_oneway(X.astype(np.float), y)
assert_array_almost_equal(f, fint, decimal=4)
assert_array_almost_equal(p, pint, decimal=4)
def test_f_classif():
# Test whether the F test yields meaningful results
# on a simple simulated classification problem
X, y = make_classification(n_samples=200, n_features=20,
n_informative=3, n_redundant=2,
n_repeated=0, n_classes=8,
n_clusters_per_class=1, flip_y=0.0,
class_sep=10, shuffle=False, random_state=0)
F, pv = f_classif(X, y)
F_sparse, pv_sparse = f_classif(sparse.csr_matrix(X), y)
assert_true((F > 0).all())
assert_true((pv > 0).all())
assert_true((pv < 1).all())
assert_true((pv[:5] < 0.05).all())
assert_true((pv[5:] > 1.e-4).all())
assert_array_almost_equal(F_sparse, F)
assert_array_almost_equal(pv_sparse, pv)
def test_f_regression():
# Test whether the F test yields meaningful results
# on a simple simulated regression problem
X, y = make_regression(n_samples=200, n_features=20, n_informative=5,
shuffle=False, random_state=0)
F, pv = f_regression(X, y)
assert_true((F > 0).all())
assert_true((pv > 0).all())
assert_true((pv < 1).all())
assert_true((pv[:5] < 0.05).all())
assert_true((pv[5:] > 1.e-4).all())
# again without centering, compare with sparse
F, pv = f_regression(X, y, center=False)
F_sparse, pv_sparse = f_regression(sparse.csr_matrix(X), y, center=False)
assert_array_almost_equal(F_sparse, F)
assert_array_almost_equal(pv_sparse, pv)
def test_f_regression_input_dtype():
# Test whether f_regression returns the same value
# for any numeric data_type
rng = np.random.RandomState(0)
X = rng.rand(10, 20)
y = np.arange(10).astype(np.int)
F1, pv1 = f_regression(X, y)
F2, pv2 = f_regression(X, y.astype(np.float))
assert_array_almost_equal(F1, F2, 5)
assert_array_almost_equal(pv1, pv2, 5)
def test_f_regression_center():
# Test whether f_regression preserves dof according to 'center' argument
# We use two centered variates so we have a simple relationship between
# F-score with variates centering and F-score without variates centering.
# Create toy example
X = np.arange(-5, 6).reshape(-1, 1) # X has zero mean
n_samples = X.size
Y = np.ones(n_samples)
Y[::2] *= -1.
Y[0] = 0. # have Y mean being null
F1, _ = f_regression(X, Y, center=True)
F2, _ = f_regression(X, Y, center=False)
assert_array_almost_equal(F1 * (n_samples - 1.) / (n_samples - 2.), F2)
assert_almost_equal(F2[0], 0.232558139) # value from statsmodels OLS
def test_f_classif_multi_class():
# Test whether the F test yields meaningful results
# on a simple simulated classification problem
X, y = make_classification(n_samples=200, n_features=20,
n_informative=3, n_redundant=2,
n_repeated=0, n_classes=8,
n_clusters_per_class=1, flip_y=0.0,
class_sep=10, shuffle=False, random_state=0)
F, pv = f_classif(X, y)
assert_true((F > 0).all())
assert_true((pv > 0).all())
assert_true((pv < 1).all())
assert_true((pv[:5] < 0.05).all())
assert_true((pv[5:] > 1.e-4).all())
def test_select_percentile_classif():
# Test whether the relative univariate feature selection
# gets the correct items in a simple classification problem
# with the percentile heuristic
X, y = make_classification(n_samples=200, n_features=20,
n_informative=3, n_redundant=2,
n_repeated=0, n_classes=8,
n_clusters_per_class=1, flip_y=0.0,
class_sep=10, shuffle=False, random_state=0)
univariate_filter = SelectPercentile(f_classif, percentile=25)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(f_classif, mode='percentile',
param=25).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(20)
gtruth[:5] = 1
assert_array_equal(support, gtruth)
def test_select_percentile_classif_sparse():
# Test whether the relative univariate feature selection
# gets the correct items in a simple classification problem
# with the percentile heuristic
X, y = make_classification(n_samples=200, n_features=20,
n_informative=3, n_redundant=2,
n_repeated=0, n_classes=8,
n_clusters_per_class=1, flip_y=0.0,
class_sep=10, shuffle=False, random_state=0)
X = sparse.csr_matrix(X)
univariate_filter = SelectPercentile(f_classif, percentile=25)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(f_classif, mode='percentile',
param=25).fit(X, y).transform(X)
assert_array_equal(X_r.toarray(), X_r2.toarray())
support = univariate_filter.get_support()
gtruth = np.zeros(20)
gtruth[:5] = 1
assert_array_equal(support, gtruth)
X_r2inv = univariate_filter.inverse_transform(X_r2)
assert_true(sparse.issparse(X_r2inv))
support_mask = safe_mask(X_r2inv, support)
assert_equal(X_r2inv.shape, X.shape)
assert_array_equal(X_r2inv[:, support_mask].toarray(), X_r.toarray())
# Check other columns are empty
assert_equal(X_r2inv.getnnz(), X_r.getnnz())
##############################################################################
# Test univariate selection in classification settings
def test_select_kbest_classif():
# Test whether the relative univariate feature selection
# gets the correct items in a simple classification problem
# with the k best heuristic
X, y = make_classification(n_samples=200, n_features=20,
n_informative=3, n_redundant=2,
n_repeated=0, n_classes=8,
n_clusters_per_class=1, flip_y=0.0,
class_sep=10, shuffle=False, random_state=0)
univariate_filter = SelectKBest(f_classif, k=5)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(
f_classif, mode='k_best', param=5).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(20)
gtruth[:5] = 1
assert_array_equal(support, gtruth)
def test_select_kbest_all():
# Test whether k="all" correctly returns all features.
X, y = make_classification(n_samples=20, n_features=10,
shuffle=False, random_state=0)
univariate_filter = SelectKBest(f_classif, k='all')
X_r = univariate_filter.fit(X, y).transform(X)
assert_array_equal(X, X_r)
def test_select_kbest_zero():
# Test whether k=0 correctly returns no features.
X, y = make_classification(n_samples=20, n_features=10,
shuffle=False, random_state=0)
univariate_filter = SelectKBest(f_classif, k=0)
univariate_filter.fit(X, y)
support = univariate_filter.get_support()
gtruth = np.zeros(10, dtype=bool)
assert_array_equal(support, gtruth)
X_selected = assert_warns_message(UserWarning, 'No features were selected',
univariate_filter.transform, X)
assert_equal(X_selected.shape, (20, 0))
def test_select_heuristics_classif():
# Test whether the relative univariate feature selection
# gets the correct items in a simple classification problem
# with the fdr, fwe and fpr heuristics
X, y = make_classification(n_samples=200, n_features=20,
n_informative=3, n_redundant=2,
n_repeated=0, n_classes=8,
n_clusters_per_class=1, flip_y=0.0,
class_sep=10, shuffle=False, random_state=0)
univariate_filter = SelectFwe(f_classif, alpha=0.01)
X_r = univariate_filter.fit(X, y).transform(X)
gtruth = np.zeros(20)
gtruth[:5] = 1
for mode in ['fdr', 'fpr', 'fwe']:
X_r2 = GenericUnivariateSelect(
f_classif, mode=mode, param=0.01).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
assert_array_almost_equal(support, gtruth)
##############################################################################
# Test univariate selection in regression settings
def assert_best_scores_kept(score_filter):
scores = score_filter.scores_
support = score_filter.get_support()
assert_array_equal(np.sort(scores[support]),
np.sort(scores)[-support.sum():])
def test_select_percentile_regression():
# Test whether the relative univariate feature selection
# gets the correct items in a simple regression problem
# with the percentile heuristic
X, y = make_regression(n_samples=200, n_features=20,
n_informative=5, shuffle=False, random_state=0)
univariate_filter = SelectPercentile(f_regression, percentile=25)
X_r = univariate_filter.fit(X, y).transform(X)
assert_best_scores_kept(univariate_filter)
X_r2 = GenericUnivariateSelect(
f_regression, mode='percentile', param=25).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(20)
gtruth[:5] = 1
assert_array_equal(support, gtruth)
X_2 = X.copy()
X_2[:, np.logical_not(support)] = 0
assert_array_equal(X_2, univariate_filter.inverse_transform(X_r))
# Check inverse_transform respects dtype
assert_array_equal(X_2.astype(bool),
univariate_filter.inverse_transform(X_r.astype(bool)))
def test_select_percentile_regression_full():
# Test whether the relative univariate feature selection
# selects all features when '100%' is asked.
X, y = make_regression(n_samples=200, n_features=20,
n_informative=5, shuffle=False, random_state=0)
univariate_filter = SelectPercentile(f_regression, percentile=100)
X_r = univariate_filter.fit(X, y).transform(X)
assert_best_scores_kept(univariate_filter)
X_r2 = GenericUnivariateSelect(
f_regression, mode='percentile', param=100).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.ones(20)
assert_array_equal(support, gtruth)
def test_invalid_percentile():
X, y = make_regression(n_samples=10, n_features=20,
n_informative=2, shuffle=False, random_state=0)
assert_raises(ValueError, SelectPercentile(percentile=-1).fit, X, y)
assert_raises(ValueError, SelectPercentile(percentile=101).fit, X, y)
assert_raises(ValueError, GenericUnivariateSelect(mode='percentile',
param=-1).fit, X, y)
assert_raises(ValueError, GenericUnivariateSelect(mode='percentile',
param=101).fit, X, y)
def test_select_kbest_regression():
# Test whether the relative univariate feature selection
# gets the correct items in a simple regression problem
# with the k best heuristic
X, y = make_regression(n_samples=200, n_features=20, n_informative=5,
shuffle=False, random_state=0, noise=10)
univariate_filter = SelectKBest(f_regression, k=5)
X_r = univariate_filter.fit(X, y).transform(X)
assert_best_scores_kept(univariate_filter)
X_r2 = GenericUnivariateSelect(
f_regression, mode='k_best', param=5).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(20)
gtruth[:5] = 1
assert_array_equal(support, gtruth)
def test_select_heuristics_regression():
# Test whether the relative univariate feature selection
# gets the correct items in a simple regression problem
# with the fpr, fdr or fwe heuristics
X, y = make_regression(n_samples=200, n_features=20, n_informative=5,
shuffle=False, random_state=0, noise=10)
univariate_filter = SelectFpr(f_regression, alpha=0.01)
X_r = univariate_filter.fit(X, y).transform(X)
gtruth = np.zeros(20)
gtruth[:5] = 1
for mode in ['fdr', 'fpr', 'fwe']:
X_r2 = GenericUnivariateSelect(
f_regression, mode=mode, param=0.01).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
assert_array_equal(support[:5], np.ones((5, ), dtype=np.bool))
assert_less(np.sum(support[5:] == 1), 3)
def test_select_fdr_regression():
# Test that fdr heuristic actually has low FDR.
def single_fdr(alpha, n_informative, random_state):
X, y = make_regression(n_samples=150, n_features=20,
n_informative=n_informative, shuffle=False,
random_state=random_state, noise=10)
with warnings.catch_warnings(record=True):
# Warnings can be raised when no features are selected
# (low alpha or very noisy data)
univariate_filter = SelectFdr(f_regression, alpha=alpha)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(
f_regression, mode='fdr', param=alpha).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
num_false_positives = np.sum(support[n_informative:] == 1)
num_true_positives = np.sum(support[:n_informative] == 1)
if num_false_positives == 0:
return 0.
false_discovery_rate = (num_false_positives /
(num_true_positives + num_false_positives))
return false_discovery_rate
for alpha in [0.001, 0.01, 0.1]:
for n_informative in [1, 5, 10]:
# As per Benjamini-Hochberg, the expected false discovery rate
# should be lower than alpha:
# FDR = E(FP / (TP + FP)) <= alpha
false_discovery_rate = np.mean([single_fdr(alpha, n_informative,
random_state) for
random_state in range(30)])
assert_greater_equal(alpha, false_discovery_rate)
# Make sure that the empirical false discovery rate increases
# with alpha:
if false_discovery_rate != 0:
assert_greater(false_discovery_rate, alpha / 10)
def test_select_fwe_regression():
# Test whether the relative univariate feature selection
# gets the correct items in a simple regression problem
# with the fwe heuristic
X, y = make_regression(n_samples=200, n_features=20,
n_informative=5, shuffle=False, random_state=0)
univariate_filter = SelectFwe(f_regression, alpha=0.01)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(
f_regression, mode='fwe', param=0.01).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(20)
gtruth[:5] = 1
assert_array_equal(support[:5], np.ones((5, ), dtype=np.bool))
assert_less(np.sum(support[5:] == 1), 2)
def test_selectkbest_tiebreaking():
# Test whether SelectKBest actually selects k features in case of ties.
# Prior to 0.11, SelectKBest would return more features than requested.
Xs = [[0, 1, 1], [0, 0, 1], [1, 0, 0], [1, 1, 0]]
y = [1]
dummy_score = lambda X, y: (X[0], X[0])
for X in Xs:
sel = SelectKBest(dummy_score, k=1)
X1 = ignore_warnings(sel.fit_transform)([X], y)
assert_equal(X1.shape[1], 1)
assert_best_scores_kept(sel)
sel = SelectKBest(dummy_score, k=2)
X2 = ignore_warnings(sel.fit_transform)([X], y)
assert_equal(X2.shape[1], 2)
assert_best_scores_kept(sel)
def test_selectpercentile_tiebreaking():
# Test if SelectPercentile selects the right n_features in case of ties.
Xs = [[0, 1, 1], [0, 0, 1], [1, 0, 0], [1, 1, 0]]
y = [1]
dummy_score = lambda X, y: (X[0], X[0])
for X in Xs:
sel = SelectPercentile(dummy_score, percentile=34)
X1 = ignore_warnings(sel.fit_transform)([X], y)
assert_equal(X1.shape[1], 1)
assert_best_scores_kept(sel)
sel = SelectPercentile(dummy_score, percentile=67)
X2 = ignore_warnings(sel.fit_transform)([X], y)
assert_equal(X2.shape[1], 2)
assert_best_scores_kept(sel)
def test_tied_pvalues():
# Test whether k-best and percentiles work with tied pvalues from chi2.
# chi2 will return the same p-values for the following features, but it
# will return different scores.
X0 = np.array([[10000, 9999, 9998], [1, 1, 1]])
y = [0, 1]
for perm in itertools.permutations((0, 1, 2)):
X = X0[:, perm]
Xt = SelectKBest(chi2, k=2).fit_transform(X, y)
assert_equal(Xt.shape, (2, 2))
assert_not_in(9998, Xt)
Xt = SelectPercentile(chi2, percentile=67).fit_transform(X, y)
assert_equal(Xt.shape, (2, 2))
assert_not_in(9998, Xt)
def test_tied_scores():
# Test for stable sorting in k-best with tied scores.
X_train = np.array([[0, 0, 0], [1, 1, 1]])
y_train = [0, 1]
for n_features in [1, 2, 3]:
sel = SelectKBest(chi2, k=n_features).fit(X_train, y_train)
X_test = sel.transform([[0, 1, 2]])
assert_array_equal(X_test[0], np.arange(3)[-n_features:])
def test_nans():
# Assert that SelectKBest and SelectPercentile can handle NaNs.
# First feature has zero variance to confuse f_classif (ANOVA) and
# make it return a NaN.
X = [[0, 1, 0], [0, -1, -1], [0, .5, .5]]
y = [1, 0, 1]
for select in (SelectKBest(f_classif, 2),
SelectPercentile(f_classif, percentile=67)):
ignore_warnings(select.fit)(X, y)
assert_array_equal(select.get_support(indices=True), np.array([1, 2]))
def test_score_func_error():
X = [[0, 1, 0], [0, -1, -1], [0, .5, .5]]
y = [1, 0, 1]
for SelectFeatures in [SelectKBest, SelectPercentile, SelectFwe,
SelectFdr, SelectFpr, GenericUnivariateSelect]:
assert_raises(TypeError, SelectFeatures(score_func=10).fit, X, y)
def test_invalid_k():
X = [[0, 1, 0], [0, -1, -1], [0, .5, .5]]
y = [1, 0, 1]
assert_raises(ValueError, SelectKBest(k=-1).fit, X, y)
assert_raises(ValueError, SelectKBest(k=4).fit, X, y)
assert_raises(ValueError,
GenericUnivariateSelect(mode='k_best', param=-1).fit, X, y)
assert_raises(ValueError,
GenericUnivariateSelect(mode='k_best', param=4).fit, X, y)
def test_f_classif_constant_feature():
# Test that f_classif warns if a feature is constant throughout.
X, y = make_classification(n_samples=10, n_features=5)
X[:, 0] = 2.0
assert_warns(UserWarning, f_classif, X, y)
def test_no_feature_selected():
rng = np.random.RandomState(0)
# Generate random uncorrelated data: a strict univariate test should
# rejects all the features
X = rng.rand(40, 10)
y = rng.randint(0, 4, size=40)
strict_selectors = [
SelectFwe(alpha=0.01).fit(X, y),
SelectFdr(alpha=0.01).fit(X, y),
SelectFpr(alpha=0.01).fit(X, y),
SelectPercentile(percentile=0).fit(X, y),
SelectKBest(k=0).fit(X, y),
]
for selector in strict_selectors:
assert_array_equal(selector.get_support(), np.zeros(10))
X_selected = assert_warns_message(
UserWarning, 'No features were selected', selector.transform, X)
assert_equal(X_selected.shape, (40, 0))
def test_mutual_info_classif():
X, y = make_classification(n_samples=100, n_features=5,
n_informative=1, n_redundant=1,
n_repeated=0, n_classes=2,
n_clusters_per_class=1, flip_y=0.0,
class_sep=10, shuffle=False, random_state=0)
# Test in KBest mode.
univariate_filter = SelectKBest(mutual_info_classif, k=2)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(
mutual_info_classif, mode='k_best', param=2).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(5)
gtruth[:2] = 1
assert_array_equal(support, gtruth)
# Test in Percentile mode.
univariate_filter = SelectPercentile(mutual_info_classif, percentile=40)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(
mutual_info_classif, mode='percentile', param=40).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(5)
gtruth[:2] = 1
assert_array_equal(support, gtruth)
def test_mutual_info_regression():
X, y = make_regression(n_samples=100, n_features=10, n_informative=2,
shuffle=False, random_state=0, noise=10)
# Test in KBest mode.
univariate_filter = SelectKBest(mutual_info_regression, k=2)
X_r = univariate_filter.fit(X, y).transform(X)
assert_best_scores_kept(univariate_filter)
X_r2 = GenericUnivariateSelect(
mutual_info_regression, mode='k_best', param=2).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(10)
gtruth[:2] = 1
assert_array_equal(support, gtruth)
# Test in Percentile mode.
univariate_filter = SelectPercentile(mutual_info_regression, percentile=20)
X_r = univariate_filter.fit(X, y).transform(X)
X_r2 = GenericUnivariateSelect(mutual_info_regression, mode='percentile',
param=20).fit(X, y).transform(X)
assert_array_equal(X_r, X_r2)
support = univariate_filter.get_support()
gtruth = np.zeros(10)
gtruth[:2] = 1
assert_array_equal(support, gtruth)
if __name__ == '__main__':
run_module_suite()
| bsd-3-clause |
shangwuhencc/scikit-learn | sklearn/utils/tests/test_testing.py | 107 | 4210 | import warnings
import unittest
import sys
from nose.tools import assert_raises
from sklearn.utils.testing import (
_assert_less,
_assert_greater,
assert_less_equal,
assert_greater_equal,
assert_warns,
assert_no_warnings,
assert_equal,
set_random_state,
assert_raise_message)
from sklearn.tree import DecisionTreeClassifier
from sklearn.discriminant_analysis import LinearDiscriminantAnalysis
try:
from nose.tools import assert_less
def test_assert_less():
# Check that the nose implementation of assert_less gives the
# same thing as the scikit's
assert_less(0, 1)
_assert_less(0, 1)
assert_raises(AssertionError, assert_less, 1, 0)
assert_raises(AssertionError, _assert_less, 1, 0)
except ImportError:
pass
try:
from nose.tools import assert_greater
def test_assert_greater():
# Check that the nose implementation of assert_less gives the
# same thing as the scikit's
assert_greater(1, 0)
_assert_greater(1, 0)
assert_raises(AssertionError, assert_greater, 0, 1)
assert_raises(AssertionError, _assert_greater, 0, 1)
except ImportError:
pass
def test_assert_less_equal():
assert_less_equal(0, 1)
assert_less_equal(1, 1)
assert_raises(AssertionError, assert_less_equal, 1, 0)
def test_assert_greater_equal():
assert_greater_equal(1, 0)
assert_greater_equal(1, 1)
assert_raises(AssertionError, assert_greater_equal, 0, 1)
def test_set_random_state():
lda = LinearDiscriminantAnalysis()
tree = DecisionTreeClassifier()
# Linear Discriminant Analysis doesn't have random state: smoke test
set_random_state(lda, 3)
set_random_state(tree, 3)
assert_equal(tree.random_state, 3)
def test_assert_raise_message():
def _raise_ValueError(message):
raise ValueError(message)
def _no_raise():
pass
assert_raise_message(ValueError, "test",
_raise_ValueError, "test")
assert_raises(AssertionError,
assert_raise_message, ValueError, "something else",
_raise_ValueError, "test")
assert_raises(ValueError,
assert_raise_message, TypeError, "something else",
_raise_ValueError, "test")
assert_raises(AssertionError,
assert_raise_message, ValueError, "test",
_no_raise)
# multiple exceptions in a tuple
assert_raises(AssertionError,
assert_raise_message, (ValueError, AttributeError),
"test", _no_raise)
# This class is inspired from numpy 1.7 with an alteration to check
# the reset warning filters after calls to assert_warns.
# This assert_warns behavior is specific to scikit-learn because
#`clean_warning_registry()` is called internally by assert_warns
# and clears all previous filters.
class TestWarns(unittest.TestCase):
def test_warn(self):
def f():
warnings.warn("yo")
return 3
# Test that assert_warns is not impacted by externally set
# filters and is reset internally.
# This is because `clean_warning_registry()` is called internally by
# assert_warns and clears all previous filters.
warnings.simplefilter("ignore", UserWarning)
assert_equal(assert_warns(UserWarning, f), 3)
# Test that the warning registry is empty after assert_warns
assert_equal(sys.modules['warnings'].filters, [])
assert_raises(AssertionError, assert_no_warnings, f)
assert_equal(assert_no_warnings(lambda x: x, 1), 1)
def test_warn_wrong_warning(self):
def f():
warnings.warn("yo", DeprecationWarning)
failed = False
filters = sys.modules['warnings'].filters[:]
try:
try:
# Should raise an AssertionError
assert_warns(UserWarning, f)
failed = True
except AssertionError:
pass
finally:
sys.modules['warnings'].filters = filters
if failed:
raise AssertionError("wrong warning caught by assert_warn")
| bsd-3-clause |
hammerlab/cohorts | cohorts/plot.py | 1 | 10847 | # Copyright (c) 2017. Mount Sinai School of Medicine
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from collections import namedtuple
from scipy.stats import mannwhitneyu, fisher_exact
import seaborn as sb
import pandas as pd
import matplotlib.pyplot as plt
from sklearn.metrics import roc_curve
from .model import bootstrap_auc
def vertical_percent(plot, percent=0.1):
"""
Using the size of the y axis, return a fraction of that size.
"""
plot_bottom, plot_top = plot.get_ylim()
return percent * (plot_top - plot_bottom)
def as_numeric(text):
try:
return float(text)
except:
return None
def hide_ticks(plot, min_tick_value=None, max_tick_value=None):
"""Hide tick values that are outside of [min_tick_value, max_tick_value]"""
for tick, tick_value in zip(plot.get_yticklabels(), plot.get_yticks()):
tick_label = as_numeric(tick_value)
if tick_label:
if (min_tick_value is not None and tick_label < min_tick_value or
max_tick_value is not None and tick_label > max_tick_value):
tick.set_visible(False)
def hide_negative_y_ticks(plot):
hide_ticks(plot, min_tick_value=0)
def only_percentage_ticks(plot):
"""
Only show ticks from 0.0 to 1.0.
"""
hide_ticks(plot, min_tick_value=0, max_tick_value=1.0)
def add_significance_indicator(plot, col_a=0, col_b=1, significant=False):
"""
Add a p-value significance indicator.
"""
plot_bottom, plot_top = plot.get_ylim()
# Give the plot a little room for the significance indicator
line_height = vertical_percent(plot, 0.1)
# Add some extra spacing below the indicator
plot_top = plot_top + line_height
# Add some extra spacing above the indicator
plot.set_ylim(top=plot_top + line_height * 2)
color = "black"
line_top = plot_top + line_height
plot.plot([col_a, col_a, col_b, col_b], [plot_top, line_top, line_top, plot_top], lw=1.5, color=color)
indicator = "*" if significant else "ns"
plot.text((col_a + col_b) * 0.5, line_top, indicator, ha="center", va="bottom", color=color)
def stripboxplot(x, y, data, ax=None, significant=None, **kwargs):
"""
Overlay a stripplot on top of a boxplot.
"""
ax = sb.boxplot(
x=x,
y=y,
data=data,
ax=ax,
fliersize=0,
**kwargs
)
plot = sb.stripplot(
x=x,
y=y,
data=data,
ax=ax,
jitter=kwargs.pop("jitter", 0.05),
color=kwargs.pop("color", "0.3"),
**kwargs
)
if data[y].min() >= 0:
hide_negative_y_ticks(plot)
if significant is not None:
add_significance_indicator(plot=plot, significant=significant)
return plot
def sided_str_from_alternative(alternative, condition):
if alternative is None:
raise ValueError("Must pick an alternative")
if alternative == "two-sided":
return alternative
# alternative hypothesis: condition is 'less' or 'greater' than no-condition
op_str = ">" if alternative == "greater" else "<"
return "one-sided: %s %s not %s" % (condition, op_str, condition)
def get_condition_mask(df, condition, condition_value):
if condition_value:
condition_mask = df[condition] == condition_value
else:
# This is necessary in the event that condition has a non-bool dtype,
# such as object. This may happen if a function returns np.nan in
# addition to True/False (later filtered down to just True/False).
# ~condition_mask will behave incorrectly if dtype is not bool.
condition_mask = df[condition].astype("bool")
return condition_mask
class FishersExactResults(namedtuple("FishersExactResults", ["oddsratio", "p_value", "sided_str", "with_condition1_series", "without_condition1_series", "plot"])):
def __str__(self):
return "FishersExactResults(oddsratio=%s, p_value=%s, sided_str='%s')" % (
self.oddsratio, self.p_value, self.sided_str)
def __repr__(self):
return self.__str__()
def fishers_exact_plot(data, condition1, condition2, ax=None,
condition1_value=None,
alternative="two-sided", **kwargs):
"""
Perform a Fisher's exact test to compare to binary columns
Parameters
----------
data: Pandas dataframe
Dataframe to retrieve information from
condition1: str
First binary column to compare (and used for test sidedness)
condition2: str
Second binary column to compare
ax : Axes, default None
Axes to plot on
condition1_value:
If `condition1` is not a binary column, split on =/!= to condition1_value
alternative:
Specify the sidedness of the test: "two-sided", "less"
or "greater"
"""
plot = sb.barplot(
x=condition1,
y=condition2,
ax=ax,
data=data,
**kwargs
)
plot.set_ylabel("Percent %s" % condition2)
condition1_mask = get_condition_mask(data, condition1, condition1_value)
count_table = pd.crosstab(data[condition1], data[condition2])
print(count_table)
oddsratio, p_value = fisher_exact(count_table, alternative=alternative)
add_significance_indicator(plot=plot, significant=p_value <= 0.05)
only_percentage_ticks(plot)
if alternative != "two-sided":
raise ValueError("We need to better understand the one-sided Fisher's Exact test")
sided_str = "two-sided"
print("Fisher's Exact Test: OR: {}, p-value={} ({})".format(oddsratio, p_value, sided_str))
return FishersExactResults(oddsratio=oddsratio,
p_value=p_value,
sided_str=sided_str,
with_condition1_series=data[condition1_mask][condition2],
without_condition1_series=data[~condition1_mask][condition2],
plot=plot)
class MannWhitneyResults(namedtuple("MannWhitneyResults", ["U", "p_value", "sided_str", "with_condition_series", "without_condition_series", "plot"])):
def __str__(self):
return "MannWhitneyResults(U=%s, p_value=%s, sided_str='%s')" % (
self.U, self.p_value, self.sided_str)
def __repr__(self):
return self.__str__()
def mann_whitney_plot(data,
condition,
distribution,
ax=None,
condition_value=None,
alternative="two-sided",
skip_plot=False,
**kwargs):
"""
Create a box plot comparing a condition and perform a
Mann Whitney test to compare the distribution in condition A v B
Parameters
----------
data: Pandas dataframe
Dataframe to retrieve information from
condition: str
Column to use as the splitting criteria
distribution: str
Column to use as the Y-axis or distribution in the test
ax : Axes, default None
Axes to plot on
condition_value:
If `condition` is not a binary column, split on =/!= to condition_value
alternative:
Specify the sidedness of the Mann-Whitney test: "two-sided", "less"
or "greater"
skip_plot:
Calculate the test statistic and p-value, but don't plot.
"""
condition_mask = get_condition_mask(data, condition, condition_value)
U, p_value = mannwhitneyu(
data[condition_mask][distribution],
data[~condition_mask][distribution],
alternative=alternative
)
plot = None
if not skip_plot:
plot = stripboxplot(
x=condition,
y=distribution,
data=data,
ax=ax,
significant=p_value <= 0.05,
**kwargs
)
sided_str = sided_str_from_alternative(alternative, condition)
print("Mann-Whitney test: U={}, p-value={} ({})".format(U, p_value, sided_str))
return MannWhitneyResults(U=U,
p_value=p_value,
sided_str=sided_str,
with_condition_series=data[condition_mask][distribution],
without_condition_series=data[~condition_mask][distribution],
plot=plot)
class CorrelationResults(namedtuple("CorrelationResults", ["coeff", "p_value", "stat_func", "series_x", "series_y", "plot"])):
def __str__(self):
return "CorrelationResults(coeff=%s, p_value=%s, stat_func=%s)" % (
self.coeff, self.p_value, self.stat_func.__name__)
def __repr__(self):
return self.__str__()
def roc_curve_plot(data, value_column, outcome_column, bootstrap_samples=100, ax=None):
"""Create a ROC curve and compute the bootstrap AUC for the given variable and outcome
Parameters
----------
data : Pandas dataframe
Dataframe to retrieve information from
value_column : str
Column to retrieve the values from
outcome_column : str
Column to use as the outcome variable
bootstrap_samples : int, optional
Number of bootstrap samples to use to compute the AUC
ax : Axes, default None
Axes to plot on
Returns
-------
(mean_bootstrap_auc, roc_plot) : (float, matplotlib plot)
Mean AUC for the given number of bootstrap samples and the plot
"""
scores = bootstrap_auc(df=data,
col=value_column,
pred_col=outcome_column,
n_bootstrap=bootstrap_samples)
mean_bootstrap_auc = scores.mean()
print("{}, Bootstrap (samples = {}) AUC:{}, std={}".format(
value_column, bootstrap_samples, mean_bootstrap_auc, scores.std()))
outcome = data[outcome_column].astype(int)
values = data[value_column]
fpr, tpr, thresholds = roc_curve(outcome, values)
if ax is None:
ax = plt.gca()
roc_plot = ax.plot(fpr, tpr, lw=1, label=value_column)
ax.set_xlim([-0.05, 1.05])
ax.set_ylim([-0.05, 1.05])
ax.set_xlabel('False Positive Rate')
ax.set_ylabel('True Positive Rate')
ax.legend(loc=2, borderaxespad=0.)
ax.set_title('{} ROC Curve (n={})'.format(value_column, len(values)))
return (mean_bootstrap_auc, roc_plot)
| apache-2.0 |
466152112/scikit-learn | examples/covariance/plot_lw_vs_oas.py | 248 | 2903 | """
=============================
Ledoit-Wolf vs OAS estimation
=============================
The usual covariance maximum likelihood estimate can be regularized
using shrinkage. Ledoit and Wolf proposed a close formula to compute
the asymptotically optimal shrinkage parameter (minimizing a MSE
criterion), yielding the Ledoit-Wolf covariance estimate.
Chen et al. proposed an improvement of the Ledoit-Wolf shrinkage
parameter, the OAS coefficient, whose convergence is significantly
better under the assumption that the data are Gaussian.
This example, inspired from Chen's publication [1], shows a comparison
of the estimated MSE of the LW and OAS methods, using Gaussian
distributed data.
[1] "Shrinkage Algorithms for MMSE Covariance Estimation"
Chen et al., IEEE Trans. on Sign. Proc., Volume 58, Issue 10, October 2010.
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from scipy.linalg import toeplitz, cholesky
from sklearn.covariance import LedoitWolf, OAS
np.random.seed(0)
###############################################################################
n_features = 100
# simulation covariance matrix (AR(1) process)
r = 0.1
real_cov = toeplitz(r ** np.arange(n_features))
coloring_matrix = cholesky(real_cov)
n_samples_range = np.arange(6, 31, 1)
repeat = 100
lw_mse = np.zeros((n_samples_range.size, repeat))
oa_mse = np.zeros((n_samples_range.size, repeat))
lw_shrinkage = np.zeros((n_samples_range.size, repeat))
oa_shrinkage = np.zeros((n_samples_range.size, repeat))
for i, n_samples in enumerate(n_samples_range):
for j in range(repeat):
X = np.dot(
np.random.normal(size=(n_samples, n_features)), coloring_matrix.T)
lw = LedoitWolf(store_precision=False, assume_centered=True)
lw.fit(X)
lw_mse[i, j] = lw.error_norm(real_cov, scaling=False)
lw_shrinkage[i, j] = lw.shrinkage_
oa = OAS(store_precision=False, assume_centered=True)
oa.fit(X)
oa_mse[i, j] = oa.error_norm(real_cov, scaling=False)
oa_shrinkage[i, j] = oa.shrinkage_
# plot MSE
plt.subplot(2, 1, 1)
plt.errorbar(n_samples_range, lw_mse.mean(1), yerr=lw_mse.std(1),
label='Ledoit-Wolf', color='g')
plt.errorbar(n_samples_range, oa_mse.mean(1), yerr=oa_mse.std(1),
label='OAS', color='r')
plt.ylabel("Squared error")
plt.legend(loc="upper right")
plt.title("Comparison of covariance estimators")
plt.xlim(5, 31)
# plot shrinkage coefficient
plt.subplot(2, 1, 2)
plt.errorbar(n_samples_range, lw_shrinkage.mean(1), yerr=lw_shrinkage.std(1),
label='Ledoit-Wolf', color='g')
plt.errorbar(n_samples_range, oa_shrinkage.mean(1), yerr=oa_shrinkage.std(1),
label='OAS', color='r')
plt.xlabel("n_samples")
plt.ylabel("Shrinkage")
plt.legend(loc="lower right")
plt.ylim(plt.ylim()[0], 1. + (plt.ylim()[1] - plt.ylim()[0]) / 10.)
plt.xlim(5, 31)
plt.show()
| bsd-3-clause |
WmHHooper/aima-python | submissions/Marszalkowski/myKMeans.py | 1 | 3040 | from sklearn import preprocessing
import matplotlib.pyplot as plt
import numpy as np
nbaPGData = [
[ 15.8, 8.2, 8.1, 1.7 ],
[ 25.4, 10.3, 10.1, 1.8 ],
[ 22.1, 5.6, 3.1, 1.1 ],
[ 16.7, 3.4, 3.7, 1.0 ],
[ 16.2, 6.9, 5.6, 1.1 ],
[ 13.1, 5.3, 4.6, 1.6 ],
[ 17.3, 4.8, 4.1, 0.8 ],
[ 17.7, 5.0, 3.8, 2.0 ],
[ 26.9, 6.6, 4.5, 1.1 ],
[ 14.2, 7.0, 3.0, 1.5 ],
[ 15.2, 5.2, 3.8, 1.0 ],
[ 19.4, 6.2, 3.1, 1.1 ],
[ 12.4, 5.3, 2.6, 1.3 ],
[ 12.7, 6.2, 4.3, 1.3 ],
[ 8.3, 8.2, 4.0, 1.1 ],
[ 24.4, 5.1, 3.8, 1.1 ],
[ 11.6, 4.4, 2.8, 1.0 ],
[ 10.0, 2.8, 2.7, 0.9 ],
[ 18.6, 7.9, 5.4, 1.7 ],
[ 12.6, 6.6, 3.2, 0.9 ],
[ 7.5, 5.6, 3.1, 0.6 ],
[ 26.4, 6.1, 5.1, 1.6 ],
[ 10.2, 7.2, 6.9, 1.7 ],
[ 8.1, 2.9, 5.7, 1.2 ],
[ 9.5, 3.2, 2.3, 0.7 ],
[ 14.6, 5.3, 2.8, 0.6 ],
[ 13.4, 6.0, 4.3, 2.0 ],
[ 7.8, 4.4, 1.8, 1.0 ],
[ 19.4, 9.6, 3.7, 1.4 ],
[ 15.3, 7.8, 4.0, 1.2 ],
[ 29.1, 11.2, 8.1, 1.5 ],
[ 31.6, 10.4, 10.7, 1.6 ],
[ 25.3, 6.6, 4.5, 1.8 ],
[ 23.2, 5.5, 3.9, 1.1 ],
[ 17.9, 6.3, 3.1, 0.9 ],
[ 23.1, 10.7, 4.2, 2.0 ],
[ 28.9, 5.9, 2.7, 0.9 ],
[ 27.0, 5.9, 4.9, 0.9 ],
[ 11.1, 9.1, 4.1, 1.7 ],
[ 20.3, 5.8, 3.8, 1.2 ],
[ 25.2, 5.8, 3.2, 1.2 ],
[ 20.5, 6.3, 3.5, 1.3 ],
[ 21.1, 6.3, 4.8, 1.4 ],
[ 13.2, 4.6, 2.2, 1.0 ],
[ 18.0, 4.4, 3.8, 0.7 ],
[ 10.1, 4.5, 1.8, 0.5 ],
[ 15.4, 7.3, 3.9, 1.5 ],
[ 18.1, 9.2, 5.0, 2.0 ],
[ 22.4, 7.0, 4.8, 1.5 ],
[ 15.6, 4.8, 3.5, 1.4 ],
[ 12.8, 6.5, 4.7, 1.1 ],
[ 7.6, 4.7, 1.9, 0.7 ],
[ 6.9, 6.6, 3.1, 1.7 ],
[ 14.5, 5.2, 2.2, 0.7 ],
[ 16.9, 4.2, 3.4, 1.0 ],
[ 11.0, 5.6, 2.3, 0.5 ],
[ 12.8, 2.7, 2.6, 1.1 ],
[ 7.8, 6.7, 5.1, 1.4 ],
[ 11.0, 3.9, 3.2, 0.7 ],
[ 20.9, 5.2, 4.4, 1.6 ],
[ 23.5, 10.4, 7.8, 2.0 ],
[ 16.9, 4.3, 7.7, 1.2 ],
[ 30.1, 6.7, 5.4, 2.1 ],
[ 18.8, 6.2, 3.0, 1.1 ],
[ 22.2, 6.2, 3.0, 1.1 ],
[ 15.7, 5.9, 2.7, 1.2 ],
[ 21.2, 6.4, 4.7, 2.1 ],
[ 19.9, 10.2, 4.9, 1.9 ],
[ 10.1, 8.7, 4.3, 2.1 ],
[ 25.1, 6.8, 4.0, 0.9 ],
[ 19.5, 10.0, 4.2, 2.1 ],
[ 12.1, 3.5, 4.0, 1.1 ],
[ 19.0, 4.6, 4.1, 1.1 ],
[ 7.6, 4.1, 3.2, 0.9 ],
[ 14.1, 5.8, 3.8, 1.0 ],
[ 11.9, 5.3, 2.4, 0.8 ],
[ 11.9, 11.7, 6.0, 2.0 ],
[ 10.7, 6.4, 3.6, 1.2 ],
[ 12.8, 5.5, 3.4, 1.0 ],
[ 16.4, 4.7, 3.4, 0.7 ],
[ 9.9, 3.4, 3.5, 1.3 ],
[ 14.1, 5.8, 2.9, 0.9 ],
[ 15.3, 6.1, 2.9, 1.2 ],
[ 19.6, 4.7, 3.0, 1.1 ],
[ 12.6, 6.5, 4.0, 3.4 ],
[ 13.2, 3.3, 3.4, 1.2 ],
[ 10.3, 5.4, 2.2, 0.5 ],
[ 15.6, 10.2, 4.3, 1.3 ],
[ 12.2, 6.4, 3.4, 1.5 ],
[ 17.6, 5.6, 4.0, 1.2 ],
[ 15.5, 7.9, 8.7, 1.4 ],
[ 15.9, 7.6, 3.0, 0.7 ],
[ 15.0, 6.0, 4.5, 1.3 ],
[ 9.0, 4.8, 2.3, 1.5 ],
[ 12.6, 2.3, 1.8, 0.7 ],
[ 27.1, 6.0, 5.3, 0.8 ],
[ 27.4, 6.3, 4.3, 1.3 ],
[ 21.5, 8.1, 3.6, 1.7 ],
[ 20.3, 6.6, 3.4, 1.2 ],
[ 17.5, 7.5, 4.0, 1.2 ],
[ 22.0, 6.4, 4.9, 1.9 ],
[ 17.5, 4.5, 4.3, 0.9 ],
[ 8.2, 4.5, 5.6, 1.0 ],
[ 16.0, 4.2, 2.7, 0.7 ],
[ 13.9, 3.9, 2.8, 1.2 ],
[ 6.7, 4.0, 4.0, 0.7 ],
[ 12.6, 7.6, 2.3, 1.3 ],
[ 7.5, 3.3, 2.6, 0.6 ],
]
normalized_data = preprocessing.normalize(nbaPGData)
Examples = {
'pgNotNormalized': {
'data': nbaPGData,
'k': [3, 2, 4],
},
'pgNormalized': {
'data': normalized_data,
'k': [2, 4, 3],
},
} | mit |
RomainBrault/scikit-learn | examples/decomposition/plot_sparse_coding.py | 60 | 4016 | """
===========================================
Sparse coding with a precomputed dictionary
===========================================
Transform a signal as a sparse combination of Ricker wavelets. This example
visually compares different sparse coding methods using the
:class:`sklearn.decomposition.SparseCoder` estimator. The Ricker (also known
as Mexican hat or the second derivative of a Gaussian) is not a particularly
good kernel to represent piecewise constant signals like this one. It can
therefore be seen how much adding different widths of atoms matters and it
therefore motivates learning the dictionary to best fit your type of signals.
The richer dictionary on the right is not larger in size, heavier subsampling
is performed in order to stay on the same order of magnitude.
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from sklearn.decomposition import SparseCoder
def ricker_function(resolution, center, width):
"""Discrete sub-sampled Ricker (Mexican hat) wavelet"""
x = np.linspace(0, resolution - 1, resolution)
x = ((2 / ((np.sqrt(3 * width) * np.pi ** 1 / 4)))
* (1 - ((x - center) ** 2 / width ** 2))
* np.exp((-(x - center) ** 2) / (2 * width ** 2)))
return x
def ricker_matrix(width, resolution, n_components):
"""Dictionary of Ricker (Mexican hat) wavelets"""
centers = np.linspace(0, resolution - 1, n_components)
D = np.empty((n_components, resolution))
for i, center in enumerate(centers):
D[i] = ricker_function(resolution, center, width)
D /= np.sqrt(np.sum(D ** 2, axis=1))[:, np.newaxis]
return D
resolution = 1024
subsampling = 3 # subsampling factor
width = 100
n_components = resolution // subsampling
# Compute a wavelet dictionary
D_fixed = ricker_matrix(width=width, resolution=resolution,
n_components=n_components)
D_multi = np.r_[tuple(ricker_matrix(width=w, resolution=resolution,
n_components=n_components // 5)
for w in (10, 50, 100, 500, 1000))]
# Generate a signal
y = np.linspace(0, resolution - 1, resolution)
first_quarter = y < resolution / 4
y[first_quarter] = 3.
y[np.logical_not(first_quarter)] = -1.
# List the different sparse coding methods in the following format:
# (title, transform_algorithm, transform_alpha, transform_n_nozero_coefs)
estimators = [('OMP', 'omp', None, 15, 'navy'),
('Lasso', 'lasso_cd', 2, None, 'turquoise'), ]
lw = 2
plt.figure(figsize=(13, 6))
for subplot, (D, title) in enumerate(zip((D_fixed, D_multi),
('fixed width', 'multiple widths'))):
plt.subplot(1, 2, subplot + 1)
plt.title('Sparse coding against %s dictionary' % title)
plt.plot(y, lw=lw, linestyle='--', label='Original signal')
# Do a wavelet approximation
for title, algo, alpha, n_nonzero, color in estimators:
coder = SparseCoder(dictionary=D, transform_n_nonzero_coefs=n_nonzero,
transform_alpha=alpha, transform_algorithm=algo)
x = coder.transform(y.reshape(1, -1))
density = len(np.flatnonzero(x))
x = np.ravel(np.dot(x, D))
squared_error = np.sum((y - x) ** 2)
plt.plot(x, color=color, lw=lw,
label='%s: %s nonzero coefs,\n%.2f error'
% (title, density, squared_error))
# Soft thresholding debiasing
coder = SparseCoder(dictionary=D, transform_algorithm='threshold',
transform_alpha=20)
x = coder.transform(y.reshape(1, -1))
_, idx = np.where(x != 0)
x[0, idx], _, _, _ = np.linalg.lstsq(D[idx, :].T, y)
x = np.ravel(np.dot(x, D))
squared_error = np.sum((y - x) ** 2)
plt.plot(x, color='darkorange', lw=lw,
label='Thresholding w/ debiasing:\n%d nonzero coefs, %.2f error'
% (len(idx), squared_error))
plt.axis('tight')
plt.legend(shadow=False, loc='best')
plt.subplots_adjust(.04, .07, .97, .90, .09, .2)
plt.show()
| bsd-3-clause |
wazeerzulfikar/scikit-learn | sklearn/decomposition/tests/test_online_lda.py | 38 | 16445 | import sys
import numpy as np
from scipy.linalg import block_diag
from scipy.sparse import csr_matrix
from scipy.special import psi
from sklearn.decomposition import LatentDirichletAllocation
from sklearn.decomposition._online_lda import (_dirichlet_expectation_1d,
_dirichlet_expectation_2d)
from sklearn.utils.testing import assert_allclose
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_greater_equal
from sklearn.utils.testing import assert_raises_regexp
from sklearn.utils.testing import if_safe_multiprocessing_with_blas
from sklearn.utils.testing import assert_warns
from sklearn.exceptions import NotFittedError
from sklearn.externals.six.moves import xrange
from sklearn.externals.six import StringIO
def _build_sparse_mtx():
# Create 3 topics and each topic has 3 distinct words.
# (Each word only belongs to a single topic.)
n_components = 3
block = n_components * np.ones((3, 3))
blocks = [block] * n_components
X = block_diag(*blocks)
X = csr_matrix(X)
return (n_components, X)
def test_lda_default_prior_params():
# default prior parameter should be `1 / topics`
# and verbose params should not affect result
n_components, X = _build_sparse_mtx()
prior = 1. / n_components
lda_1 = LatentDirichletAllocation(n_components=n_components,
doc_topic_prior=prior,
topic_word_prior=prior, random_state=0)
lda_2 = LatentDirichletAllocation(n_components=n_components,
random_state=0)
topic_distr_1 = lda_1.fit_transform(X)
topic_distr_2 = lda_2.fit_transform(X)
assert_almost_equal(topic_distr_1, topic_distr_2)
def test_lda_fit_batch():
# Test LDA batch learning_offset (`fit` method with 'batch' learning)
rng = np.random.RandomState(0)
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components,
evaluate_every=1, learning_method='batch',
random_state=rng)
lda.fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for component in lda.components_:
# Find top 3 words in each LDA component
top_idx = set(component.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_fit_online():
# Test LDA online learning (`fit` method with 'online' learning)
rng = np.random.RandomState(0)
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components,
learning_offset=10., evaluate_every=1,
learning_method='online', random_state=rng)
lda.fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for component in lda.components_:
# Find top 3 words in each LDA component
top_idx = set(component.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_partial_fit():
# Test LDA online learning (`partial_fit` method)
# (same as test_lda_batch)
rng = np.random.RandomState(0)
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components,
learning_offset=10., total_samples=100,
random_state=rng)
for i in xrange(3):
lda.partial_fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for c in lda.components_:
top_idx = set(c.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_dense_input():
# Test LDA with dense input.
rng = np.random.RandomState(0)
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components,
learning_method='batch', random_state=rng)
lda.fit(X.toarray())
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for component in lda.components_:
# Find top 3 words in each LDA component
top_idx = set(component.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_transform():
# Test LDA transform.
# Transform result cannot be negative and should be normalized
rng = np.random.RandomState(0)
X = rng.randint(5, size=(20, 10))
n_components = 3
lda = LatentDirichletAllocation(n_components=n_components,
random_state=rng)
X_trans = lda.fit_transform(X)
assert_true((X_trans > 0.0).any())
assert_array_almost_equal(np.sum(X_trans, axis=1),
np.ones(X_trans.shape[0]))
def test_lda_fit_transform():
# Test LDA fit_transform & transform
# fit_transform and transform result should be the same
for method in ('online', 'batch'):
rng = np.random.RandomState(0)
X = rng.randint(10, size=(50, 20))
lda = LatentDirichletAllocation(n_components=5, learning_method=method,
random_state=rng)
X_fit = lda.fit_transform(X)
X_trans = lda.transform(X)
assert_array_almost_equal(X_fit, X_trans, 4)
def test_lda_partial_fit_dim_mismatch():
# test `n_features` mismatch in `partial_fit`
rng = np.random.RandomState(0)
n_components = rng.randint(3, 6)
n_col = rng.randint(6, 10)
X_1 = np.random.randint(4, size=(10, n_col))
X_2 = np.random.randint(4, size=(10, n_col + 1))
lda = LatentDirichletAllocation(n_components=n_components,
learning_offset=5., total_samples=20,
random_state=rng)
lda.partial_fit(X_1)
assert_raises_regexp(ValueError, r"^The provided data has",
lda.partial_fit, X_2)
def test_invalid_params():
# test `_check_params` method
X = np.ones((5, 10))
invalid_models = (
('n_components', LatentDirichletAllocation(n_components=0)),
('learning_method',
LatentDirichletAllocation(learning_method='unknown')),
('total_samples', LatentDirichletAllocation(total_samples=0)),
('learning_offset', LatentDirichletAllocation(learning_offset=-1)),
)
for param, model in invalid_models:
regex = r"^Invalid %r parameter" % param
assert_raises_regexp(ValueError, regex, model.fit, X)
def test_lda_negative_input():
# test pass dense matrix with sparse negative input.
X = -np.ones((5, 10))
lda = LatentDirichletAllocation()
regex = r"^Negative values in data passed"
assert_raises_regexp(ValueError, regex, lda.fit, X)
def test_lda_no_component_error():
# test `transform` and `perplexity` before `fit`
rng = np.random.RandomState(0)
X = rng.randint(4, size=(20, 10))
lda = LatentDirichletAllocation()
regex = r"^no 'components_' attribute"
assert_raises_regexp(NotFittedError, regex, lda.transform, X)
assert_raises_regexp(NotFittedError, regex, lda.perplexity, X)
def test_lda_transform_mismatch():
# test `n_features` mismatch in partial_fit and transform
rng = np.random.RandomState(0)
X = rng.randint(4, size=(20, 10))
X_2 = rng.randint(4, size=(10, 8))
n_components = rng.randint(3, 6)
lda = LatentDirichletAllocation(n_components=n_components,
random_state=rng)
lda.partial_fit(X)
assert_raises_regexp(ValueError, r"^The provided data has",
lda.partial_fit, X_2)
@if_safe_multiprocessing_with_blas
def test_lda_multi_jobs():
n_components, X = _build_sparse_mtx()
# Test LDA batch training with multi CPU
for method in ('online', 'batch'):
rng = np.random.RandomState(0)
lda = LatentDirichletAllocation(n_components=n_components, n_jobs=2,
learning_method=method,
evaluate_every=1, random_state=rng)
lda.fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for c in lda.components_:
top_idx = set(c.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
@if_safe_multiprocessing_with_blas
def test_lda_partial_fit_multi_jobs():
# Test LDA online training with multi CPU
rng = np.random.RandomState(0)
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components, n_jobs=2,
learning_offset=5., total_samples=30,
random_state=rng)
for i in range(2):
lda.partial_fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for c in lda.components_:
top_idx = set(c.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_preplexity_mismatch():
# test dimension mismatch in `perplexity` method
rng = np.random.RandomState(0)
n_components = rng.randint(3, 6)
n_samples = rng.randint(6, 10)
X = np.random.randint(4, size=(n_samples, 10))
lda = LatentDirichletAllocation(n_components=n_components,
learning_offset=5., total_samples=20,
random_state=rng)
lda.fit(X)
# invalid samples
invalid_n_samples = rng.randint(4, size=(n_samples + 1, n_components))
assert_raises_regexp(ValueError, r'Number of samples',
lda._perplexity_precomp_distr, X, invalid_n_samples)
# invalid topic number
invalid_n_components = rng.randint(4, size=(n_samples, n_components + 1))
assert_raises_regexp(ValueError, r'Number of topics',
lda._perplexity_precomp_distr, X,
invalid_n_components)
def test_lda_perplexity():
# Test LDA perplexity for batch training
# perplexity should be lower after each iteration
n_components, X = _build_sparse_mtx()
for method in ('online', 'batch'):
lda_1 = LatentDirichletAllocation(n_components=n_components,
max_iter=1, learning_method=method,
total_samples=100, random_state=0)
lda_2 = LatentDirichletAllocation(n_components=n_components,
max_iter=10, learning_method=method,
total_samples=100, random_state=0)
lda_1.fit(X)
perp_1 = lda_1.perplexity(X, sub_sampling=False)
lda_2.fit(X)
perp_2 = lda_2.perplexity(X, sub_sampling=False)
assert_greater_equal(perp_1, perp_2)
perp_1_subsampling = lda_1.perplexity(X, sub_sampling=True)
perp_2_subsampling = lda_2.perplexity(X, sub_sampling=True)
assert_greater_equal(perp_1_subsampling, perp_2_subsampling)
def test_lda_score():
# Test LDA score for batch training
# score should be higher after each iteration
n_components, X = _build_sparse_mtx()
for method in ('online', 'batch'):
lda_1 = LatentDirichletAllocation(n_components=n_components,
max_iter=1, learning_method=method,
total_samples=100, random_state=0)
lda_2 = LatentDirichletAllocation(n_components=n_components,
max_iter=10, learning_method=method,
total_samples=100, random_state=0)
lda_1.fit_transform(X)
score_1 = lda_1.score(X)
lda_2.fit_transform(X)
score_2 = lda_2.score(X)
assert_greater_equal(score_2, score_1)
def test_perplexity_input_format():
# Test LDA perplexity for sparse and dense input
# score should be the same for both dense and sparse input
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components, max_iter=1,
learning_method='batch',
total_samples=100, random_state=0)
lda.fit(X)
perp_1 = lda.perplexity(X)
perp_2 = lda.perplexity(X.toarray())
assert_almost_equal(perp_1, perp_2)
def test_lda_score_perplexity():
# Test the relationship between LDA score and perplexity
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components, max_iter=10,
random_state=0)
lda.fit(X)
perplexity_1 = lda.perplexity(X, sub_sampling=False)
score = lda.score(X)
perplexity_2 = np.exp(-1. * (score / np.sum(X.data)))
assert_almost_equal(perplexity_1, perplexity_2)
def test_lda_fit_perplexity():
# Test that the perplexity computed during fit is consistent with what is
# returned by the perplexity method
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components, max_iter=1,
learning_method='batch', random_state=0,
evaluate_every=1)
lda.fit(X)
# Perplexity computed at end of fit method
perplexity1 = lda.bound_
# Result of perplexity method on the train set
perplexity2 = lda.perplexity(X)
assert_almost_equal(perplexity1, perplexity2)
def test_doc_topic_distr_deprecation():
# Test that the appropriate warning message is displayed when a user
# attempts to pass the doc_topic_distr argument to the perplexity method
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components, max_iter=1,
learning_method='batch',
total_samples=100, random_state=0)
distr1 = lda.fit_transform(X)
distr2 = None
assert_warns(DeprecationWarning, lda.perplexity, X, distr1)
assert_warns(DeprecationWarning, lda.perplexity, X, distr2)
def test_lda_empty_docs():
"""Test LDA on empty document (all-zero rows)."""
Z = np.zeros((5, 4))
for X in [Z, csr_matrix(Z)]:
lda = LatentDirichletAllocation(max_iter=750).fit(X)
assert_almost_equal(lda.components_.sum(axis=0),
np.ones(lda.components_.shape[1]))
def test_dirichlet_expectation():
"""Test Cython version of Dirichlet expectation calculation."""
x = np.logspace(-100, 10, 10000)
expectation = np.empty_like(x)
_dirichlet_expectation_1d(x, 0, expectation)
assert_allclose(expectation, np.exp(psi(x) - psi(np.sum(x))),
atol=1e-19)
x = x.reshape(100, 100)
assert_allclose(_dirichlet_expectation_2d(x),
psi(x) - psi(np.sum(x, axis=1)[:, np.newaxis]),
rtol=1e-11, atol=3e-9)
def check_verbosity(verbose, evaluate_every, expected_lines,
expected_perplexities):
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_components=n_components, max_iter=3,
learning_method='batch',
verbose=verbose,
evaluate_every=evaluate_every,
random_state=0)
out = StringIO()
old_out, sys.stdout = sys.stdout, out
try:
lda.fit(X)
finally:
sys.stdout = old_out
n_lines = out.getvalue().count('\n')
n_perplexity = out.getvalue().count('perplexity')
assert_equal(expected_lines, n_lines)
assert_equal(expected_perplexities, n_perplexity)
def test_verbosity():
for verbose, evaluate_every, expected_lines, expected_perplexities in [
(False, 1, 0, 0),
(False, 0, 0, 0),
(True, 0, 3, 0),
(True, 1, 3, 3),
(True, 2, 3, 1),
]:
yield (check_verbosity, verbose, evaluate_every, expected_lines,
expected_perplexities)
def test_lda_n_topics_deprecation():
n_components, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=10, learning_method='batch')
assert_warns(DeprecationWarning, lda.fit, X)
| bsd-3-clause |
daeilkim/refinery | refinery/fact_classifier/classify_ex.py | 1 | 1262 | from sklearn import svm
from sklearn.feature_extraction import DictVectorizer
from collections import defaultdict
import pickle
v = DictVectorizer()
#TODO : need to tokenize the words before using them as features!
def main():
def munge(s):
ps = s.split()
label = int(ps[0])
ws = defaultdict(int)
for w in ps[1:]:
ws[w] += 1
return [label,ws]
data = [munge(l.strip()) for l in open("/home/chonger/Downloads/annotations.txt")]
labels = [x[0] for x in data]
dicts = [x[1] for x in data]
feats = v.fit_transform(dicts)
ttsplit = int(len(labels) * .8)
clf = svm.SVC(kernel='linear', class_weight={1: 10})
#clf = svm.SVC()
clf.fit(feats[:ttsplit],labels[:ttsplit])
print clf.score(feats[ttsplit:],labels[ttsplit:])
tot = defaultdict(int)
tr = defaultdict(int)
for ex in labels[ttsplit:]:
tr[ex] += 1
for ex in feats[ttsplit:]:
tot[(clf.predict(ex).tolist())[0]] += 1
print tr
print tot
print feats[0]
print feats[1]
f = open("/home/chonger/factsvm",'w')
pickle.dump(clf,f)
f.close()
f = open("/home/chonger/factfeat",'w')
pickle.dump(v,f)
f.close()
if __name__ == "__main__":
main()
| mit |
Nyker510/scikit-learn | examples/neighbors/plot_classification.py | 287 | 1790 | """
================================
Nearest Neighbors Classification
================================
Sample usage of Nearest Neighbors classification.
It will plot the decision boundaries for each class.
"""
print(__doc__)
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.colors import ListedColormap
from sklearn import neighbors, datasets
n_neighbors = 15
# import some data to play with
iris = datasets.load_iris()
X = iris.data[:, :2] # we only take the first two features. We could
# avoid this ugly slicing by using a two-dim dataset
y = iris.target
h = .02 # step size in the mesh
# Create color maps
cmap_light = ListedColormap(['#FFAAAA', '#AAFFAA', '#AAAAFF'])
cmap_bold = ListedColormap(['#FF0000', '#00FF00', '#0000FF'])
for weights in ['uniform', 'distance']:
# we create an instance of Neighbours Classifier and fit the data.
clf = neighbors.KNeighborsClassifier(n_neighbors, weights=weights)
clf.fit(X, y)
# Plot the decision boundary. For that, we will assign a color to each
# point in the mesh [x_min, m_max]x[y_min, y_max].
x_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1
y_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1
xx, yy = np.meshgrid(np.arange(x_min, x_max, h),
np.arange(y_min, y_max, h))
Z = clf.predict(np.c_[xx.ravel(), yy.ravel()])
# Put the result into a color plot
Z = Z.reshape(xx.shape)
plt.figure()
plt.pcolormesh(xx, yy, Z, cmap=cmap_light)
# Plot also the training points
plt.scatter(X[:, 0], X[:, 1], c=y, cmap=cmap_bold)
plt.xlim(xx.min(), xx.max())
plt.ylim(yy.min(), yy.max())
plt.title("3-Class classification (k = %i, weights = '%s')"
% (n_neighbors, weights))
plt.show()
| bsd-3-clause |
aminert/scikit-learn | sklearn/preprocessing/tests/test_data.py | 113 | 38432 | import warnings
import numpy as np
import numpy.linalg as la
from scipy import sparse
from distutils.version import LooseVersion
from sklearn.utils.testing import assert_almost_equal, clean_warning_registry
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_greater_equal
from sklearn.utils.testing import assert_less_equal
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_raises_regex
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import assert_false
from sklearn.utils.testing import assert_warns_message
from sklearn.utils.testing import assert_no_warnings
from sklearn.utils.sparsefuncs import mean_variance_axis
from sklearn.preprocessing.data import _transform_selected
from sklearn.preprocessing.data import Binarizer
from sklearn.preprocessing.data import KernelCenterer
from sklearn.preprocessing.data import Normalizer
from sklearn.preprocessing.data import normalize
from sklearn.preprocessing.data import OneHotEncoder
from sklearn.preprocessing.data import StandardScaler
from sklearn.preprocessing.data import scale
from sklearn.preprocessing.data import MinMaxScaler
from sklearn.preprocessing.data import minmax_scale
from sklearn.preprocessing.data import MaxAbsScaler
from sklearn.preprocessing.data import maxabs_scale
from sklearn.preprocessing.data import RobustScaler
from sklearn.preprocessing.data import robust_scale
from sklearn.preprocessing.data import add_dummy_feature
from sklearn.preprocessing.data import PolynomialFeatures
from sklearn.utils.validation import DataConversionWarning
from sklearn import datasets
iris = datasets.load_iris()
def toarray(a):
if hasattr(a, "toarray"):
a = a.toarray()
return a
def test_polynomial_features():
# Test Polynomial Features
X1 = np.arange(6)[:, np.newaxis]
P1 = np.hstack([np.ones_like(X1),
X1, X1 ** 2, X1 ** 3])
deg1 = 3
X2 = np.arange(6).reshape((3, 2))
x1 = X2[:, :1]
x2 = X2[:, 1:]
P2 = np.hstack([x1 ** 0 * x2 ** 0,
x1 ** 1 * x2 ** 0,
x1 ** 0 * x2 ** 1,
x1 ** 2 * x2 ** 0,
x1 ** 1 * x2 ** 1,
x1 ** 0 * x2 ** 2])
deg2 = 2
for (deg, X, P) in [(deg1, X1, P1), (deg2, X2, P2)]:
P_test = PolynomialFeatures(deg, include_bias=True).fit_transform(X)
assert_array_almost_equal(P_test, P)
P_test = PolynomialFeatures(deg, include_bias=False).fit_transform(X)
assert_array_almost_equal(P_test, P[:, 1:])
interact = PolynomialFeatures(2, interaction_only=True, include_bias=True)
X_poly = interact.fit_transform(X)
assert_array_almost_equal(X_poly, P2[:, [0, 1, 2, 4]])
def test_scaler_1d():
# Test scaling of dataset along single axis
rng = np.random.RandomState(0)
X = rng.randn(5)
X_orig_copy = X.copy()
scaler = StandardScaler()
X_scaled = scaler.fit(X).transform(X, copy=False)
assert_array_almost_equal(X_scaled.mean(axis=0), 0.0)
assert_array_almost_equal(X_scaled.std(axis=0), 1.0)
# check inverse transform
X_scaled_back = scaler.inverse_transform(X_scaled)
assert_array_almost_equal(X_scaled_back, X_orig_copy)
# Test with 1D list
X = [0., 1., 2, 0.4, 1.]
scaler = StandardScaler()
X_scaled = scaler.fit(X).transform(X, copy=False)
assert_array_almost_equal(X_scaled.mean(axis=0), 0.0)
assert_array_almost_equal(X_scaled.std(axis=0), 1.0)
X_scaled = scale(X)
assert_array_almost_equal(X_scaled.mean(axis=0), 0.0)
assert_array_almost_equal(X_scaled.std(axis=0), 1.0)
X = np.ones(5)
assert_array_equal(scale(X, with_mean=False), X)
def test_standard_scaler_numerical_stability():
"""Test numerical stability of scaling"""
# np.log(1e-5) is taken because of its floating point representation
# was empirically found to cause numerical problems with np.mean & np.std.
x = np.zeros(8, dtype=np.float64) + np.log(1e-5, dtype=np.float64)
if LooseVersion(np.__version__) >= LooseVersion('1.9'):
# This does not raise a warning as the number of samples is too low
# to trigger the problem in recent numpy
x_scaled = assert_no_warnings(scale, x)
assert_array_almost_equal(scale(x), np.zeros(8))
else:
w = "standard deviation of the data is probably very close to 0"
x_scaled = assert_warns_message(UserWarning, w, scale, x)
assert_array_almost_equal(x_scaled, np.zeros(8))
# with 2 more samples, the std computation run into numerical issues:
x = np.zeros(10, dtype=np.float64) + np.log(1e-5, dtype=np.float64)
w = "standard deviation of the data is probably very close to 0"
x_scaled = assert_warns_message(UserWarning, w, scale, x)
assert_array_almost_equal(x_scaled, np.zeros(10))
x = np.ones(10, dtype=np.float64) * 1e-100
x_small_scaled = assert_no_warnings(scale, x)
assert_array_almost_equal(x_small_scaled, np.zeros(10))
# Large values can cause (often recoverable) numerical stability issues:
x_big = np.ones(10, dtype=np.float64) * 1e100
w = "Dataset may contain too large values"
x_big_scaled = assert_warns_message(UserWarning, w, scale, x_big)
assert_array_almost_equal(x_big_scaled, np.zeros(10))
assert_array_almost_equal(x_big_scaled, x_small_scaled)
x_big_centered = assert_warns_message(UserWarning, w, scale, x_big,
with_std=False)
assert_array_almost_equal(x_big_centered, np.zeros(10))
assert_array_almost_equal(x_big_centered, x_small_scaled)
def test_scaler_2d_arrays():
# Test scaling of 2d array along first axis
rng = np.random.RandomState(0)
X = rng.randn(4, 5)
X[:, 0] = 0.0 # first feature is always of zero
scaler = StandardScaler()
X_scaled = scaler.fit(X).transform(X, copy=True)
assert_false(np.any(np.isnan(X_scaled)))
assert_array_almost_equal(X_scaled.mean(axis=0), 5 * [0.0])
assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.])
# Check that X has been copied
assert_true(X_scaled is not X)
# check inverse transform
X_scaled_back = scaler.inverse_transform(X_scaled)
assert_true(X_scaled_back is not X)
assert_true(X_scaled_back is not X_scaled)
assert_array_almost_equal(X_scaled_back, X)
X_scaled = scale(X, axis=1, with_std=False)
assert_false(np.any(np.isnan(X_scaled)))
assert_array_almost_equal(X_scaled.mean(axis=1), 4 * [0.0])
X_scaled = scale(X, axis=1, with_std=True)
assert_false(np.any(np.isnan(X_scaled)))
assert_array_almost_equal(X_scaled.mean(axis=1), 4 * [0.0])
assert_array_almost_equal(X_scaled.std(axis=1), 4 * [1.0])
# Check that the data hasn't been modified
assert_true(X_scaled is not X)
X_scaled = scaler.fit(X).transform(X, copy=False)
assert_false(np.any(np.isnan(X_scaled)))
assert_array_almost_equal(X_scaled.mean(axis=0), 5 * [0.0])
assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.])
# Check that X has not been copied
assert_true(X_scaled is X)
X = rng.randn(4, 5)
X[:, 0] = 1.0 # first feature is a constant, non zero feature
scaler = StandardScaler()
X_scaled = scaler.fit(X).transform(X, copy=True)
assert_false(np.any(np.isnan(X_scaled)))
assert_array_almost_equal(X_scaled.mean(axis=0), 5 * [0.0])
assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.])
# Check that X has not been copied
assert_true(X_scaled is not X)
def test_min_max_scaler_iris():
X = iris.data
scaler = MinMaxScaler()
# default params
X_trans = scaler.fit_transform(X)
assert_array_almost_equal(X_trans.min(axis=0), 0)
assert_array_almost_equal(X_trans.min(axis=0), 0)
assert_array_almost_equal(X_trans.max(axis=0), 1)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv)
# not default params: min=1, max=2
scaler = MinMaxScaler(feature_range=(1, 2))
X_trans = scaler.fit_transform(X)
assert_array_almost_equal(X_trans.min(axis=0), 1)
assert_array_almost_equal(X_trans.max(axis=0), 2)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv)
# min=-.5, max=.6
scaler = MinMaxScaler(feature_range=(-.5, .6))
X_trans = scaler.fit_transform(X)
assert_array_almost_equal(X_trans.min(axis=0), -.5)
assert_array_almost_equal(X_trans.max(axis=0), .6)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv)
# raises on invalid range
scaler = MinMaxScaler(feature_range=(2, 1))
assert_raises(ValueError, scaler.fit, X)
def test_min_max_scaler_zero_variance_features():
# Check min max scaler on toy data with zero variance features
X = [[0., 1., +0.5],
[0., 1., -0.1],
[0., 1., +1.1]]
X_new = [[+0., 2., 0.5],
[-1., 1., 0.0],
[+0., 1., 1.5]]
# default params
scaler = MinMaxScaler()
X_trans = scaler.fit_transform(X)
X_expected_0_1 = [[0., 0., 0.5],
[0., 0., 0.0],
[0., 0., 1.0]]
assert_array_almost_equal(X_trans, X_expected_0_1)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv)
X_trans_new = scaler.transform(X_new)
X_expected_0_1_new = [[+0., 1., 0.500],
[-1., 0., 0.083],
[+0., 0., 1.333]]
assert_array_almost_equal(X_trans_new, X_expected_0_1_new, decimal=2)
# not default params
scaler = MinMaxScaler(feature_range=(1, 2))
X_trans = scaler.fit_transform(X)
X_expected_1_2 = [[1., 1., 1.5],
[1., 1., 1.0],
[1., 1., 2.0]]
assert_array_almost_equal(X_trans, X_expected_1_2)
# function interface
X_trans = minmax_scale(X)
assert_array_almost_equal(X_trans, X_expected_0_1)
X_trans = minmax_scale(X, feature_range=(1, 2))
assert_array_almost_equal(X_trans, X_expected_1_2)
def test_minmax_scale_axis1():
X = iris.data
X_trans = minmax_scale(X, axis=1)
assert_array_almost_equal(np.min(X_trans, axis=1), 0)
assert_array_almost_equal(np.max(X_trans, axis=1), 1)
def test_min_max_scaler_1d():
# Test scaling of dataset along single axis
rng = np.random.RandomState(0)
X = rng.randn(5)
X_orig_copy = X.copy()
scaler = MinMaxScaler()
X_scaled = scaler.fit(X).transform(X)
assert_array_almost_equal(X_scaled.min(axis=0), 0.0)
assert_array_almost_equal(X_scaled.max(axis=0), 1.0)
# check inverse transform
X_scaled_back = scaler.inverse_transform(X_scaled)
assert_array_almost_equal(X_scaled_back, X_orig_copy)
# Test with 1D list
X = [0., 1., 2, 0.4, 1.]
scaler = MinMaxScaler()
X_scaled = scaler.fit(X).transform(X)
assert_array_almost_equal(X_scaled.min(axis=0), 0.0)
assert_array_almost_equal(X_scaled.max(axis=0), 1.0)
# Constant feature.
X = np.zeros(5)
scaler = MinMaxScaler()
X_scaled = scaler.fit(X).transform(X)
assert_greater_equal(X_scaled.min(), 0.)
assert_less_equal(X_scaled.max(), 1.)
def test_scaler_without_centering():
rng = np.random.RandomState(42)
X = rng.randn(4, 5)
X[:, 0] = 0.0 # first feature is always of zero
X_csr = sparse.csr_matrix(X)
X_csc = sparse.csc_matrix(X)
assert_raises(ValueError, StandardScaler().fit, X_csr)
null_transform = StandardScaler(with_mean=False, with_std=False, copy=True)
X_null = null_transform.fit_transform(X_csr)
assert_array_equal(X_null.data, X_csr.data)
X_orig = null_transform.inverse_transform(X_null)
assert_array_equal(X_orig.data, X_csr.data)
scaler = StandardScaler(with_mean=False).fit(X)
X_scaled = scaler.transform(X, copy=True)
assert_false(np.any(np.isnan(X_scaled)))
scaler_csr = StandardScaler(with_mean=False).fit(X_csr)
X_csr_scaled = scaler_csr.transform(X_csr, copy=True)
assert_false(np.any(np.isnan(X_csr_scaled.data)))
scaler_csc = StandardScaler(with_mean=False).fit(X_csc)
X_csc_scaled = scaler_csr.transform(X_csc, copy=True)
assert_false(np.any(np.isnan(X_csc_scaled.data)))
assert_equal(scaler.mean_, scaler_csr.mean_)
assert_array_almost_equal(scaler.std_, scaler_csr.std_)
assert_equal(scaler.mean_, scaler_csc.mean_)
assert_array_almost_equal(scaler.std_, scaler_csc.std_)
assert_array_almost_equal(
X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2)
assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.])
X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis(X_csr_scaled, 0)
assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0))
assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0))
# Check that X has not been modified (copy)
assert_true(X_scaled is not X)
assert_true(X_csr_scaled is not X_csr)
X_scaled_back = scaler.inverse_transform(X_scaled)
assert_true(X_scaled_back is not X)
assert_true(X_scaled_back is not X_scaled)
assert_array_almost_equal(X_scaled_back, X)
X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled)
assert_true(X_csr_scaled_back is not X_csr)
assert_true(X_csr_scaled_back is not X_csr_scaled)
assert_array_almost_equal(X_csr_scaled_back.toarray(), X)
X_csc_scaled_back = scaler_csr.inverse_transform(X_csc_scaled.tocsc())
assert_true(X_csc_scaled_back is not X_csc)
assert_true(X_csc_scaled_back is not X_csc_scaled)
assert_array_almost_equal(X_csc_scaled_back.toarray(), X)
def test_scaler_int():
# test that scaler converts integer input to floating
# for both sparse and dense matrices
rng = np.random.RandomState(42)
X = rng.randint(20, size=(4, 5))
X[:, 0] = 0 # first feature is always of zero
X_csr = sparse.csr_matrix(X)
X_csc = sparse.csc_matrix(X)
null_transform = StandardScaler(with_mean=False, with_std=False, copy=True)
clean_warning_registry()
with warnings.catch_warnings(record=True):
X_null = null_transform.fit_transform(X_csr)
assert_array_equal(X_null.data, X_csr.data)
X_orig = null_transform.inverse_transform(X_null)
assert_array_equal(X_orig.data, X_csr.data)
clean_warning_registry()
with warnings.catch_warnings(record=True):
scaler = StandardScaler(with_mean=False).fit(X)
X_scaled = scaler.transform(X, copy=True)
assert_false(np.any(np.isnan(X_scaled)))
clean_warning_registry()
with warnings.catch_warnings(record=True):
scaler_csr = StandardScaler(with_mean=False).fit(X_csr)
X_csr_scaled = scaler_csr.transform(X_csr, copy=True)
assert_false(np.any(np.isnan(X_csr_scaled.data)))
clean_warning_registry()
with warnings.catch_warnings(record=True):
scaler_csc = StandardScaler(with_mean=False).fit(X_csc)
X_csc_scaled = scaler_csr.transform(X_csc, copy=True)
assert_false(np.any(np.isnan(X_csc_scaled.data)))
assert_equal(scaler.mean_, scaler_csr.mean_)
assert_array_almost_equal(scaler.std_, scaler_csr.std_)
assert_equal(scaler.mean_, scaler_csc.mean_)
assert_array_almost_equal(scaler.std_, scaler_csc.std_)
assert_array_almost_equal(
X_scaled.mean(axis=0),
[0., 1.109, 1.856, 21., 1.559], 2)
assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.])
X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis(
X_csr_scaled.astype(np.float), 0)
assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0))
assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0))
# Check that X has not been modified (copy)
assert_true(X_scaled is not X)
assert_true(X_csr_scaled is not X_csr)
X_scaled_back = scaler.inverse_transform(X_scaled)
assert_true(X_scaled_back is not X)
assert_true(X_scaled_back is not X_scaled)
assert_array_almost_equal(X_scaled_back, X)
X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled)
assert_true(X_csr_scaled_back is not X_csr)
assert_true(X_csr_scaled_back is not X_csr_scaled)
assert_array_almost_equal(X_csr_scaled_back.toarray(), X)
X_csc_scaled_back = scaler_csr.inverse_transform(X_csc_scaled.tocsc())
assert_true(X_csc_scaled_back is not X_csc)
assert_true(X_csc_scaled_back is not X_csc_scaled)
assert_array_almost_equal(X_csc_scaled_back.toarray(), X)
def test_scaler_without_copy():
# Check that StandardScaler.fit does not change input
rng = np.random.RandomState(42)
X = rng.randn(4, 5)
X[:, 0] = 0.0 # first feature is always of zero
X_csr = sparse.csr_matrix(X)
X_copy = X.copy()
StandardScaler(copy=False).fit(X)
assert_array_equal(X, X_copy)
X_csr_copy = X_csr.copy()
StandardScaler(with_mean=False, copy=False).fit(X_csr)
assert_array_equal(X_csr.toarray(), X_csr_copy.toarray())
def test_scale_sparse_with_mean_raise_exception():
rng = np.random.RandomState(42)
X = rng.randn(4, 5)
X_csr = sparse.csr_matrix(X)
# check scaling and fit with direct calls on sparse data
assert_raises(ValueError, scale, X_csr, with_mean=True)
assert_raises(ValueError, StandardScaler(with_mean=True).fit, X_csr)
# check transform and inverse_transform after a fit on a dense array
scaler = StandardScaler(with_mean=True).fit(X)
assert_raises(ValueError, scaler.transform, X_csr)
X_transformed_csr = sparse.csr_matrix(scaler.transform(X))
assert_raises(ValueError, scaler.inverse_transform, X_transformed_csr)
def test_scale_input_finiteness_validation():
# Check if non finite inputs raise ValueError
X = [np.nan, 5, 6, 7, 8]
assert_raises_regex(ValueError,
"Input contains NaN, infinity or a value too large",
scale, X)
X = [np.inf, 5, 6, 7, 8]
assert_raises_regex(ValueError,
"Input contains NaN, infinity or a value too large",
scale, X)
def test_scale_function_without_centering():
rng = np.random.RandomState(42)
X = rng.randn(4, 5)
X[:, 0] = 0.0 # first feature is always of zero
X_csr = sparse.csr_matrix(X)
X_scaled = scale(X, with_mean=False)
assert_false(np.any(np.isnan(X_scaled)))
X_csr_scaled = scale(X_csr, with_mean=False)
assert_false(np.any(np.isnan(X_csr_scaled.data)))
# test csc has same outcome
X_csc_scaled = scale(X_csr.tocsc(), with_mean=False)
assert_array_almost_equal(X_scaled, X_csc_scaled.toarray())
# raises value error on axis != 0
assert_raises(ValueError, scale, X_csr, with_mean=False, axis=1)
assert_array_almost_equal(X_scaled.mean(axis=0),
[0., -0.01, 2.24, -0.35, -0.78], 2)
assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.])
# Check that X has not been copied
assert_true(X_scaled is not X)
X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis(X_csr_scaled, 0)
assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0))
assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0))
def test_robust_scaler_2d_arrays():
"""Test robust scaling of 2d array along first axis"""
rng = np.random.RandomState(0)
X = rng.randn(4, 5)
X[:, 0] = 0.0 # first feature is always of zero
scaler = RobustScaler()
X_scaled = scaler.fit(X).transform(X)
assert_array_almost_equal(np.median(X_scaled, axis=0), 5 * [0.0])
assert_array_almost_equal(X_scaled.std(axis=0)[0], 0)
def test_robust_scaler_iris():
X = iris.data
scaler = RobustScaler()
X_trans = scaler.fit_transform(X)
assert_array_almost_equal(np.median(X_trans, axis=0), 0)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv)
q = np.percentile(X_trans, q=(25, 75), axis=0)
iqr = q[1] - q[0]
assert_array_almost_equal(iqr, 1)
def test_robust_scale_axis1():
X = iris.data
X_trans = robust_scale(X, axis=1)
assert_array_almost_equal(np.median(X_trans, axis=1), 0)
q = np.percentile(X_trans, q=(25, 75), axis=1)
iqr = q[1] - q[0]
assert_array_almost_equal(iqr, 1)
def test_robust_scaler_zero_variance_features():
"""Check RobustScaler on toy data with zero variance features"""
X = [[0., 1., +0.5],
[0., 1., -0.1],
[0., 1., +1.1]]
scaler = RobustScaler()
X_trans = scaler.fit_transform(X)
# NOTE: for such a small sample size, what we expect in the third column
# depends HEAVILY on the method used to calculate quantiles. The values
# here were calculated to fit the quantiles produces by np.percentile
# using numpy 1.9 Calculating quantiles with
# scipy.stats.mstats.scoreatquantile or scipy.stats.mstats.mquantiles
# would yield very different results!
X_expected = [[0., 0., +0.0],
[0., 0., -1.0],
[0., 0., +1.0]]
assert_array_almost_equal(X_trans, X_expected)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv)
# make sure new data gets transformed correctly
X_new = [[+0., 2., 0.5],
[-1., 1., 0.0],
[+0., 1., 1.5]]
X_trans_new = scaler.transform(X_new)
X_expected_new = [[+0., 1., +0.],
[-1., 0., -0.83333],
[+0., 0., +1.66667]]
assert_array_almost_equal(X_trans_new, X_expected_new, decimal=3)
def test_maxabs_scaler_zero_variance_features():
"""Check MaxAbsScaler on toy data with zero variance features"""
X = [[0., 1., +0.5],
[0., 1., -0.3],
[0., 1., +1.5],
[0., 0., +0.0]]
scaler = MaxAbsScaler()
X_trans = scaler.fit_transform(X)
X_expected = [[0., 1., 1.0 / 3.0],
[0., 1., -0.2],
[0., 1., 1.0],
[0., 0., 0.0]]
assert_array_almost_equal(X_trans, X_expected)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv)
# make sure new data gets transformed correctly
X_new = [[+0., 2., 0.5],
[-1., 1., 0.0],
[+0., 1., 1.5]]
X_trans_new = scaler.transform(X_new)
X_expected_new = [[+0., 2.0, 1.0 / 3.0],
[-1., 1.0, 0.0],
[+0., 1.0, 1.0]]
assert_array_almost_equal(X_trans_new, X_expected_new, decimal=2)
# sparse data
X_csr = sparse.csr_matrix(X)
X_trans = scaler.fit_transform(X_csr)
X_expected = [[0., 1., 1.0 / 3.0],
[0., 1., -0.2],
[0., 1., 1.0],
[0., 0., 0.0]]
assert_array_almost_equal(X_trans.A, X_expected)
X_trans_inv = scaler.inverse_transform(X_trans)
assert_array_almost_equal(X, X_trans_inv.A)
def test_maxabs_scaler_large_negative_value():
"""Check MaxAbsScaler on toy data with a large negative value"""
X = [[0., 1., +0.5, -1.0],
[0., 1., -0.3, -0.5],
[0., 1., -100.0, 0.0],
[0., 0., +0.0, -2.0]]
scaler = MaxAbsScaler()
X_trans = scaler.fit_transform(X)
X_expected = [[0., 1., 0.005, -0.5],
[0., 1., -0.003, -0.25],
[0., 1., -1.0, 0.0],
[0., 0., 0.0, -1.0]]
assert_array_almost_equal(X_trans, X_expected)
def test_warning_scaling_integers():
# Check warning when scaling integer data
X = np.array([[1, 2, 0],
[0, 0, 0]], dtype=np.uint8)
w = "Data with input dtype uint8 was converted to float64"
clean_warning_registry()
assert_warns_message(DataConversionWarning, w, scale, X)
assert_warns_message(DataConversionWarning, w, StandardScaler().fit, X)
assert_warns_message(DataConversionWarning, w, MinMaxScaler().fit, X)
def test_normalizer_l1():
rng = np.random.RandomState(0)
X_dense = rng.randn(4, 5)
X_sparse_unpruned = sparse.csr_matrix(X_dense)
# set the row number 3 to zero
X_dense[3, :] = 0.0
# set the row number 3 to zero without pruning (can happen in real life)
indptr_3 = X_sparse_unpruned.indptr[3]
indptr_4 = X_sparse_unpruned.indptr[4]
X_sparse_unpruned.data[indptr_3:indptr_4] = 0.0
# build the pruned variant using the regular constructor
X_sparse_pruned = sparse.csr_matrix(X_dense)
# check inputs that support the no-copy optim
for X in (X_dense, X_sparse_pruned, X_sparse_unpruned):
normalizer = Normalizer(norm='l1', copy=True)
X_norm = normalizer.transform(X)
assert_true(X_norm is not X)
X_norm1 = toarray(X_norm)
normalizer = Normalizer(norm='l1', copy=False)
X_norm = normalizer.transform(X)
assert_true(X_norm is X)
X_norm2 = toarray(X_norm)
for X_norm in (X_norm1, X_norm2):
row_sums = np.abs(X_norm).sum(axis=1)
for i in range(3):
assert_almost_equal(row_sums[i], 1.0)
assert_almost_equal(row_sums[3], 0.0)
# check input for which copy=False won't prevent a copy
for init in (sparse.coo_matrix, sparse.csc_matrix, sparse.lil_matrix):
X = init(X_dense)
X_norm = normalizer = Normalizer(norm='l2', copy=False).transform(X)
assert_true(X_norm is not X)
assert_true(isinstance(X_norm, sparse.csr_matrix))
X_norm = toarray(X_norm)
for i in range(3):
assert_almost_equal(row_sums[i], 1.0)
assert_almost_equal(la.norm(X_norm[3]), 0.0)
def test_normalizer_l2():
rng = np.random.RandomState(0)
X_dense = rng.randn(4, 5)
X_sparse_unpruned = sparse.csr_matrix(X_dense)
# set the row number 3 to zero
X_dense[3, :] = 0.0
# set the row number 3 to zero without pruning (can happen in real life)
indptr_3 = X_sparse_unpruned.indptr[3]
indptr_4 = X_sparse_unpruned.indptr[4]
X_sparse_unpruned.data[indptr_3:indptr_4] = 0.0
# build the pruned variant using the regular constructor
X_sparse_pruned = sparse.csr_matrix(X_dense)
# check inputs that support the no-copy optim
for X in (X_dense, X_sparse_pruned, X_sparse_unpruned):
normalizer = Normalizer(norm='l2', copy=True)
X_norm1 = normalizer.transform(X)
assert_true(X_norm1 is not X)
X_norm1 = toarray(X_norm1)
normalizer = Normalizer(norm='l2', copy=False)
X_norm2 = normalizer.transform(X)
assert_true(X_norm2 is X)
X_norm2 = toarray(X_norm2)
for X_norm in (X_norm1, X_norm2):
for i in range(3):
assert_almost_equal(la.norm(X_norm[i]), 1.0)
assert_almost_equal(la.norm(X_norm[3]), 0.0)
# check input for which copy=False won't prevent a copy
for init in (sparse.coo_matrix, sparse.csc_matrix, sparse.lil_matrix):
X = init(X_dense)
X_norm = normalizer = Normalizer(norm='l2', copy=False).transform(X)
assert_true(X_norm is not X)
assert_true(isinstance(X_norm, sparse.csr_matrix))
X_norm = toarray(X_norm)
for i in range(3):
assert_almost_equal(la.norm(X_norm[i]), 1.0)
assert_almost_equal(la.norm(X_norm[3]), 0.0)
def test_normalizer_max():
rng = np.random.RandomState(0)
X_dense = rng.randn(4, 5)
X_sparse_unpruned = sparse.csr_matrix(X_dense)
# set the row number 3 to zero
X_dense[3, :] = 0.0
# set the row number 3 to zero without pruning (can happen in real life)
indptr_3 = X_sparse_unpruned.indptr[3]
indptr_4 = X_sparse_unpruned.indptr[4]
X_sparse_unpruned.data[indptr_3:indptr_4] = 0.0
# build the pruned variant using the regular constructor
X_sparse_pruned = sparse.csr_matrix(X_dense)
# check inputs that support the no-copy optim
for X in (X_dense, X_sparse_pruned, X_sparse_unpruned):
normalizer = Normalizer(norm='max', copy=True)
X_norm1 = normalizer.transform(X)
assert_true(X_norm1 is not X)
X_norm1 = toarray(X_norm1)
normalizer = Normalizer(norm='max', copy=False)
X_norm2 = normalizer.transform(X)
assert_true(X_norm2 is X)
X_norm2 = toarray(X_norm2)
for X_norm in (X_norm1, X_norm2):
row_maxs = X_norm.max(axis=1)
for i in range(3):
assert_almost_equal(row_maxs[i], 1.0)
assert_almost_equal(row_maxs[3], 0.0)
# check input for which copy=False won't prevent a copy
for init in (sparse.coo_matrix, sparse.csc_matrix, sparse.lil_matrix):
X = init(X_dense)
X_norm = normalizer = Normalizer(norm='l2', copy=False).transform(X)
assert_true(X_norm is not X)
assert_true(isinstance(X_norm, sparse.csr_matrix))
X_norm = toarray(X_norm)
for i in range(3):
assert_almost_equal(row_maxs[i], 1.0)
assert_almost_equal(la.norm(X_norm[3]), 0.0)
def test_normalize():
# Test normalize function
# Only tests functionality not used by the tests for Normalizer.
X = np.random.RandomState(37).randn(3, 2)
assert_array_equal(normalize(X, copy=False),
normalize(X.T, axis=0, copy=False).T)
assert_raises(ValueError, normalize, [[0]], axis=2)
assert_raises(ValueError, normalize, [[0]], norm='l3')
def test_binarizer():
X_ = np.array([[1, 0, 5], [2, 3, -1]])
for init in (np.array, list, sparse.csr_matrix, sparse.csc_matrix):
X = init(X_.copy())
binarizer = Binarizer(threshold=2.0, copy=True)
X_bin = toarray(binarizer.transform(X))
assert_equal(np.sum(X_bin == 0), 4)
assert_equal(np.sum(X_bin == 1), 2)
X_bin = binarizer.transform(X)
assert_equal(sparse.issparse(X), sparse.issparse(X_bin))
binarizer = Binarizer(copy=True).fit(X)
X_bin = toarray(binarizer.transform(X))
assert_true(X_bin is not X)
assert_equal(np.sum(X_bin == 0), 2)
assert_equal(np.sum(X_bin == 1), 4)
binarizer = Binarizer(copy=True)
X_bin = binarizer.transform(X)
assert_true(X_bin is not X)
X_bin = toarray(X_bin)
assert_equal(np.sum(X_bin == 0), 2)
assert_equal(np.sum(X_bin == 1), 4)
binarizer = Binarizer(copy=False)
X_bin = binarizer.transform(X)
if init is not list:
assert_true(X_bin is X)
X_bin = toarray(X_bin)
assert_equal(np.sum(X_bin == 0), 2)
assert_equal(np.sum(X_bin == 1), 4)
binarizer = Binarizer(threshold=-0.5, copy=True)
for init in (np.array, list):
X = init(X_.copy())
X_bin = toarray(binarizer.transform(X))
assert_equal(np.sum(X_bin == 0), 1)
assert_equal(np.sum(X_bin == 1), 5)
X_bin = binarizer.transform(X)
# Cannot use threshold < 0 for sparse
assert_raises(ValueError, binarizer.transform, sparse.csc_matrix(X))
def test_center_kernel():
# Test that KernelCenterer is equivalent to StandardScaler
# in feature space
rng = np.random.RandomState(0)
X_fit = rng.random_sample((5, 4))
scaler = StandardScaler(with_std=False)
scaler.fit(X_fit)
X_fit_centered = scaler.transform(X_fit)
K_fit = np.dot(X_fit, X_fit.T)
# center fit time matrix
centerer = KernelCenterer()
K_fit_centered = np.dot(X_fit_centered, X_fit_centered.T)
K_fit_centered2 = centerer.fit_transform(K_fit)
assert_array_almost_equal(K_fit_centered, K_fit_centered2)
# center predict time matrix
X_pred = rng.random_sample((2, 4))
K_pred = np.dot(X_pred, X_fit.T)
X_pred_centered = scaler.transform(X_pred)
K_pred_centered = np.dot(X_pred_centered, X_fit_centered.T)
K_pred_centered2 = centerer.transform(K_pred)
assert_array_almost_equal(K_pred_centered, K_pred_centered2)
def test_fit_transform():
rng = np.random.RandomState(0)
X = rng.random_sample((5, 4))
for obj in ((StandardScaler(), Normalizer(), Binarizer())):
X_transformed = obj.fit(X).transform(X)
X_transformed2 = obj.fit_transform(X)
assert_array_equal(X_transformed, X_transformed2)
def test_add_dummy_feature():
X = [[1, 0], [0, 1], [0, 1]]
X = add_dummy_feature(X)
assert_array_equal(X, [[1, 1, 0], [1, 0, 1], [1, 0, 1]])
def test_add_dummy_feature_coo():
X = sparse.coo_matrix([[1, 0], [0, 1], [0, 1]])
X = add_dummy_feature(X)
assert_true(sparse.isspmatrix_coo(X), X)
assert_array_equal(X.toarray(), [[1, 1, 0], [1, 0, 1], [1, 0, 1]])
def test_add_dummy_feature_csc():
X = sparse.csc_matrix([[1, 0], [0, 1], [0, 1]])
X = add_dummy_feature(X)
assert_true(sparse.isspmatrix_csc(X), X)
assert_array_equal(X.toarray(), [[1, 1, 0], [1, 0, 1], [1, 0, 1]])
def test_add_dummy_feature_csr():
X = sparse.csr_matrix([[1, 0], [0, 1], [0, 1]])
X = add_dummy_feature(X)
assert_true(sparse.isspmatrix_csr(X), X)
assert_array_equal(X.toarray(), [[1, 1, 0], [1, 0, 1], [1, 0, 1]])
def test_one_hot_encoder_sparse():
# Test OneHotEncoder's fit and transform.
X = [[3, 2, 1], [0, 1, 1]]
enc = OneHotEncoder()
# discover max values automatically
X_trans = enc.fit_transform(X).toarray()
assert_equal(X_trans.shape, (2, 5))
assert_array_equal(enc.active_features_,
np.where([1, 0, 0, 1, 0, 1, 1, 0, 1])[0])
assert_array_equal(enc.feature_indices_, [0, 4, 7, 9])
# check outcome
assert_array_equal(X_trans,
[[0., 1., 0., 1., 1.],
[1., 0., 1., 0., 1.]])
# max value given as 3
enc = OneHotEncoder(n_values=4)
X_trans = enc.fit_transform(X)
assert_equal(X_trans.shape, (2, 4 * 3))
assert_array_equal(enc.feature_indices_, [0, 4, 8, 12])
# max value given per feature
enc = OneHotEncoder(n_values=[3, 2, 2])
X = [[1, 0, 1], [0, 1, 1]]
X_trans = enc.fit_transform(X)
assert_equal(X_trans.shape, (2, 3 + 2 + 2))
assert_array_equal(enc.n_values_, [3, 2, 2])
# check that testing with larger feature works:
X = np.array([[2, 0, 1], [0, 1, 1]])
enc.transform(X)
# test that an error is raised when out of bounds:
X_too_large = [[0, 2, 1], [0, 1, 1]]
assert_raises(ValueError, enc.transform, X_too_large)
assert_raises(ValueError, OneHotEncoder(n_values=2).fit_transform, X)
# test that error is raised when wrong number of features
assert_raises(ValueError, enc.transform, X[:, :-1])
# test that error is raised when wrong number of features in fit
# with prespecified n_values
assert_raises(ValueError, enc.fit, X[:, :-1])
# test exception on wrong init param
assert_raises(TypeError, OneHotEncoder(n_values=np.int).fit, X)
enc = OneHotEncoder()
# test negative input to fit
assert_raises(ValueError, enc.fit, [[0], [-1]])
# test negative input to transform
enc.fit([[0], [1]])
assert_raises(ValueError, enc.transform, [[0], [-1]])
def test_one_hot_encoder_dense():
# check for sparse=False
X = [[3, 2, 1], [0, 1, 1]]
enc = OneHotEncoder(sparse=False)
# discover max values automatically
X_trans = enc.fit_transform(X)
assert_equal(X_trans.shape, (2, 5))
assert_array_equal(enc.active_features_,
np.where([1, 0, 0, 1, 0, 1, 1, 0, 1])[0])
assert_array_equal(enc.feature_indices_, [0, 4, 7, 9])
# check outcome
assert_array_equal(X_trans,
np.array([[0., 1., 0., 1., 1.],
[1., 0., 1., 0., 1.]]))
def _check_transform_selected(X, X_expected, sel):
for M in (X, sparse.csr_matrix(X)):
Xtr = _transform_selected(M, Binarizer().transform, sel)
assert_array_equal(toarray(Xtr), X_expected)
def test_transform_selected():
X = [[3, 2, 1], [0, 1, 1]]
X_expected = [[1, 2, 1], [0, 1, 1]]
_check_transform_selected(X, X_expected, [0])
_check_transform_selected(X, X_expected, [True, False, False])
X_expected = [[1, 1, 1], [0, 1, 1]]
_check_transform_selected(X, X_expected, [0, 1, 2])
_check_transform_selected(X, X_expected, [True, True, True])
_check_transform_selected(X, X_expected, "all")
_check_transform_selected(X, X, [])
_check_transform_selected(X, X, [False, False, False])
def _run_one_hot(X, X2, cat):
enc = OneHotEncoder(categorical_features=cat)
Xtr = enc.fit_transform(X)
X2tr = enc.transform(X2)
return Xtr, X2tr
def _check_one_hot(X, X2, cat, n_features):
ind = np.where(cat)[0]
# With mask
A, B = _run_one_hot(X, X2, cat)
# With indices
C, D = _run_one_hot(X, X2, ind)
# Check shape
assert_equal(A.shape, (2, n_features))
assert_equal(B.shape, (1, n_features))
assert_equal(C.shape, (2, n_features))
assert_equal(D.shape, (1, n_features))
# Check that mask and indices give the same results
assert_array_equal(toarray(A), toarray(C))
assert_array_equal(toarray(B), toarray(D))
def test_one_hot_encoder_categorical_features():
X = np.array([[3, 2, 1], [0, 1, 1]])
X2 = np.array([[1, 1, 1]])
cat = [True, False, False]
_check_one_hot(X, X2, cat, 4)
# Edge case: all non-categorical
cat = [False, False, False]
_check_one_hot(X, X2, cat, 3)
# Edge case: all categorical
cat = [True, True, True]
_check_one_hot(X, X2, cat, 5)
def test_one_hot_encoder_unknown_transform():
X = np.array([[0, 2, 1], [1, 0, 3], [1, 0, 2]])
y = np.array([[4, 1, 1]])
# Test that one hot encoder raises error for unknown features
# present during transform.
oh = OneHotEncoder(handle_unknown='error')
oh.fit(X)
assert_raises(ValueError, oh.transform, y)
# Test the ignore option, ignores unknown features.
oh = OneHotEncoder(handle_unknown='ignore')
oh.fit(X)
assert_array_equal(
oh.transform(y).toarray(),
np.array([[0., 0., 0., 0., 1., 0., 0.]])
)
# Raise error if handle_unknown is neither ignore or error.
oh = OneHotEncoder(handle_unknown='42')
oh.fit(X)
assert_raises(ValueError, oh.transform, y)
| bsd-3-clause |
MechCoder/scikit-learn | sklearn/metrics/tests/test_score_objects.py | 33 | 17877 | import pickle
import tempfile
import shutil
import os
import numbers
import numpy as np
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_raises_regexp
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import ignore_warnings
from sklearn.utils.testing import assert_not_equal
from sklearn.utils.testing import assert_warns_message
from sklearn.base import BaseEstimator
from sklearn.metrics import (f1_score, r2_score, roc_auc_score, fbeta_score,
log_loss, precision_score, recall_score)
from sklearn.metrics import cluster as cluster_module
from sklearn.metrics.scorer import (check_scoring, _PredictScorer,
_passthrough_scorer)
from sklearn.metrics import make_scorer, get_scorer, SCORERS
from sklearn.svm import LinearSVC
from sklearn.pipeline import make_pipeline
from sklearn.cluster import KMeans
from sklearn.dummy import DummyRegressor
from sklearn.linear_model import Ridge, LogisticRegression
from sklearn.tree import DecisionTreeClassifier, DecisionTreeRegressor
from sklearn.datasets import make_blobs
from sklearn.datasets import make_classification
from sklearn.datasets import make_multilabel_classification
from sklearn.datasets import load_diabetes
from sklearn.model_selection import train_test_split, cross_val_score
from sklearn.model_selection import GridSearchCV
from sklearn.multiclass import OneVsRestClassifier
from sklearn.externals import joblib
REGRESSION_SCORERS = ['r2', 'neg_mean_absolute_error',
'neg_mean_squared_error', 'neg_mean_squared_log_error',
'neg_median_absolute_error', 'mean_absolute_error',
'mean_squared_error', 'median_absolute_error']
CLF_SCORERS = ['accuracy', 'f1', 'f1_weighted', 'f1_macro', 'f1_micro',
'roc_auc', 'average_precision', 'precision',
'precision_weighted', 'precision_macro', 'precision_micro',
'recall', 'recall_weighted', 'recall_macro', 'recall_micro',
'neg_log_loss', 'log_loss']
# All supervised cluster scorers (They behave like classification metric)
CLUSTER_SCORERS = ["adjusted_rand_score",
"homogeneity_score",
"completeness_score",
"v_measure_score",
"mutual_info_score",
"adjusted_mutual_info_score",
"normalized_mutual_info_score",
"fowlkes_mallows_score"]
MULTILABEL_ONLY_SCORERS = ['precision_samples', 'recall_samples', 'f1_samples']
def _make_estimators(X_train, y_train, y_ml_train):
# Make estimators that make sense to test various scoring methods
sensible_regr = DummyRegressor(strategy='median')
sensible_regr.fit(X_train, y_train)
sensible_clf = DecisionTreeClassifier(random_state=0)
sensible_clf.fit(X_train, y_train)
sensible_ml_clf = DecisionTreeClassifier(random_state=0)
sensible_ml_clf.fit(X_train, y_ml_train)
return dict(
[(name, sensible_regr) for name in REGRESSION_SCORERS] +
[(name, sensible_clf) for name in CLF_SCORERS] +
[(name, sensible_clf) for name in CLUSTER_SCORERS] +
[(name, sensible_ml_clf) for name in MULTILABEL_ONLY_SCORERS]
)
X_mm, y_mm, y_ml_mm = None, None, None
ESTIMATORS = None
TEMP_FOLDER = None
def setup_module():
# Create some memory mapped data
global X_mm, y_mm, y_ml_mm, TEMP_FOLDER, ESTIMATORS
TEMP_FOLDER = tempfile.mkdtemp(prefix='sklearn_test_score_objects_')
X, y = make_classification(n_samples=30, n_features=5, random_state=0)
_, y_ml = make_multilabel_classification(n_samples=X.shape[0],
random_state=0)
filename = os.path.join(TEMP_FOLDER, 'test_data.pkl')
joblib.dump((X, y, y_ml), filename)
X_mm, y_mm, y_ml_mm = joblib.load(filename, mmap_mode='r')
ESTIMATORS = _make_estimators(X_mm, y_mm, y_ml_mm)
def teardown_module():
global X_mm, y_mm, y_ml_mm, TEMP_FOLDER, ESTIMATORS
# GC closes the mmap file descriptors
X_mm, y_mm, y_ml_mm, ESTIMATORS = None, None, None, None
shutil.rmtree(TEMP_FOLDER)
class EstimatorWithoutFit(object):
"""Dummy estimator to test check_scoring"""
pass
class EstimatorWithFit(BaseEstimator):
"""Dummy estimator to test check_scoring"""
def fit(self, X, y):
return self
class EstimatorWithFitAndScore(object):
"""Dummy estimator to test check_scoring"""
def fit(self, X, y):
return self
def score(self, X, y):
return 1.0
class EstimatorWithFitAndPredict(object):
"""Dummy estimator to test check_scoring"""
def fit(self, X, y):
self.y = y
return self
def predict(self, X):
return self.y
class DummyScorer(object):
"""Dummy scorer that always returns 1."""
def __call__(self, est, X, y):
return 1
def test_all_scorers_repr():
# Test that all scorers have a working repr
for name, scorer in SCORERS.items():
repr(scorer)
def test_check_scoring():
# Test all branches of check_scoring
estimator = EstimatorWithoutFit()
pattern = (r"estimator should be an estimator implementing 'fit' method,"
r" .* was passed")
assert_raises_regexp(TypeError, pattern, check_scoring, estimator)
estimator = EstimatorWithFitAndScore()
estimator.fit([[1]], [1])
scorer = check_scoring(estimator)
assert_true(scorer is _passthrough_scorer)
assert_almost_equal(scorer(estimator, [[1]], [1]), 1.0)
estimator = EstimatorWithFitAndPredict()
estimator.fit([[1]], [1])
pattern = (r"If no scoring is specified, the estimator passed should have"
r" a 'score' method\. The estimator .* does not\.")
assert_raises_regexp(TypeError, pattern, check_scoring, estimator)
scorer = check_scoring(estimator, "accuracy")
assert_almost_equal(scorer(estimator, [[1]], [1]), 1.0)
estimator = EstimatorWithFit()
scorer = check_scoring(estimator, "accuracy")
assert_true(isinstance(scorer, _PredictScorer))
estimator = EstimatorWithFit()
scorer = check_scoring(estimator, allow_none=True)
assert_true(scorer is None)
def test_check_scoring_gridsearchcv():
# test that check_scoring works on GridSearchCV and pipeline.
# slightly redundant non-regression test.
grid = GridSearchCV(LinearSVC(), param_grid={'C': [.1, 1]})
scorer = check_scoring(grid, "f1")
assert_true(isinstance(scorer, _PredictScorer))
pipe = make_pipeline(LinearSVC())
scorer = check_scoring(pipe, "f1")
assert_true(isinstance(scorer, _PredictScorer))
# check that cross_val_score definitely calls the scorer
# and doesn't make any assumptions about the estimator apart from having a
# fit.
scores = cross_val_score(EstimatorWithFit(), [[1], [2], [3]], [1, 0, 1],
scoring=DummyScorer())
assert_array_equal(scores, 1)
def test_make_scorer():
# Sanity check on the make_scorer factory function.
f = lambda *args: 0
assert_raises(ValueError, make_scorer, f, needs_threshold=True,
needs_proba=True)
def test_classification_scores():
# Test classification scorers.
X, y = make_blobs(random_state=0, centers=2)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf = LinearSVC(random_state=0)
clf.fit(X_train, y_train)
for prefix, metric in [('f1', f1_score), ('precision', precision_score),
('recall', recall_score)]:
score1 = get_scorer('%s_weighted' % prefix)(clf, X_test, y_test)
score2 = metric(y_test, clf.predict(X_test), pos_label=None,
average='weighted')
assert_almost_equal(score1, score2)
score1 = get_scorer('%s_macro' % prefix)(clf, X_test, y_test)
score2 = metric(y_test, clf.predict(X_test), pos_label=None,
average='macro')
assert_almost_equal(score1, score2)
score1 = get_scorer('%s_micro' % prefix)(clf, X_test, y_test)
score2 = metric(y_test, clf.predict(X_test), pos_label=None,
average='micro')
assert_almost_equal(score1, score2)
score1 = get_scorer('%s' % prefix)(clf, X_test, y_test)
score2 = metric(y_test, clf.predict(X_test), pos_label=1)
assert_almost_equal(score1, score2)
# test fbeta score that takes an argument
scorer = make_scorer(fbeta_score, beta=2)
score1 = scorer(clf, X_test, y_test)
score2 = fbeta_score(y_test, clf.predict(X_test), beta=2)
assert_almost_equal(score1, score2)
# test that custom scorer can be pickled
unpickled_scorer = pickle.loads(pickle.dumps(scorer))
score3 = unpickled_scorer(clf, X_test, y_test)
assert_almost_equal(score1, score3)
# smoke test the repr:
repr(fbeta_score)
def test_regression_scorers():
# Test regression scorers.
diabetes = load_diabetes()
X, y = diabetes.data, diabetes.target
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf = Ridge()
clf.fit(X_train, y_train)
score1 = get_scorer('r2')(clf, X_test, y_test)
score2 = r2_score(y_test, clf.predict(X_test))
assert_almost_equal(score1, score2)
def test_thresholded_scorers():
# Test scorers that take thresholds.
X, y = make_blobs(random_state=0, centers=2)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf = LogisticRegression(random_state=0)
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.decision_function(X_test))
score3 = roc_auc_score(y_test, clf.predict_proba(X_test)[:, 1])
assert_almost_equal(score1, score2)
assert_almost_equal(score1, score3)
logscore = get_scorer('neg_log_loss')(clf, X_test, y_test)
logloss = log_loss(y_test, clf.predict_proba(X_test))
assert_almost_equal(-logscore, logloss)
# same for an estimator without decision_function
clf = DecisionTreeClassifier()
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.predict_proba(X_test)[:, 1])
assert_almost_equal(score1, score2)
# test with a regressor (no decision_function)
reg = DecisionTreeRegressor()
reg.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(reg, X_test, y_test)
score2 = roc_auc_score(y_test, reg.predict(X_test))
assert_almost_equal(score1, score2)
# Test that an exception is raised on more than two classes
X, y = make_blobs(random_state=0, centers=3)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf.fit(X_train, y_train)
assert_raises(ValueError, get_scorer('roc_auc'), clf, X_test, y_test)
def test_thresholded_scorers_multilabel_indicator_data():
# Test that the scorer work with multilabel-indicator format
# for multilabel and multi-output multi-class classifier
X, y = make_multilabel_classification(allow_unlabeled=False,
random_state=0)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
# Multi-output multi-class predict_proba
clf = DecisionTreeClassifier()
clf.fit(X_train, y_train)
y_proba = clf.predict_proba(X_test)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, np.vstack(p[:, -1] for p in y_proba).T)
assert_almost_equal(score1, score2)
# Multi-output multi-class decision_function
# TODO Is there any yet?
clf = DecisionTreeClassifier()
clf.fit(X_train, y_train)
clf._predict_proba = clf.predict_proba
clf.predict_proba = None
clf.decision_function = lambda X: [p[:, 1] for p in clf._predict_proba(X)]
y_proba = clf.decision_function(X_test)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, np.vstack(p for p in y_proba).T)
assert_almost_equal(score1, score2)
# Multilabel predict_proba
clf = OneVsRestClassifier(DecisionTreeClassifier())
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.predict_proba(X_test))
assert_almost_equal(score1, score2)
# Multilabel decision function
clf = OneVsRestClassifier(LinearSVC(random_state=0))
clf.fit(X_train, y_train)
score1 = get_scorer('roc_auc')(clf, X_test, y_test)
score2 = roc_auc_score(y_test, clf.decision_function(X_test))
assert_almost_equal(score1, score2)
def test_supervised_cluster_scorers():
# Test clustering scorers against gold standard labeling.
X, y = make_blobs(random_state=0, centers=2)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
km = KMeans(n_clusters=3)
km.fit(X_train)
for name in CLUSTER_SCORERS:
score1 = get_scorer(name)(km, X_test, y_test)
score2 = getattr(cluster_module, name)(y_test, km.predict(X_test))
assert_almost_equal(score1, score2)
@ignore_warnings
def test_raises_on_score_list():
# Test that when a list of scores is returned, we raise proper errors.
X, y = make_blobs(random_state=0)
f1_scorer_no_average = make_scorer(f1_score, average=None)
clf = DecisionTreeClassifier()
assert_raises(ValueError, cross_val_score, clf, X, y,
scoring=f1_scorer_no_average)
grid_search = GridSearchCV(clf, scoring=f1_scorer_no_average,
param_grid={'max_depth': [1, 2]})
assert_raises(ValueError, grid_search.fit, X, y)
@ignore_warnings
def test_scorer_sample_weight():
# Test that scorers support sample_weight or raise sensible errors
# Unlike the metrics invariance test, in the scorer case it's harder
# to ensure that, on the classifier output, weighted and unweighted
# scores really should be unequal.
X, y = make_classification(random_state=0)
_, y_ml = make_multilabel_classification(n_samples=X.shape[0],
random_state=0)
split = train_test_split(X, y, y_ml, random_state=0)
X_train, X_test, y_train, y_test, y_ml_train, y_ml_test = split
sample_weight = np.ones_like(y_test)
sample_weight[:10] = 0
# get sensible estimators for each metric
estimator = _make_estimators(X_train, y_train, y_ml_train)
for name, scorer in SCORERS.items():
if name in MULTILABEL_ONLY_SCORERS:
target = y_ml_test
else:
target = y_test
try:
weighted = scorer(estimator[name], X_test, target,
sample_weight=sample_weight)
ignored = scorer(estimator[name], X_test[10:], target[10:])
unweighted = scorer(estimator[name], X_test, target)
assert_not_equal(weighted, unweighted,
msg="scorer {0} behaves identically when "
"called with sample weights: {1} vs "
"{2}".format(name, weighted, unweighted))
assert_almost_equal(weighted, ignored,
err_msg="scorer {0} behaves differently when "
"ignoring samples and setting sample_weight to"
" 0: {1} vs {2}".format(name, weighted,
ignored))
except TypeError as e:
assert_true("sample_weight" in str(e),
"scorer {0} raises unhelpful exception when called "
"with sample weights: {1}".format(name, str(e)))
@ignore_warnings # UndefinedMetricWarning for P / R scores
def check_scorer_memmap(scorer_name):
scorer, estimator = SCORERS[scorer_name], ESTIMATORS[scorer_name]
if scorer_name in MULTILABEL_ONLY_SCORERS:
score = scorer(estimator, X_mm, y_ml_mm)
else:
score = scorer(estimator, X_mm, y_mm)
assert isinstance(score, numbers.Number), scorer_name
def test_scorer_memmap_input():
# Non-regression test for #6147: some score functions would
# return singleton memmap when computed on memmap data instead of scalar
# float values.
for name in SCORERS.keys():
yield check_scorer_memmap, name
def test_deprecated_names():
X, y = make_blobs(random_state=0, centers=2)
X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=0)
clf = LogisticRegression(random_state=0)
clf.fit(X_train, y_train)
for name in ('mean_absolute_error', 'mean_squared_error',
'median_absolute_error', 'log_loss'):
warning_msg = "Scoring method %s was renamed to" % name
for scorer in (get_scorer(name), SCORERS[name]):
assert_warns_message(DeprecationWarning,
warning_msg,
scorer, clf, X, y)
assert_warns_message(DeprecationWarning,
warning_msg,
cross_val_score, clf, X, y, scoring=name)
def test_scoring_is_not_metric():
assert_raises_regexp(ValueError, 'make_scorer', check_scoring,
LogisticRegression(), f1_score)
assert_raises_regexp(ValueError, 'make_scorer', check_scoring,
LogisticRegression(), roc_auc_score)
assert_raises_regexp(ValueError, 'make_scorer', check_scoring,
Ridge(), r2_score)
assert_raises_regexp(ValueError, 'make_scorer', check_scoring,
KMeans(), cluster_module.adjusted_rand_score)
| bsd-3-clause |
alexsavio/scikit-learn | benchmarks/bench_mnist.py | 38 | 6799 | """
=======================
MNIST dataset benchmark
=======================
Benchmark on the MNIST dataset. The dataset comprises 70,000 samples
and 784 features. Here, we consider the task of predicting
10 classes - digits from 0 to 9 from their raw images. By contrast to the
covertype dataset, the feature space is homogenous.
Example of output :
[..]
Classification performance:
===========================
Classifier train-time test-time error-rate
------------------------------------------------------------
MLP_adam 53.46s 0.11s 0.0224
Nystroem-SVM 112.97s 0.92s 0.0228
MultilayerPerceptron 24.33s 0.14s 0.0287
ExtraTrees 42.99s 0.57s 0.0294
RandomForest 42.70s 0.49s 0.0318
SampledRBF-SVM 135.81s 0.56s 0.0486
LinearRegression-SAG 16.67s 0.06s 0.0824
CART 20.69s 0.02s 0.1219
dummy 0.00s 0.01s 0.8973
"""
from __future__ import division, print_function
# Author: Issam H. Laradji
# Arnaud Joly <[email protected]>
# License: BSD 3 clause
import os
from time import time
import argparse
import numpy as np
from sklearn.datasets import fetch_mldata
from sklearn.datasets import get_data_home
from sklearn.ensemble import ExtraTreesClassifier
from sklearn.ensemble import RandomForestClassifier
from sklearn.dummy import DummyClassifier
from sklearn.externals.joblib import Memory
from sklearn.kernel_approximation import Nystroem
from sklearn.kernel_approximation import RBFSampler
from sklearn.metrics import zero_one_loss
from sklearn.pipeline import make_pipeline
from sklearn.svm import LinearSVC
from sklearn.tree import DecisionTreeClassifier
from sklearn.utils import check_array
from sklearn.linear_model import LogisticRegression
from sklearn.neural_network import MLPClassifier
# Memoize the data extraction and memory map the resulting
# train / test splits in readonly mode
memory = Memory(os.path.join(get_data_home(), 'mnist_benchmark_data'),
mmap_mode='r')
@memory.cache
def load_data(dtype=np.float32, order='F'):
"""Load the data, then cache and memmap the train/test split"""
######################################################################
# Load dataset
print("Loading dataset...")
data = fetch_mldata('MNIST original')
X = check_array(data['data'], dtype=dtype, order=order)
y = data["target"]
# Normalize features
X = X / 255
# Create train-test split (as [Joachims, 2006])
print("Creating train-test split...")
n_train = 60000
X_train = X[:n_train]
y_train = y[:n_train]
X_test = X[n_train:]
y_test = y[n_train:]
return X_train, X_test, y_train, y_test
ESTIMATORS = {
"dummy": DummyClassifier(),
'CART': DecisionTreeClassifier(),
'ExtraTrees': ExtraTreesClassifier(n_estimators=100),
'RandomForest': RandomForestClassifier(n_estimators=100),
'Nystroem-SVM': make_pipeline(
Nystroem(gamma=0.015, n_components=1000), LinearSVC(C=100)),
'SampledRBF-SVM': make_pipeline(
RBFSampler(gamma=0.015, n_components=1000), LinearSVC(C=100)),
'LinearRegression-SAG': LogisticRegression(solver='sag', tol=1e-1, C=1e4),
'MultilayerPerceptron': MLPClassifier(
hidden_layer_sizes=(100, 100), max_iter=400, alpha=1e-4,
algorithm='sgd', learning_rate_init=0.2, momentum=0.9, verbose=1,
tol=1e-4, random_state=1),
'MLP-adam': MLPClassifier(
hidden_layer_sizes=(100, 100), max_iter=400, alpha=1e-4,
algorithm='adam', learning_rate_init=0.001, verbose=1,
tol=1e-4, random_state=1)
}
if __name__ == "__main__":
parser = argparse.ArgumentParser()
parser.add_argument('--classifiers', nargs="+",
choices=ESTIMATORS, type=str,
default=['ExtraTrees', 'Nystroem-SVM'],
help="list of classifiers to benchmark.")
parser.add_argument('--n-jobs', nargs="?", default=1, type=int,
help="Number of concurrently running workers for "
"models that support parallelism.")
parser.add_argument('--order', nargs="?", default="C", type=str,
choices=["F", "C"],
help="Allow to choose between fortran and C ordered "
"data")
parser.add_argument('--random-seed', nargs="?", default=0, type=int,
help="Common seed used by random number generator.")
args = vars(parser.parse_args())
print(__doc__)
X_train, X_test, y_train, y_test = load_data(order=args["order"])
print("")
print("Dataset statistics:")
print("===================")
print("%s %d" % ("number of features:".ljust(25), X_train.shape[1]))
print("%s %d" % ("number of classes:".ljust(25), np.unique(y_train).size))
print("%s %s" % ("data type:".ljust(25), X_train.dtype))
print("%s %d (size=%dMB)" % ("number of train samples:".ljust(25),
X_train.shape[0], int(X_train.nbytes / 1e6)))
print("%s %d (size=%dMB)" % ("number of test samples:".ljust(25),
X_test.shape[0], int(X_test.nbytes / 1e6)))
print()
print("Training Classifiers")
print("====================")
error, train_time, test_time = {}, {}, {}
for name in sorted(args["classifiers"]):
print("Training %s ... " % name, end="")
estimator = ESTIMATORS[name]
estimator_params = estimator.get_params()
estimator.set_params(**{p: args["random_seed"]
for p in estimator_params
if p.endswith("random_state")})
if "n_jobs" in estimator_params:
estimator.set_params(n_jobs=args["n_jobs"])
time_start = time()
estimator.fit(X_train, y_train)
train_time[name] = time() - time_start
time_start = time()
y_pred = estimator.predict(X_test)
test_time[name] = time() - time_start
error[name] = zero_one_loss(y_test, y_pred)
print("done")
print()
print("Classification performance:")
print("===========================")
print("{0: <24} {1: >10} {2: >11} {3: >12}"
"".format("Classifier ", "train-time", "test-time", "error-rate"))
print("-" * 60)
for name in sorted(args["classifiers"], key=error.get):
print("{0: <23} {1: >10.2f}s {2: >10.2f}s {3: >12.4f}"
"".format(name, train_time[name], test_time[name], error[name]))
print()
| bsd-3-clause |
chengsoonong/acton | acton/database.py | 1 | 72157 | """Wrapper class for databases."""
from abc import ABC, abstractmethod
from inspect import Traceback
import json
import logging
import os.path
import tempfile
from typing import Iterable, List, Sequence
import warnings
import time
from acton.proto.acton_pb2 import Database as DatabasePB
import astropy.io.ascii as io_ascii
import astropy.io.fits as io_fits
import astropy.table
import h5py
import numpy
import pandas
import sklearn.preprocessing
from numpy.random import multivariate_normal
LabelEncoderPB = DatabasePB.LabelEncoder
def product(seq: Iterable[int]):
"""Finds the product of a list of ints.
Arguments
---------
seq
List of ints.
Returns
-------
int
Product.
"""
prod = 1
for i in seq:
prod *= i
return prod
def serialise_encoder(
encoder: sklearn.preprocessing.LabelEncoder) -> LabelEncoderPB:
"""Serialises a LabelEncoder as a protobuf.
Parameters
----------
encoder
LabelEncoder.
Returns
-------
LabelEncoderPB
Protobuf representing the LabelEncoder.
"""
proto = LabelEncoderPB()
if not hasattr(encoder, 'classes_'):
return proto
for i, class_label in enumerate(encoder.classes_):
encoding = proto.encoding.add()
encoding.class_label = str(class_label)
encoding.class_int = i
return proto
class Database(ABC):
"""Base class for database wrappers."""
@abstractmethod
def __enter__(self):
return self
@abstractmethod
def __exit__(self, exc_type: Exception, exc_val: object, exc_tb: Traceback):
pass
@abstractmethod
def read_features(self, ids: Sequence[int]) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
ids
Iterable of IDs.
Returns
-------
numpy.ndarray
N x D array of feature vectors.
"""
@abstractmethod
def read_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
Returns
-------
numpy.ndarray
T x N x F array of label vectors.
"""
@abstractmethod
def write_features(self, ids: Sequence[int], features: numpy.ndarray):
"""Writes feature vectors to the database.
Parameters
----------
ids
Iterable of IDs.
features
N x D array of feature vectors. The ith row corresponds to the ith
ID in `ids`.
"""
@abstractmethod
def write_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int],
labels: numpy.ndarray):
"""Writes label vectors to the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
labels
T x N x D array of label vectors. The ith row corresponds to the ith
labeller ID in `labeller_ids` and the jth column corresponds to the
jth instance ID in `instance_ids`.
"""
@abstractmethod
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
@abstractmethod
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
@abstractmethod
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
class HDF5Database(Database):
"""Database wrapping an HDF5 file as a context manager.
Attributes
----------
path : str
Path to HDF5 file.
_h5_file : h5py.File
HDF5 file object.
"""
def __init__(self, path: str):
self.path = path
def __enter__(self):
self._open_hdf5()
return self
def __exit__(self, exc_type: Exception, exc_val: object, exc_tb: Traceback):
self._h5_file.close()
delattr(self, '_h5_file')
def _assert_open(self):
"""Asserts that the HDF5 file is ready to be read to/written from.
Raises
------
AssertionError
"""
assert hasattr(self, '_h5_file'), ('HDF5 database must be used as a '
'context manager.')
def _open_hdf5(self):
"""Opens the HDF5 file and creates it if it doesn't exist.
Notes
-----
The HDF5 file will be stored in self._h5_file.
"""
try:
self._h5_file = h5py.File(self.path, 'r+')
except OSError:
with h5py.File(self.path, 'w') as h5_file:
self._setup_hdf5(h5_file)
self._h5_file = h5py.File(self.path, 'r+')
class ManagedHDF5Database(HDF5Database):
"""Database using an HDF5 file.
Notes
-----
This database uses an internal schema. For reading files from disk, use
another Database.
Attributes
----------
path : str
Path to HDF5 file.
label_dtype : str
Data type of labels.
feature_dtype : str
Data type of features.
_h5_file : h5py.File
Opened HDF5 file.
_sync_attrs : List[str]
List of instance attributes to sync with the HDF5 file's attributes.
"""
def __init__(self, path: str, label_dtype: str=None,
feature_dtype: str=None):
"""
Parameters
----------
path
Path to HDF5 file.
label_dtype
Data type of labels. If not provided then it will be read from the
database file; if the database file does not exist then the default
type of 'float32' will be used.
feature_dtype
Data type of features. If not provided then it will be read from the
database file; if the database file does not exist then the default
type of 'float32' will be used.
"""
super().__init__(path)
self.label_dtype = label_dtype
self._default_label_dtype = 'float32'
self.feature_dtype = feature_dtype
self._default_feature_dtype = 'float32'
# List of attributes to keep in sync with the HDF5 file.
self._sync_attrs = ['label_dtype', 'feature_dtype']
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
proto = DatabasePB()
proto.path = self.path
proto.class_name = 'ManagedHDF5Database'
db_kwargs = {
'label_dtype': self.label_dtype,
'feature_dtype': self.feature_dtype}
for key, value in db_kwargs.items():
kwarg = proto.kwarg.add()
kwarg.key = key
kwarg.value = json.dumps(value)
# No encoder for a managed DB - assume that labels are encoded already.
# proto.label_encoder.CopyFrom(serialise_encoder(self.label_encoder))
return proto
def _open_hdf5(self):
"""Opens the HDF5 file and creates it if it doesn't exist.
Notes
-----
The HDF5 file will be stored in self._h5_file.
"""
super()._open_hdf5()
# Load attrs from HDF5 file if we haven't specified them.
for attr in self._sync_attrs:
if getattr(self, attr) is None:
setattr(self, attr, self._h5_file.attrs[attr])
self._validate_hdf5()
def write_features(self, ids: Sequence[int], features: numpy.ndarray):
"""Writes feature vectors to the database.
Parameters
----------
ids
Iterable of IDs.
features:
N x D array of feature vectors. The ith row corresponds to the ith
ID in `ids`.
Returns
-------
numpy.ndarray
N x D array of feature vectors.
"""
self._assert_open()
# Input validation.
if len(ids) != len(features):
raise ValueError('Must have same number of IDs and features.')
if self._h5_file.attrs['n_features'] == -1:
# This is the first time we've stored features, so make a record of
# the dimensionality.
self._h5_file.attrs['n_features'] = features.shape[1]
elif self._h5_file.attrs['n_features'] != features.shape[1]:
raise ValueError(
'Expected features to have dimensionality {}, got {}'.format(
self._h5_file.attrs['n_features'], features.shape[1]))
# Early termination.
if not ids:
return
# Cast the features to the right type.
if features.dtype != self.feature_dtype:
warnings.warn('Casting features from type {} to type {}.'.format(
features.dtype, self.feature_dtype))
features = features.astype(self.feature_dtype)
# Resize the feature array if we need to store more IDs than before.
max_id = max(ids) + 1
if max_id > self._h5_file['features'].shape[0]:
self._h5_file['features'].resize(
(max_id, self._h5_file.attrs['n_features']))
# Store the feature vectors.
# TODO(MatthewJA): Vectorise this. This could be tricky as HDF5 doesn't
# fully support NumPy's fancy indexing.
for id_, feature in zip(ids, features):
self._h5_file['features'][id_, :] = feature
# Add the IDs to the database.
known_ids = set(self.get_known_instance_ids())
new_ids = [i for i in ids if i not in known_ids]
n_new_ids = len(new_ids)
n_old_ids = self._h5_file['instance_ids'].shape[0]
self._h5_file['instance_ids'].resize((n_old_ids + n_new_ids,))
self._h5_file['instance_ids'][-n_new_ids:] = numpy.array(
new_ids, dtype=int)
def read_features(self, ids: Sequence[int]) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
ids
Iterable of IDs.
Returns
-------
numpy.ndarray
N x D array of feature vectors.
"""
self._assert_open()
if self._h5_file.attrs['n_features'] == -1 and ids:
raise KeyError('No features stored in database.')
# Allocate the features array.
features = numpy.zeros((len(ids), self._h5_file.attrs['n_features']),
dtype=self._h5_file.attrs['feature_dtype'])
# Loop through each ID we want to query and put the associated feature
# into the features array.
features = self._h5_file['features'].value[ids, :]
features = numpy.asarray(
features, dtype=self._h5_file.attrs['feature_dtype'])
return features
def write_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int],
labels: numpy.ndarray):
"""Writes label vectors to the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
labels
T x N x D array of label vectors. The ith row corresponds to the ith
labeller ID in `labeller_ids` and the jth column corresponds to the
jth instance ID in `instance_ids`.
"""
self._assert_open()
# Input validation.
if len(labeller_ids) != labels.shape[0]:
raise ValueError(
'labels array has incorrect number of labellers:'
' expected {}, got {}.'.format(len(labeller_ids),
labels.shape[0]))
if len(instance_ids) != labels.shape[1]:
raise ValueError(
'labels array has incorrect number of instances:'
' expected {}, got {}.'.format(len(instance_ids),
labels.shape[1]))
if self._h5_file.attrs['label_dim'] == -1:
# This is the first time we've stored labels, so make a record of
# the dimensionality.
self._h5_file.attrs['label_dim'] = labels.shape[2]
elif self._h5_file.attrs['label_dim'] != labels.shape[2]:
raise ValueError(
'Expected labels to have dimensionality {}, got {}'.format(
self._h5_file.attrs['label_dim'], labels.shape[2]))
# Early termination.
if not labeller_ids or not instance_ids:
return
# Cast the labels to the right type.
if labels.dtype != self.label_dtype:
warnings.warn('Casting labels from type {} to type {}.'.format(
labels.dtype, self.label_dtype))
labels = labels.astype(self.label_dtype)
# Resize the label array if necessary.
max_labeller_id = max(labeller_ids) + 1
max_instance_id = max(instance_ids) + 1
if (max_labeller_id > self._h5_file['labels'].shape[0] or
max_instance_id > self._h5_file['labels'].shape[1]):
self._h5_file['labels'].resize(
(max_labeller_id, max_instance_id,
self._h5_file.attrs['label_dim']))
# Store the labels.
# TODO(MatthewJA): Vectorise this.
for labeller_idx, labeller_id in enumerate(labeller_ids):
for instance_idx, instance_id in enumerate(instance_ids):
label = labels[labeller_idx, instance_idx]
self._h5_file['labels'][
labeller_id, instance_id, :] = label
logging.debug(
'New label array size: {}'.format(self._h5_file['labels'].shape))
# Add the instance IDs to the database.
known_instance_ids = set(self.get_known_instance_ids())
new_instance_ids = [i for i in instance_ids
if i not in known_instance_ids]
n_new_instance_ids = len(new_instance_ids)
n_old_instance_ids = self._h5_file['instance_ids'].shape[0]
if n_new_instance_ids:
self._h5_file['instance_ids'].resize(
(n_old_instance_ids + n_new_instance_ids,))
self._h5_file['instance_ids'][-n_new_instance_ids:] = numpy.array(
new_instance_ids, dtype=int)
# Add the labeller IDs to the database.
known_labeller_ids = set(self.get_known_labeller_ids())
new_labeller_ids = [i for i in labeller_ids
if i not in known_labeller_ids]
n_new_labeller_ids = len(new_labeller_ids)
n_old_labeller_ids = self._h5_file['labeller_ids'].shape[0]
if n_new_labeller_ids:
self._h5_file['labeller_ids'].resize(
(n_old_labeller_ids + n_new_labeller_ids,))
self._h5_file['labeller_ids'][-n_new_labeller_ids:] = numpy.array(
new_labeller_ids, dtype=int)
def read_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
Returns
-------
numpy.ndarray
T x N x F array of label vectors.
"""
self._assert_open()
if self._h5_file.attrs['label_dim'] == -1 and (
labeller_ids or instance_ids):
raise KeyError('No labels stored in database.')
labels = self._h5_file['labels'].value[labeller_ids][:, instance_ids, :]
labels = numpy.asarray(labels, dtype=self._h5_file.attrs['label_dtype'])
return labels
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
self._assert_open()
return [id_ for id_ in self._h5_file['instance_ids']]
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
self._assert_open()
return [id_ for id_ in self._h5_file['labeller_ids']]
def _setup_hdf5(self, h5_file: h5py.File):
"""Sets up an HDF5 file to work as a database.
Parameters
----------
h5_file
HDF5 file to set up. Must be opened in write mode.
"""
if self.label_dtype is None:
self.label_dtype = self._default_label_dtype
if self.feature_dtype is None:
self.feature_dtype = self._default_feature_dtype
h5_file.create_dataset('features', shape=(0, 0),
dtype=self.feature_dtype,
maxshape=(None, None))
h5_file.create_dataset('labels', shape=(0, 0, 0),
dtype=self.label_dtype,
maxshape=(None, None, None))
h5_file.create_dataset('instance_ids', shape=(0,),
dtype=int, maxshape=(None,))
h5_file.create_dataset('labeller_ids', shape=(0,),
dtype=int, maxshape=(None,))
h5_file.attrs['label_dtype'] = self.label_dtype
h5_file.attrs['feature_dtype'] = self.feature_dtype
h5_file.attrs['n_features'] = -1
h5_file.attrs['label_dim'] = -1
def _validate_hdf5(self):
"""Checks that self._h5_file has the correct schema.
Raises
------
ValueError
"""
try:
assert 'features' in self._h5_file
assert 'labels' in self._h5_file
assert 'instance_ids' in self._h5_file
assert 'labeller_ids' in self._h5_file
assert len(self._h5_file['features'].shape) == 2
assert len(self._h5_file['labels'].shape) == 3
assert len(self._h5_file['instance_ids'].shape) == 1
assert len(self._h5_file['labeller_ids'].shape) == 1
except AssertionError:
raise ValueError(
'File {} is not a valid database.'.format(self.path))
for attr in self._sync_attrs:
assert getattr(self, attr) is not None
if self._h5_file.attrs[attr] != getattr(self, attr):
raise ValueError('Incompatible {}: expected {}, got {}'.format(
attr, getattr(self, attr), self._h5_file.attrs[attr]))
class GraphDatabase(HDF5Database):
"""Manage database handling knowledge graph factorization,
Attributes
-----------
path: str
Path to HDF5 file.
"""
def __init__(self, path: str):
"""
Parameters
----------
path
Path to HDF5 file.
"""
self.path = path
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
proto = DatabasePB()
proto.path = self.path
proto.class_name = 'ManagedHDF5Database'
db_kwargs = {
'label_dtype': self.label_dtype,
'feature_dtype': self.feature_dtype}
for key, value in db_kwargs.items():
kwarg = proto.kwarg.add()
kwarg.key = key
kwarg.value = json.dumps(value)
# No encoder for a managed DB - assume that labels are encoded already.
# proto.label_encoder.CopyFrom(serialise_encoder(self.label_encoder))
return proto
def _open_hdf5(self):
"""Opens the HDF5 file and creates it if it doesn't exist.
Notes
-----
The HDF5 file will be stored in self._h5_file.
"""
try:
self._h5_file = h5py.File(self.path, 'r+')
except OSError:
with h5py.File(self.path, 'w') as h5_file:
self._setup_hdf5(h5_file)
self._h5_file = h5py.File(self.path, 'r+')
def _setup_hdf5(self, h5_file: h5py.File):
"""Sets up an HDF5 file to work as a database.
Parameters
----------
h5_file
HDF5 file to set up. Must be opened in write mode.
"""
h5_file.create_dataset('features_E',
shape=(0, 0, 0),
maxshape=(None, None, None))
h5_file.create_dataset('features_R',
shape=(0, 0, 0, 0),
maxshape=(None, None, None, None))
h5_file.create_dataset('labels',
shape=(0, 0, 0),
maxshape=(None, None, None))
h5_file.attrs['n_entities'] = -1
h5_file.attrs['n_relations'] = -1
h5_file.attrs['n_dim'] = -1
h5_file.attrs['n_particles'] = -1
def _validate_hdf5(self):
"""Checks that self._h5_file has the correct schema.
Raises
------
ValueError
"""
try:
assert 'features_E' in self._h5_file
assert 'features_R' in self._h5_file
assert 'labels' in self._h5_file
assert len(self._h5_file['features_E'].shape) == 3
assert len(self._h5_file['features_R'].shape) == 4
assert len(self._h5_file['labels'].shape) == 3
except AssertionError:
raise ValueError(
'File {} is not a valid database.'.format(self.path))
def write_labels(self,
labels: numpy.ndarray):
"""Writes label vectors to the database.
Parameters
----------
labels
K x N x N array of label vectors.
K is the number of relations, N is the number of entities.
"""
self._assert_open()
# Input validation.
if self._h5_file.attrs['n_relations'] == -1:
# This is the first time we've stored labels, so make a record of
# the dimensionality.
self._h5_file.attrs['n_relations'] = labels.shape[0]
elif self._h5_file.attrs['n_relations'] != labels.shape[0]:
raise ValueError(
'Expected number of relations {}, glot {}'.format(
self._h5_file.attrs['n_relations'], labels.shape[0]))
if self._h5_file.attrs['n_entities'] == -1:
# This is the first time we've stored labels, so make a record of
# the dimensionality.
self._h5_file.attrs['n_entities'] = labels.shape[1]
elif self._h5_file.attrs['n_entities'] != labels.shape[1]:
raise ValueError(
'Expected number of entities {}, glot {}'.format(
self._h5_file.attrs['n_entities'], labels.shape[1]))
# Resize the label array if necessary.
if (labels.shape[0] > self._h5_file['labels'].shape[0] or
labels.shape[1] > self._h5_file['labels'].shape[1] or
labels.shape[2] > self._h5_file['labels'].shape[2]):
self._h5_file['labels'].resize(labels.shape)
# Store the labels.
# TODO(MatthewJA): Vectorise this.
for i in range(labels.shape[0]):
self._h5_file['labels'][i, :] = labels[i, :]
logging.debug(
'New label array size: {}'.format(self._h5_file['labels'].shape))
def write_features(self,
features_E: numpy.ndarray,
features_R: numpy.ndarray):
"""Writes feature vectors to the database.
Parameters
----------
features_E:
P x N x D array of entity feature vectors.
P is the number of particles.
N is the number of entities.
D is the number of latent variable dimensions.
features_R:
P x K x D x D array of relation feature vectors.
P is the number of particles.
K is the number of relations.
D is the number of latent variable dimensions.
"""
self._assert_open()
n_particles = features_E.shape[0]
assert features_E.shape[0] == features_R.shape[0]
n_entities = features_E.shape[1]
n_relations = features_R.shape[1]
n_dim = features_E.shape[2]
assert features_E.shape[2] == features_R.shape[2] == features_R.shape[3]
# Input validation.
if self._h5_file.attrs['n_relations'] == -1:
# This is the first time we've stored labels, so make a record of
# the dimensionality.
self._h5_file.attrs['n_relations'] = n_relations
elif self._h5_file.attrs['n_relations'] != n_relations:
raise ValueError(
'Expected number of relations {}, glot {}'.format(
self._h5_file.attrs['n_relations'], n_relations))
if self._h5_file.attrs['n_entities'] == -1:
# This is the first time we've stored labels, so make a record of
# the dimensionality.
self._h5_file.attrs['n_entities'] = n_entities
elif self._h5_file.attrs['n_entities'] != n_entities:
raise ValueError(
'Expected number of entities {}, glot {}'.format(
self._h5_file.attrs['n_entities'], n_entities))
if self._h5_file.attrs['n_dim'] == -1:
# This is the first time we've stored labels, so make a record of
# the dimensionality.
self._h5_file.attrs['n_dim'] = n_dim
elif self._h5_file.attrs['n_dim'] != n_dim:
raise ValueError(
'Expected number of latent dimensions {}, glot {}'.format(
self._h5_file.attrs['n_dim'], n_dim))
if self._h5_file.attrs['n_particles'] == -1:
# This is the first time we've stored labels, so make a record of
# the dimensionality.
self._h5_file.attrs['n_particles'] = n_particles
elif self._h5_file.attrs['n_particles'] != n_particles:
raise ValueError(
'Expected number of partibles {}, glot {}'.format(
self._h5_file.attrs['n_particles'], n_particles))
# Resize the feature array if we need to store more IDs than before.
if (features_E.shape[0] > self._h5_file['features_E'].shape[0] or
features_E.shape[1] > self._h5_file['features_E'].shape[1] or
features_E.shape[2] > self._h5_file['features_E'].shape[2]):
self._h5_file['features_E'].resize(features_E.shape)
if (features_R.shape[0] > self._h5_file['features_R'].shape[0] or
features_R.shape[1] > self._h5_file['features_R'].shape[1] or
features_R.shape[2] > self._h5_file['features_R'].shape[2]):
self._h5_file['features_R'].resize(features_R.shape)
# Store the feature vectors.
# TODO(MatthewJA): Vectorise this. This could be tricky as HDF5 doesn't
# fully support NumPy's fancy indexing.
for id_, feature in enumerate(features_E):
self._h5_file['features_E'][id_, :] = feature
for id_, feature in enumerate(features_R):
self._h5_file['features_R'][id_, :, :] = feature
logging.debug(
'New feature E array size: {}'.format(
self._h5_file['features_E'].shape))
logging.debug(
'New feature R array size: {}'.format(
self._h5_file['features_R'].shape))
def read_labels(self,
instance_ids: Sequence[tuple]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
instance_ids
sequence of ids to be read labels
empty list indicates reading all labels in once
Returns
-------
numpy.ndarray
array of label vectors.
"""
self._assert_open()
n_entities = self._h5_file.attrs['n_entities']
n_relations = self._h5_file.attrs['n_relations']
if (n_entities == -1 or n_relations == -1):
raise KeyError('No labels stored in database.')
if len(instance_ids) == 0:
return numpy.asarray(self._h5_file['labels'].value)
else:
labels = []
for tuple_ in instance_ids:
r_k, e_i, e_j = tuple_
labels.append(self._h5_file['labels'].value[r_k, e_i, e_j])
return numpy.asarray(labels)
def read_features(self) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
Returns
-------
E
numpy.ndarray
P x N x D array of feature vectors.
R
list
each element is numpy.ndarray
P x K x D x D array of feature vectors.
"""
self._assert_open()
if self._h5_file.attrs['n_particles'] == -1:
raise KeyError('No features stored in database.')
# Allocate the features array.
features_E = numpy.zeros((self._h5_file.attrs['n_particles'],
self._h5_file.attrs['n_entities']),
self._h5_file.attrs['n_dim'])
features_R = numpy.zeros((self._h5_file.attrs['n_particles'],
self._h5_file.attrs['n_relations'],
self._h5_file.attrs['n_dim'],
self._h5_file.attrs['n_dim']))
# Loop through each ID we want to query and put the associated feature
# into the features array.
features_E = self._h5_file['features_E'].value
features_R = self._h5_file['features_R'].value
features_E = numpy.asarray(features_E)
features_R = numpy.asarray(features_R)
return features_E, features_R
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
self._assert_open()
return [id_ for id_ in self._h5_file['instance_ids']]
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
self._assert_open()
return [id_ for id_ in self._h5_file['labeller_ids']]
class HDF5Reader(HDF5Database):
"""Reads HDF5 databases.
Attributes
----------
feature_cols : List[str]
List of feature datasets.
label_col : str
Name of label dataset.
n_features : int
Number of features.
n_instances : int
Number of instances.
n_labels : int
Number of labels per instance.
path : str
Path to HDF5 file.
encode_labels : bool
Whether to encode labels as integers.
label_encoder : sklearn.preprocessing.LabelEncoder
Encodes labels as integers.
_h5_file : h5py.File
HDF5 file object.
_is_multidimensional : bool
Whether the features are in a multidimensional dataset.
"""
def __init__(self, path: str, feature_cols: List[str], label_col: str,
encode_labels: bool=True,
label_encoder: sklearn.preprocessing.LabelEncoder=None):
"""
Parameters
----------
path
Path to HDF5 file.
feature_cols
List of feature datasets. If only one feature dataset is specified,
this dataset is allowed to be a multidimensional dataset and contain
multiple features.
label_col
Name of label dataset.
encode_labels
Whether to encode labels as integers.
label_encoder
Encodes labels as integers. If not specified, the label column will
be read and a label encoding generated.
"""
super().__init__(path)
if not feature_cols:
raise ValueError('Must specify feature columns for HDF5.')
self.feature_cols = feature_cols
self.label_col = label_col
self.encode_labels = encode_labels
self.label_encoder = label_encoder
if self.label_encoder and not self.encode_labels:
raise ValueError('label_encoder specified but encode_labels is '
'False')
if self.label_encoder is None:
self.label_encoder = sklearn.preprocessing.LabelEncoder()
with h5py.File(self.path, 'r') as data:
is_multidimensional = any(len(data[f_col].shape) > 1 or
not product(data[f_col].shape[1:]) == 1
for f_col in feature_cols)
if is_multidimensional and len(feature_cols) != 1:
raise ValueError(
'Feature arrays and feature columns cannot be mixed. '
'To read in features from a multidimensional dataset, '
'only specify one feature column name.')
self._is_multidimensional = is_multidimensional
self.n_instances = data[label_col].shape[0]
if len(data[label_col].shape) == 1:
self.n_labels = 1
else:
assert len(data[label_col].shape) == 2
self.n_labels = data[label_col].shape[1]
if is_multidimensional:
self.n_features = data[feature_cols[0]].shape[1]
else:
self.n_features = len(feature_cols)
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
proto = DatabasePB()
proto.path = self.path
proto.class_name = 'HDF5Reader'
db_kwargs = {
'feature_cols': self.feature_cols,
'label_col': self.label_col,
'encode_labels': self.encode_labels}
for key, value in db_kwargs.items():
kwarg = proto.kwarg.add()
kwarg.key = key
kwarg.value = json.dumps(value)
proto.label_encoder.CopyFrom(serialise_encoder(self.label_encoder))
return proto
def read_features(self, ids: Sequence[int]) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
ids
Iterable of IDs.
Returns
-------
numpy.ndarray
N x D array of feature vectors.
"""
# TODO(MatthewJA): Optimise this.
self._assert_open()
# For each ID, get the corresponding features.
if self._is_multidimensional:
# If there are duplicates in ids, then this will crash with an
# OSError! (and a very cryptic error message...) To get around this,
# we'll first get all the unique IDs.
unique_ids = []
unique_ids_set = set() # For lookups.
id_to_index = {} # For reconstructing the features.
for id_ in ids:
if id_ not in unique_ids_set:
unique_ids.append(id_)
unique_ids_set.add(id_)
id_to_index[id_] = len(unique_ids) - 1
# Then index with just the unique IDs.
features_ = self._h5_file[self.feature_cols[0]][unique_ids]
# Finally, reconstruct the features array.
features = numpy.zeros((len(ids), features_.shape[1]))
for index, id_ in enumerate(ids):
index_ = id_to_index[id_]
features[index, :] = features_[index_, :]
return features
else:
# Allocate output array.
features = numpy.zeros((len(ids), len(self.feature_cols)))
# Read each feature.
features_h5 = self._h5_file[self.feature_cols[0]]
for feature_idx, feature_name in enumerate(self.feature_cols):
features[ids, feature_idx] = features_h5[feature_name][ids]
return numpy.nan_to_num(features)
def read_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
Returns
-------
numpy.ndarray
T x N x F array of label vectors.
"""
self._assert_open()
if len(labeller_ids) > 1:
raise NotImplementedError('Multiple labellers not yet supported.')
# TODO(MatthewJA): Optimise this.
# For each ID, get the corresponding labels.
# If there are duplicates in ids, then this will crash with an
# OSError! (and a very cryptic error message...) To get around this,
# we'll first get all the unique IDs.
unique_ids = []
unique_ids_set = set() # For lookups.
id_to_index = {} # For reconstructing the labels.
for id_ in instance_ids:
if id_ not in unique_ids_set:
unique_ids.append(id_)
unique_ids_set.add(id_)
id_to_index[id_] = len(unique_ids) - 1
# Then index with just the unique IDs.
labels_ = self._h5_file[self.label_col][unique_ids].reshape(
(1, len(unique_ids), -1))
# Finally, reconstruct the labels array.
labels = numpy.zeros(
(1, len(instance_ids), labels_.shape[2]),
dtype=labels_.dtype)
for index, id_ in enumerate(instance_ids):
index_ = id_to_index[id_]
labels[0, index, :] = labels_[0, index_, :]
if labels.shape[2] != 1:
raise NotImplementedError('Multidimensional labels not currently '
'supported.')
# Encode labels.
if self.encode_labels:
labels = numpy.apply_along_axis(
self.label_encoder.fit_transform,
axis=1,
arr=labels.reshape(labels.shape[:2])
).reshape(labels.shape)
return labels
def write_features(self, ids: Sequence[int], features: numpy.ndarray):
raise PermissionError('Cannot write to read-only database.')
def write_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int],
labels: numpy.ndarray):
raise PermissionError('Cannot write to read-only database.')
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
self._assert_open()
return [i for i in range(self.n_instances)]
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
raise NotImplementedError()
class ASCIIReader(Database):
"""Reads ASCII databases.
Attributes
----------
feature_cols : List[str]
List of feature columns.
label_col : str
Name of label column.
max_id_length : int
Maximum length of IDs.
n_features : int
Number of features.
n_instances : int
Number of instances.
n_labels : int
Number of labels per instance.
path : str
Path to ASCII file.
encode_labels : bool
Whether to encode labels as integers.
label_encoder : sklearn.preprocessing.LabelEncoder
Encodes labels as integers.
_db : Database
Underlying ManagedHDF5Database.
_db_filepath : str
Path of underlying HDF5 database.
_tempdir : str
Temporary directory where the underlying HDF5 database is stored.
"""
def __init__(self, path: str, feature_cols: List[str], label_col: str,
encode_labels: bool=True,
label_encoder: sklearn.preprocessing.LabelEncoder=None):
"""
Parameters
----------
path
Path to ASCII file.
feature_cols
List of feature columns.
label_col
Name of label column.
encode_labels
Whether to encode labels as integers.
label_encoder
Encodes labels as integers. If not specified, the label column will
be read and a label encoding generated.
"""
self.path = path
self.feature_cols = feature_cols
self.label_col = label_col
self.encode_labels = encode_labels
self.label_encoder = label_encoder
if self.label_encoder and not self.encode_labels:
raise ValueError('label_encoder specified but encode_labels is '
'False')
if self.label_encoder is None:
self.label_encoder = sklearn.preprocessing.LabelEncoder()
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
proto = DatabasePB()
proto.path = self.path
proto.class_name = 'ASCIIReader'
db_kwargs = {
'feature_cols': self.feature_cols,
'label_col': self.label_col,
'encode_labels': self.encode_labels}
for key, value in db_kwargs.items():
kwarg = proto.kwarg.add()
kwarg.key = key
kwarg.value = json.dumps(value)
proto.label_encoder.CopyFrom(serialise_encoder(self.label_encoder))
return proto
def _db_from_ascii(self,
db: Database,
data: astropy.table.Table,
feature_cols: Sequence[str],
label_col: str,
ids: Sequence[int]):
"""Reads an ASCII table into a database.
Notes
-----
The entire file is copied into memory.
Arguments
---------
db
Database.
data
ASCII table.
feature_cols
List of column names of the features. If empty, all non-label and
non-ID columns will be used.
label_col
Column name of the labels.
ids
List of instance IDs.
"""
# Read in features.
columns = data.keys()
if not feature_cols:
# If there are no features given, use all columns.
feature_cols = [c for c in columns if c != label_col]
# This converts the features from a table to an array.
features = data[feature_cols].as_array()
features = features.view(numpy.float64).reshape(features.shape + (-1,))
# Read in labels.
labels = numpy.array(
data[label_col]).reshape((1, -1, 1))
# We want to support multiple labellers in the future, but currently
# don't. So every labeller is the same, ID = 0.
labeller_ids = [0]
# Encode labels.
if self.encode_labels:
labels = numpy.apply_along_axis(
self.label_encoder.fit_transform,
axis=1,
arr=labels.reshape(labels.shape[:2])
).reshape(labels.shape)
# Write to database.
db.write_features(ids, features)
db.write_labels(labeller_ids, ids, labels)
def __enter__(self):
self._tempdir = tempfile.TemporaryDirectory(prefix='acton')
# Read the whole file into a DB.
self._db_filepath = os.path.join(self._tempdir.name, 'db.h5')
data = io_ascii.read(self.path)
ids = list(range(len(data[self.label_col])))
max_label_len = max(len(str(i)) for i in data[self.label_col])
label_dtype = '<S{}'.format(max_label_len)
self._db = ManagedHDF5Database(
self._db_filepath,
label_dtype=label_dtype,
feature_dtype='float64')
self._db.__enter__()
try:
# We want to handle the encoding ourselves.
self._db_from_ascii(self._db, data, self.feature_cols,
self.label_col, ids, encode_labels=False)
except TypeError:
# Encoding isn't supported in the underlying database.
self._db_from_ascii(self._db, data, self.feature_cols,
self.label_col, ids)
return self
def __exit__(self, exc_type: Exception, exc_val: object, exc_tb: Traceback):
self._db.__exit__(exc_type, exc_val, exc_tb)
self._tempdir.cleanup()
delattr(self, '_db')
def read_features(self, ids: Sequence[int]) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
ids
Iterable of IDs.
Returns
-------
numpy.ndarray
N x D array of feature vectors.
"""
return self._db.read_features(ids)
def read_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
Returns
-------
numpy.ndarray
T x N x F array of label vectors.
"""
# N.B. Labels are encoded in _db_from_ascii.
return self._db.read_labels(labeller_ids, instance_ids)
def write_features(self, ids: Sequence[int], features: numpy.ndarray):
raise NotImplementedError('Cannot write to read-only database.')
def write_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int],
labels: numpy.ndarray):
raise NotImplementedError('Cannot write to read-only database.')
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
return self._db.get_known_instance_ids()
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
return self._db.get_known_labeller_ids()
class GraphReader(Database):
"""Reads ASCII databases for graph based structure
Input file:
List of known facts,
formatted as relation_id \tab entity_id1 \tab entity_id2,
means entity_id1 has relation_id relation with entity_id2,
Both entity-id and relation-id start from 0.
Output labels:
K x N x N ndarrays,
where K is the number of relations,
N is the number of entities.
0 represents invalid facts, 1 represents valid facts.
Output features:
E is N x D latent features of the entities.
R is K x D x D latent features of the relations.
Features are initially random/gibbs sampled,
will be sequentially updated after getting labels
Attributes
----------
path : str
Path to ASCII file.
_db : Database
Underlying ManagedHDF5Database.
_db_filepath : str
Path of underlying HDF5 database.
_tempdir : str
Temporary directory where the underlying HDF5 database is stored.
n_dim
Number of latent features (size of latent dimension).
n_particles:
Number of particles for Thompson sampling.
gibbs_init
Indicates how to sample features (gibbs/random).
var_r
variance of prior of R
var_e
variance of prior of E
var_x
variance of X
obs_mask
Mask tensor of observed triples.
given_r
whether there is any R given for initialization
"""
def __init__(self, path: str, n_dim: int, n_particles: int = 5,
gibbs_init: bool = True, var_r: int = 1, var_e: int = 1,
var_x: float = 0.01, obs_mask: numpy.ndarray= None,
given_r: numpy.ndarray = None):
"""
Parameters
----------
path
Path to ASCII file.
n_dim
Number of latent features (size of latent dimension).
n_particles:
Number of particles for Thompson sampling.
gibbs_init
Indicates how to sample features (gibbs/random).
var_r
variance of prior of R
var_e
variance of prior of E
var_x
variance of X
obs_mask
Mask tensor of observed triples.
given_r
Given features R if any
"""
self.path = path
self.n_dim = n_dim
self.n_particles = n_particles
self.gibbs_init = gibbs_init
self.var_r = var_r
self.var_e = var_e
self.var_x = var_x
self.obs_mask = obs_mask
self.given_r = given_r
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
proto = DatabasePB()
proto.path = self.path
proto.class_name = 'LabelOnlyASCIIReader'
db_kwargs = {
'n_dim': self.n_dim,
'n_particles': self.n_particles, }
for key, value in db_kwargs.items():
kwarg = proto.kwarg.add()
kwarg.key = key
kwarg.value = json.dumps(value)
return proto
def _db_from_ascii(self,
db: Database,
data: astropy.table.Table,
):
"""Reads an ASCII table into a database.
Notes
-----
The entire file is copied into memory.
Arguments
---------
db
Database.
data
ASCII table.
"""
# triples: relation_id entity_id1 entity_id2
# e.g. (0,2,4) represents entity 2 and 4 have relation 0
triples = data.as_array()
triples = triples.view(numpy.int).reshape((triples.shape[0], 3))
self.n_relations = max(triples[:, 0]) + 1
self.n_entities = max(triples[:, 1]) + 1
assert self.n_entities == max(triples[:, -1]) + 1
# only support one labeller
# construct label tensor X = {0,1}^{K x N x N}
X = numpy.zeros((self.n_relations, self.n_entities, self.n_entities))
for i in triples:
X[i[0], i[1], i[2]] = 1
# Initailize features E,R
self.E = list()
self.R = list()
self.RE = numpy.zeros([self.n_relations, self.n_entities, self.n_dim])
self.RTE = numpy.zeros([self.n_relations, self.n_entities, self.n_dim])
if isinstance(self.obs_mask, type(None)):
self.obs_mask = numpy.zeros_like(X)
else:
logging.info(
"Initial Total, Positive, Negative Obs : %d / %d / %d",
numpy.sum(self.obs_mask),
numpy.sum(X[self.obs_mask == 1]),
numpy.sum(self.obs_mask) - numpy.sum(X[self.obs_mask == 1]))
cur_obs = numpy.zeros_like(X)
for k in range(self.n_relations):
cur_obs[k][self.obs_mask[k] == 1] = X[k][self.obs_mask[k] == 1]
self.obs_sum = numpy.sum(numpy.sum(self.obs_mask, 1), 1)
self.valid_relations = numpy.nonzero(numpy.sum(numpy.sum(X, 1), 1))[0]
self.features = numpy.zeros(
[2 * self.n_entities * self.n_relations, self.n_dim])
self.xi = numpy.zeros([2 * self.n_entities * self.n_relations])
# cur_obs[cur_obs.nonzero()] = 1
if self.gibbs_init and numpy.sum(self.obs_sum) != 0:
# initialize latent variables with gibbs sampling
E = numpy.random.random([self.n_entities, self.n_dim])
R = numpy.random.random([self.n_relations, self.n_dim, self.n_dim])
for gi in range(20):
tic = time.time()
if isinstance(self.given_r, type(None)):
self._sample_relations(
cur_obs, self.obs_mask, E, R, self.var_r)
self._sample_entities(
cur_obs, self.obs_mask, E, R, self.var_e)
else:
self._sample_entities(
cur_obs, self.obs_mask, E, R, self.var_e)
logging.info("Gibbs Init %d: %f", gi, time.time() - tic)
for p in range(self.n_particles):
self.E.append(E.copy())
self.R.append(R.copy())
else:
# random initialization
for p in range(self.n_particles):
self.E.append(numpy.random.random(
[self.n_entities, self.n_dim]))
self.R.append(numpy.random.random(
[self.n_relations, self.n_dim, self.n_dim]))
self.E = numpy.asarray(self.E)
self.R = numpy.asarray(self.R)
# Write to database.
db.write_features(self.E, self.R)
db.write_labels(X)
def __enter__(self):
self._tempdir = tempfile.TemporaryDirectory(prefix='acton')
# Read the whole file into a DB.
self._db_filepath = os.path.join(self._tempdir.name, 'db.h5')
data = io_ascii.read(self.path)
self._db = GraphDatabase(self._db_filepath)
self._db.__enter__()
self._db_from_ascii(self._db, data)
return self
def __exit__(self, exc_type: Exception, exc_val: object, exc_tb: Traceback):
self._db.__exit__(exc_type, exc_val, exc_tb)
self._tempdir.cleanup()
delattr(self, '_db')
def read_features(self) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
Returns
-------
E
numpy.ndarray
P x N x D array of feature vectors.
R
list
each element is numpy.ndarray
P x K x D x D array of feature vectors.
N x D array of feature vectors.
"""
return self._db.read_features()
def read_labels(self,
instance_ids: Sequence[tuple]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
Returns
-------
numpy.ndarray
array of label vectors.
"""
# N.B. Labels are encoded in _db_from_ascii.
return self._db.read_labels(instance_ids)
def write_features(self, ids: Sequence[int], features: numpy.ndarray):
raise NotImplementedError('Cannot write to read-only database.')
def write_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int],
labels: numpy.ndarray):
raise NotImplementedError('Cannot write to read-only database.')
def _sample_entities(self, X, mask, E, R, var_e, sample_idx=None):
RE = self.RE
RTE = self.RTE
for k in range(self.n_relations):
RE[k] = numpy.dot(R[k], E.T).T
RTE[k] = numpy.dot(R[k].T, E.T).T
if isinstance(sample_idx, type(None)):
sample_idx = range(self.n_entities)
for i in sample_idx:
self._sample_entity(X, mask, E, R, i, var_e, RE, RTE)
for k in range(self.n_relations):
RE[k][i] = numpy.dot(R[k], E[i])
RTE[k][i] = numpy.dot(R[k].T, E[i])
def _sample_entity(self, X, mask, E, R, i, var_e, RE=None, RTE=None):
nz_r = mask[:, i, :].nonzero()
nz_c = mask[:, :, i].nonzero()
nnz_r = nz_r[0].size
nnz_c = nz_c[0].size
nnz_all = nnz_r + nnz_c
self.features[:nnz_r] = RE[nz_r]
self.features[nnz_r:nnz_all] = RTE[nz_c]
self.xi[:nnz_r] = X[:, i, :][nz_r]
self.xi[nnz_r:nnz_all] = X[:, :, i][nz_c]
_xi = self.xi[:nnz_all] * self.features[:nnz_all].T
xi = numpy.sum(_xi, 1) / self.var_x
_lambda = numpy.identity(self.n_dim) / var_e
_lambda += numpy.dot(
self.features[:nnz_all].T,
self.features[:nnz_all]) / self.var_x
inv_lambda = numpy.linalg.inv(_lambda)
mu = numpy.dot(inv_lambda, xi)
E[i] = multivariate_normal(mu, inv_lambda)
numpy.mean(numpy.diag(inv_lambda))
# logging.debug('Mean variance E, %d, %f', i, mean_var)
def _sample_relations(self, X, mask, E, R, var_r):
EXE = numpy.kron(E, E)
for k in self.valid_relations:
if self.obs_sum[k] != 0:
self._sample_relation(X, mask, E, R, k, EXE, var_r)
else:
R[k] = numpy.random.normal(
0, var_r, size=[self.n_dim, self.n_dim])
def _sample_relation(self, X, mask, E, R, k, EXE, var_r):
_lambda = numpy.identity(self.n_dim ** 2) / var_r
xi = numpy.zeros(self.n_dim ** 2)
kron = EXE[mask[k].flatten() == 1]
if kron.shape[0] != 0:
_lambda += numpy.dot(kron.T, kron)
xi += numpy.sum(X[k, mask[k] == 1].flatten() * kron.T, 1)
_lambda /= self.var_x
# mu = numpy.linalg.solve(_lambda, xi) / self.var_x
inv_lambda = numpy.linalg.inv(_lambda)
mu = numpy.dot(inv_lambda, xi) / self.var_x
# R[k] = normal(mu, _lambda).reshape([self.n_dim, self.n_dim])
R[k] = multivariate_normal(
mu, inv_lambda).reshape([self.n_dim, self.n_dim])
numpy.mean(numpy.diag(inv_lambda))
# logging.info('Mean variance R, %d, %f', k, mean_var)
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
return self._db.get_known_instance_ids()
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
return self._db.get_known_labeller_ids()
class PandasReader(Database):
"""Reads HDF5 databases.
Attributes
----------
feature_cols : List[str]
List of feature datasets.
label_col : str
Name of label dataset.
n_features : int
Number of features.
n_instances : int
Number of instances.
n_labels : int
Number of labels per instance.
path : str
Path to HDF5 file.
encode_labels : bool
Whether to encode labels as integers.
label_encoder : sklearn.preprocessing.LabelEncoder
Encodes labels as integers.
_df : pandas.DataFrame
Pandas dataframe.
"""
def __init__(self, path: str, feature_cols: List[str], label_col: str,
key: str, encode_labels: bool=True,
label_encoder: sklearn.preprocessing.LabelEncoder=None):
"""
Parameters
----------
path
Path to HDF5 file.
feature_cols
List of feature columns. If none are specified, then all non-label,
non-ID columns will be used.
label_col
Name of label dataset.
key
Pandas key.
encode_labels
Whether to encode labels as integers.
label_encoder
Encodes labels as integers. If not specified, the label column will
be read and a label encoding generated.
"""
self.path = path
self.feature_cols = feature_cols
self.label_col = label_col
self.key = key
self._df = pandas.read_hdf(self.path, self.key)
self.encode_labels = encode_labels
self.label_encoder = label_encoder
if self.label_encoder and not self.encode_labels:
raise ValueError('label_encoder specified but encode_labels is '
'False')
if self.label_encoder is None:
self.label_encoder = sklearn.preprocessing.LabelEncoder()
if not self.feature_cols:
self.feature_cols = [k for k in self._df.keys()
if k != self.label_col]
self.n_instances = len(self._df[self.label_col])
self.n_features = len(self.feature_cols)
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
proto = DatabasePB()
proto.path = self.path
proto.class_name = 'PandasReader'
db_kwargs = {
'feature_cols': self.feature_cols,
'label_col': self.label_col,
'key': self.key,
'encode_labels': self.encode_labels}
for key, value in db_kwargs.items():
kwarg = proto.kwarg.add()
kwarg.key = key
kwarg.value = json.dumps(value)
proto.label_encoder.CopyFrom(serialise_encoder(self.label_encoder))
return proto
def __enter__(self):
return self
def __exit__(self, exc_type: Exception, exc_val: object, exc_tb: Traceback):
delattr(self, '_df')
def read_features(self, ids: Sequence[int]) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
ids
Iterable of IDs.
Returns
-------
numpy.ndarray
N x D array of feature vectors.
"""
# TODO(MatthewJA): Optimise this.
# Allocate output features array.
features = numpy.zeros((len(ids), self.n_features))
# For each ID, get the corresponding features.
for out_index, id_ in enumerate(ids):
sel = self._df.iloc[id_]
for feature_index, feature in enumerate(self.feature_cols):
features[out_index, feature_index] = sel[feature]
return features
def read_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
Returns
-------
numpy.ndarray
T x N x 1 array of label vectors.
"""
# Draw a label to get the dtype.
dtype = type(self._df.iloc[0][self.label_col])
# Allocate output labels array.
labels = numpy.zeros(
(len(labeller_ids), len(instance_ids), 1),
dtype=dtype)
if len(labeller_ids) > 1:
raise NotImplementedError('Multiple labellers not yet supported.')
# For each ID, get the corresponding labels.
for out_index, id_ in enumerate(instance_ids):
sel = self._df.iloc[int(id_)]
labels[0, out_index, 0] = sel[self.label_col]
if labels.shape[2] != 1:
raise NotImplementedError('Multidimensional labels not currently '
'supported.')
# Encode labels.
if self.encode_labels:
labels = numpy.apply_along_axis(
self.label_encoder.fit_transform,
axis=1,
arr=labels.reshape(labels.shape[:2])
).reshape(labels.shape)
return labels
def write_features(self, ids: Sequence[int], features: numpy.ndarray):
raise PermissionError('Cannot write to read-only database.')
def write_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int],
labels: numpy.ndarray):
raise PermissionError('Cannot write to read-only database.')
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
return [i for i in range(self.n_instances)]
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
raise NotImplementedError()
class FITSReader(Database):
"""Reads FITS databases.
Attributes
----------
hdu_index : int
Index of HDU in the FITS file.
feature_cols : List[str]
List of feature columns.
label_col : str
Name of label column.
n_features : int
Number of features.
n_instances : int
Number of instances.
n_labels : int
Number of labels per instance.
path : str
Path to FITS file.
encode_labels : bool
Whether to encode labels as integers.
label_encoder : sklearn.preprocessing.LabelEncoder
Encodes labels as integers.
_hdulist : astropy.io.fits.HDUList
FITS HDUList.
"""
def __init__(self, path: str, feature_cols: List[str], label_col: str,
hdu_index: int=1, encode_labels: bool=True,
label_encoder: sklearn.preprocessing.LabelEncoder=None):
"""
Parameters
----------
path
Path to FITS file.
feature_cols
List of feature columns. If none are specified, then all non-label,
non-ID columns will be used.
label_col
Name of label dataset.
hdu_index
Index of HDU in the FITS file. Default is 1, i.e., the first
extension in the FITS file.
encode_labels
Whether to encode labels as integers.
label_encoder
Encodes labels as integers. If not specified, the label column will
be read and a label encoding generated.
"""
self.path = path
self.feature_cols = feature_cols
self.label_col = label_col
self.hdu_index = hdu_index
self.encode_labels = encode_labels
self.label_encoder = label_encoder
if self.label_encoder and not self.encode_labels:
raise ValueError('label_encoder specified but encode_labels is '
'False')
if self.label_encoder is None:
self.label_encoder = sklearn.preprocessing.LabelEncoder()
# These will be set when the FITS file is opened.
self.n_instances = None
self.n_features = None
def to_proto(self) -> DatabasePB:
"""Serialises this database as a protobuf.
Returns
-------
DatabasePB
Protobuf representing this database.
"""
proto = DatabasePB()
proto.path = self.path
proto.class_name = 'FITSReader'
db_kwargs = {
'feature_cols': self.feature_cols,
'label_col': self.label_col,
'hdu_index': self.hdu_index,
'encode_labels': self.encode_labels}
for key, value in db_kwargs.items():
kwarg = proto.kwarg.add()
kwarg.key = key
kwarg.value = json.dumps(value)
proto.label_encoder.CopyFrom(serialise_encoder(self.label_encoder))
return proto
def __enter__(self):
self._hdulist = io_fits.open(self.path)
# If we haven't specified columns, use all except the label column.
cols = self._hdulist[self.hdu_index].columns.names
if not self.feature_cols:
self.feature_cols = [k for k in cols if k != self.label_col]
self.n_features = len(self.feature_cols)
self.n_instances = \
self._hdulist[self.hdu_index].data[self.label_col].ravel().shape[0]
return self
def __exit__(self, exc_type: Exception, exc_val: object, exc_tb: Traceback):
self._hdulist.close()
delattr(self, '_hdulist')
def read_features(self, ids: Sequence[int]) -> numpy.ndarray:
"""Reads feature vectors from the database.
Parameters
----------
ids
Iterable of IDs.
Returns
-------
numpy.ndarray
N x D array of feature vectors.
"""
# TODO(MatthewJA): Optimise this.
# Allocate output features array.
features = numpy.zeros((len(ids), self.n_features))
for f_index, col in enumerate(self.feature_cols):
col = self._hdulist[self.hdu_index].data[col]
features[:, f_index] = col[ids]
return features
def read_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int]) -> numpy.ndarray:
"""Reads label vectors from the database.
Parameters
----------
labeller_ids
Iterable of labeller IDs.
instance_ids
Iterable of instance IDs.
Returns
-------
numpy.p
T x N x 1 array of label vectors.
"""
label_col = self._hdulist[self.hdu_index].data[self.label_col]
labels = label_col[instance_ids].reshape((1, -1, 1))
# Encode labels.
if self.encode_labels:
labels = numpy.apply_along_axis(
self.label_encoder.fit_transform,
axis=1,
arr=labels.reshape(labels.shape[:2])
).reshape(labels.shape)
return labels
def write_features(self, ids: Sequence[int], features: numpy.ndarray):
raise PermissionError('Cannot write to read-only database.')
def write_labels(self,
labeller_ids: Sequence[int],
instance_ids: Sequence[int],
labels: numpy.ndarray):
raise PermissionError('Cannot write to read-only database.')
def get_known_instance_ids(self) -> List[int]:
"""Returns a list of known instance IDs.
Returns
-------
List[str]
A list of known instance IDs.
"""
return [i for i in range(self.n_instances)]
def get_known_labeller_ids(self) -> List[int]:
"""Returns a list of known labeller IDs.
Returns
-------
List[str]
A list of known labeller IDs.
"""
raise NotImplementedError()
# For safe string-based access to database classes.
DATABASES = {
'ASCIIReader': ASCIIReader,
'GraphReader': GraphReader,
'HDF5Reader': HDF5Reader,
'FITSReader': FITSReader,
'ManagedHDF5Database': ManagedHDF5Database,
'GraphDatabase': GraphDatabase,
'PandasReader': PandasReader,
}
| bsd-3-clause |
manazhao/tf_recsys | tensorflow/examples/learn/hdf5_classification.py | 75 | 2899 | # Copyright 2016 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Example of DNNClassifier for Iris plant dataset, hdf5 format."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import numpy as np
from sklearn import datasets
from sklearn import metrics
from sklearn import model_selection
import tensorflow as tf
import h5py # pylint: disable=g-bad-import-order
X_FEATURE = 'x' # Name of the input feature.
def main(unused_argv):
# Load dataset.
iris = datasets.load_iris()
x_train, x_test, y_train, y_test = model_selection.train_test_split(
iris.data, iris.target, test_size=0.2, random_state=42)
# Note that we are saving and load iris data as h5 format as a simple
# demonstration here.
h5f = h5py.File('/tmp/test_hdf5.h5', 'w')
h5f.create_dataset('X_train', data=x_train)
h5f.create_dataset('X_test', data=x_test)
h5f.create_dataset('y_train', data=y_train)
h5f.create_dataset('y_test', data=y_test)
h5f.close()
h5f = h5py.File('/tmp/test_hdf5.h5', 'r')
x_train = np.array(h5f['X_train'])
x_test = np.array(h5f['X_test'])
y_train = np.array(h5f['y_train'])
y_test = np.array(h5f['y_test'])
# Build 3 layer DNN with 10, 20, 10 units respectively.
feature_columns = [
tf.feature_column.numeric_column(
X_FEATURE, shape=np.array(x_train).shape[1:])]
classifier = tf.estimator.DNNClassifier(
feature_columns=feature_columns, hidden_units=[10, 20, 10], n_classes=3)
# Train.
train_input_fn = tf.estimator.inputs.numpy_input_fn(
x={X_FEATURE: x_train}, y=y_train, num_epochs=None, shuffle=True)
classifier.train(input_fn=train_input_fn, steps=200)
# Predict.
test_input_fn = tf.estimator.inputs.numpy_input_fn(
x={X_FEATURE: x_test}, y=y_test, num_epochs=1, shuffle=False)
predictions = classifier.predict(input_fn=test_input_fn)
y_predicted = np.array(list(p['class_ids'] for p in predictions))
y_predicted = y_predicted.reshape(np.array(y_test).shape)
# Score with sklearn.
score = metrics.accuracy_score(y_test, y_predicted)
print('Accuracy (sklearn): {0:f}'.format(score))
# Score with tensorflow.
scores = classifier.evaluate(input_fn=test_input_fn)
print('Accuracy (tensorflow): {0:f}'.format(scores['accuracy']))
if __name__ == '__main__':
tf.app.run()
| apache-2.0 |
nomadcube/scikit-learn | examples/applications/topics_extraction_with_nmf.py | 106 | 2313 | """
========================================================
Topics extraction with Non-Negative Matrix Factorization
========================================================
This is a proof of concept application of Non Negative Matrix
Factorization of the term frequency matrix of a corpus of documents so
as to extract an additive model of the topic structure of the corpus.
The output is a list of topics, each represented as a list of terms
(weights are not shown).
The default parameters (n_samples / n_features / n_topics) should make
the example runnable in a couple of tens of seconds. You can try to
increase the dimensions of the problem, but be aware than the time complexity
is polynomial.
"""
# Author: Olivier Grisel <[email protected]>
# Lars Buitinck <[email protected]>
# License: BSD 3 clause
from __future__ import print_function
from time import time
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.decomposition import NMF
from sklearn.datasets import fetch_20newsgroups
n_samples = 2000
n_features = 1000
n_topics = 10
n_top_words = 20
# Load the 20 newsgroups dataset and vectorize it. We use a few heuristics
# to filter out useless terms early on: the posts are stripped of headers,
# footers and quoted replies, and common English words, words occurring in
# only one document or in at least 95% of the documents are removed.
t0 = time()
print("Loading dataset and extracting TF-IDF features...")
dataset = fetch_20newsgroups(shuffle=True, random_state=1,
remove=('headers', 'footers', 'quotes'))
vectorizer = TfidfVectorizer(max_df=0.95, min_df=2, max_features=n_features,
stop_words='english')
tfidf = vectorizer.fit_transform(dataset.data[:n_samples])
print("done in %0.3fs." % (time() - t0))
# Fit the NMF model
print("Fitting the NMF model with n_samples=%d and n_features=%d..."
% (n_samples, n_features))
nmf = NMF(n_components=n_topics, random_state=1).fit(tfidf)
print("done in %0.3fs." % (time() - t0))
feature_names = vectorizer.get_feature_names()
for topic_idx, topic in enumerate(nmf.components_):
print("Topic #%d:" % topic_idx)
print(" ".join([feature_names[i]
for i in topic.argsort()[:-n_top_words - 1:-1]]))
print()
| bsd-3-clause |
pratapvardhan/scikit-learn | examples/linear_model/plot_sparse_recovery.py | 70 | 7486 | """
============================================================
Sparse recovery: feature selection for sparse linear models
============================================================
Given a small number of observations, we want to recover which features
of X are relevant to explain y. For this :ref:`sparse linear models
<l1_feature_selection>` can outperform standard statistical tests if the
true model is sparse, i.e. if a small fraction of the features are
relevant.
As detailed in :ref:`the compressive sensing notes
<compressive_sensing>`, the ability of L1-based approach to identify the
relevant variables depends on the sparsity of the ground truth, the
number of samples, the number of features, the conditioning of the
design matrix on the signal subspace, the amount of noise, and the
absolute value of the smallest non-zero coefficient [Wainwright2006]
(http://statistics.berkeley.edu/sites/default/files/tech-reports/709.pdf).
Here we keep all parameters constant and vary the conditioning of the
design matrix. For a well-conditioned design matrix (small mutual
incoherence) we are exactly in compressive sensing conditions (i.i.d
Gaussian sensing matrix), and L1-recovery with the Lasso performs very
well. For an ill-conditioned matrix (high mutual incoherence),
regressors are very correlated, and the Lasso randomly selects one.
However, randomized-Lasso can recover the ground truth well.
In each situation, we first vary the alpha parameter setting the sparsity
of the estimated model and look at the stability scores of the randomized
Lasso. This analysis, knowing the ground truth, shows an optimal regime
in which relevant features stand out from the irrelevant ones. If alpha
is chosen too small, non-relevant variables enter the model. On the
opposite, if alpha is selected too large, the Lasso is equivalent to
stepwise regression, and thus brings no advantage over a univariate
F-test.
In a second time, we set alpha and compare the performance of different
feature selection methods, using the area under curve (AUC) of the
precision-recall.
"""
print(__doc__)
# Author: Alexandre Gramfort and Gael Varoquaux
# License: BSD 3 clause
import warnings
import matplotlib.pyplot as plt
import numpy as np
from scipy import linalg
from sklearn.linear_model import (RandomizedLasso, lasso_stability_path,
LassoLarsCV)
from sklearn.feature_selection import f_regression
from sklearn.preprocessing import StandardScaler
from sklearn.metrics import auc, precision_recall_curve
from sklearn.ensemble import ExtraTreesRegressor
from sklearn.utils.extmath import pinvh
from sklearn.exceptions import ConvergenceWarning
def mutual_incoherence(X_relevant, X_irelevant):
"""Mutual incoherence, as defined by formula (26a) of [Wainwright2006].
"""
projector = np.dot(np.dot(X_irelevant.T, X_relevant),
pinvh(np.dot(X_relevant.T, X_relevant)))
return np.max(np.abs(projector).sum(axis=1))
for conditioning in (1, 1e-4):
###########################################################################
# Simulate regression data with a correlated design
n_features = 501
n_relevant_features = 3
noise_level = .2
coef_min = .2
# The Donoho-Tanner phase transition is around n_samples=25: below we
# will completely fail to recover in the well-conditioned case
n_samples = 25
block_size = n_relevant_features
rng = np.random.RandomState(42)
# The coefficients of our model
coef = np.zeros(n_features)
coef[:n_relevant_features] = coef_min + rng.rand(n_relevant_features)
# The correlation of our design: variables correlated by blocs of 3
corr = np.zeros((n_features, n_features))
for i in range(0, n_features, block_size):
corr[i:i + block_size, i:i + block_size] = 1 - conditioning
corr.flat[::n_features + 1] = 1
corr = linalg.cholesky(corr)
# Our design
X = rng.normal(size=(n_samples, n_features))
X = np.dot(X, corr)
# Keep [Wainwright2006] (26c) constant
X[:n_relevant_features] /= np.abs(
linalg.svdvals(X[:n_relevant_features])).max()
X = StandardScaler().fit_transform(X.copy())
# The output variable
y = np.dot(X, coef)
y /= np.std(y)
# We scale the added noise as a function of the average correlation
# between the design and the output variable
y += noise_level * rng.normal(size=n_samples)
mi = mutual_incoherence(X[:, :n_relevant_features],
X[:, n_relevant_features:])
###########################################################################
# Plot stability selection path, using a high eps for early stopping
# of the path, to save computation time
alpha_grid, scores_path = lasso_stability_path(X, y, random_state=42,
eps=0.05)
plt.figure()
# We plot the path as a function of alpha/alpha_max to the power 1/3: the
# power 1/3 scales the path less brutally than the log, and enables to
# see the progression along the path
hg = plt.plot(alpha_grid[1:] ** .333, scores_path[coef != 0].T[1:], 'r')
hb = plt.plot(alpha_grid[1:] ** .333, scores_path[coef == 0].T[1:], 'k')
ymin, ymax = plt.ylim()
plt.xlabel(r'$(\alpha / \alpha_{max})^{1/3}$')
plt.ylabel('Stability score: proportion of times selected')
plt.title('Stability Scores Path - Mutual incoherence: %.1f' % mi)
plt.axis('tight')
plt.legend((hg[0], hb[0]), ('relevant features', 'irrelevant features'),
loc='best')
###########################################################################
# Plot the estimated stability scores for a given alpha
# Use 6-fold cross-validation rather than the default 3-fold: it leads to
# a better choice of alpha:
# Stop the user warnings outputs- they are not necessary for the example
# as it is specifically set up to be challenging.
with warnings.catch_warnings():
warnings.simplefilter('ignore', UserWarning)
warnings.simplefilter('ignore', ConvergenceWarning)
lars_cv = LassoLarsCV(cv=6).fit(X, y)
# Run the RandomizedLasso: we use a paths going down to .1*alpha_max
# to avoid exploring the regime in which very noisy variables enter
# the model
alphas = np.linspace(lars_cv.alphas_[0], .1 * lars_cv.alphas_[0], 6)
clf = RandomizedLasso(alpha=alphas, random_state=42).fit(X, y)
trees = ExtraTreesRegressor(100).fit(X, y)
# Compare with F-score
F, _ = f_regression(X, y)
plt.figure()
for name, score in [('F-test', F),
('Stability selection', clf.scores_),
('Lasso coefs', np.abs(lars_cv.coef_)),
('Trees', trees.feature_importances_),
]:
precision, recall, thresholds = precision_recall_curve(coef != 0,
score)
plt.semilogy(np.maximum(score / np.max(score), 1e-4),
label="%s. AUC: %.3f" % (name, auc(recall, precision)))
plt.plot(np.where(coef != 0)[0], [2e-4] * n_relevant_features, 'mo',
label="Ground truth")
plt.xlabel("Features")
plt.ylabel("Score")
# Plot only the 100 first coefficients
plt.xlim(0, 100)
plt.legend(loc='best')
plt.title('Feature selection scores - Mutual incoherence: %.1f'
% mi)
plt.show()
| bsd-3-clause |
jjx02230808/project0223 | examples/cluster/plot_kmeans_assumptions.py | 270 | 2040 | """
====================================
Demonstration of k-means assumptions
====================================
This example is meant to illustrate situations where k-means will produce
unintuitive and possibly unexpected clusters. In the first three plots, the
input data does not conform to some implicit assumption that k-means makes and
undesirable clusters are produced as a result. In the last plot, k-means
returns intuitive clusters despite unevenly sized blobs.
"""
print(__doc__)
# Author: Phil Roth <[email protected]>
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from sklearn.cluster import KMeans
from sklearn.datasets import make_blobs
plt.figure(figsize=(12, 12))
n_samples = 1500
random_state = 170
X, y = make_blobs(n_samples=n_samples, random_state=random_state)
# Incorrect number of clusters
y_pred = KMeans(n_clusters=2, random_state=random_state).fit_predict(X)
plt.subplot(221)
plt.scatter(X[:, 0], X[:, 1], c=y_pred)
plt.title("Incorrect Number of Blobs")
# Anisotropicly distributed data
transformation = [[ 0.60834549, -0.63667341], [-0.40887718, 0.85253229]]
X_aniso = np.dot(X, transformation)
y_pred = KMeans(n_clusters=3, random_state=random_state).fit_predict(X_aniso)
plt.subplot(222)
plt.scatter(X_aniso[:, 0], X_aniso[:, 1], c=y_pred)
plt.title("Anisotropicly Distributed Blobs")
# Different variance
X_varied, y_varied = make_blobs(n_samples=n_samples,
cluster_std=[1.0, 2.5, 0.5],
random_state=random_state)
y_pred = KMeans(n_clusters=3, random_state=random_state).fit_predict(X_varied)
plt.subplot(223)
plt.scatter(X_varied[:, 0], X_varied[:, 1], c=y_pred)
plt.title("Unequal Variance")
# Unevenly sized blobs
X_filtered = np.vstack((X[y == 0][:500], X[y == 1][:100], X[y == 2][:10]))
y_pred = KMeans(n_clusters=3, random_state=random_state).fit_predict(X_filtered)
plt.subplot(224)
plt.scatter(X_filtered[:, 0], X_filtered[:, 1], c=y_pred)
plt.title("Unevenly Sized Blobs")
plt.show()
| bsd-3-clause |
fclesio/learning-space | Lightning Talk @Movile - ML with Scikit-Learn/Recipes/MeanShift.py | 1 | 1580 | # Mean Shift: http://scikit-learn.org/stable/auto_examples/cluster/plot_mean_shift.html#example-cluster-plot-mean-shift-py
print(__doc__)
import numpy as np
from sklearn.cluster import MeanShift, estimate_bandwidth
from sklearn.datasets.samples_generator import make_blobs
###############################################################################
# Generate sample data
centers = [[1, 1], [-1, -1], [1, -1]]
X, _ = make_blobs(n_samples=10000, centers=centers, cluster_std=0.6)
###############################################################################
# Compute clustering with MeanShift
# The following bandwidth can be automatically detected using
bandwidth = estimate_bandwidth(X, quantile=0.2, n_samples=500)
ms = MeanShift(bandwidth=bandwidth, bin_seeding=True)
ms.fit(X)
labels = ms.labels_
cluster_centers = ms.cluster_centers_
labels_unique = np.unique(labels)
n_clusters_ = len(labels_unique)
print("number of estimated clusters : %d" % n_clusters_)
###############################################################################
# Plot result
import matplotlib.pyplot as plt
from itertools import cycle
plt.figure(1)
plt.clf()
colors = cycle('bgrcmykbgrcmykbgrcmykbgrcmyk')
for k, col in zip(range(n_clusters_), colors):
my_members = labels == k
cluster_center = cluster_centers[k]
plt.plot(X[my_members, 0], X[my_members, 1], col + '.')
plt.plot(cluster_center[0], cluster_center[1], 'o', markerfacecolor=col,
markeredgecolor='k', markersize=14)
plt.title('Estimated number of clusters: %d' % n_clusters_)
plt.show()
| gpl-2.0 |
vigilv/scikit-learn | examples/ensemble/plot_adaboost_multiclass.py | 354 | 4124 | """
=====================================
Multi-class AdaBoosted Decision Trees
=====================================
This example reproduces Figure 1 of Zhu et al [1] and shows how boosting can
improve prediction accuracy on a multi-class problem. The classification
dataset is constructed by taking a ten-dimensional standard normal distribution
and defining three classes separated by nested concentric ten-dimensional
spheres such that roughly equal numbers of samples are in each class (quantiles
of the :math:`\chi^2` distribution).
The performance of the SAMME and SAMME.R [1] algorithms are compared. SAMME.R
uses the probability estimates to update the additive model, while SAMME uses
the classifications only. As the example illustrates, the SAMME.R algorithm
typically converges faster than SAMME, achieving a lower test error with fewer
boosting iterations. The error of each algorithm on the test set after each
boosting iteration is shown on the left, the classification error on the test
set of each tree is shown in the middle, and the boost weight of each tree is
shown on the right. All trees have a weight of one in the SAMME.R algorithm and
therefore are not shown.
.. [1] J. Zhu, H. Zou, S. Rosset, T. Hastie, "Multi-class AdaBoost", 2009.
"""
print(__doc__)
# Author: Noel Dawe <[email protected]>
#
# License: BSD 3 clause
from sklearn.externals.six.moves import zip
import matplotlib.pyplot as plt
from sklearn.datasets import make_gaussian_quantiles
from sklearn.ensemble import AdaBoostClassifier
from sklearn.metrics import accuracy_score
from sklearn.tree import DecisionTreeClassifier
X, y = make_gaussian_quantiles(n_samples=13000, n_features=10,
n_classes=3, random_state=1)
n_split = 3000
X_train, X_test = X[:n_split], X[n_split:]
y_train, y_test = y[:n_split], y[n_split:]
bdt_real = AdaBoostClassifier(
DecisionTreeClassifier(max_depth=2),
n_estimators=600,
learning_rate=1)
bdt_discrete = AdaBoostClassifier(
DecisionTreeClassifier(max_depth=2),
n_estimators=600,
learning_rate=1.5,
algorithm="SAMME")
bdt_real.fit(X_train, y_train)
bdt_discrete.fit(X_train, y_train)
real_test_errors = []
discrete_test_errors = []
for real_test_predict, discrete_train_predict in zip(
bdt_real.staged_predict(X_test), bdt_discrete.staged_predict(X_test)):
real_test_errors.append(
1. - accuracy_score(real_test_predict, y_test))
discrete_test_errors.append(
1. - accuracy_score(discrete_train_predict, y_test))
n_trees_discrete = len(bdt_discrete)
n_trees_real = len(bdt_real)
# Boosting might terminate early, but the following arrays are always
# n_estimators long. We crop them to the actual number of trees here:
discrete_estimator_errors = bdt_discrete.estimator_errors_[:n_trees_discrete]
real_estimator_errors = bdt_real.estimator_errors_[:n_trees_real]
discrete_estimator_weights = bdt_discrete.estimator_weights_[:n_trees_discrete]
plt.figure(figsize=(15, 5))
plt.subplot(131)
plt.plot(range(1, n_trees_discrete + 1),
discrete_test_errors, c='black', label='SAMME')
plt.plot(range(1, n_trees_real + 1),
real_test_errors, c='black',
linestyle='dashed', label='SAMME.R')
plt.legend()
plt.ylim(0.18, 0.62)
plt.ylabel('Test Error')
plt.xlabel('Number of Trees')
plt.subplot(132)
plt.plot(range(1, n_trees_discrete + 1), discrete_estimator_errors,
"b", label='SAMME', alpha=.5)
plt.plot(range(1, n_trees_real + 1), real_estimator_errors,
"r", label='SAMME.R', alpha=.5)
plt.legend()
plt.ylabel('Error')
plt.xlabel('Number of Trees')
plt.ylim((.2,
max(real_estimator_errors.max(),
discrete_estimator_errors.max()) * 1.2))
plt.xlim((-20, len(bdt_discrete) + 20))
plt.subplot(133)
plt.plot(range(1, n_trees_discrete + 1), discrete_estimator_weights,
"b", label='SAMME')
plt.legend()
plt.ylabel('Weight')
plt.xlabel('Number of Trees')
plt.ylim((0, discrete_estimator_weights.max() * 1.2))
plt.xlim((-20, n_trees_discrete + 20))
# prevent overlapping y-axis labels
plt.subplots_adjust(wspace=0.25)
plt.show()
| bsd-3-clause |
vshtanko/scikit-learn | examples/linear_model/plot_lasso_lars.py | 363 | 1080 | #!/usr/bin/env python
"""
=====================
Lasso path using LARS
=====================
Computes Lasso Path along the regularization parameter using the LARS
algorithm on the diabetes dataset. Each color represents a different
feature of the coefficient vector, and this is displayed as a function
of the regularization parameter.
"""
print(__doc__)
# Author: Fabian Pedregosa <[email protected]>
# Alexandre Gramfort <[email protected]>
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from sklearn import linear_model
from sklearn import datasets
diabetes = datasets.load_diabetes()
X = diabetes.data
y = diabetes.target
print("Computing regularization path using the LARS ...")
alphas, _, coefs = linear_model.lars_path(X, y, method='lasso', verbose=True)
xx = np.sum(np.abs(coefs.T), axis=1)
xx /= xx[-1]
plt.plot(xx, coefs.T)
ymin, ymax = plt.ylim()
plt.vlines(xx, ymin, ymax, linestyle='dashed')
plt.xlabel('|coef| / max|coef|')
plt.ylabel('Coefficients')
plt.title('LASSO Path')
plt.axis('tight')
plt.show()
| bsd-3-clause |
pv/scikit-learn | sklearn/tests/test_cross_validation.py | 70 | 41943 | """Test the cross_validation module"""
from __future__ import division
import warnings
import numpy as np
from scipy.sparse import coo_matrix
from scipy import stats
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import assert_false
from sklearn.utils.testing import assert_equal
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_raises
from sklearn.utils.testing import assert_greater
from sklearn.utils.testing import assert_less
from sklearn.utils.testing import assert_not_equal
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_array_equal
from sklearn.utils.testing import assert_warns_message
from sklearn.utils.testing import ignore_warnings
from sklearn.utils.mocking import CheckingClassifier, MockDataFrame
from sklearn import cross_validation as cval
from sklearn.datasets import make_regression
from sklearn.datasets import load_boston
from sklearn.datasets import load_digits
from sklearn.datasets import load_iris
from sklearn.metrics import explained_variance_score
from sklearn.metrics import make_scorer
from sklearn.metrics import precision_score
from sklearn.externals import six
from sklearn.externals.six.moves import zip
from sklearn.linear_model import Ridge
from sklearn.neighbors import KNeighborsClassifier
from sklearn.svm import SVC
from sklearn.cluster import KMeans
from sklearn.preprocessing import Imputer, LabelBinarizer
from sklearn.pipeline import Pipeline
class MockClassifier(object):
"""Dummy classifier to test the cross-validation"""
def __init__(self, a=0, allow_nd=False):
self.a = a
self.allow_nd = allow_nd
def fit(self, X, Y=None, sample_weight=None, class_prior=None,
sparse_sample_weight=None, sparse_param=None, dummy_int=None,
dummy_str=None, dummy_obj=None, callback=None):
"""The dummy arguments are to test that this fit function can
accept non-array arguments through cross-validation, such as:
- int
- str (this is actually array-like)
- object
- function
"""
self.dummy_int = dummy_int
self.dummy_str = dummy_str
self.dummy_obj = dummy_obj
if callback is not None:
callback(self)
if self.allow_nd:
X = X.reshape(len(X), -1)
if X.ndim >= 3 and not self.allow_nd:
raise ValueError('X cannot be d')
if sample_weight is not None:
assert_true(sample_weight.shape[0] == X.shape[0],
'MockClassifier extra fit_param sample_weight.shape[0]'
' is {0}, should be {1}'.format(sample_weight.shape[0],
X.shape[0]))
if class_prior is not None:
assert_true(class_prior.shape[0] == len(np.unique(y)),
'MockClassifier extra fit_param class_prior.shape[0]'
' is {0}, should be {1}'.format(class_prior.shape[0],
len(np.unique(y))))
if sparse_sample_weight is not None:
fmt = ('MockClassifier extra fit_param sparse_sample_weight'
'.shape[0] is {0}, should be {1}')
assert_true(sparse_sample_weight.shape[0] == X.shape[0],
fmt.format(sparse_sample_weight.shape[0], X.shape[0]))
if sparse_param is not None:
fmt = ('MockClassifier extra fit_param sparse_param.shape '
'is ({0}, {1}), should be ({2}, {3})')
assert_true(sparse_param.shape == P_sparse.shape,
fmt.format(sparse_param.shape[0],
sparse_param.shape[1],
P_sparse.shape[0], P_sparse.shape[1]))
return self
def predict(self, T):
if self.allow_nd:
T = T.reshape(len(T), -1)
return T[:, 0]
def score(self, X=None, Y=None):
return 1. / (1 + np.abs(self.a))
def get_params(self, deep=False):
return {'a': self.a, 'allow_nd': self.allow_nd}
X = np.ones((10, 2))
X_sparse = coo_matrix(X)
W_sparse = coo_matrix((np.array([1]), (np.array([1]), np.array([0]))),
shape=(10, 1))
P_sparse = coo_matrix(np.eye(5))
y = np.arange(10) // 2
##############################################################################
# Tests
def check_valid_split(train, test, n_samples=None):
# Use python sets to get more informative assertion failure messages
train, test = set(train), set(test)
# Train and test split should not overlap
assert_equal(train.intersection(test), set())
if n_samples is not None:
# Check that the union of train an test split cover all the indices
assert_equal(train.union(test), set(range(n_samples)))
def check_cv_coverage(cv, expected_n_iter=None, n_samples=None):
# Check that a all the samples appear at least once in a test fold
if expected_n_iter is not None:
assert_equal(len(cv), expected_n_iter)
else:
expected_n_iter = len(cv)
collected_test_samples = set()
iterations = 0
for train, test in cv:
check_valid_split(train, test, n_samples=n_samples)
iterations += 1
collected_test_samples.update(test)
# Check that the accumulated test samples cover the whole dataset
assert_equal(iterations, expected_n_iter)
if n_samples is not None:
assert_equal(collected_test_samples, set(range(n_samples)))
def test_kfold_valueerrors():
# Check that errors are raised if there is not enough samples
assert_raises(ValueError, cval.KFold, 3, 4)
# Check that a warning is raised if the least populated class has too few
# members.
y = [3, 3, -1, -1, 2]
cv = assert_warns_message(Warning, "The least populated class",
cval.StratifiedKFold, y, 3)
# Check that despite the warning the folds are still computed even
# though all the classes are not necessarily represented at on each
# side of the split at each split
check_cv_coverage(cv, expected_n_iter=3, n_samples=len(y))
# Error when number of folds is <= 1
assert_raises(ValueError, cval.KFold, 2, 0)
assert_raises(ValueError, cval.KFold, 2, 1)
assert_raises(ValueError, cval.StratifiedKFold, y, 0)
assert_raises(ValueError, cval.StratifiedKFold, y, 1)
# When n is not integer:
assert_raises(ValueError, cval.KFold, 2.5, 2)
# When n_folds is not integer:
assert_raises(ValueError, cval.KFold, 5, 1.5)
assert_raises(ValueError, cval.StratifiedKFold, y, 1.5)
def test_kfold_indices():
# Check all indices are returned in the test folds
kf = cval.KFold(300, 3)
check_cv_coverage(kf, expected_n_iter=3, n_samples=300)
# Check all indices are returned in the test folds even when equal-sized
# folds are not possible
kf = cval.KFold(17, 3)
check_cv_coverage(kf, expected_n_iter=3, n_samples=17)
def test_kfold_no_shuffle():
# Manually check that KFold preserves the data ordering on toy datasets
splits = iter(cval.KFold(4, 2))
train, test = next(splits)
assert_array_equal(test, [0, 1])
assert_array_equal(train, [2, 3])
train, test = next(splits)
assert_array_equal(test, [2, 3])
assert_array_equal(train, [0, 1])
splits = iter(cval.KFold(5, 2))
train, test = next(splits)
assert_array_equal(test, [0, 1, 2])
assert_array_equal(train, [3, 4])
train, test = next(splits)
assert_array_equal(test, [3, 4])
assert_array_equal(train, [0, 1, 2])
def test_stratified_kfold_no_shuffle():
# Manually check that StratifiedKFold preserves the data ordering as much
# as possible on toy datasets in order to avoid hiding sample dependencies
# when possible
splits = iter(cval.StratifiedKFold([1, 1, 0, 0], 2))
train, test = next(splits)
assert_array_equal(test, [0, 2])
assert_array_equal(train, [1, 3])
train, test = next(splits)
assert_array_equal(test, [1, 3])
assert_array_equal(train, [0, 2])
splits = iter(cval.StratifiedKFold([1, 1, 1, 0, 0, 0, 0], 2))
train, test = next(splits)
assert_array_equal(test, [0, 1, 3, 4])
assert_array_equal(train, [2, 5, 6])
train, test = next(splits)
assert_array_equal(test, [2, 5, 6])
assert_array_equal(train, [0, 1, 3, 4])
def test_stratified_kfold_ratios():
# Check that stratified kfold preserves label ratios in individual splits
# Repeat with shuffling turned off and on
n_samples = 1000
labels = np.array([4] * int(0.10 * n_samples) +
[0] * int(0.89 * n_samples) +
[1] * int(0.01 * n_samples))
for shuffle in [False, True]:
for train, test in cval.StratifiedKFold(labels, 5, shuffle=shuffle):
assert_almost_equal(np.sum(labels[train] == 4) / len(train), 0.10,
2)
assert_almost_equal(np.sum(labels[train] == 0) / len(train), 0.89,
2)
assert_almost_equal(np.sum(labels[train] == 1) / len(train), 0.01,
2)
assert_almost_equal(np.sum(labels[test] == 4) / len(test), 0.10, 2)
assert_almost_equal(np.sum(labels[test] == 0) / len(test), 0.89, 2)
assert_almost_equal(np.sum(labels[test] == 1) / len(test), 0.01, 2)
def test_kfold_balance():
# Check that KFold returns folds with balanced sizes
for kf in [cval.KFold(i, 5) for i in range(11, 17)]:
sizes = []
for _, test in kf:
sizes.append(len(test))
assert_true((np.max(sizes) - np.min(sizes)) <= 1)
assert_equal(np.sum(sizes), kf.n)
def test_stratifiedkfold_balance():
# Check that KFold returns folds with balanced sizes (only when
# stratification is possible)
# Repeat with shuffling turned off and on
labels = [0] * 3 + [1] * 14
for shuffle in [False, True]:
for skf in [cval.StratifiedKFold(labels[:i], 3, shuffle=shuffle)
for i in range(11, 17)]:
sizes = []
for _, test in skf:
sizes.append(len(test))
assert_true((np.max(sizes) - np.min(sizes)) <= 1)
assert_equal(np.sum(sizes), skf.n)
def test_shuffle_kfold():
# Check the indices are shuffled properly, and that all indices are
# returned in the different test folds
kf = cval.KFold(300, 3, shuffle=True, random_state=0)
ind = np.arange(300)
all_folds = None
for train, test in kf:
sorted_array = np.arange(100)
assert_true(np.any(sorted_array != ind[train]))
sorted_array = np.arange(101, 200)
assert_true(np.any(sorted_array != ind[train]))
sorted_array = np.arange(201, 300)
assert_true(np.any(sorted_array != ind[train]))
if all_folds is None:
all_folds = ind[test].copy()
else:
all_folds = np.concatenate((all_folds, ind[test]))
all_folds.sort()
assert_array_equal(all_folds, ind)
def test_shuffle_stratifiedkfold():
# Check that shuffling is happening when requested, and for proper
# sample coverage
labels = [0] * 20 + [1] * 20
kf0 = list(cval.StratifiedKFold(labels, 5, shuffle=True, random_state=0))
kf1 = list(cval.StratifiedKFold(labels, 5, shuffle=True, random_state=1))
for (_, test0), (_, test1) in zip(kf0, kf1):
assert_true(set(test0) != set(test1))
check_cv_coverage(kf0, expected_n_iter=5, n_samples=40)
def test_kfold_can_detect_dependent_samples_on_digits(): # see #2372
# The digits samples are dependent: they are apparently grouped by authors
# although we don't have any information on the groups segment locations
# for this data. We can highlight this fact be computing k-fold cross-
# validation with and without shuffling: we observe that the shuffling case
# wrongly makes the IID assumption and is therefore too optimistic: it
# estimates a much higher accuracy (around 0.96) than than the non
# shuffling variant (around 0.86).
digits = load_digits()
X, y = digits.data[:800], digits.target[:800]
model = SVC(C=10, gamma=0.005)
n = len(y)
cv = cval.KFold(n, 5, shuffle=False)
mean_score = cval.cross_val_score(model, X, y, cv=cv).mean()
assert_greater(0.88, mean_score)
assert_greater(mean_score, 0.85)
# Shuffling the data artificially breaks the dependency and hides the
# overfitting of the model with regards to the writing style of the authors
# by yielding a seriously overestimated score:
cv = cval.KFold(n, 5, shuffle=True, random_state=0)
mean_score = cval.cross_val_score(model, X, y, cv=cv).mean()
assert_greater(mean_score, 0.95)
cv = cval.KFold(n, 5, shuffle=True, random_state=1)
mean_score = cval.cross_val_score(model, X, y, cv=cv).mean()
assert_greater(mean_score, 0.95)
# Similarly, StratifiedKFold should try to shuffle the data as little
# as possible (while respecting the balanced class constraints)
# and thus be able to detect the dependency by not overestimating
# the CV score either. As the digits dataset is approximately balanced
# the estimated mean score is close to the score measured with
# non-shuffled KFold
cv = cval.StratifiedKFold(y, 5)
mean_score = cval.cross_val_score(model, X, y, cv=cv).mean()
assert_greater(0.88, mean_score)
assert_greater(mean_score, 0.85)
def test_shuffle_split():
ss1 = cval.ShuffleSplit(10, test_size=0.2, random_state=0)
ss2 = cval.ShuffleSplit(10, test_size=2, random_state=0)
ss3 = cval.ShuffleSplit(10, test_size=np.int32(2), random_state=0)
for typ in six.integer_types:
ss4 = cval.ShuffleSplit(10, test_size=typ(2), random_state=0)
for t1, t2, t3, t4 in zip(ss1, ss2, ss3, ss4):
assert_array_equal(t1[0], t2[0])
assert_array_equal(t2[0], t3[0])
assert_array_equal(t3[0], t4[0])
assert_array_equal(t1[1], t2[1])
assert_array_equal(t2[1], t3[1])
assert_array_equal(t3[1], t4[1])
def test_stratified_shuffle_split_init():
y = np.asarray([0, 1, 1, 1, 2, 2, 2])
# Check that error is raised if there is a class with only one sample
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, 3, 0.2)
# Check that error is raised if the test set size is smaller than n_classes
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, 3, 2)
# Check that error is raised if the train set size is smaller than
# n_classes
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, 3, 3, 2)
y = np.asarray([0, 0, 0, 1, 1, 1, 2, 2, 2])
# Check that errors are raised if there is not enough samples
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, 3, 0.5, 0.6)
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, 3, 8, 0.6)
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, 3, 0.6, 8)
# Train size or test size too small
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, train_size=2)
assert_raises(ValueError, cval.StratifiedShuffleSplit, y, test_size=2)
def test_stratified_shuffle_split_iter():
ys = [np.array([1, 1, 1, 1, 2, 2, 2, 3, 3, 3, 3, 3]),
np.array([0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3]),
np.array([0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2, 3, 0, 1, 2]),
np.array([1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4]),
np.array([-1] * 800 + [1] * 50)
]
for y in ys:
sss = cval.StratifiedShuffleSplit(y, 6, test_size=0.33,
random_state=0)
for train, test in sss:
assert_array_equal(np.unique(y[train]), np.unique(y[test]))
# Checks if folds keep classes proportions
p_train = (np.bincount(np.unique(y[train], return_inverse=True)[1])
/ float(len(y[train])))
p_test = (np.bincount(np.unique(y[test], return_inverse=True)[1])
/ float(len(y[test])))
assert_array_almost_equal(p_train, p_test, 1)
assert_equal(y[train].size + y[test].size, y.size)
assert_array_equal(np.lib.arraysetops.intersect1d(train, test), [])
def test_stratified_shuffle_split_even():
# Test the StratifiedShuffleSplit, indices are drawn with a
# equal chance
n_folds = 5
n_iter = 1000
def assert_counts_are_ok(idx_counts, p):
# Here we test that the distribution of the counts
# per index is close enough to a binomial
threshold = 0.05 / n_splits
bf = stats.binom(n_splits, p)
for count in idx_counts:
p = bf.pmf(count)
assert_true(p > threshold,
"An index is not drawn with chance corresponding "
"to even draws")
for n_samples in (6, 22):
labels = np.array((n_samples // 2) * [0, 1])
splits = cval.StratifiedShuffleSplit(labels, n_iter=n_iter,
test_size=1. / n_folds,
random_state=0)
train_counts = [0] * n_samples
test_counts = [0] * n_samples
n_splits = 0
for train, test in splits:
n_splits += 1
for counter, ids in [(train_counts, train), (test_counts, test)]:
for id in ids:
counter[id] += 1
assert_equal(n_splits, n_iter)
assert_equal(len(train), splits.n_train)
assert_equal(len(test), splits.n_test)
assert_equal(len(set(train).intersection(test)), 0)
label_counts = np.unique(labels)
assert_equal(splits.test_size, 1.0 / n_folds)
assert_equal(splits.n_train + splits.n_test, len(labels))
assert_equal(len(label_counts), 2)
ex_test_p = float(splits.n_test) / n_samples
ex_train_p = float(splits.n_train) / n_samples
assert_counts_are_ok(train_counts, ex_train_p)
assert_counts_are_ok(test_counts, ex_test_p)
def test_predefinedsplit_with_kfold_split():
# Check that PredefinedSplit can reproduce a split generated by Kfold.
folds = -1 * np.ones(10)
kf_train = []
kf_test = []
for i, (train_ind, test_ind) in enumerate(cval.KFold(10, 5, shuffle=True)):
kf_train.append(train_ind)
kf_test.append(test_ind)
folds[test_ind] = i
ps_train = []
ps_test = []
ps = cval.PredefinedSplit(folds)
for train_ind, test_ind in ps:
ps_train.append(train_ind)
ps_test.append(test_ind)
assert_array_equal(ps_train, kf_train)
assert_array_equal(ps_test, kf_test)
def test_leave_label_out_changing_labels():
# Check that LeaveOneLabelOut and LeavePLabelOut work normally if
# the labels variable is changed before calling __iter__
labels = np.array([0, 1, 2, 1, 1, 2, 0, 0])
labels_changing = np.array(labels, copy=True)
lolo = cval.LeaveOneLabelOut(labels)
lolo_changing = cval.LeaveOneLabelOut(labels_changing)
lplo = cval.LeavePLabelOut(labels, p=2)
lplo_changing = cval.LeavePLabelOut(labels_changing, p=2)
labels_changing[:] = 0
for llo, llo_changing in [(lolo, lolo_changing), (lplo, lplo_changing)]:
for (train, test), (train_chan, test_chan) in zip(llo, llo_changing):
assert_array_equal(train, train_chan)
assert_array_equal(test, test_chan)
def test_cross_val_score():
clf = MockClassifier()
for a in range(-10, 10):
clf.a = a
# Smoke test
scores = cval.cross_val_score(clf, X, y)
assert_array_equal(scores, clf.score(X, y))
# test with multioutput y
scores = cval.cross_val_score(clf, X_sparse, X)
assert_array_equal(scores, clf.score(X_sparse, X))
scores = cval.cross_val_score(clf, X_sparse, y)
assert_array_equal(scores, clf.score(X_sparse, y))
# test with multioutput y
scores = cval.cross_val_score(clf, X_sparse, X)
assert_array_equal(scores, clf.score(X_sparse, X))
# test with X and y as list
list_check = lambda x: isinstance(x, list)
clf = CheckingClassifier(check_X=list_check)
scores = cval.cross_val_score(clf, X.tolist(), y.tolist())
clf = CheckingClassifier(check_y=list_check)
scores = cval.cross_val_score(clf, X, y.tolist())
assert_raises(ValueError, cval.cross_val_score, clf, X, y,
scoring="sklearn")
# test with 3d X and
X_3d = X[:, :, np.newaxis]
clf = MockClassifier(allow_nd=True)
scores = cval.cross_val_score(clf, X_3d, y)
clf = MockClassifier(allow_nd=False)
assert_raises(ValueError, cval.cross_val_score, clf, X_3d, y)
def test_cross_val_score_pandas():
# check cross_val_score doesn't destroy pandas dataframe
types = [(MockDataFrame, MockDataFrame)]
try:
from pandas import Series, DataFrame
types.append((Series, DataFrame))
except ImportError:
pass
for TargetType, InputFeatureType in types:
# X dataframe, y series
X_df, y_ser = InputFeatureType(X), TargetType(y)
check_df = lambda x: isinstance(x, InputFeatureType)
check_series = lambda x: isinstance(x, TargetType)
clf = CheckingClassifier(check_X=check_df, check_y=check_series)
cval.cross_val_score(clf, X_df, y_ser)
def test_cross_val_score_mask():
# test that cross_val_score works with boolean masks
svm = SVC(kernel="linear")
iris = load_iris()
X, y = iris.data, iris.target
cv_indices = cval.KFold(len(y), 5)
scores_indices = cval.cross_val_score(svm, X, y, cv=cv_indices)
cv_indices = cval.KFold(len(y), 5)
cv_masks = []
for train, test in cv_indices:
mask_train = np.zeros(len(y), dtype=np.bool)
mask_test = np.zeros(len(y), dtype=np.bool)
mask_train[train] = 1
mask_test[test] = 1
cv_masks.append((train, test))
scores_masks = cval.cross_val_score(svm, X, y, cv=cv_masks)
assert_array_equal(scores_indices, scores_masks)
def test_cross_val_score_precomputed():
# test for svm with precomputed kernel
svm = SVC(kernel="precomputed")
iris = load_iris()
X, y = iris.data, iris.target
linear_kernel = np.dot(X, X.T)
score_precomputed = cval.cross_val_score(svm, linear_kernel, y)
svm = SVC(kernel="linear")
score_linear = cval.cross_val_score(svm, X, y)
assert_array_equal(score_precomputed, score_linear)
# Error raised for non-square X
svm = SVC(kernel="precomputed")
assert_raises(ValueError, cval.cross_val_score, svm, X, y)
# test error is raised when the precomputed kernel is not array-like
# or sparse
assert_raises(ValueError, cval.cross_val_score, svm,
linear_kernel.tolist(), y)
def test_cross_val_score_fit_params():
clf = MockClassifier()
n_samples = X.shape[0]
n_classes = len(np.unique(y))
DUMMY_INT = 42
DUMMY_STR = '42'
DUMMY_OBJ = object()
def assert_fit_params(clf):
# Function to test that the values are passed correctly to the
# classifier arguments for non-array type
assert_equal(clf.dummy_int, DUMMY_INT)
assert_equal(clf.dummy_str, DUMMY_STR)
assert_equal(clf.dummy_obj, DUMMY_OBJ)
fit_params = {'sample_weight': np.ones(n_samples),
'class_prior': np.ones(n_classes) / n_classes,
'sparse_sample_weight': W_sparse,
'sparse_param': P_sparse,
'dummy_int': DUMMY_INT,
'dummy_str': DUMMY_STR,
'dummy_obj': DUMMY_OBJ,
'callback': assert_fit_params}
cval.cross_val_score(clf, X, y, fit_params=fit_params)
def test_cross_val_score_score_func():
clf = MockClassifier()
_score_func_args = []
def score_func(y_test, y_predict):
_score_func_args.append((y_test, y_predict))
return 1.0
with warnings.catch_warnings(record=True):
scoring = make_scorer(score_func)
score = cval.cross_val_score(clf, X, y, scoring=scoring)
assert_array_equal(score, [1.0, 1.0, 1.0])
assert len(_score_func_args) == 3
def test_cross_val_score_errors():
class BrokenEstimator:
pass
assert_raises(TypeError, cval.cross_val_score, BrokenEstimator(), X)
def test_train_test_split_errors():
assert_raises(ValueError, cval.train_test_split)
assert_raises(ValueError, cval.train_test_split, range(3), train_size=1.1)
assert_raises(ValueError, cval.train_test_split, range(3), test_size=0.6,
train_size=0.6)
assert_raises(ValueError, cval.train_test_split, range(3),
test_size=np.float32(0.6), train_size=np.float32(0.6))
assert_raises(ValueError, cval.train_test_split, range(3),
test_size="wrong_type")
assert_raises(ValueError, cval.train_test_split, range(3), test_size=2,
train_size=4)
assert_raises(TypeError, cval.train_test_split, range(3),
some_argument=1.1)
assert_raises(ValueError, cval.train_test_split, range(3), range(42))
def test_train_test_split():
X = np.arange(100).reshape((10, 10))
X_s = coo_matrix(X)
y = np.arange(10)
# simple test
split = cval.train_test_split(X, y, test_size=None, train_size=.5)
X_train, X_test, y_train, y_test = split
assert_equal(len(y_test), len(y_train))
# test correspondence of X and y
assert_array_equal(X_train[:, 0], y_train * 10)
assert_array_equal(X_test[:, 0], y_test * 10)
# conversion of lists to arrays (deprecated?)
with warnings.catch_warnings(record=True):
split = cval.train_test_split(X, X_s, y.tolist(), allow_lists=False)
X_train, X_test, X_s_train, X_s_test, y_train, y_test = split
assert_array_equal(X_train, X_s_train.toarray())
assert_array_equal(X_test, X_s_test.toarray())
# don't convert lists to anything else by default
split = cval.train_test_split(X, X_s, y.tolist())
X_train, X_test, X_s_train, X_s_test, y_train, y_test = split
assert_true(isinstance(y_train, list))
assert_true(isinstance(y_test, list))
# allow nd-arrays
X_4d = np.arange(10 * 5 * 3 * 2).reshape(10, 5, 3, 2)
y_3d = np.arange(10 * 7 * 11).reshape(10, 7, 11)
split = cval.train_test_split(X_4d, y_3d)
assert_equal(split[0].shape, (7, 5, 3, 2))
assert_equal(split[1].shape, (3, 5, 3, 2))
assert_equal(split[2].shape, (7, 7, 11))
assert_equal(split[3].shape, (3, 7, 11))
# test stratification option
y = np.array([1, 1, 1, 1, 2, 2, 2, 2])
for test_size, exp_test_size in zip([2, 4, 0.25, 0.5, 0.75],
[2, 4, 2, 4, 6]):
train, test = cval.train_test_split(y,
test_size=test_size,
stratify=y,
random_state=0)
assert_equal(len(test), exp_test_size)
assert_equal(len(test) + len(train), len(y))
# check the 1:1 ratio of ones and twos in the data is preserved
assert_equal(np.sum(train == 1), np.sum(train == 2))
def train_test_split_pandas():
# check cross_val_score doesn't destroy pandas dataframe
types = [MockDataFrame]
try:
from pandas import DataFrame
types.append(DataFrame)
except ImportError:
pass
for InputFeatureType in types:
# X dataframe
X_df = InputFeatureType(X)
X_train, X_test = cval.train_test_split(X_df)
assert_true(isinstance(X_train, InputFeatureType))
assert_true(isinstance(X_test, InputFeatureType))
def train_test_split_mock_pandas():
# X mock dataframe
X_df = MockDataFrame(X)
X_train, X_test = cval.train_test_split(X_df)
assert_true(isinstance(X_train, MockDataFrame))
assert_true(isinstance(X_test, MockDataFrame))
X_train_arr, X_test_arr = cval.train_test_split(X_df, allow_lists=False)
assert_true(isinstance(X_train_arr, np.ndarray))
assert_true(isinstance(X_test_arr, np.ndarray))
def test_cross_val_score_with_score_func_classification():
iris = load_iris()
clf = SVC(kernel='linear')
# Default score (should be the accuracy score)
scores = cval.cross_val_score(clf, iris.data, iris.target, cv=5)
assert_array_almost_equal(scores, [0.97, 1., 0.97, 0.97, 1.], 2)
# Correct classification score (aka. zero / one score) - should be the
# same as the default estimator score
zo_scores = cval.cross_val_score(clf, iris.data, iris.target,
scoring="accuracy", cv=5)
assert_array_almost_equal(zo_scores, [0.97, 1., 0.97, 0.97, 1.], 2)
# F1 score (class are balanced so f1_score should be equal to zero/one
# score
f1_scores = cval.cross_val_score(clf, iris.data, iris.target,
scoring="f1_weighted", cv=5)
assert_array_almost_equal(f1_scores, [0.97, 1., 0.97, 0.97, 1.], 2)
def test_cross_val_score_with_score_func_regression():
X, y = make_regression(n_samples=30, n_features=20, n_informative=5,
random_state=0)
reg = Ridge()
# Default score of the Ridge regression estimator
scores = cval.cross_val_score(reg, X, y, cv=5)
assert_array_almost_equal(scores, [0.94, 0.97, 0.97, 0.99, 0.92], 2)
# R2 score (aka. determination coefficient) - should be the
# same as the default estimator score
r2_scores = cval.cross_val_score(reg, X, y, scoring="r2", cv=5)
assert_array_almost_equal(r2_scores, [0.94, 0.97, 0.97, 0.99, 0.92], 2)
# Mean squared error; this is a loss function, so "scores" are negative
mse_scores = cval.cross_val_score(reg, X, y, cv=5,
scoring="mean_squared_error")
expected_mse = np.array([-763.07, -553.16, -274.38, -273.26, -1681.99])
assert_array_almost_equal(mse_scores, expected_mse, 2)
# Explained variance
scoring = make_scorer(explained_variance_score)
ev_scores = cval.cross_val_score(reg, X, y, cv=5, scoring=scoring)
assert_array_almost_equal(ev_scores, [0.94, 0.97, 0.97, 0.99, 0.92], 2)
def test_permutation_score():
iris = load_iris()
X = iris.data
X_sparse = coo_matrix(X)
y = iris.target
svm = SVC(kernel='linear')
cv = cval.StratifiedKFold(y, 2)
score, scores, pvalue = cval.permutation_test_score(
svm, X, y, n_permutations=30, cv=cv, scoring="accuracy")
assert_greater(score, 0.9)
assert_almost_equal(pvalue, 0.0, 1)
score_label, _, pvalue_label = cval.permutation_test_score(
svm, X, y, n_permutations=30, cv=cv, scoring="accuracy",
labels=np.ones(y.size), random_state=0)
assert_true(score_label == score)
assert_true(pvalue_label == pvalue)
# check that we obtain the same results with a sparse representation
svm_sparse = SVC(kernel='linear')
cv_sparse = cval.StratifiedKFold(y, 2)
score_label, _, pvalue_label = cval.permutation_test_score(
svm_sparse, X_sparse, y, n_permutations=30, cv=cv_sparse,
scoring="accuracy", labels=np.ones(y.size), random_state=0)
assert_true(score_label == score)
assert_true(pvalue_label == pvalue)
# test with custom scoring object
def custom_score(y_true, y_pred):
return (((y_true == y_pred).sum() - (y_true != y_pred).sum())
/ y_true.shape[0])
scorer = make_scorer(custom_score)
score, _, pvalue = cval.permutation_test_score(
svm, X, y, n_permutations=100, scoring=scorer, cv=cv, random_state=0)
assert_almost_equal(score, .93, 2)
assert_almost_equal(pvalue, 0.01, 3)
# set random y
y = np.mod(np.arange(len(y)), 3)
score, scores, pvalue = cval.permutation_test_score(
svm, X, y, n_permutations=30, cv=cv, scoring="accuracy")
assert_less(score, 0.5)
assert_greater(pvalue, 0.2)
def test_cross_val_generator_with_indices():
X = np.array([[1, 2], [3, 4], [5, 6], [7, 8]])
y = np.array([1, 1, 2, 2])
labels = np.array([1, 2, 3, 4])
# explicitly passing indices value is deprecated
loo = cval.LeaveOneOut(4)
lpo = cval.LeavePOut(4, 2)
kf = cval.KFold(4, 2)
skf = cval.StratifiedKFold(y, 2)
lolo = cval.LeaveOneLabelOut(labels)
lopo = cval.LeavePLabelOut(labels, 2)
ps = cval.PredefinedSplit([1, 1, 2, 2])
ss = cval.ShuffleSplit(2)
for cv in [loo, lpo, kf, skf, lolo, lopo, ss, ps]:
for train, test in cv:
assert_not_equal(np.asarray(train).dtype.kind, 'b')
assert_not_equal(np.asarray(train).dtype.kind, 'b')
X[train], X[test]
y[train], y[test]
@ignore_warnings
def test_cross_val_generator_with_default_indices():
X = np.array([[1, 2], [3, 4], [5, 6], [7, 8]])
y = np.array([1, 1, 2, 2])
labels = np.array([1, 2, 3, 4])
loo = cval.LeaveOneOut(4)
lpo = cval.LeavePOut(4, 2)
kf = cval.KFold(4, 2)
skf = cval.StratifiedKFold(y, 2)
lolo = cval.LeaveOneLabelOut(labels)
lopo = cval.LeavePLabelOut(labels, 2)
ss = cval.ShuffleSplit(2)
ps = cval.PredefinedSplit([1, 1, 2, 2])
for cv in [loo, lpo, kf, skf, lolo, lopo, ss, ps]:
for train, test in cv:
assert_not_equal(np.asarray(train).dtype.kind, 'b')
assert_not_equal(np.asarray(train).dtype.kind, 'b')
X[train], X[test]
y[train], y[test]
def test_shufflesplit_errors():
assert_raises(ValueError, cval.ShuffleSplit, 10, test_size=2.0)
assert_raises(ValueError, cval.ShuffleSplit, 10, test_size=1.0)
assert_raises(ValueError, cval.ShuffleSplit, 10, test_size=0.1,
train_size=0.95)
assert_raises(ValueError, cval.ShuffleSplit, 10, test_size=11)
assert_raises(ValueError, cval.ShuffleSplit, 10, test_size=10)
assert_raises(ValueError, cval.ShuffleSplit, 10, test_size=8, train_size=3)
assert_raises(ValueError, cval.ShuffleSplit, 10, train_size=1j)
assert_raises(ValueError, cval.ShuffleSplit, 10, test_size=None,
train_size=None)
def test_shufflesplit_reproducible():
# Check that iterating twice on the ShuffleSplit gives the same
# sequence of train-test when the random_state is given
ss = cval.ShuffleSplit(10, random_state=21)
assert_array_equal(list(a for a, b in ss), list(a for a, b in ss))
def test_safe_split_with_precomputed_kernel():
clf = SVC()
clfp = SVC(kernel="precomputed")
iris = load_iris()
X, y = iris.data, iris.target
K = np.dot(X, X.T)
cv = cval.ShuffleSplit(X.shape[0], test_size=0.25, random_state=0)
tr, te = list(cv)[0]
X_tr, y_tr = cval._safe_split(clf, X, y, tr)
K_tr, y_tr2 = cval._safe_split(clfp, K, y, tr)
assert_array_almost_equal(K_tr, np.dot(X_tr, X_tr.T))
X_te, y_te = cval._safe_split(clf, X, y, te, tr)
K_te, y_te2 = cval._safe_split(clfp, K, y, te, tr)
assert_array_almost_equal(K_te, np.dot(X_te, X_tr.T))
def test_cross_val_score_allow_nans():
# Check that cross_val_score allows input data with NaNs
X = np.arange(200, dtype=np.float64).reshape(10, -1)
X[2, :] = np.nan
y = np.repeat([0, 1], X.shape[0] / 2)
p = Pipeline([
('imputer', Imputer(strategy='mean', missing_values='NaN')),
('classifier', MockClassifier()),
])
cval.cross_val_score(p, X, y, cv=5)
def test_train_test_split_allow_nans():
# Check that train_test_split allows input data with NaNs
X = np.arange(200, dtype=np.float64).reshape(10, -1)
X[2, :] = np.nan
y = np.repeat([0, 1], X.shape[0] / 2)
cval.train_test_split(X, y, test_size=0.2, random_state=42)
def test_permutation_test_score_allow_nans():
# Check that permutation_test_score allows input data with NaNs
X = np.arange(200, dtype=np.float64).reshape(10, -1)
X[2, :] = np.nan
y = np.repeat([0, 1], X.shape[0] / 2)
p = Pipeline([
('imputer', Imputer(strategy='mean', missing_values='NaN')),
('classifier', MockClassifier()),
])
cval.permutation_test_score(p, X, y, cv=5)
def test_check_cv_return_types():
X = np.ones((9, 2))
cv = cval.check_cv(3, X, classifier=False)
assert_true(isinstance(cv, cval.KFold))
y_binary = np.array([0, 1, 0, 1, 0, 0, 1, 1, 1])
cv = cval.check_cv(3, X, y_binary, classifier=True)
assert_true(isinstance(cv, cval.StratifiedKFold))
y_multiclass = np.array([0, 1, 0, 1, 2, 1, 2, 0, 2])
cv = cval.check_cv(3, X, y_multiclass, classifier=True)
assert_true(isinstance(cv, cval.StratifiedKFold))
X = np.ones((5, 2))
y_seq_of_seqs = [[], [1, 2], [3], [0, 1, 3], [2]]
with warnings.catch_warnings(record=True):
# deprecated sequence of sequence format
cv = cval.check_cv(3, X, y_seq_of_seqs, classifier=True)
assert_true(isinstance(cv, cval.KFold))
y_indicator_matrix = LabelBinarizer().fit_transform(y_seq_of_seqs)
cv = cval.check_cv(3, X, y_indicator_matrix, classifier=True)
assert_true(isinstance(cv, cval.KFold))
y_multioutput = np.array([[1, 2], [0, 3], [0, 0], [3, 1], [2, 0]])
cv = cval.check_cv(3, X, y_multioutput, classifier=True)
assert_true(isinstance(cv, cval.KFold))
def test_cross_val_score_multilabel():
X = np.array([[-3, 4], [2, 4], [3, 3], [0, 2], [-3, 1],
[-2, 1], [0, 0], [-2, -1], [-1, -2], [1, -2]])
y = np.array([[1, 1], [0, 1], [0, 1], [0, 1], [1, 1],
[0, 1], [1, 0], [1, 1], [1, 0], [0, 0]])
clf = KNeighborsClassifier(n_neighbors=1)
scoring_micro = make_scorer(precision_score, average='micro')
scoring_macro = make_scorer(precision_score, average='macro')
scoring_samples = make_scorer(precision_score, average='samples')
score_micro = cval.cross_val_score(clf, X, y, scoring=scoring_micro, cv=5)
score_macro = cval.cross_val_score(clf, X, y, scoring=scoring_macro, cv=5)
score_samples = cval.cross_val_score(clf, X, y,
scoring=scoring_samples, cv=5)
assert_almost_equal(score_micro, [1, 1 / 2, 3 / 4, 1 / 2, 1 / 3])
assert_almost_equal(score_macro, [1, 1 / 2, 3 / 4, 1 / 2, 1 / 4])
assert_almost_equal(score_samples, [1, 1 / 2, 3 / 4, 1 / 2, 1 / 4])
def test_cross_val_predict():
boston = load_boston()
X, y = boston.data, boston.target
cv = cval.KFold(len(boston.target))
est = Ridge()
# Naive loop (should be same as cross_val_predict):
preds2 = np.zeros_like(y)
for train, test in cv:
est.fit(X[train], y[train])
preds2[test] = est.predict(X[test])
preds = cval.cross_val_predict(est, X, y, cv=cv)
assert_array_almost_equal(preds, preds2)
preds = cval.cross_val_predict(est, X, y)
assert_equal(len(preds), len(y))
cv = cval.LeaveOneOut(len(y))
preds = cval.cross_val_predict(est, X, y, cv=cv)
assert_equal(len(preds), len(y))
Xsp = X.copy()
Xsp *= (Xsp > np.median(Xsp))
Xsp = coo_matrix(Xsp)
preds = cval.cross_val_predict(est, Xsp, y)
assert_array_almost_equal(len(preds), len(y))
preds = cval.cross_val_predict(KMeans(), X)
assert_equal(len(preds), len(y))
def bad_cv():
for i in range(4):
yield np.array([0, 1, 2, 3]), np.array([4, 5, 6, 7, 8])
assert_raises(ValueError, cval.cross_val_predict, est, X, y, cv=bad_cv())
def test_cross_val_predict_input_types():
clf = Ridge()
# Smoke test
predictions = cval.cross_val_predict(clf, X, y)
assert_equal(predictions.shape, (10,))
# test with multioutput y
predictions = cval.cross_val_predict(clf, X_sparse, X)
assert_equal(predictions.shape, (10, 2))
predictions = cval.cross_val_predict(clf, X_sparse, y)
assert_array_equal(predictions.shape, (10,))
# test with multioutput y
predictions = cval.cross_val_predict(clf, X_sparse, X)
assert_array_equal(predictions.shape, (10, 2))
# test with X and y as list
list_check = lambda x: isinstance(x, list)
clf = CheckingClassifier(check_X=list_check)
predictions = cval.cross_val_predict(clf, X.tolist(), y.tolist())
clf = CheckingClassifier(check_y=list_check)
predictions = cval.cross_val_predict(clf, X, y.tolist())
# test with 3d X and
X_3d = X[:, :, np.newaxis]
check_3d = lambda x: x.ndim == 3
clf = CheckingClassifier(check_X=check_3d)
predictions = cval.cross_val_predict(clf, X_3d, y)
assert_array_equal(predictions.shape, (10,))
def test_cross_val_predict_pandas():
# check cross_val_score doesn't destroy pandas dataframe
types = [(MockDataFrame, MockDataFrame)]
try:
from pandas import Series, DataFrame
types.append((Series, DataFrame))
except ImportError:
pass
for TargetType, InputFeatureType in types:
# X dataframe, y series
X_df, y_ser = InputFeatureType(X), TargetType(y)
check_df = lambda x: isinstance(x, InputFeatureType)
check_series = lambda x: isinstance(x, TargetType)
clf = CheckingClassifier(check_X=check_df, check_y=check_series)
cval.cross_val_predict(clf, X_df, y_ser)
def test_sparse_fit_params():
iris = load_iris()
X, y = iris.data, iris.target
clf = MockClassifier()
fit_params = {'sparse_sample_weight': coo_matrix(np.eye(X.shape[0]))}
a = cval.cross_val_score(clf, X, y, fit_params=fit_params)
assert_array_equal(a, np.ones(3))
def test_check_is_partition():
p = np.arange(100)
assert_true(cval._check_is_partition(p, 100))
assert_false(cval._check_is_partition(np.delete(p, 23), 100))
p[0] = 23
assert_false(cval._check_is_partition(p, 100))
| bsd-3-clause |
pythonvietnam/scikit-learn | examples/ensemble/plot_adaboost_twoclass.py | 347 | 3268 | """
==================
Two-class AdaBoost
==================
This example fits an AdaBoosted decision stump on a non-linearly separable
classification dataset composed of two "Gaussian quantiles" clusters
(see :func:`sklearn.datasets.make_gaussian_quantiles`) and plots the decision
boundary and decision scores. The distributions of decision scores are shown
separately for samples of class A and B. The predicted class label for each
sample is determined by the sign of the decision score. Samples with decision
scores greater than zero are classified as B, and are otherwise classified
as A. The magnitude of a decision score determines the degree of likeness with
the predicted class label. Additionally, a new dataset could be constructed
containing a desired purity of class B, for example, by only selecting samples
with a decision score above some value.
"""
print(__doc__)
# Author: Noel Dawe <[email protected]>
#
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from sklearn.ensemble import AdaBoostClassifier
from sklearn.tree import DecisionTreeClassifier
from sklearn.datasets import make_gaussian_quantiles
# Construct dataset
X1, y1 = make_gaussian_quantiles(cov=2.,
n_samples=200, n_features=2,
n_classes=2, random_state=1)
X2, y2 = make_gaussian_quantiles(mean=(3, 3), cov=1.5,
n_samples=300, n_features=2,
n_classes=2, random_state=1)
X = np.concatenate((X1, X2))
y = np.concatenate((y1, - y2 + 1))
# Create and fit an AdaBoosted decision tree
bdt = AdaBoostClassifier(DecisionTreeClassifier(max_depth=1),
algorithm="SAMME",
n_estimators=200)
bdt.fit(X, y)
plot_colors = "br"
plot_step = 0.02
class_names = "AB"
plt.figure(figsize=(10, 5))
# Plot the decision boundaries
plt.subplot(121)
x_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1
y_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1
xx, yy = np.meshgrid(np.arange(x_min, x_max, plot_step),
np.arange(y_min, y_max, plot_step))
Z = bdt.predict(np.c_[xx.ravel(), yy.ravel()])
Z = Z.reshape(xx.shape)
cs = plt.contourf(xx, yy, Z, cmap=plt.cm.Paired)
plt.axis("tight")
# Plot the training points
for i, n, c in zip(range(2), class_names, plot_colors):
idx = np.where(y == i)
plt.scatter(X[idx, 0], X[idx, 1],
c=c, cmap=plt.cm.Paired,
label="Class %s" % n)
plt.xlim(x_min, x_max)
plt.ylim(y_min, y_max)
plt.legend(loc='upper right')
plt.xlabel('x')
plt.ylabel('y')
plt.title('Decision Boundary')
# Plot the two-class decision scores
twoclass_output = bdt.decision_function(X)
plot_range = (twoclass_output.min(), twoclass_output.max())
plt.subplot(122)
for i, n, c in zip(range(2), class_names, plot_colors):
plt.hist(twoclass_output[y == i],
bins=10,
range=plot_range,
facecolor=c,
label='Class %s' % n,
alpha=.5)
x1, x2, y1, y2 = plt.axis()
plt.axis((x1, x2, y1, y2 * 1.2))
plt.legend(loc='upper right')
plt.ylabel('Samples')
plt.xlabel('Score')
plt.title('Decision Scores')
plt.tight_layout()
plt.subplots_adjust(wspace=0.35)
plt.show()
| bsd-3-clause |
jkarnows/scikit-learn | sklearn/utils/fixes.py | 29 | 12072 | """Compatibility fixes for older version of python, numpy and scipy
If you add content to this file, please give the version of the package
at which the fixe is no longer needed.
"""
# Authors: Emmanuelle Gouillart <[email protected]>
# Gael Varoquaux <[email protected]>
# Fabian Pedregosa <[email protected]>
# Lars Buitinck
#
# License: BSD 3 clause
import inspect
import warnings
import sys
import functools
import numpy as np
import scipy.sparse as sp
import scipy
def _parse_version(version_string):
version = []
for x in version_string.split('.'):
try:
version.append(int(x))
except ValueError:
# x may be of the form dev-1ea1592
version.append(x)
return tuple(version)
np_version = _parse_version(np.__version__)
sp_version = _parse_version(scipy.__version__)
try:
from scipy.special import expit # SciPy >= 0.10
with np.errstate(invalid='ignore', over='ignore'):
if np.isnan(expit(1000)): # SciPy < 0.14
raise ImportError("no stable expit in scipy.special")
except ImportError:
def expit(x, out=None):
"""Logistic sigmoid function, ``1 / (1 + exp(-x))``.
See sklearn.utils.extmath.log_logistic for the log of this function.
"""
if out is None:
out = np.empty(np.atleast_1d(x).shape, dtype=np.float64)
out[:] = x
# 1 / (1 + exp(-x)) = (1 + tanh(x / 2)) / 2
# This way of computing the logistic is both fast and stable.
out *= .5
np.tanh(out, out)
out += 1
out *= .5
return out.reshape(np.shape(x))
# little danse to see if np.copy has an 'order' keyword argument
if 'order' in inspect.getargspec(np.copy)[0]:
def safe_copy(X):
# Copy, but keep the order
return np.copy(X, order='K')
else:
# Before an 'order' argument was introduced, numpy wouldn't muck with
# the ordering
safe_copy = np.copy
try:
if (not np.allclose(np.divide(.4, 1, casting="unsafe"),
np.divide(.4, 1, casting="unsafe", dtype=np.float))
or not np.allclose(np.divide(.4, 1), .4)):
raise TypeError('Divide not working with dtype: '
'https://github.com/numpy/numpy/issues/3484')
divide = np.divide
except TypeError:
# Compat for old versions of np.divide that do not provide support for
# the dtype args
def divide(x1, x2, out=None, dtype=None):
out_orig = out
if out is None:
out = np.asarray(x1, dtype=dtype)
if out is x1:
out = x1.copy()
else:
if out is not x1:
out[:] = x1
if dtype is not None and out.dtype != dtype:
out = out.astype(dtype)
out /= x2
if out_orig is None and np.isscalar(x1):
out = np.asscalar(out)
return out
try:
np.array(5).astype(float, copy=False)
except TypeError:
# Compat where astype accepted no copy argument
def astype(array, dtype, copy=True):
if not copy and array.dtype == dtype:
return array
return array.astype(dtype)
else:
astype = np.ndarray.astype
try:
with warnings.catch_warnings(record=True):
# Don't raise the numpy deprecation warnings that appear in
# 1.9, but avoid Python bug due to simplefilter('ignore')
warnings.simplefilter('always')
sp.csr_matrix([1.0, 2.0, 3.0]).max(axis=0)
except (TypeError, AttributeError):
# in scipy < 14.0, sparse matrix min/max doesn't accept an `axis` argument
# the following code is taken from the scipy 0.14 codebase
def _minor_reduce(X, ufunc):
major_index = np.flatnonzero(np.diff(X.indptr))
if X.data.size == 0 and major_index.size == 0:
# Numpy < 1.8.0 don't handle empty arrays in reduceat
value = np.zeros_like(X.data)
else:
value = ufunc.reduceat(X.data, X.indptr[major_index])
return major_index, value
def _min_or_max_axis(X, axis, min_or_max):
N = X.shape[axis]
if N == 0:
raise ValueError("zero-size array to reduction operation")
M = X.shape[1 - axis]
mat = X.tocsc() if axis == 0 else X.tocsr()
mat.sum_duplicates()
major_index, value = _minor_reduce(mat, min_or_max)
not_full = np.diff(mat.indptr)[major_index] < N
value[not_full] = min_or_max(value[not_full], 0)
mask = value != 0
major_index = np.compress(mask, major_index)
value = np.compress(mask, value)
from scipy.sparse import coo_matrix
if axis == 0:
res = coo_matrix((value, (np.zeros(len(value)), major_index)),
dtype=X.dtype, shape=(1, M))
else:
res = coo_matrix((value, (major_index, np.zeros(len(value)))),
dtype=X.dtype, shape=(M, 1))
return res.A.ravel()
def _sparse_min_or_max(X, axis, min_or_max):
if axis is None:
if 0 in X.shape:
raise ValueError("zero-size array to reduction operation")
zero = X.dtype.type(0)
if X.nnz == 0:
return zero
m = min_or_max.reduce(X.data.ravel())
if X.nnz != np.product(X.shape):
m = min_or_max(zero, m)
return m
if axis < 0:
axis += 2
if (axis == 0) or (axis == 1):
return _min_or_max_axis(X, axis, min_or_max)
else:
raise ValueError("invalid axis, use 0 for rows, or 1 for columns")
def sparse_min_max(X, axis):
return (_sparse_min_or_max(X, axis, np.minimum),
_sparse_min_or_max(X, axis, np.maximum))
else:
def sparse_min_max(X, axis):
return (X.min(axis=axis).toarray().ravel(),
X.max(axis=axis).toarray().ravel())
try:
from numpy import argpartition
except ImportError:
# numpy.argpartition was introduced in v 1.8.0
def argpartition(a, kth, axis=-1, kind='introselect', order=None):
return np.argsort(a, axis=axis, order=order)
try:
from itertools import combinations_with_replacement
except ImportError:
# Backport of itertools.combinations_with_replacement for Python 2.6,
# from Python 3.4 documentation (http://tinyurl.com/comb-w-r), copyright
# Python Software Foundation (https://docs.python.org/3/license.html)
def combinations_with_replacement(iterable, r):
# combinations_with_replacement('ABC', 2) --> AA AB AC BB BC CC
pool = tuple(iterable)
n = len(pool)
if not n and r:
return
indices = [0] * r
yield tuple(pool[i] for i in indices)
while True:
for i in reversed(range(r)):
if indices[i] != n - 1:
break
else:
return
indices[i:] = [indices[i] + 1] * (r - i)
yield tuple(pool[i] for i in indices)
try:
from numpy import isclose
except ImportError:
def isclose(a, b, rtol=1.e-5, atol=1.e-8, equal_nan=False):
"""
Returns a boolean array where two arrays are element-wise equal within
a tolerance.
This function was added to numpy v1.7.0, and the version you are
running has been backported from numpy v1.8.1. See its documentation
for more details.
"""
def within_tol(x, y, atol, rtol):
with np.errstate(invalid='ignore'):
result = np.less_equal(abs(x - y), atol + rtol * abs(y))
if np.isscalar(a) and np.isscalar(b):
result = bool(result)
return result
x = np.array(a, copy=False, subok=True, ndmin=1)
y = np.array(b, copy=False, subok=True, ndmin=1)
xfin = np.isfinite(x)
yfin = np.isfinite(y)
if all(xfin) and all(yfin):
return within_tol(x, y, atol, rtol)
else:
finite = xfin & yfin
cond = np.zeros_like(finite, subok=True)
# Since we're using boolean indexing, x & y must be the same shape.
# Ideally, we'd just do x, y = broadcast_arrays(x, y). It's in
# lib.stride_tricks, though, so we can't import it here.
x = x * np.ones_like(cond)
y = y * np.ones_like(cond)
# Avoid subtraction with infinite/nan values...
cond[finite] = within_tol(x[finite], y[finite], atol, rtol)
# Check for equality of infinite values...
cond[~finite] = (x[~finite] == y[~finite])
if equal_nan:
# Make NaN == NaN
cond[np.isnan(x) & np.isnan(y)] = True
return cond
if np_version < (1, 7):
# Prior to 1.7.0, np.frombuffer wouldn't work for empty first arg.
def frombuffer_empty(buf, dtype):
if len(buf) == 0:
return np.empty(0, dtype=dtype)
else:
return np.frombuffer(buf, dtype=dtype)
else:
frombuffer_empty = np.frombuffer
if np_version < (1, 8):
def in1d(ar1, ar2, assume_unique=False, invert=False):
# Backport of numpy function in1d 1.8.1 to support numpy 1.6.2
# Ravel both arrays, behavior for the first array could be different
ar1 = np.asarray(ar1).ravel()
ar2 = np.asarray(ar2).ravel()
# This code is significantly faster when the condition is satisfied.
if len(ar2) < 10 * len(ar1) ** 0.145:
if invert:
mask = np.ones(len(ar1), dtype=np.bool)
for a in ar2:
mask &= (ar1 != a)
else:
mask = np.zeros(len(ar1), dtype=np.bool)
for a in ar2:
mask |= (ar1 == a)
return mask
# Otherwise use sorting
if not assume_unique:
ar1, rev_idx = np.unique(ar1, return_inverse=True)
ar2 = np.unique(ar2)
ar = np.concatenate((ar1, ar2))
# We need this to be a stable sort, so always use 'mergesort'
# here. The values from the first array should always come before
# the values from the second array.
order = ar.argsort(kind='mergesort')
sar = ar[order]
if invert:
bool_ar = (sar[1:] != sar[:-1])
else:
bool_ar = (sar[1:] == sar[:-1])
flag = np.concatenate((bool_ar, [invert]))
indx = order.argsort(kind='mergesort')[:len(ar1)]
if assume_unique:
return flag[indx]
else:
return flag[indx][rev_idx]
else:
from numpy import in1d
if sp_version < (0, 15):
# Backport fix for scikit-learn/scikit-learn#2986 / scipy/scipy#4142
from ._scipy_sparse_lsqr_backport import lsqr as sparse_lsqr
else:
from scipy.sparse.linalg import lsqr as sparse_lsqr
if sys.version_info < (2, 7, 0):
# partial cannot be pickled in Python 2.6
# http://bugs.python.org/issue1398
class partial(object):
def __init__(self, func, *args, **keywords):
functools.update_wrapper(self, func)
self.func = func
self.args = args
self.keywords = keywords
def __call__(self, *args, **keywords):
args = self.args + args
kwargs = self.keywords.copy()
kwargs.update(keywords)
return self.func(*args, **kwargs)
else:
from functools import partial
if np_version < (1, 6, 2):
# Allow bincount to accept empty arrays
# https://github.com/numpy/numpy/commit/40f0844846a9d7665616b142407a3d74cb65a040
def bincount(x, weights=None, minlength=None):
if len(x) > 0:
return np.bincount(x, weights, minlength)
else:
if minlength is None:
minlength = 0
minlength = np.asscalar(np.asarray(minlength, dtype=np.intp))
return np.zeros(minlength, dtype=np.intp)
else:
from numpy import bincount
| bsd-3-clause |
jaeilepp/mne-python | examples/realtime/plot_compute_rt_decoder.py | 4 | 3942 | """
=======================
Decoding real-time data
=======================
Supervised machine learning applied to MEG data in sensor space.
Here the classifier is updated every 5 trials and the decoding
accuracy is plotted
"""
# Authors: Mainak Jas <[email protected]>
#
# License: BSD (3-clause)
import numpy as np
import matplotlib.pyplot as plt
import mne
from mne.realtime import MockRtClient, RtEpochs
from mne.datasets import sample
print(__doc__)
# Fiff file to simulate the realtime client
data_path = sample.data_path()
raw_fname = data_path + '/MEG/sample/sample_audvis_filt-0-40_raw.fif'
raw = mne.io.read_raw_fif(raw_fname, preload=True)
tmin, tmax = -0.2, 0.5
event_id = dict(aud_l=1, vis_l=3)
tr_percent = 60 # Training percentage
min_trials = 10 # minimum trials after which decoding should start
# select gradiometers
picks = mne.pick_types(raw.info, meg='grad', eeg=False, eog=True,
stim=True, exclude=raw.info['bads'])
# create the mock-client object
rt_client = MockRtClient(raw)
# create the real-time epochs object
rt_epochs = RtEpochs(rt_client, event_id, tmin, tmax, picks=picks, decim=1,
reject=dict(grad=4000e-13, eog=150e-6), baseline=None,
isi_max=4.)
# start the acquisition
rt_epochs.start()
# send raw buffers
rt_client.send_data(rt_epochs, picks, tmin=0, tmax=90, buffer_size=1000)
# Decoding in sensor space using a linear SVM
n_times = len(rt_epochs.times)
from sklearn import preprocessing # noqa
from sklearn.svm import SVC # noqa
from sklearn.pipeline import Pipeline # noqa
from sklearn.cross_validation import cross_val_score, ShuffleSplit # noqa
from mne.decoding import Vectorizer, FilterEstimator # noqa
scores_x, scores, std_scores = [], [], []
# don't highpass filter because it's epoched data and the signal length
# is small
filt = FilterEstimator(rt_epochs.info, None, 40)
scaler = preprocessing.StandardScaler()
vectorizer = Vectorizer()
clf = SVC(C=1, kernel='linear')
concat_classifier = Pipeline([('filter', filt), ('vector', vectorizer),
('scaler', scaler), ('svm', clf)])
data_picks = mne.pick_types(rt_epochs.info, meg='grad', eeg=False, eog=True,
stim=False, exclude=raw.info['bads'])
ax = plt.subplot(111)
ax.set_xlabel('Trials')
ax.set_ylabel('Classification score (% correct)')
ax.set_title('Real-time decoding')
ax.set_xlim([min_trials, 50])
ax.set_ylim([30, 105])
plt.axhline(50, color='k', linestyle='--', label="Chance level")
plt.show(block=False)
for ev_num, ev in enumerate(rt_epochs.iter_evoked()):
print("Just got epoch %d" % (ev_num + 1))
if ev_num == 0:
X = ev.data[None, data_picks, :]
y = int(ev.comment) # the comment attribute contains the event_id
else:
X = np.concatenate((X, ev.data[None, data_picks, :]), axis=0)
y = np.append(y, int(ev.comment))
if ev_num >= min_trials:
cv = ShuffleSplit(len(y), 5, test_size=0.2, random_state=42)
scores_t = cross_val_score(concat_classifier, X, y, cv=cv,
n_jobs=1) * 100
std_scores.append(scores_t.std())
scores.append(scores_t.mean())
scores_x.append(ev_num)
# Plot accuracy
plt.plot(scores_x[-2:], scores[-2:], '-x', color='b',
label="Classif. score")
ax.hold(True)
ax.plot(scores_x[-1], scores[-1])
hyp_limits = (np.asarray(scores) - np.asarray(std_scores),
np.asarray(scores) + np.asarray(std_scores))
fill = plt.fill_between(scores_x, hyp_limits[0], y2=hyp_limits[1],
color='b', alpha=0.5)
plt.pause(0.01)
plt.draw()
ax.collections.remove(fill) # Remove old fill area
plt.fill_between(scores_x, hyp_limits[0], y2=hyp_limits[1], color='b',
alpha=0.5)
plt.draw() # Final figure
| bsd-3-clause |
MaxPowerWasTaken/MaxPowerWasTaken.github.io | jupyter_notebooks/mnist code scratch.py | 1 | 2227 | #!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Thu Jun 22 00:52:20 2017
@author: max
"""
import math
import random
import numpy as np
import pandas as pd
from sklearn.datasets import fetch_mldata
from sklearn.cross_validation import train_test_split
import matplotlib.pyplot as plt
from sklearn.manifold import TSNE
import os
os.chdir('/home/max/model_idiot/content/jupyter_notebooks')
# load mnist data
mnist = fetch_mldata('MNIST original', data_home='datasets/')
# Convert sklearn 'datasets bunch' object to Pandas
y = pd.Series(mnist.target).astype('int').astype('category')
X = pd.DataFrame(mnist.data)
# Change column-names in X to reflect that they are pixel values
X.columns = ['pixel_'+str(x) for x in range(X.shape[1])]
# Prepare to plot 9 random images
images_to_plot = 9
random_indices = random.sample(range(70000), images_to_plot)
sample_images = X.loc[random_indices, :]
sample_labels = y.loc[random_indices]
X_train, X_test, y_train, y_test = train_test_split(X,y, test_size = .4)
from sklearn.pipeline import make_pipeline
from sklearn.decomposition import PCA
tsne = TSNE()
tsne
# It is highly recommended to use another dimensionality reduction method (e.g. PCA for dense data or
# TruncatedSVD for sparse data) to reduce the number of dimensions to a reasonable amount (e.g. 50)
# if the number of features is very high.
rows=1000
sample_indices = random.sample(range(X_train.shape[0]), rows)
X_train_sample = X_train.iloc[sample_indices,:]
y_train_sample = y_train.iloc[sample_indices]
# https://www.reddit.com/r/MachineLearning/comments/47kf7w/scikitlearn_tsne_implementation/ (suggests lr=200)
pca_preprocessed_tsne = make_pipeline(PCA(n_components=50), TSNE(n_components=2, learning_rate=200, perplexity=50))
embedded_data = pca_preprocessed_tsne.fit_transform(X_train_sample)
plt.figure()
ax = plt.subplot(111)
X = embedded_data
for i in range(X.shape[0]):
print(i)
print(X[i, 0], X[i, 1])
print(str(y_train_sample.iloc[i]))
print(y_train_sample.iloc[i])
plt.text(X[i, 0], X[i, 1], str(y_train_sample.iloc[i]),
color=plt.cm.Set1(y_train_sample.iloc[i] / 10.),
fontdict={'weight': 'bold', 'size': 9})
plt.show()
| gpl-3.0 |
pratapvardhan/scikit-learn | sklearn/externals/joblib/testing.py | 45 | 2720 | """
Helper for testing.
"""
import sys
import warnings
import os.path
import re
import subprocess
import threading
from sklearn.externals.joblib._compat import PY3_OR_LATER
def warnings_to_stdout():
""" Redirect all warnings to stdout.
"""
showwarning_orig = warnings.showwarning
def showwarning(msg, cat, fname, lno, file=None, line=0):
showwarning_orig(msg, cat, os.path.basename(fname), line, sys.stdout)
warnings.showwarning = showwarning
#warnings.simplefilter('always')
try:
from nose.tools import assert_raises_regex
except ImportError:
# For Python 2.7
try:
from nose.tools import assert_raises_regexp as assert_raises_regex
except ImportError:
# for Python 2.6
def assert_raises_regex(expected_exception, expected_regexp,
callable_obj=None, *args, **kwargs):
"""Helper function to check for message patterns in exceptions"""
not_raised = False
try:
callable_obj(*args, **kwargs)
not_raised = True
except Exception as e:
error_message = str(e)
if not re.compile(expected_regexp).search(error_message):
raise AssertionError("Error message should match pattern "
"%r. %r does not." %
(expected_regexp, error_message))
if not_raised:
raise AssertionError("Should have raised %r" %
expected_exception(expected_regexp))
def check_subprocess_call(cmd, timeout=1, stdout_regex=None):
"""Runs a command in a subprocess with timeout in seconds.
Also checks returncode is zero and stdout if stdout_regex is set.
"""
proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
def kill_process():
proc.kill()
timer = threading.Timer(timeout, kill_process)
try:
timer.start()
stdout, stderr = proc.communicate()
if PY3_OR_LATER:
stdout, stderr = stdout.decode(), stderr.decode()
if proc.returncode != 0:
message = (
'Non-zero return code: {0}.\nStdout:\n{1}\n'
'Stderr:\n{2}').format(
proc.returncode, stdout, stderr)
raise ValueError(message)
if (stdout_regex is not None and
not re.search(stdout_regex, stdout)):
raise ValueError(
"Unexpected output: '{0!r}' does not match:\n{1!r}".format(
stdout_regex, stdout))
finally:
timer.cancel()
| bsd-3-clause |
lin-credible/scikit-learn | examples/svm/plot_svm_scale_c.py | 223 | 5375 | """
==============================================
Scaling the regularization parameter for SVCs
==============================================
The following example illustrates the effect of scaling the
regularization parameter when using :ref:`svm` for
:ref:`classification <svm_classification>`.
For SVC classification, we are interested in a risk minimization for the
equation:
.. math::
C \sum_{i=1, n} \mathcal{L} (f(x_i), y_i) + \Omega (w)
where
- :math:`C` is used to set the amount of regularization
- :math:`\mathcal{L}` is a `loss` function of our samples
and our model parameters.
- :math:`\Omega` is a `penalty` function of our model parameters
If we consider the loss function to be the individual error per
sample, then the data-fit term, or the sum of the error for each sample, will
increase as we add more samples. The penalization term, however, will not
increase.
When using, for example, :ref:`cross validation <cross_validation>`, to
set the amount of regularization with `C`, there will be a
different amount of samples between the main problem and the smaller problems
within the folds of the cross validation.
Since our loss function is dependent on the amount of samples, the latter
will influence the selected value of `C`.
The question that arises is `How do we optimally adjust C to
account for the different amount of training samples?`
The figures below are used to illustrate the effect of scaling our
`C` to compensate for the change in the number of samples, in the
case of using an `l1` penalty, as well as the `l2` penalty.
l1-penalty case
-----------------
In the `l1` case, theory says that prediction consistency
(i.e. that under given hypothesis, the estimator
learned predicts as well as a model knowing the true distribution)
is not possible because of the bias of the `l1`. It does say, however,
that model consistency, in terms of finding the right set of non-zero
parameters as well as their signs, can be achieved by scaling
`C1`.
l2-penalty case
-----------------
The theory says that in order to achieve prediction consistency, the
penalty parameter should be kept constant
as the number of samples grow.
Simulations
------------
The two figures below plot the values of `C` on the `x-axis` and the
corresponding cross-validation scores on the `y-axis`, for several different
fractions of a generated data-set.
In the `l1` penalty case, the cross-validation-error correlates best with
the test-error, when scaling our `C` with the number of samples, `n`,
which can be seen in the first figure.
For the `l2` penalty case, the best result comes from the case where `C`
is not scaled.
.. topic:: Note:
Two separate datasets are used for the two different plots. The reason
behind this is the `l1` case works better on sparse data, while `l2`
is better suited to the non-sparse case.
"""
print(__doc__)
# Author: Andreas Mueller <[email protected]>
# Jaques Grobler <[email protected]>
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from sklearn.svm import LinearSVC
from sklearn.cross_validation import ShuffleSplit
from sklearn.grid_search import GridSearchCV
from sklearn.utils import check_random_state
from sklearn import datasets
rnd = check_random_state(1)
# set up dataset
n_samples = 100
n_features = 300
# l1 data (only 5 informative features)
X_1, y_1 = datasets.make_classification(n_samples=n_samples,
n_features=n_features, n_informative=5,
random_state=1)
# l2 data: non sparse, but less features
y_2 = np.sign(.5 - rnd.rand(n_samples))
X_2 = rnd.randn(n_samples, n_features / 5) + y_2[:, np.newaxis]
X_2 += 5 * rnd.randn(n_samples, n_features / 5)
clf_sets = [(LinearSVC(penalty='l1', loss='squared_hinge', dual=False,
tol=1e-3),
np.logspace(-2.3, -1.3, 10), X_1, y_1),
(LinearSVC(penalty='l2', loss='squared_hinge', dual=True,
tol=1e-4),
np.logspace(-4.5, -2, 10), X_2, y_2)]
colors = ['b', 'g', 'r', 'c']
for fignum, (clf, cs, X, y) in enumerate(clf_sets):
# set up the plot for each regressor
plt.figure(fignum, figsize=(9, 10))
for k, train_size in enumerate(np.linspace(0.3, 0.7, 3)[::-1]):
param_grid = dict(C=cs)
# To get nice curve, we need a large number of iterations to
# reduce the variance
grid = GridSearchCV(clf, refit=False, param_grid=param_grid,
cv=ShuffleSplit(n=n_samples, train_size=train_size,
n_iter=250, random_state=1))
grid.fit(X, y)
scores = [x[1] for x in grid.grid_scores_]
scales = [(1, 'No scaling'),
((n_samples * train_size), '1/n_samples'),
]
for subplotnum, (scaler, name) in enumerate(scales):
plt.subplot(2, 1, subplotnum + 1)
plt.xlabel('C')
plt.ylabel('CV Score')
grid_cs = cs * float(scaler) # scale the C's
plt.semilogx(grid_cs, scores, label="fraction %.2f" %
train_size)
plt.title('scaling=%s, penalty=%s, loss=%s' %
(name, clf.penalty, clf.loss))
plt.legend(loc="best")
plt.show()
| bsd-3-clause |
zaxtax/scikit-learn | sklearn/decomposition/tests/test_online_lda.py | 5 | 13165 | import numpy as np
from scipy.linalg import block_diag
from scipy.sparse import csr_matrix
from scipy.special import psi
from sklearn.decomposition import LatentDirichletAllocation
from sklearn.decomposition._online_lda import (_dirichlet_expectation_1d,
_dirichlet_expectation_2d)
from sklearn.utils.testing import assert_allclose
from sklearn.utils.testing import assert_true
from sklearn.utils.testing import assert_array_almost_equal
from sklearn.utils.testing import assert_almost_equal
from sklearn.utils.testing import assert_greater_equal
from sklearn.utils.testing import assert_raises_regexp
from sklearn.utils.testing import if_safe_multiprocessing_with_blas
from sklearn.exceptions import NotFittedError
from sklearn.externals.six.moves import xrange
def _build_sparse_mtx():
# Create 3 topics and each topic has 3 distinct words.
# (Each word only belongs to a single topic.)
n_topics = 3
block = n_topics * np.ones((3, 3))
blocks = [block] * n_topics
X = block_diag(*blocks)
X = csr_matrix(X)
return (n_topics, X)
def test_lda_default_prior_params():
# default prior parameter should be `1 / topics`
# and verbose params should not affect result
n_topics, X = _build_sparse_mtx()
prior = 1. / n_topics
lda_1 = LatentDirichletAllocation(n_topics=n_topics, doc_topic_prior=prior,
topic_word_prior=prior, random_state=0)
lda_2 = LatentDirichletAllocation(n_topics=n_topics, random_state=0)
topic_distr_1 = lda_1.fit_transform(X)
topic_distr_2 = lda_2.fit_transform(X)
assert_almost_equal(topic_distr_1, topic_distr_2)
def test_lda_fit_batch():
# Test LDA batch learning_offset (`fit` method with 'batch' learning)
rng = np.random.RandomState(0)
n_topics, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=n_topics, evaluate_every=1,
learning_method='batch', random_state=rng)
lda.fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for component in lda.components_:
# Find top 3 words in each LDA component
top_idx = set(component.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_fit_online():
# Test LDA online learning (`fit` method with 'online' learning)
rng = np.random.RandomState(0)
n_topics, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=n_topics, learning_offset=10.,
evaluate_every=1, learning_method='online',
random_state=rng)
lda.fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for component in lda.components_:
# Find top 3 words in each LDA component
top_idx = set(component.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_partial_fit():
# Test LDA online learning (`partial_fit` method)
# (same as test_lda_batch)
rng = np.random.RandomState(0)
n_topics, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=n_topics, learning_offset=10.,
total_samples=100, random_state=rng)
for i in xrange(3):
lda.partial_fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for c in lda.components_:
top_idx = set(c.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_dense_input():
# Test LDA with dense input.
rng = np.random.RandomState(0)
n_topics, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=n_topics, learning_method='batch',
random_state=rng)
lda.fit(X.toarray())
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for component in lda.components_:
# Find top 3 words in each LDA component
top_idx = set(component.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_transform():
# Test LDA transform.
# Transform result cannot be negative
rng = np.random.RandomState(0)
X = rng.randint(5, size=(20, 10))
n_topics = 3
lda = LatentDirichletAllocation(n_topics=n_topics, random_state=rng)
X_trans = lda.fit_transform(X)
assert_true((X_trans > 0.0).any())
def test_lda_fit_transform():
# Test LDA fit_transform & transform
# fit_transform and transform result should be the same
for method in ('online', 'batch'):
rng = np.random.RandomState(0)
X = rng.randint(10, size=(50, 20))
lda = LatentDirichletAllocation(n_topics=5, learning_method=method,
random_state=rng)
X_fit = lda.fit_transform(X)
X_trans = lda.transform(X)
assert_array_almost_equal(X_fit, X_trans, 4)
def test_lda_partial_fit_dim_mismatch():
# test `n_features` mismatch in `partial_fit`
rng = np.random.RandomState(0)
n_topics = rng.randint(3, 6)
n_col = rng.randint(6, 10)
X_1 = np.random.randint(4, size=(10, n_col))
X_2 = np.random.randint(4, size=(10, n_col + 1))
lda = LatentDirichletAllocation(n_topics=n_topics, learning_offset=5.,
total_samples=20, random_state=rng)
lda.partial_fit(X_1)
assert_raises_regexp(ValueError, r"^The provided data has",
lda.partial_fit, X_2)
def test_invalid_params():
# test `_check_params` method
X = np.ones((5, 10))
invalid_models = (
('n_topics', LatentDirichletAllocation(n_topics=0)),
('learning_method',
LatentDirichletAllocation(learning_method='unknown')),
('total_samples', LatentDirichletAllocation(total_samples=0)),
('learning_offset', LatentDirichletAllocation(learning_offset=-1)),
)
for param, model in invalid_models:
regex = r"^Invalid %r parameter" % param
assert_raises_regexp(ValueError, regex, model.fit, X)
def test_lda_negative_input():
# test pass dense matrix with sparse negative input.
X = -np.ones((5, 10))
lda = LatentDirichletAllocation()
regex = r"^Negative values in data passed"
assert_raises_regexp(ValueError, regex, lda.fit, X)
def test_lda_no_component_error():
# test `transform` and `perplexity` before `fit`
rng = np.random.RandomState(0)
X = rng.randint(4, size=(20, 10))
lda = LatentDirichletAllocation()
regex = r"^no 'components_' attribute"
assert_raises_regexp(NotFittedError, regex, lda.transform, X)
assert_raises_regexp(NotFittedError, regex, lda.perplexity, X)
def test_lda_transform_mismatch():
# test `n_features` mismatch in partial_fit and transform
rng = np.random.RandomState(0)
X = rng.randint(4, size=(20, 10))
X_2 = rng.randint(4, size=(10, 8))
n_topics = rng.randint(3, 6)
lda = LatentDirichletAllocation(n_topics=n_topics, random_state=rng)
lda.partial_fit(X)
assert_raises_regexp(ValueError, r"^The provided data has",
lda.partial_fit, X_2)
@if_safe_multiprocessing_with_blas
def test_lda_multi_jobs():
n_topics, X = _build_sparse_mtx()
# Test LDA batch training with multi CPU
for method in ('online', 'batch'):
rng = np.random.RandomState(0)
lda = LatentDirichletAllocation(n_topics=n_topics, n_jobs=2,
learning_method=method,
random_state=rng)
lda.fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for c in lda.components_:
top_idx = set(c.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
@if_safe_multiprocessing_with_blas
def test_lda_partial_fit_multi_jobs():
# Test LDA online training with multi CPU
rng = np.random.RandomState(0)
n_topics, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=n_topics, n_jobs=2,
learning_offset=5., total_samples=30,
random_state=rng)
for i in range(2):
lda.partial_fit(X)
correct_idx_grps = [(0, 1, 2), (3, 4, 5), (6, 7, 8)]
for c in lda.components_:
top_idx = set(c.argsort()[-3:][::-1])
assert_true(tuple(sorted(top_idx)) in correct_idx_grps)
def test_lda_preplexity_mismatch():
# test dimension mismatch in `perplexity` method
rng = np.random.RandomState(0)
n_topics = rng.randint(3, 6)
n_samples = rng.randint(6, 10)
X = np.random.randint(4, size=(n_samples, 10))
lda = LatentDirichletAllocation(n_topics=n_topics, learning_offset=5.,
total_samples=20, random_state=rng)
lda.fit(X)
# invalid samples
invalid_n_samples = rng.randint(4, size=(n_samples + 1, n_topics))
assert_raises_regexp(ValueError, r'Number of samples', lda.perplexity, X,
invalid_n_samples)
# invalid topic number
invalid_n_topics = rng.randint(4, size=(n_samples, n_topics + 1))
assert_raises_regexp(ValueError, r'Number of topics', lda.perplexity, X,
invalid_n_topics)
def test_lda_perplexity():
# Test LDA perplexity for batch training
# perplexity should be lower after each iteration
n_topics, X = _build_sparse_mtx()
for method in ('online', 'batch'):
lda_1 = LatentDirichletAllocation(n_topics=n_topics, max_iter=1,
learning_method=method,
total_samples=100, random_state=0)
lda_2 = LatentDirichletAllocation(n_topics=n_topics, max_iter=10,
learning_method=method,
total_samples=100, random_state=0)
distr_1 = lda_1.fit_transform(X)
perp_1 = lda_1.perplexity(X, distr_1, sub_sampling=False)
distr_2 = lda_2.fit_transform(X)
perp_2 = lda_2.perplexity(X, distr_2, sub_sampling=False)
assert_greater_equal(perp_1, perp_2)
perp_1_subsampling = lda_1.perplexity(X, distr_1, sub_sampling=True)
perp_2_subsampling = lda_2.perplexity(X, distr_2, sub_sampling=True)
assert_greater_equal(perp_1_subsampling, perp_2_subsampling)
def test_lda_score():
# Test LDA score for batch training
# score should be higher after each iteration
n_topics, X = _build_sparse_mtx()
for method in ('online', 'batch'):
lda_1 = LatentDirichletAllocation(n_topics=n_topics, max_iter=1,
learning_method=method,
total_samples=100, random_state=0)
lda_2 = LatentDirichletAllocation(n_topics=n_topics, max_iter=10,
learning_method=method,
total_samples=100, random_state=0)
lda_1.fit_transform(X)
score_1 = lda_1.score(X)
lda_2.fit_transform(X)
score_2 = lda_2.score(X)
assert_greater_equal(score_2, score_1)
def test_perplexity_input_format():
# Test LDA perplexity for sparse and dense input
# score should be the same for both dense and sparse input
n_topics, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=n_topics, max_iter=1,
learning_method='batch',
total_samples=100, random_state=0)
distr = lda.fit_transform(X)
perp_1 = lda.perplexity(X)
perp_2 = lda.perplexity(X, distr)
perp_3 = lda.perplexity(X.toarray(), distr)
assert_almost_equal(perp_1, perp_2)
assert_almost_equal(perp_1, perp_3)
def test_lda_score_perplexity():
# Test the relationship between LDA score and perplexity
n_topics, X = _build_sparse_mtx()
lda = LatentDirichletAllocation(n_topics=n_topics, max_iter=10,
random_state=0)
distr = lda.fit_transform(X)
perplexity_1 = lda.perplexity(X, distr, sub_sampling=False)
score = lda.score(X)
perplexity_2 = np.exp(-1. * (score / np.sum(X.data)))
assert_almost_equal(perplexity_1, perplexity_2)
def test_lda_empty_docs():
"""Test LDA on empty document (all-zero rows)."""
Z = np.zeros((5, 4))
for X in [Z, csr_matrix(Z)]:
lda = LatentDirichletAllocation(max_iter=750).fit(X)
assert_almost_equal(lda.components_.sum(axis=0),
np.ones(lda.components_.shape[1]))
def test_dirichlet_expectation():
"""Test Cython version of Dirichlet expectation calculation."""
x = np.logspace(-100, 10, 10000)
expectation = np.empty_like(x)
_dirichlet_expectation_1d(x, 0, expectation)
assert_allclose(expectation, np.exp(psi(x) - psi(np.sum(x))),
atol=1e-19)
x = x.reshape(100, 100)
assert_allclose(_dirichlet_expectation_2d(x),
psi(x) - psi(np.sum(x, axis=1)[:, np.newaxis]),
rtol=1e-11, atol=3e-9)
| bsd-3-clause |
alexeyum/scikit-learn | examples/semi_supervised/plot_label_propagation_digits.py | 55 | 2723 | """
===================================================
Label Propagation digits: Demonstrating performance
===================================================
This example demonstrates the power of semisupervised learning by
training a Label Spreading model to classify handwritten digits
with sets of very few labels.
The handwritten digit dataset has 1797 total points. The model will
be trained using all points, but only 30 will be labeled. Results
in the form of a confusion matrix and a series of metrics over each
class will be very good.
At the end, the top 10 most uncertain predictions will be shown.
"""
print(__doc__)
# Authors: Clay Woolam <[email protected]>
# License: BSD
import numpy as np
import matplotlib.pyplot as plt
from scipy import stats
from sklearn import datasets
from sklearn.semi_supervised import label_propagation
from sklearn.metrics import confusion_matrix, classification_report
digits = datasets.load_digits()
rng = np.random.RandomState(0)
indices = np.arange(len(digits.data))
rng.shuffle(indices)
X = digits.data[indices[:330]]
y = digits.target[indices[:330]]
images = digits.images[indices[:330]]
n_total_samples = len(y)
n_labeled_points = 30
indices = np.arange(n_total_samples)
unlabeled_set = indices[n_labeled_points:]
# shuffle everything around
y_train = np.copy(y)
y_train[unlabeled_set] = -1
###############################################################################
# Learn with LabelSpreading
lp_model = label_propagation.LabelSpreading(gamma=0.25, max_iter=5)
lp_model.fit(X, y_train)
predicted_labels = lp_model.transduction_[unlabeled_set]
true_labels = y[unlabeled_set]
cm = confusion_matrix(true_labels, predicted_labels, labels=lp_model.classes_)
print("Label Spreading model: %d labeled & %d unlabeled points (%d total)" %
(n_labeled_points, n_total_samples - n_labeled_points, n_total_samples))
print(classification_report(true_labels, predicted_labels))
print("Confusion matrix")
print(cm)
# calculate uncertainty values for each transduced distribution
pred_entropies = stats.distributions.entropy(lp_model.label_distributions_.T)
# pick the top 10 most uncertain labels
uncertainty_index = np.argsort(pred_entropies)[-10:]
###############################################################################
# plot
f = plt.figure(figsize=(7, 5))
for index, image_index in enumerate(uncertainty_index):
image = images[image_index]
sub = f.add_subplot(2, 5, index + 1)
sub.imshow(image, cmap=plt.cm.gray_r)
plt.xticks([])
plt.yticks([])
sub.set_title('predict: %i\ntrue: %i' % (
lp_model.transduction_[image_index], y[image_index]))
f.suptitle('Learning with small amount of labeled data')
plt.show()
| bsd-3-clause |
vibhorag/scikit-learn | sklearn/cross_decomposition/pls_.py | 187 | 28507 | """
The :mod:`sklearn.pls` module implements Partial Least Squares (PLS).
"""
# Author: Edouard Duchesnay <[email protected]>
# License: BSD 3 clause
from ..base import BaseEstimator, RegressorMixin, TransformerMixin
from ..utils import check_array, check_consistent_length
from ..externals import six
import warnings
from abc import ABCMeta, abstractmethod
import numpy as np
from scipy import linalg
from ..utils import arpack
from ..utils.validation import check_is_fitted
__all__ = ['PLSCanonical', 'PLSRegression', 'PLSSVD']
def _nipals_twoblocks_inner_loop(X, Y, mode="A", max_iter=500, tol=1e-06,
norm_y_weights=False):
"""Inner loop of the iterative NIPALS algorithm.
Provides an alternative to the svd(X'Y); returns the first left and right
singular vectors of X'Y. See PLS for the meaning of the parameters. It is
similar to the Power method for determining the eigenvectors and
eigenvalues of a X'Y.
"""
y_score = Y[:, [0]]
x_weights_old = 0
ite = 1
X_pinv = Y_pinv = None
eps = np.finfo(X.dtype).eps
# Inner loop of the Wold algo.
while True:
# 1.1 Update u: the X weights
if mode == "B":
if X_pinv is None:
X_pinv = linalg.pinv(X) # compute once pinv(X)
x_weights = np.dot(X_pinv, y_score)
else: # mode A
# Mode A regress each X column on y_score
x_weights = np.dot(X.T, y_score) / np.dot(y_score.T, y_score)
# 1.2 Normalize u
x_weights /= np.sqrt(np.dot(x_weights.T, x_weights)) + eps
# 1.3 Update x_score: the X latent scores
x_score = np.dot(X, x_weights)
# 2.1 Update y_weights
if mode == "B":
if Y_pinv is None:
Y_pinv = linalg.pinv(Y) # compute once pinv(Y)
y_weights = np.dot(Y_pinv, x_score)
else:
# Mode A regress each Y column on x_score
y_weights = np.dot(Y.T, x_score) / np.dot(x_score.T, x_score)
# 2.2 Normalize y_weights
if norm_y_weights:
y_weights /= np.sqrt(np.dot(y_weights.T, y_weights)) + eps
# 2.3 Update y_score: the Y latent scores
y_score = np.dot(Y, y_weights) / (np.dot(y_weights.T, y_weights) + eps)
# y_score = np.dot(Y, y_weights) / np.dot(y_score.T, y_score) ## BUG
x_weights_diff = x_weights - x_weights_old
if np.dot(x_weights_diff.T, x_weights_diff) < tol or Y.shape[1] == 1:
break
if ite == max_iter:
warnings.warn('Maximum number of iterations reached')
break
x_weights_old = x_weights
ite += 1
return x_weights, y_weights, ite
def _svd_cross_product(X, Y):
C = np.dot(X.T, Y)
U, s, Vh = linalg.svd(C, full_matrices=False)
u = U[:, [0]]
v = Vh.T[:, [0]]
return u, v
def _center_scale_xy(X, Y, scale=True):
""" Center X, Y and scale if the scale parameter==True
Returns
-------
X, Y, x_mean, y_mean, x_std, y_std
"""
# center
x_mean = X.mean(axis=0)
X -= x_mean
y_mean = Y.mean(axis=0)
Y -= y_mean
# scale
if scale:
x_std = X.std(axis=0, ddof=1)
x_std[x_std == 0.0] = 1.0
X /= x_std
y_std = Y.std(axis=0, ddof=1)
y_std[y_std == 0.0] = 1.0
Y /= y_std
else:
x_std = np.ones(X.shape[1])
y_std = np.ones(Y.shape[1])
return X, Y, x_mean, y_mean, x_std, y_std
class _PLS(six.with_metaclass(ABCMeta), BaseEstimator, TransformerMixin,
RegressorMixin):
"""Partial Least Squares (PLS)
This class implements the generic PLS algorithm, constructors' parameters
allow to obtain a specific implementation such as:
- PLS2 regression, i.e., PLS 2 blocks, mode A, with asymmetric deflation
and unnormalized y weights such as defined by [Tenenhaus 1998] p. 132.
With univariate response it implements PLS1.
- PLS canonical, i.e., PLS 2 blocks, mode A, with symmetric deflation and
normalized y weights such as defined by [Tenenhaus 1998] (p. 132) and
[Wegelin et al. 2000]. This parametrization implements the original Wold
algorithm.
We use the terminology defined by [Wegelin et al. 2000].
This implementation uses the PLS Wold 2 blocks algorithm based on two
nested loops:
(i) The outer loop iterate over components.
(ii) The inner loop estimates the weights vectors. This can be done
with two algo. (a) the inner loop of the original NIPALS algo. or (b) a
SVD on residuals cross-covariance matrices.
n_components : int, number of components to keep. (default 2).
scale : boolean, scale data? (default True)
deflation_mode : str, "canonical" or "regression". See notes.
mode : "A" classical PLS and "B" CCA. See notes.
norm_y_weights: boolean, normalize Y weights to one? (default False)
algorithm : string, "nipals" or "svd"
The algorithm used to estimate the weights. It will be called
n_components times, i.e. once for each iteration of the outer loop.
max_iter : an integer, the maximum number of iterations (default 500)
of the NIPALS inner loop (used only if algorithm="nipals")
tol : non-negative real, default 1e-06
The tolerance used in the iterative algorithm.
copy : boolean, default True
Whether the deflation should be done on a copy. Let the default
value to True unless you don't care about side effects.
Attributes
----------
x_weights_ : array, [p, n_components]
X block weights vectors.
y_weights_ : array, [q, n_components]
Y block weights vectors.
x_loadings_ : array, [p, n_components]
X block loadings vectors.
y_loadings_ : array, [q, n_components]
Y block loadings vectors.
x_scores_ : array, [n_samples, n_components]
X scores.
y_scores_ : array, [n_samples, n_components]
Y scores.
x_rotations_ : array, [p, n_components]
X block to latents rotations.
y_rotations_ : array, [q, n_components]
Y block to latents rotations.
coef_: array, [p, q]
The coefficients of the linear model: ``Y = X coef_ + Err``
n_iter_ : array-like
Number of iterations of the NIPALS inner loop for each
component. Not useful if the algorithm given is "svd".
References
----------
Jacob A. Wegelin. A survey of Partial Least Squares (PLS) methods, with
emphasis on the two-block case. Technical Report 371, Department of
Statistics, University of Washington, Seattle, 2000.
In French but still a reference:
Tenenhaus, M. (1998). La regression PLS: theorie et pratique. Paris:
Editions Technic.
See also
--------
PLSCanonical
PLSRegression
CCA
PLS_SVD
"""
@abstractmethod
def __init__(self, n_components=2, scale=True, deflation_mode="regression",
mode="A", algorithm="nipals", norm_y_weights=False,
max_iter=500, tol=1e-06, copy=True):
self.n_components = n_components
self.deflation_mode = deflation_mode
self.mode = mode
self.norm_y_weights = norm_y_weights
self.scale = scale
self.algorithm = algorithm
self.max_iter = max_iter
self.tol = tol
self.copy = copy
def fit(self, X, Y):
"""Fit model to data.
Parameters
----------
X : array-like, shape = [n_samples, n_features]
Training vectors, where n_samples in the number of samples and
n_features is the number of predictors.
Y : array-like of response, shape = [n_samples, n_targets]
Target vectors, where n_samples in the number of samples and
n_targets is the number of response variables.
"""
# copy since this will contains the residuals (deflated) matrices
check_consistent_length(X, Y)
X = check_array(X, dtype=np.float64, copy=self.copy)
Y = check_array(Y, dtype=np.float64, copy=self.copy, ensure_2d=False)
if Y.ndim == 1:
Y = Y.reshape(-1, 1)
n = X.shape[0]
p = X.shape[1]
q = Y.shape[1]
if self.n_components < 1 or self.n_components > p:
raise ValueError('Invalid number of components: %d' %
self.n_components)
if self.algorithm not in ("svd", "nipals"):
raise ValueError("Got algorithm %s when only 'svd' "
"and 'nipals' are known" % self.algorithm)
if self.algorithm == "svd" and self.mode == "B":
raise ValueError('Incompatible configuration: mode B is not '
'implemented with svd algorithm')
if self.deflation_mode not in ["canonical", "regression"]:
raise ValueError('The deflation mode is unknown')
# Scale (in place)
X, Y, self.x_mean_, self.y_mean_, self.x_std_, self.y_std_\
= _center_scale_xy(X, Y, self.scale)
# Residuals (deflated) matrices
Xk = X
Yk = Y
# Results matrices
self.x_scores_ = np.zeros((n, self.n_components))
self.y_scores_ = np.zeros((n, self.n_components))
self.x_weights_ = np.zeros((p, self.n_components))
self.y_weights_ = np.zeros((q, self.n_components))
self.x_loadings_ = np.zeros((p, self.n_components))
self.y_loadings_ = np.zeros((q, self.n_components))
self.n_iter_ = []
# NIPALS algo: outer loop, over components
for k in range(self.n_components):
if np.all(np.dot(Yk.T, Yk) < np.finfo(np.double).eps):
# Yk constant
warnings.warn('Y residual constant at iteration %s' % k)
break
# 1) weights estimation (inner loop)
# -----------------------------------
if self.algorithm == "nipals":
x_weights, y_weights, n_iter_ = \
_nipals_twoblocks_inner_loop(
X=Xk, Y=Yk, mode=self.mode, max_iter=self.max_iter,
tol=self.tol, norm_y_weights=self.norm_y_weights)
self.n_iter_.append(n_iter_)
elif self.algorithm == "svd":
x_weights, y_weights = _svd_cross_product(X=Xk, Y=Yk)
# compute scores
x_scores = np.dot(Xk, x_weights)
if self.norm_y_weights:
y_ss = 1
else:
y_ss = np.dot(y_weights.T, y_weights)
y_scores = np.dot(Yk, y_weights) / y_ss
# test for null variance
if np.dot(x_scores.T, x_scores) < np.finfo(np.double).eps:
warnings.warn('X scores are null at iteration %s' % k)
break
# 2) Deflation (in place)
# ----------------------
# Possible memory footprint reduction may done here: in order to
# avoid the allocation of a data chunk for the rank-one
# approximations matrix which is then subtracted to Xk, we suggest
# to perform a column-wise deflation.
#
# - regress Xk's on x_score
x_loadings = np.dot(Xk.T, x_scores) / np.dot(x_scores.T, x_scores)
# - subtract rank-one approximations to obtain remainder matrix
Xk -= np.dot(x_scores, x_loadings.T)
if self.deflation_mode == "canonical":
# - regress Yk's on y_score, then subtract rank-one approx.
y_loadings = (np.dot(Yk.T, y_scores)
/ np.dot(y_scores.T, y_scores))
Yk -= np.dot(y_scores, y_loadings.T)
if self.deflation_mode == "regression":
# - regress Yk's on x_score, then subtract rank-one approx.
y_loadings = (np.dot(Yk.T, x_scores)
/ np.dot(x_scores.T, x_scores))
Yk -= np.dot(x_scores, y_loadings.T)
# 3) Store weights, scores and loadings # Notation:
self.x_scores_[:, k] = x_scores.ravel() # T
self.y_scores_[:, k] = y_scores.ravel() # U
self.x_weights_[:, k] = x_weights.ravel() # W
self.y_weights_[:, k] = y_weights.ravel() # C
self.x_loadings_[:, k] = x_loadings.ravel() # P
self.y_loadings_[:, k] = y_loadings.ravel() # Q
# Such that: X = TP' + Err and Y = UQ' + Err
# 4) rotations from input space to transformed space (scores)
# T = X W(P'W)^-1 = XW* (W* : p x k matrix)
# U = Y C(Q'C)^-1 = YC* (W* : q x k matrix)
self.x_rotations_ = np.dot(
self.x_weights_,
linalg.pinv(np.dot(self.x_loadings_.T, self.x_weights_)))
if Y.shape[1] > 1:
self.y_rotations_ = np.dot(
self.y_weights_,
linalg.pinv(np.dot(self.y_loadings_.T, self.y_weights_)))
else:
self.y_rotations_ = np.ones(1)
if True or self.deflation_mode == "regression":
# FIXME what's with the if?
# Estimate regression coefficient
# Regress Y on T
# Y = TQ' + Err,
# Then express in function of X
# Y = X W(P'W)^-1Q' + Err = XB + Err
# => B = W*Q' (p x q)
self.coef_ = np.dot(self.x_rotations_, self.y_loadings_.T)
self.coef_ = (1. / self.x_std_.reshape((p, 1)) * self.coef_ *
self.y_std_)
return self
def transform(self, X, Y=None, copy=True):
"""Apply the dimension reduction learned on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q], optional
Training vectors, where n_samples in the number of samples and
q is the number of response variables.
copy : boolean, default True
Whether to copy X and Y, or perform in-place normalization.
Returns
-------
x_scores if Y is not given, (x_scores, y_scores) otherwise.
"""
check_is_fitted(self, 'x_mean_')
X = check_array(X, copy=copy)
# Normalize
X -= self.x_mean_
X /= self.x_std_
# Apply rotation
x_scores = np.dot(X, self.x_rotations_)
if Y is not None:
Y = check_array(Y, ensure_2d=False, copy=copy)
if Y.ndim == 1:
Y = Y.reshape(-1, 1)
Y -= self.y_mean_
Y /= self.y_std_
y_scores = np.dot(Y, self.y_rotations_)
return x_scores, y_scores
return x_scores
def predict(self, X, copy=True):
"""Apply the dimension reduction learned on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
copy : boolean, default True
Whether to copy X and Y, or perform in-place normalization.
Notes
-----
This call requires the estimation of a p x q matrix, which may
be an issue in high dimensional space.
"""
check_is_fitted(self, 'x_mean_')
X = check_array(X, copy=copy)
# Normalize
X -= self.x_mean_
X /= self.x_std_
Ypred = np.dot(X, self.coef_)
return Ypred + self.y_mean_
def fit_transform(self, X, y=None, **fit_params):
"""Learn and apply the dimension reduction on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q], optional
Training vectors, where n_samples in the number of samples and
q is the number of response variables.
copy : boolean, default True
Whether to copy X and Y, or perform in-place normalization.
Returns
-------
x_scores if Y is not given, (x_scores, y_scores) otherwise.
"""
check_is_fitted(self, 'x_mean_')
return self.fit(X, y, **fit_params).transform(X, y)
class PLSRegression(_PLS):
"""PLS regression
PLSRegression implements the PLS 2 blocks regression known as PLS2 or PLS1
in case of one dimensional response.
This class inherits from _PLS with mode="A", deflation_mode="regression",
norm_y_weights=False and algorithm="nipals".
Read more in the :ref:`User Guide <cross_decomposition>`.
Parameters
----------
n_components : int, (default 2)
Number of components to keep.
scale : boolean, (default True)
whether to scale the data
max_iter : an integer, (default 500)
the maximum number of iterations of the NIPALS inner loop (used
only if algorithm="nipals")
tol : non-negative real
Tolerance used in the iterative algorithm default 1e-06.
copy : boolean, default True
Whether the deflation should be done on a copy. Let the default
value to True unless you don't care about side effect
Attributes
----------
x_weights_ : array, [p, n_components]
X block weights vectors.
y_weights_ : array, [q, n_components]
Y block weights vectors.
x_loadings_ : array, [p, n_components]
X block loadings vectors.
y_loadings_ : array, [q, n_components]
Y block loadings vectors.
x_scores_ : array, [n_samples, n_components]
X scores.
y_scores_ : array, [n_samples, n_components]
Y scores.
x_rotations_ : array, [p, n_components]
X block to latents rotations.
y_rotations_ : array, [q, n_components]
Y block to latents rotations.
coef_: array, [p, q]
The coefficients of the linear model: ``Y = X coef_ + Err``
n_iter_ : array-like
Number of iterations of the NIPALS inner loop for each
component.
Notes
-----
For each component k, find weights u, v that optimizes:
``max corr(Xk u, Yk v) * var(Xk u) var(Yk u)``, such that ``|u| = 1``
Note that it maximizes both the correlations between the scores and the
intra-block variances.
The residual matrix of X (Xk+1) block is obtained by the deflation on
the current X score: x_score.
The residual matrix of Y (Yk+1) block is obtained by deflation on the
current X score. This performs the PLS regression known as PLS2. This
mode is prediction oriented.
This implementation provides the same results that 3 PLS packages
provided in the R language (R-project):
- "mixOmics" with function pls(X, Y, mode = "regression")
- "plspm " with function plsreg2(X, Y)
- "pls" with function oscorespls.fit(X, Y)
Examples
--------
>>> from sklearn.cross_decomposition import PLSRegression
>>> X = [[0., 0., 1.], [1.,0.,0.], [2.,2.,2.], [2.,5.,4.]]
>>> Y = [[0.1, -0.2], [0.9, 1.1], [6.2, 5.9], [11.9, 12.3]]
>>> pls2 = PLSRegression(n_components=2)
>>> pls2.fit(X, Y)
... # doctest: +NORMALIZE_WHITESPACE
PLSRegression(copy=True, max_iter=500, n_components=2, scale=True,
tol=1e-06)
>>> Y_pred = pls2.predict(X)
References
----------
Jacob A. Wegelin. A survey of Partial Least Squares (PLS) methods, with
emphasis on the two-block case. Technical Report 371, Department of
Statistics, University of Washington, Seattle, 2000.
In french but still a reference:
Tenenhaus, M. (1998). La regression PLS: theorie et pratique. Paris:
Editions Technic.
"""
def __init__(self, n_components=2, scale=True,
max_iter=500, tol=1e-06, copy=True):
_PLS.__init__(self, n_components=n_components, scale=scale,
deflation_mode="regression", mode="A",
norm_y_weights=False, max_iter=max_iter, tol=tol,
copy=copy)
class PLSCanonical(_PLS):
""" PLSCanonical implements the 2 blocks canonical PLS of the original Wold
algorithm [Tenenhaus 1998] p.204, referred as PLS-C2A in [Wegelin 2000].
This class inherits from PLS with mode="A" and deflation_mode="canonical",
norm_y_weights=True and algorithm="nipals", but svd should provide similar
results up to numerical errors.
Read more in the :ref:`User Guide <cross_decomposition>`.
Parameters
----------
scale : boolean, scale data? (default True)
algorithm : string, "nipals" or "svd"
The algorithm used to estimate the weights. It will be called
n_components times, i.e. once for each iteration of the outer loop.
max_iter : an integer, (default 500)
the maximum number of iterations of the NIPALS inner loop (used
only if algorithm="nipals")
tol : non-negative real, default 1e-06
the tolerance used in the iterative algorithm
copy : boolean, default True
Whether the deflation should be done on a copy. Let the default
value to True unless you don't care about side effect
n_components : int, number of components to keep. (default 2).
Attributes
----------
x_weights_ : array, shape = [p, n_components]
X block weights vectors.
y_weights_ : array, shape = [q, n_components]
Y block weights vectors.
x_loadings_ : array, shape = [p, n_components]
X block loadings vectors.
y_loadings_ : array, shape = [q, n_components]
Y block loadings vectors.
x_scores_ : array, shape = [n_samples, n_components]
X scores.
y_scores_ : array, shape = [n_samples, n_components]
Y scores.
x_rotations_ : array, shape = [p, n_components]
X block to latents rotations.
y_rotations_ : array, shape = [q, n_components]
Y block to latents rotations.
n_iter_ : array-like
Number of iterations of the NIPALS inner loop for each
component. Not useful if the algorithm provided is "svd".
Notes
-----
For each component k, find weights u, v that optimize::
max corr(Xk u, Yk v) * var(Xk u) var(Yk u), such that ``|u| = |v| = 1``
Note that it maximizes both the correlations between the scores and the
intra-block variances.
The residual matrix of X (Xk+1) block is obtained by the deflation on the
current X score: x_score.
The residual matrix of Y (Yk+1) block is obtained by deflation on the
current Y score. This performs a canonical symmetric version of the PLS
regression. But slightly different than the CCA. This is mostly used
for modeling.
This implementation provides the same results that the "plspm" package
provided in the R language (R-project), using the function plsca(X, Y).
Results are equal or collinear with the function
``pls(..., mode = "canonical")`` of the "mixOmics" package. The difference
relies in the fact that mixOmics implementation does not exactly implement
the Wold algorithm since it does not normalize y_weights to one.
Examples
--------
>>> from sklearn.cross_decomposition import PLSCanonical
>>> X = [[0., 0., 1.], [1.,0.,0.], [2.,2.,2.], [2.,5.,4.]]
>>> Y = [[0.1, -0.2], [0.9, 1.1], [6.2, 5.9], [11.9, 12.3]]
>>> plsca = PLSCanonical(n_components=2)
>>> plsca.fit(X, Y)
... # doctest: +NORMALIZE_WHITESPACE
PLSCanonical(algorithm='nipals', copy=True, max_iter=500, n_components=2,
scale=True, tol=1e-06)
>>> X_c, Y_c = plsca.transform(X, Y)
References
----------
Jacob A. Wegelin. A survey of Partial Least Squares (PLS) methods, with
emphasis on the two-block case. Technical Report 371, Department of
Statistics, University of Washington, Seattle, 2000.
Tenenhaus, M. (1998). La regression PLS: theorie et pratique. Paris:
Editions Technic.
See also
--------
CCA
PLSSVD
"""
def __init__(self, n_components=2, scale=True, algorithm="nipals",
max_iter=500, tol=1e-06, copy=True):
_PLS.__init__(self, n_components=n_components, scale=scale,
deflation_mode="canonical", mode="A",
norm_y_weights=True, algorithm=algorithm,
max_iter=max_iter, tol=tol, copy=copy)
class PLSSVD(BaseEstimator, TransformerMixin):
"""Partial Least Square SVD
Simply perform a svd on the crosscovariance matrix: X'Y
There are no iterative deflation here.
Read more in the :ref:`User Guide <cross_decomposition>`.
Parameters
----------
n_components : int, default 2
Number of components to keep.
scale : boolean, default True
Whether to scale X and Y.
copy : boolean, default True
Whether to copy X and Y, or perform in-place computations.
Attributes
----------
x_weights_ : array, [p, n_components]
X block weights vectors.
y_weights_ : array, [q, n_components]
Y block weights vectors.
x_scores_ : array, [n_samples, n_components]
X scores.
y_scores_ : array, [n_samples, n_components]
Y scores.
See also
--------
PLSCanonical
CCA
"""
def __init__(self, n_components=2, scale=True, copy=True):
self.n_components = n_components
self.scale = scale
self.copy = copy
def fit(self, X, Y):
# copy since this will contains the centered data
check_consistent_length(X, Y)
X = check_array(X, dtype=np.float64, copy=self.copy)
Y = check_array(Y, dtype=np.float64, copy=self.copy, ensure_2d=False)
if Y.ndim == 1:
Y = Y.reshape(-1, 1)
if self.n_components > max(Y.shape[1], X.shape[1]):
raise ValueError("Invalid number of components n_components=%d"
" with X of shape %s and Y of shape %s."
% (self.n_components, str(X.shape), str(Y.shape)))
# Scale (in place)
X, Y, self.x_mean_, self.y_mean_, self.x_std_, self.y_std_ =\
_center_scale_xy(X, Y, self.scale)
# svd(X'Y)
C = np.dot(X.T, Y)
# The arpack svds solver only works if the number of extracted
# components is smaller than rank(X) - 1. Hence, if we want to extract
# all the components (C.shape[1]), we have to use another one. Else,
# let's use arpacks to compute only the interesting components.
if self.n_components >= np.min(C.shape):
U, s, V = linalg.svd(C, full_matrices=False)
else:
U, s, V = arpack.svds(C, k=self.n_components)
V = V.T
self.x_scores_ = np.dot(X, U)
self.y_scores_ = np.dot(Y, V)
self.x_weights_ = U
self.y_weights_ = V
return self
def transform(self, X, Y=None):
"""Apply the dimension reduction learned on the train data."""
check_is_fitted(self, 'x_mean_')
X = check_array(X, dtype=np.float64)
Xr = (X - self.x_mean_) / self.x_std_
x_scores = np.dot(Xr, self.x_weights_)
if Y is not None:
if Y.ndim == 1:
Y = Y.reshape(-1, 1)
Yr = (Y - self.y_mean_) / self.y_std_
y_scores = np.dot(Yr, self.y_weights_)
return x_scores, y_scores
return x_scores
def fit_transform(self, X, y=None, **fit_params):
"""Learn and apply the dimension reduction on the train data.
Parameters
----------
X : array-like of predictors, shape = [n_samples, p]
Training vectors, where n_samples in the number of samples and
p is the number of predictors.
Y : array-like of response, shape = [n_samples, q], optional
Training vectors, where n_samples in the number of samples and
q is the number of response variables.
Returns
-------
x_scores if Y is not given, (x_scores, y_scores) otherwise.
"""
return self.fit(X, y, **fit_params).transform(X, y)
| bsd-3-clause |
kirangonella/BuildingMachineLearningSystemsWithPython | ch02/figure1.py | 22 | 1199 | # This code is supporting material for the book
# Building Machine Learning Systems with Python
# by Willi Richert and Luis Pedro Coelho
# published by PACKT Publishing
#
# It is made available under the MIT License
from matplotlib import pyplot as plt
# We load the data with load_iris from sklearn
from sklearn.datasets import load_iris
# load_iris returns an object with several fields
data = load_iris()
features = data.data
feature_names = data.feature_names
target = data.target
target_names = data.target_names
fig,axes = plt.subplots(2, 3)
pairs = [(0, 1), (0, 2), (0, 3), (1, 2), (1, 3), (2, 3)]
# Set up 3 different pairs of (color, marker)
color_markers = [
('r', '>'),
('g', 'o'),
('b', 'x'),
]
for i, (p0, p1) in enumerate(pairs):
ax = axes.flat[i]
for t in range(3):
# Use a different color/marker for each class `t`
c,marker = color_markers[t]
ax.scatter(features[target == t, p0], features[
target == t, p1], marker=marker, c=c)
ax.set_xlabel(feature_names[p0])
ax.set_ylabel(feature_names[p1])
ax.set_xticks([])
ax.set_yticks([])
fig.tight_layout()
fig.savefig('figure1.png')
| mit |
themrmax/scikit-learn | sklearn/linear_model/omp.py | 8 | 31640 | """Orthogonal matching pursuit algorithms
"""
# Author: Vlad Niculae
#
# License: BSD 3 clause
import warnings
import numpy as np
from scipy import linalg
from scipy.linalg.lapack import get_lapack_funcs
from .base import LinearModel, _pre_fit
from ..base import RegressorMixin
from ..utils import as_float_array, check_array, check_X_y
from ..model_selection import check_cv
from ..externals.joblib import Parallel, delayed
solve_triangular_args = {'check_finite': False}
premature = """ Orthogonal matching pursuit ended prematurely due to linear
dependence in the dictionary. The requested precision might not have been met.
"""
def _cholesky_omp(X, y, n_nonzero_coefs, tol=None, copy_X=True,
return_path=False):
"""Orthogonal Matching Pursuit step using the Cholesky decomposition.
Parameters
----------
X : array, shape (n_samples, n_features)
Input dictionary. Columns are assumed to have unit norm.
y : array, shape (n_samples,)
Input targets
n_nonzero_coefs : int
Targeted number of non-zero elements
tol : float
Targeted squared error, if not None overrides n_nonzero_coefs.
copy_X : bool, optional
Whether the design matrix X must be copied by the algorithm. A false
value is only helpful if X is already Fortran-ordered, otherwise a
copy is made anyway.
return_path : bool, optional. Default: False
Whether to return every value of the nonzero coefficients along the
forward path. Useful for cross-validation.
Returns
-------
gamma : array, shape (n_nonzero_coefs,)
Non-zero elements of the solution
idx : array, shape (n_nonzero_coefs,)
Indices of the positions of the elements in gamma within the solution
vector
coef : array, shape (n_features, n_nonzero_coefs)
The first k values of column k correspond to the coefficient value
for the active features at that step. The lower left triangle contains
garbage. Only returned if ``return_path=True``.
n_active : int
Number of active features at convergence.
"""
if copy_X:
X = X.copy('F')
else: # even if we are allowed to overwrite, still copy it if bad order
X = np.asfortranarray(X)
min_float = np.finfo(X.dtype).eps
nrm2, swap = linalg.get_blas_funcs(('nrm2', 'swap'), (X,))
potrs, = get_lapack_funcs(('potrs',), (X,))
alpha = np.dot(X.T, y)
residual = y
gamma = np.empty(0)
n_active = 0
indices = np.arange(X.shape[1]) # keeping track of swapping
max_features = X.shape[1] if tol is not None else n_nonzero_coefs
if solve_triangular_args:
# new scipy, don't need to initialize because check_finite=False
L = np.empty((max_features, max_features), dtype=X.dtype)
else:
# old scipy, we need the garbage upper triangle to be non-Inf
L = np.zeros((max_features, max_features), dtype=X.dtype)
L[0, 0] = 1.
if return_path:
coefs = np.empty_like(L)
while True:
lam = np.argmax(np.abs(np.dot(X.T, residual)))
if lam < n_active or alpha[lam] ** 2 < min_float:
# atom already selected or inner product too small
warnings.warn(premature, RuntimeWarning, stacklevel=2)
break
if n_active > 0:
# Updates the Cholesky decomposition of X' X
L[n_active, :n_active] = np.dot(X[:, :n_active].T, X[:, lam])
linalg.solve_triangular(L[:n_active, :n_active],
L[n_active, :n_active],
trans=0, lower=1,
overwrite_b=True,
**solve_triangular_args)
v = nrm2(L[n_active, :n_active]) ** 2
if 1 - v <= min_float: # selected atoms are dependent
warnings.warn(premature, RuntimeWarning, stacklevel=2)
break
L[n_active, n_active] = np.sqrt(1 - v)
X.T[n_active], X.T[lam] = swap(X.T[n_active], X.T[lam])
alpha[n_active], alpha[lam] = alpha[lam], alpha[n_active]
indices[n_active], indices[lam] = indices[lam], indices[n_active]
n_active += 1
# solves LL'x = y as a composition of two triangular systems
gamma, _ = potrs(L[:n_active, :n_active], alpha[:n_active], lower=True,
overwrite_b=False)
if return_path:
coefs[:n_active, n_active - 1] = gamma
residual = y - np.dot(X[:, :n_active], gamma)
if tol is not None and nrm2(residual) ** 2 <= tol:
break
elif n_active == max_features:
break
if return_path:
return gamma, indices[:n_active], coefs[:, :n_active], n_active
else:
return gamma, indices[:n_active], n_active
def _gram_omp(Gram, Xy, n_nonzero_coefs, tol_0=None, tol=None,
copy_Gram=True, copy_Xy=True, return_path=False):
"""Orthogonal Matching Pursuit step on a precomputed Gram matrix.
This function uses the Cholesky decomposition method.
Parameters
----------
Gram : array, shape (n_features, n_features)
Gram matrix of the input data matrix
Xy : array, shape (n_features,)
Input targets
n_nonzero_coefs : int
Targeted number of non-zero elements
tol_0 : float
Squared norm of y, required if tol is not None.
tol : float
Targeted squared error, if not None overrides n_nonzero_coefs.
copy_Gram : bool, optional
Whether the gram matrix must be copied by the algorithm. A false
value is only helpful if it is already Fortran-ordered, otherwise a
copy is made anyway.
copy_Xy : bool, optional
Whether the covariance vector Xy must be copied by the algorithm.
If False, it may be overwritten.
return_path : bool, optional. Default: False
Whether to return every value of the nonzero coefficients along the
forward path. Useful for cross-validation.
Returns
-------
gamma : array, shape (n_nonzero_coefs,)
Non-zero elements of the solution
idx : array, shape (n_nonzero_coefs,)
Indices of the positions of the elements in gamma within the solution
vector
coefs : array, shape (n_features, n_nonzero_coefs)
The first k values of column k correspond to the coefficient value
for the active features at that step. The lower left triangle contains
garbage. Only returned if ``return_path=True``.
n_active : int
Number of active features at convergence.
"""
Gram = Gram.copy('F') if copy_Gram else np.asfortranarray(Gram)
if copy_Xy:
Xy = Xy.copy()
min_float = np.finfo(Gram.dtype).eps
nrm2, swap = linalg.get_blas_funcs(('nrm2', 'swap'), (Gram,))
potrs, = get_lapack_funcs(('potrs',), (Gram,))
indices = np.arange(len(Gram)) # keeping track of swapping
alpha = Xy
tol_curr = tol_0
delta = 0
gamma = np.empty(0)
n_active = 0
max_features = len(Gram) if tol is not None else n_nonzero_coefs
if solve_triangular_args:
# new scipy, don't need to initialize because check_finite=False
L = np.empty((max_features, max_features), dtype=Gram.dtype)
else:
# old scipy, we need the garbage upper triangle to be non-Inf
L = np.zeros((max_features, max_features), dtype=Gram.dtype)
L[0, 0] = 1.
if return_path:
coefs = np.empty_like(L)
while True:
lam = np.argmax(np.abs(alpha))
if lam < n_active or alpha[lam] ** 2 < min_float:
# selected same atom twice, or inner product too small
warnings.warn(premature, RuntimeWarning, stacklevel=3)
break
if n_active > 0:
L[n_active, :n_active] = Gram[lam, :n_active]
linalg.solve_triangular(L[:n_active, :n_active],
L[n_active, :n_active],
trans=0, lower=1,
overwrite_b=True,
**solve_triangular_args)
v = nrm2(L[n_active, :n_active]) ** 2
if 1 - v <= min_float: # selected atoms are dependent
warnings.warn(premature, RuntimeWarning, stacklevel=3)
break
L[n_active, n_active] = np.sqrt(1 - v)
Gram[n_active], Gram[lam] = swap(Gram[n_active], Gram[lam])
Gram.T[n_active], Gram.T[lam] = swap(Gram.T[n_active], Gram.T[lam])
indices[n_active], indices[lam] = indices[lam], indices[n_active]
Xy[n_active], Xy[lam] = Xy[lam], Xy[n_active]
n_active += 1
# solves LL'x = y as a composition of two triangular systems
gamma, _ = potrs(L[:n_active, :n_active], Xy[:n_active], lower=True,
overwrite_b=False)
if return_path:
coefs[:n_active, n_active - 1] = gamma
beta = np.dot(Gram[:, :n_active], gamma)
alpha = Xy - beta
if tol is not None:
tol_curr += delta
delta = np.inner(gamma, beta[:n_active])
tol_curr -= delta
if abs(tol_curr) <= tol:
break
elif n_active == max_features:
break
if return_path:
return gamma, indices[:n_active], coefs[:, :n_active], n_active
else:
return gamma, indices[:n_active], n_active
def orthogonal_mp(X, y, n_nonzero_coefs=None, tol=None, precompute=False,
copy_X=True, return_path=False,
return_n_iter=False):
"""Orthogonal Matching Pursuit (OMP)
Solves n_targets Orthogonal Matching Pursuit problems.
An instance of the problem has the form:
When parametrized by the number of non-zero coefficients using
`n_nonzero_coefs`:
argmin ||y - X\gamma||^2 subject to ||\gamma||_0 <= n_{nonzero coefs}
When parametrized by error using the parameter `tol`:
argmin ||\gamma||_0 subject to ||y - X\gamma||^2 <= tol
Read more in the :ref:`User Guide <omp>`.
Parameters
----------
X : array, shape (n_samples, n_features)
Input data. Columns are assumed to have unit norm.
y : array, shape (n_samples,) or (n_samples, n_targets)
Input targets
n_nonzero_coefs : int
Desired number of non-zero entries in the solution. If None (by
default) this value is set to 10% of n_features.
tol : float
Maximum norm of the residual. If not None, overrides n_nonzero_coefs.
precompute : {True, False, 'auto'},
Whether to perform precomputations. Improves performance when n_targets
or n_samples is very large.
copy_X : bool, optional
Whether the design matrix X must be copied by the algorithm. A false
value is only helpful if X is already Fortran-ordered, otherwise a
copy is made anyway.
return_path : bool, optional. Default: False
Whether to return every value of the nonzero coefficients along the
forward path. Useful for cross-validation.
return_n_iter : bool, optional default False
Whether or not to return the number of iterations.
Returns
-------
coef : array, shape (n_features,) or (n_features, n_targets)
Coefficients of the OMP solution. If `return_path=True`, this contains
the whole coefficient path. In this case its shape is
(n_features, n_features) or (n_features, n_targets, n_features) and
iterating over the last axis yields coefficients in increasing order
of active features.
n_iters : array-like or int
Number of active features across every target. Returned only if
`return_n_iter` is set to True.
See also
--------
OrthogonalMatchingPursuit
orthogonal_mp_gram
lars_path
decomposition.sparse_encode
Notes
-----
Orthogonal matching pursuit was introduced in S. Mallat, Z. Zhang,
Matching pursuits with time-frequency dictionaries, IEEE Transactions on
Signal Processing, Vol. 41, No. 12. (December 1993), pp. 3397-3415.
(http://blanche.polytechnique.fr/~mallat/papiers/MallatPursuit93.pdf)
This implementation is based on Rubinstein, R., Zibulevsky, M. and Elad,
M., Efficient Implementation of the K-SVD Algorithm using Batch Orthogonal
Matching Pursuit Technical Report - CS Technion, April 2008.
http://www.cs.technion.ac.il/~ronrubin/Publications/KSVD-OMP-v2.pdf
"""
X = check_array(X, order='F', copy=copy_X)
copy_X = False
if y.ndim == 1:
y = y.reshape(-1, 1)
y = check_array(y)
if y.shape[1] > 1: # subsequent targets will be affected
copy_X = True
if n_nonzero_coefs is None and tol is None:
# default for n_nonzero_coefs is 0.1 * n_features
# but at least one.
n_nonzero_coefs = max(int(0.1 * X.shape[1]), 1)
if tol is not None and tol < 0:
raise ValueError("Epsilon cannot be negative")
if tol is None and n_nonzero_coefs <= 0:
raise ValueError("The number of atoms must be positive")
if tol is None and n_nonzero_coefs > X.shape[1]:
raise ValueError("The number of atoms cannot be more than the number "
"of features")
if precompute == 'auto':
precompute = X.shape[0] > X.shape[1]
if precompute:
G = np.dot(X.T, X)
G = np.asfortranarray(G)
Xy = np.dot(X.T, y)
if tol is not None:
norms_squared = np.sum((y ** 2), axis=0)
else:
norms_squared = None
return orthogonal_mp_gram(G, Xy, n_nonzero_coefs, tol, norms_squared,
copy_Gram=copy_X, copy_Xy=False,
return_path=return_path)
if return_path:
coef = np.zeros((X.shape[1], y.shape[1], X.shape[1]))
else:
coef = np.zeros((X.shape[1], y.shape[1]))
n_iters = []
for k in range(y.shape[1]):
out = _cholesky_omp(
X, y[:, k], n_nonzero_coefs, tol,
copy_X=copy_X, return_path=return_path)
if return_path:
_, idx, coefs, n_iter = out
coef = coef[:, :, :len(idx)]
for n_active, x in enumerate(coefs.T):
coef[idx[:n_active + 1], k, n_active] = x[:n_active + 1]
else:
x, idx, n_iter = out
coef[idx, k] = x
n_iters.append(n_iter)
if y.shape[1] == 1:
n_iters = n_iters[0]
if return_n_iter:
return np.squeeze(coef), n_iters
else:
return np.squeeze(coef)
def orthogonal_mp_gram(Gram, Xy, n_nonzero_coefs=None, tol=None,
norms_squared=None, copy_Gram=True,
copy_Xy=True, return_path=False,
return_n_iter=False):
"""Gram Orthogonal Matching Pursuit (OMP)
Solves n_targets Orthogonal Matching Pursuit problems using only
the Gram matrix X.T * X and the product X.T * y.
Read more in the :ref:`User Guide <omp>`.
Parameters
----------
Gram : array, shape (n_features, n_features)
Gram matrix of the input data: X.T * X
Xy : array, shape (n_features,) or (n_features, n_targets)
Input targets multiplied by X: X.T * y
n_nonzero_coefs : int
Desired number of non-zero entries in the solution. If None (by
default) this value is set to 10% of n_features.
tol : float
Maximum norm of the residual. If not None, overrides n_nonzero_coefs.
norms_squared : array-like, shape (n_targets,)
Squared L2 norms of the lines of y. Required if tol is not None.
copy_Gram : bool, optional
Whether the gram matrix must be copied by the algorithm. A false
value is only helpful if it is already Fortran-ordered, otherwise a
copy is made anyway.
copy_Xy : bool, optional
Whether the covariance vector Xy must be copied by the algorithm.
If False, it may be overwritten.
return_path : bool, optional. Default: False
Whether to return every value of the nonzero coefficients along the
forward path. Useful for cross-validation.
return_n_iter : bool, optional default False
Whether or not to return the number of iterations.
Returns
-------
coef : array, shape (n_features,) or (n_features, n_targets)
Coefficients of the OMP solution. If `return_path=True`, this contains
the whole coefficient path. In this case its shape is
(n_features, n_features) or (n_features, n_targets, n_features) and
iterating over the last axis yields coefficients in increasing order
of active features.
n_iters : array-like or int
Number of active features across every target. Returned only if
`return_n_iter` is set to True.
See also
--------
OrthogonalMatchingPursuit
orthogonal_mp
lars_path
decomposition.sparse_encode
Notes
-----
Orthogonal matching pursuit was introduced in G. Mallat, Z. Zhang,
Matching pursuits with time-frequency dictionaries, IEEE Transactions on
Signal Processing, Vol. 41, No. 12. (December 1993), pp. 3397-3415.
(http://blanche.polytechnique.fr/~mallat/papiers/MallatPursuit93.pdf)
This implementation is based on Rubinstein, R., Zibulevsky, M. and Elad,
M., Efficient Implementation of the K-SVD Algorithm using Batch Orthogonal
Matching Pursuit Technical Report - CS Technion, April 2008.
http://www.cs.technion.ac.il/~ronrubin/Publications/KSVD-OMP-v2.pdf
"""
Gram = check_array(Gram, order='F', copy=copy_Gram)
Xy = np.asarray(Xy)
if Xy.ndim > 1 and Xy.shape[1] > 1:
# or subsequent target will be affected
copy_Gram = True
if Xy.ndim == 1:
Xy = Xy[:, np.newaxis]
if tol is not None:
norms_squared = [norms_squared]
if n_nonzero_coefs is None and tol is None:
n_nonzero_coefs = int(0.1 * len(Gram))
if tol is not None and norms_squared is None:
raise ValueError('Gram OMP needs the precomputed norms in order '
'to evaluate the error sum of squares.')
if tol is not None and tol < 0:
raise ValueError("Epsilon cannot be negative")
if tol is None and n_nonzero_coefs <= 0:
raise ValueError("The number of atoms must be positive")
if tol is None and n_nonzero_coefs > len(Gram):
raise ValueError("The number of atoms cannot be more than the number "
"of features")
if return_path:
coef = np.zeros((len(Gram), Xy.shape[1], len(Gram)))
else:
coef = np.zeros((len(Gram), Xy.shape[1]))
n_iters = []
for k in range(Xy.shape[1]):
out = _gram_omp(
Gram, Xy[:, k], n_nonzero_coefs,
norms_squared[k] if tol is not None else None, tol,
copy_Gram=copy_Gram, copy_Xy=copy_Xy,
return_path=return_path)
if return_path:
_, idx, coefs, n_iter = out
coef = coef[:, :, :len(idx)]
for n_active, x in enumerate(coefs.T):
coef[idx[:n_active + 1], k, n_active] = x[:n_active + 1]
else:
x, idx, n_iter = out
coef[idx, k] = x
n_iters.append(n_iter)
if Xy.shape[1] == 1:
n_iters = n_iters[0]
if return_n_iter:
return np.squeeze(coef), n_iters
else:
return np.squeeze(coef)
class OrthogonalMatchingPursuit(LinearModel, RegressorMixin):
"""Orthogonal Matching Pursuit model (OMP)
Parameters
----------
n_nonzero_coefs : int, optional
Desired number of non-zero entries in the solution. If None (by
default) this value is set to 10% of n_features.
tol : float, optional
Maximum norm of the residual. If not None, overrides n_nonzero_coefs.
fit_intercept : boolean, optional
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
precompute : {True, False, 'auto'}, default 'auto'
Whether to use a precomputed Gram and Xy matrix to speed up
calculations. Improves performance when `n_targets` or `n_samples` is
very large. Note that if you already have such matrices, you can pass
them directly to the fit method.
Read more in the :ref:`User Guide <omp>`.
Attributes
----------
coef_ : array, shape (n_features,) or (n_targets, n_features)
parameter vector (w in the formula)
intercept_ : float or array, shape (n_targets,)
independent term in decision function.
n_iter_ : int or array-like
Number of active features across every target.
Notes
-----
Orthogonal matching pursuit was introduced in G. Mallat, Z. Zhang,
Matching pursuits with time-frequency dictionaries, IEEE Transactions on
Signal Processing, Vol. 41, No. 12. (December 1993), pp. 3397-3415.
(http://blanche.polytechnique.fr/~mallat/papiers/MallatPursuit93.pdf)
This implementation is based on Rubinstein, R., Zibulevsky, M. and Elad,
M., Efficient Implementation of the K-SVD Algorithm using Batch Orthogonal
Matching Pursuit Technical Report - CS Technion, April 2008.
http://www.cs.technion.ac.il/~ronrubin/Publications/KSVD-OMP-v2.pdf
See also
--------
orthogonal_mp
orthogonal_mp_gram
lars_path
Lars
LassoLars
decomposition.sparse_encode
"""
def __init__(self, n_nonzero_coefs=None, tol=None, fit_intercept=True,
normalize=True, precompute='auto'):
self.n_nonzero_coefs = n_nonzero_coefs
self.tol = tol
self.fit_intercept = fit_intercept
self.normalize = normalize
self.precompute = precompute
def fit(self, X, y):
"""Fit the model using X, y as training data.
Parameters
----------
X : array-like, shape (n_samples, n_features)
Training data.
y : array-like, shape (n_samples,) or (n_samples, n_targets)
Target values.
Returns
-------
self : object
returns an instance of self.
"""
X, y = check_X_y(X, y, multi_output=True, y_numeric=True)
n_features = X.shape[1]
X, y, X_offset, y_offset, X_scale, Gram, Xy = \
_pre_fit(X, y, None, self.precompute, self.normalize,
self.fit_intercept, copy=True)
if y.ndim == 1:
y = y[:, np.newaxis]
if self.n_nonzero_coefs is None and self.tol is None:
# default for n_nonzero_coefs is 0.1 * n_features
# but at least one.
self.n_nonzero_coefs_ = max(int(0.1 * n_features), 1)
else:
self.n_nonzero_coefs_ = self.n_nonzero_coefs
if Gram is False:
coef_, self.n_iter_ = orthogonal_mp(
X, y, self.n_nonzero_coefs_, self.tol,
precompute=False, copy_X=True,
return_n_iter=True)
else:
norms_sq = np.sum(y ** 2, axis=0) if self.tol is not None else None
coef_, self.n_iter_ = orthogonal_mp_gram(
Gram, Xy=Xy, n_nonzero_coefs=self.n_nonzero_coefs_,
tol=self.tol, norms_squared=norms_sq,
copy_Gram=True, copy_Xy=True,
return_n_iter=True)
self.coef_ = coef_.T
self._set_intercept(X_offset, y_offset, X_scale)
return self
def _omp_path_residues(X_train, y_train, X_test, y_test, copy=True,
fit_intercept=True, normalize=True, max_iter=100):
"""Compute the residues on left-out data for a full LARS path
Parameters
-----------
X_train : array, shape (n_samples, n_features)
The data to fit the LARS on
y_train : array, shape (n_samples)
The target variable to fit LARS on
X_test : array, shape (n_samples, n_features)
The data to compute the residues on
y_test : array, shape (n_samples)
The target variable to compute the residues on
copy : boolean, optional
Whether X_train, X_test, y_train and y_test should be copied. If
False, they may be overwritten.
fit_intercept : boolean
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
max_iter : integer, optional
Maximum numbers of iterations to perform, therefore maximum features
to include. 100 by default.
Returns
-------
residues : array, shape (n_samples, max_features)
Residues of the prediction on the test data
"""
if copy:
X_train = X_train.copy()
y_train = y_train.copy()
X_test = X_test.copy()
y_test = y_test.copy()
if fit_intercept:
X_mean = X_train.mean(axis=0)
X_train -= X_mean
X_test -= X_mean
y_mean = y_train.mean(axis=0)
y_train = as_float_array(y_train, copy=False)
y_train -= y_mean
y_test = as_float_array(y_test, copy=False)
y_test -= y_mean
if normalize:
norms = np.sqrt(np.sum(X_train ** 2, axis=0))
nonzeros = np.flatnonzero(norms)
X_train[:, nonzeros] /= norms[nonzeros]
coefs = orthogonal_mp(X_train, y_train, n_nonzero_coefs=max_iter, tol=None,
precompute=False, copy_X=False,
return_path=True)
if coefs.ndim == 1:
coefs = coefs[:, np.newaxis]
if normalize:
coefs[nonzeros] /= norms[nonzeros][:, np.newaxis]
return np.dot(coefs.T, X_test.T) - y_test
class OrthogonalMatchingPursuitCV(LinearModel, RegressorMixin):
"""Cross-validated Orthogonal Matching Pursuit model (OMP)
Parameters
----------
copy : bool, optional
Whether the design matrix X must be copied by the algorithm. A false
value is only helpful if X is already Fortran-ordered, otherwise a
copy is made anyway.
fit_intercept : boolean, optional
whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(e.g. data is expected to be already centered).
normalize : boolean, optional, default True
This parameter is ignored when ``fit_intercept`` is set to False.
If True, the regressors X will be normalized before regression by
subtracting the mean and dividing by the l2-norm.
If you wish to standardize, please use
:class:`sklearn.preprocessing.StandardScaler` before calling ``fit``
on an estimator with ``normalize=False``.
max_iter : integer, optional
Maximum numbers of iterations to perform, therefore maximum features
to include. 10% of ``n_features`` but at least 5 if available.
cv : int, cross-validation generator or an iterable, optional
Determines the cross-validation splitting strategy.
Possible inputs for cv are:
- None, to use the default 3-fold cross-validation,
- integer, to specify the number of folds.
- An object to be used as a cross-validation generator.
- An iterable yielding train/test splits.
For integer/None inputs, :class:`KFold` is used.
Refer :ref:`User Guide <cross_validation>` for the various
cross-validation strategies that can be used here.
n_jobs : integer, optional
Number of CPUs to use during the cross validation. If ``-1``, use
all the CPUs
verbose : boolean or integer, optional
Sets the verbosity amount
Read more in the :ref:`User Guide <omp>`.
Attributes
----------
intercept_ : float or array, shape (n_targets,)
Independent term in decision function.
coef_ : array, shape (n_features,) or (n_targets, n_features)
Parameter vector (w in the problem formulation).
n_nonzero_coefs_ : int
Estimated number of non-zero coefficients giving the best mean squared
error over the cross-validation folds.
n_iter_ : int or array-like
Number of active features across every target for the model refit with
the best hyperparameters got by cross-validating across all folds.
See also
--------
orthogonal_mp
orthogonal_mp_gram
lars_path
Lars
LassoLars
OrthogonalMatchingPursuit
LarsCV
LassoLarsCV
decomposition.sparse_encode
"""
def __init__(self, copy=True, fit_intercept=True, normalize=True,
max_iter=None, cv=None, n_jobs=1, verbose=False):
self.copy = copy
self.fit_intercept = fit_intercept
self.normalize = normalize
self.max_iter = max_iter
self.cv = cv
self.n_jobs = n_jobs
self.verbose = verbose
def fit(self, X, y):
"""Fit the model using X, y as training data.
Parameters
----------
X : array-like, shape [n_samples, n_features]
Training data.
y : array-like, shape [n_samples]
Target values.
Returns
-------
self : object
returns an instance of self.
"""
X, y = check_X_y(X, y, y_numeric=True, ensure_min_features=2,
estimator=self)
X = as_float_array(X, copy=False, force_all_finite=False)
cv = check_cv(self.cv, classifier=False)
max_iter = (min(max(int(0.1 * X.shape[1]), 5), X.shape[1])
if not self.max_iter
else self.max_iter)
cv_paths = Parallel(n_jobs=self.n_jobs, verbose=self.verbose)(
delayed(_omp_path_residues)(
X[train], y[train], X[test], y[test], self.copy,
self.fit_intercept, self.normalize, max_iter)
for train, test in cv.split(X))
min_early_stop = min(fold.shape[0] for fold in cv_paths)
mse_folds = np.array([(fold[:min_early_stop] ** 2).mean(axis=1)
for fold in cv_paths])
best_n_nonzero_coefs = np.argmin(mse_folds.mean(axis=0)) + 1
self.n_nonzero_coefs_ = best_n_nonzero_coefs
omp = OrthogonalMatchingPursuit(n_nonzero_coefs=best_n_nonzero_coefs,
fit_intercept=self.fit_intercept,
normalize=self.normalize)
omp.fit(X, y)
self.coef_ = omp.coef_
self.intercept_ = omp.intercept_
self.n_iter_ = omp.n_iter_
return self
| bsd-3-clause |
shikhardb/scikit-learn | sklearn/tree/export.py | 30 | 4529 | """
This module defines export functions for decision trees.
"""
# Authors: Gilles Louppe <[email protected]>
# Peter Prettenhofer <[email protected]>
# Brian Holt <[email protected]>
# Noel Dawe <[email protected]>
# Satrajit Gosh <[email protected]>
# Licence: BSD 3 clause
from ..externals import six
from . import _tree
def export_graphviz(decision_tree, out_file="tree.dot", feature_names=None,
max_depth=None):
"""Export a decision tree in DOT format.
This function generates a GraphViz representation of the decision tree,
which is then written into `out_file`. Once exported, graphical renderings
can be generated using, for example::
$ dot -Tps tree.dot -o tree.ps (PostScript format)
$ dot -Tpng tree.dot -o tree.png (PNG format)
The sample counts that are shown are weighted with any sample_weights that
might be present.
Parameters
----------
decision_tree : decision tree classifier
The decision tree to be exported to GraphViz.
out_file : file object or string, optional (default="tree.dot")
Handle or name of the output file.
feature_names : list of strings, optional (default=None)
Names of each of the features.
max_depth : int, optional (default=None)
The maximum depth of the representation. If None, the tree is fully
generated.
Examples
--------
>>> from sklearn.datasets import load_iris
>>> from sklearn import tree
>>> clf = tree.DecisionTreeClassifier()
>>> iris = load_iris()
>>> clf = clf.fit(iris.data, iris.target)
>>> tree.export_graphviz(clf,
... out_file='tree.dot') # doctest: +SKIP
"""
def node_to_str(tree, node_id, criterion):
if not isinstance(criterion, six.string_types):
criterion = "impurity"
value = tree.value[node_id]
if tree.n_outputs == 1:
value = value[0, :]
if tree.children_left[node_id] == _tree.TREE_LEAF:
return "%s = %.4f\\nsamples = %s\\nvalue = %s" \
% (criterion,
tree.impurity[node_id],
tree.n_node_samples[node_id],
value)
else:
if feature_names is not None:
feature = feature_names[tree.feature[node_id]]
else:
feature = "X[%s]" % tree.feature[node_id]
return "%s <= %.4f\\n%s = %s\\nsamples = %s" \
% (feature,
tree.threshold[node_id],
criterion,
tree.impurity[node_id],
tree.n_node_samples[node_id])
def recurse(tree, node_id, criterion, parent=None, depth=0):
if node_id == _tree.TREE_LEAF:
raise ValueError("Invalid node_id %s" % _tree.TREE_LEAF)
left_child = tree.children_left[node_id]
right_child = tree.children_right[node_id]
# Add node with description
if max_depth is None or depth <= max_depth:
out_file.write('%d [label="%s", shape="box"] ;\n' %
(node_id, node_to_str(tree, node_id, criterion)))
if parent is not None:
# Add edge to parent
out_file.write('%d -> %d ;\n' % (parent, node_id))
if left_child != _tree.TREE_LEAF:
recurse(tree, left_child, criterion=criterion, parent=node_id,
depth=depth + 1)
recurse(tree, right_child, criterion=criterion, parent=node_id,
depth=depth + 1)
else:
out_file.write('%d [label="(...)", shape="box"] ;\n' % node_id)
if parent is not None:
# Add edge to parent
out_file.write('%d -> %d ;\n' % (parent, node_id))
own_file = False
try:
if isinstance(out_file, six.string_types):
if six.PY3:
out_file = open(out_file, "w", encoding="utf-8")
else:
out_file = open(out_file, "wb")
own_file = True
out_file.write("digraph Tree {\n")
if isinstance(decision_tree, _tree.Tree):
recurse(decision_tree, 0, criterion="impurity")
else:
recurse(decision_tree.tree_, 0, criterion=decision_tree.criterion)
out_file.write("}")
finally:
if own_file:
out_file.close()
| bsd-3-clause |
yanlend/scikit-learn | sklearn/feature_selection/tests/test_base.py | 143 | 3670 | import numpy as np
from scipy import sparse as sp
from nose.tools import assert_raises, assert_equal
from numpy.testing import assert_array_equal
from sklearn.base import BaseEstimator
from sklearn.feature_selection.base import SelectorMixin
from sklearn.utils import check_array
class StepSelector(SelectorMixin, BaseEstimator):
"""Retain every `step` features (beginning with 0)"""
def __init__(self, step=2):
self.step = step
def fit(self, X, y=None):
X = check_array(X, 'csc')
self.n_input_feats = X.shape[1]
return self
def _get_support_mask(self):
mask = np.zeros(self.n_input_feats, dtype=bool)
mask[::self.step] = True
return mask
support = [True, False] * 5
support_inds = [0, 2, 4, 6, 8]
X = np.arange(20).reshape(2, 10)
Xt = np.arange(0, 20, 2).reshape(2, 5)
Xinv = X.copy()
Xinv[:, 1::2] = 0
y = [0, 1]
feature_names = list('ABCDEFGHIJ')
feature_names_t = feature_names[::2]
feature_names_inv = np.array(feature_names)
feature_names_inv[1::2] = ''
def test_transform_dense():
sel = StepSelector()
Xt_actual = sel.fit(X, y).transform(X)
Xt_actual2 = StepSelector().fit_transform(X, y)
assert_array_equal(Xt, Xt_actual)
assert_array_equal(Xt, Xt_actual2)
# Check dtype matches
assert_equal(np.int32, sel.transform(X.astype(np.int32)).dtype)
assert_equal(np.float32, sel.transform(X.astype(np.float32)).dtype)
# Check 1d list and other dtype:
names_t_actual = sel.transform([feature_names])
assert_array_equal(feature_names_t, names_t_actual.ravel())
# Check wrong shape raises error
assert_raises(ValueError, sel.transform, np.array([[1], [2]]))
def test_transform_sparse():
sparse = sp.csc_matrix
sel = StepSelector()
Xt_actual = sel.fit(sparse(X)).transform(sparse(X))
Xt_actual2 = sel.fit_transform(sparse(X))
assert_array_equal(Xt, Xt_actual.toarray())
assert_array_equal(Xt, Xt_actual2.toarray())
# Check dtype matches
assert_equal(np.int32, sel.transform(sparse(X).astype(np.int32)).dtype)
assert_equal(np.float32, sel.transform(sparse(X).astype(np.float32)).dtype)
# Check wrong shape raises error
assert_raises(ValueError, sel.transform, np.array([[1], [2]]))
def test_inverse_transform_dense():
sel = StepSelector()
Xinv_actual = sel.fit(X, y).inverse_transform(Xt)
assert_array_equal(Xinv, Xinv_actual)
# Check dtype matches
assert_equal(np.int32,
sel.inverse_transform(Xt.astype(np.int32)).dtype)
assert_equal(np.float32,
sel.inverse_transform(Xt.astype(np.float32)).dtype)
# Check 1d list and other dtype:
names_inv_actual = sel.inverse_transform([feature_names_t])
assert_array_equal(feature_names_inv, names_inv_actual.ravel())
# Check wrong shape raises error
assert_raises(ValueError, sel.inverse_transform, np.array([[1], [2]]))
def test_inverse_transform_sparse():
sparse = sp.csc_matrix
sel = StepSelector()
Xinv_actual = sel.fit(sparse(X)).inverse_transform(sparse(Xt))
assert_array_equal(Xinv, Xinv_actual.toarray())
# Check dtype matches
assert_equal(np.int32,
sel.inverse_transform(sparse(Xt).astype(np.int32)).dtype)
assert_equal(np.float32,
sel.inverse_transform(sparse(Xt).astype(np.float32)).dtype)
# Check wrong shape raises error
assert_raises(ValueError, sel.inverse_transform, np.array([[1], [2]]))
def test_get_support():
sel = StepSelector()
sel.fit(X, y)
assert_array_equal(support, sel.get_support())
assert_array_equal(support_inds, sel.get_support(indices=True))
| bsd-3-clause |
MicrosoftGenomics/FaST-LMM | fastlmm/association/LeaveOneChromosomeOut.py | 2 | 2547 | #!/usr/bin/env python2.7
#
# Written (W) 2014 Christian Widmer
# Copyright (C) 2014 Microsoft Research
"""
Created on 2014-03-11
@author: Christian Widmer
@summary: Module for performing GWAS
"""
import logging
import numpy as np
import scipy as sp
import pandas as pd
from scipy import stats
import pylab
import time
import fastlmm.inference as fastlmm
import fastlmm.util.util as util
from fastlmm.pyplink.snpreader.Bed import Bed
from fastlmm.util.pickle_io import load, save
from fastlmm.util.util import argintersect_left
class LeaveOneChromosomeOut(object):
"""LeaveOneChromosomeOut cross validation iterator (based on sklearn).
Provides train/test indices to split data in train test sets. Split
dataset into k consecutive folds according to which chromosome they belong to.
Each fold is then used a validation set once while the k - 1 remaining
fold form the training set.
Parameters
----------
chr : list
List of chromosome identifiers
indices : boolean, optional (default True)
Return train/test split as arrays of indices, rather than a boolean
mask array. Integer indices are required when dealing with sparse
matrices, since those cannot be indexed by boolean masks.
random_state : int or RandomState
Pseudo number generator state used for random sampling.
"""
def __init__(self, chr_names, indices=True, random_state=None):
#random_state = check_random_state(random_state)
self.chr_names = np.array(chr_names)
self.unique_chr_names = list(set(chr_names))
self.unique_chr_names.sort()
assert len(self.unique_chr_names) > 1
self.n = len(self.chr_names)
self.n_folds = len(self.unique_chr_names)
self.indices = indices
self.idxs = np.arange(self.n)
def __iter__(self):
if self.indices:
ind = np.arange(self.n)
for chr_name in self.unique_chr_names:
test_index = self.chr_names == chr_name
train_index = np.logical_not(test_index)
if self.indices:
train_index = ind[train_index]
test_index = ind[test_index]
yield train_index, test_index
def __repr__(self):
return '%s.%s(n=%i, n_folds=%i)' % (
self.__class__.__module__,
self.__class__.__name__,
self.n,
self.n_folds,
)
def __len__(self):
return self.n_folds
| apache-2.0 |
DailyActie/Surrogate-Model | 01-codes/scikit-learn-master/examples/cluster/plot_cluster_comparison.py | 1 | 4683 | """
=========================================================
Comparing different clustering algorithms on toy datasets
=========================================================
This example aims at showing characteristics of different
clustering algorithms on datasets that are "interesting"
but still in 2D. The last dataset is an example of a 'null'
situation for clustering: the data is homogeneous, and
there is no good clustering.
While these examples give some intuition about the algorithms,
this intuition might not apply to very high dimensional data.
The results could be improved by tweaking the parameters for
each clustering strategy, for instance setting the number of
clusters for the methods that needs this parameter
specified. Note that affinity propagation has a tendency to
create many clusters. Thus in this example its two parameters
(damping and per-point preference) were set to to mitigate this
behavior.
"""
print(__doc__)
import time
import matplotlib.pyplot as plt
import numpy as np
from sklearn import cluster, datasets
from sklearn.neighbors import kneighbors_graph
from sklearn.preprocessing import StandardScaler
np.random.seed(0)
# Generate datasets. We choose the size big enough to see the scalability
# of the algorithms, but not too big to avoid too long running times
n_samples = 1500
noisy_circles = datasets.make_circles(n_samples=n_samples, factor=.5,
noise=.05)
noisy_moons = datasets.make_moons(n_samples=n_samples, noise=.05)
blobs = datasets.make_blobs(n_samples=n_samples, random_state=8)
no_structure = np.random.rand(n_samples, 2), None
colors = np.array([x for x in 'bgrcmykbgrcmykbgrcmykbgrcmyk'])
colors = np.hstack([colors] * 20)
clustering_names = [
'MiniBatchKMeans', 'AffinityPropagation', 'MeanShift',
'SpectralClustering', 'Ward', 'AgglomerativeClustering',
'DBSCAN', 'Birch']
plt.figure(figsize=(len(clustering_names) * 2 + 3, 9.5))
plt.subplots_adjust(left=.02, right=.98, bottom=.001, top=.96, wspace=.05,
hspace=.01)
plot_num = 1
datasets = [noisy_circles, noisy_moons, blobs, no_structure]
for i_dataset, dataset in enumerate(datasets):
X, y = dataset
# normalize dataset for easier parameter selection
X = StandardScaler().fit_transform(X)
# estimate bandwidth for mean shift
bandwidth = cluster.estimate_bandwidth(X, quantile=0.3)
# connectivity matrix for structured Ward
connectivity = kneighbors_graph(X, n_neighbors=10, include_self=False)
# make connectivity symmetric
connectivity = 0.5 * (connectivity + connectivity.T)
# create clustering estimators
ms = cluster.MeanShift(bandwidth=bandwidth, bin_seeding=True)
two_means = cluster.MiniBatchKMeans(n_clusters=2)
ward = cluster.AgglomerativeClustering(n_clusters=2, linkage='ward',
connectivity=connectivity)
spectral = cluster.SpectralClustering(n_clusters=2,
eigen_solver='arpack',
affinity="nearest_neighbors")
dbscan = cluster.DBSCAN(eps=.2)
affinity_propagation = cluster.AffinityPropagation(damping=.9,
preference=-200)
average_linkage = cluster.AgglomerativeClustering(
linkage="average", affinity="cityblock", n_clusters=2,
connectivity=connectivity)
birch = cluster.Birch(n_clusters=2)
clustering_algorithms = [
two_means, affinity_propagation, ms, spectral, ward, average_linkage,
dbscan, birch]
for name, algorithm in zip(clustering_names, clustering_algorithms):
# predict cluster memberships
t0 = time.time()
algorithm.fit(X)
t1 = time.time()
if hasattr(algorithm, 'labels_'):
y_pred = algorithm.labels_.astype(np.int)
else:
y_pred = algorithm.predict(X)
# plot
plt.subplot(4, len(clustering_algorithms), plot_num)
if i_dataset == 0:
plt.title(name, size=18)
plt.scatter(X[:, 0], X[:, 1], color=colors[y_pred].tolist(), s=10)
if hasattr(algorithm, 'cluster_centers_'):
centers = algorithm.cluster_centers_
center_colors = colors[:len(centers)]
plt.scatter(centers[:, 0], centers[:, 1], s=100, c=center_colors)
plt.xlim(-2, 2)
plt.ylim(-2, 2)
plt.xticks(())
plt.yticks(())
plt.text(.99, .01, ('%.2fs' % (t1 - t0)).lstrip('0'),
transform=plt.gca().transAxes, size=15,
horizontalalignment='right')
plot_num += 1
plt.show()
| mit |
martinpilat/dag-evaluate | custom_models.py | 1 | 6526 | __author__ = 'Martin'
import pandas as pd
import numpy as np
from scipy import stats
from sklearn import cross_validation
from sklearn import ensemble
def is_transformer(cls):
return hasattr(cls, '__dageva_type') and cls.__dageva_type == 'transformer'
def is_predictor(cls):
return hasattr(cls, '__dageva_type') and cls.__dageva_type == 'predictor'
def make_transformer(cls):
"""
Adds Transformer to the bases of the cls class, useful in order to distinguish between transformers and predictors.
:param cls: The class to turn into a Transformer
:return: A class equivalent to cls, but with Transformer among its bases
"""
cls.__dageva_type = 'transformer'
return cls
def make_predictor(cls):
"""
Adds Predictor to the bases of the cls class, useful in order to distinguish between transformers and predictors.
:param cls: The class to turn into a Predictor
:return: A class equivalent to cls, but with Predictor among its bases
"""
cls.__dageva_type = 'predictor'
return cls
class KMeansSplitter:
def __init__(self, k):
from sklearn import cluster
self.kmeans = cluster.KMeans(n_clusters=k)
self.sorted_outputs = None
self.weight_idx = []
def fit(self, x, y, sample_weight=None):
self.kmeans.fit(x, y)
preds = self.kmeans.predict(x)
out = []
for i in range(self.kmeans.n_clusters):
idx = [n for n in range(len(preds)) if preds[n] == i]
self.weight_idx.append(idx)
if isinstance(x, pd.DataFrame):
out.append(x.iloc[idx])
else:
out.append(x[idx])
mins = [len(x.index) for x in out]
self.sorted_outputs = list(np.argsort(mins))
self.weight_idx = [self.weight_idx[i] for i in self.sorted_outputs]
return self
def transform(self, x):
preds = self.kmeans.predict(x)
out = []
for i in range(self.kmeans.n_clusters):
idx = [n for n in range(len(preds)) if preds[n] == i]
if isinstance(x, pd.DataFrame):
out.append(x.iloc[idx])
else:
out.append(x[idx])
return [out[i] for i in self.sorted_outputs]
class ConstantModel:
def __init__(self, cls):
self.cls = cls
def fit(self, x, y):
return self
def predict(self, x):
return pd.Series(np.array([self.cls]*len(x)), index=x.index)
class Aggregator:
def aggregate(self, x, y):
pass
class Voter(Aggregator):
def fit(self, x, y):
return self
def union_aggregate(self, x, y):
f_list, t_list = x, y
f_frame, t_frame = pd.DataFrame(), pd.Series()
for i in range(len(t_list)):
fl = f_list[i]
assert isinstance(fl, pd.DataFrame)
if fl.columns.dtype == np.dtype('int64'):
cols = map(lambda z: str(id(fl)) + '_' + str(z), fl.columns)
fl.columns = cols
t_frame = t_frame.append(t_list[i])
f_frame = f_frame.append(f_list[i])
f_frame.sort_index(inplace=True)
t_frame = t_frame.sort_index()
return f_frame, t_frame
def aggregate(self, x, y):
if not all([x[0].index.equals(xi.index) for xi in x]):
return self.union_aggregate(x, y)
res = pd.DataFrame(index=y[0].index)
for i in range(len(y)):
res["p"+str(i)] = y[i]
modes = res.apply(lambda row: stats.mode(row, axis=None)[0][0], axis=1)
if modes.empty:
return x[0], pd.Series()
return x[0], pd.Series(modes, index=y[0].index)
class Workflow:
def __init__(self, dag=None):
self.dag = dag
self.sample_weight = None
self.classes_ = None
def fit(self, X, y, sample_weight=None):
import eval #TODO: Refactor to remove circular imports
self.models = eval.train_dag(self.dag, train_data=(X, y), sample_weight=sample_weight)
self.classes_ = np.unique(y)
return self
def predict(self, X):
import eval #TODO: Refactor to remove circular imports
return np.array(eval.test_dag(self.dag, self.models, test_data=(X, None)))
def transform(self, X):
import eval
return eval.test_dag(self.dag, self.models, test_data=(X, None), output='feats_only')
def get_params(self, deep=False):
return {'dag': self.dag}
def set_params(self, **params):
if 'sample_weight' in params:
self.sample_weight = params['sample_weight']
class Stacker(Aggregator):
def __init__(self, sub_dags=None, initial_dag=None):
self.sub_dags = sub_dags
self.initial_dag = initial_dag
def fit(self, X, y, sample_weight=None):
import eval
preds = [[] for _ in self.sub_dags]
for train_idx, test_idx in cross_validation.StratifiedKFold(y, n_folds=5):
tr_X, tr_y = X.iloc[train_idx], y.iloc[train_idx]
tst_X, tst_y = X.iloc[test_idx], y.iloc[test_idx]
wf_init = Workflow(self.initial_dag)
wf_init.fit(tr_X, tr_y, sample_weight=sample_weight)
preproc_X, preproc_y = eval.test_dag(self.initial_dag, wf_init.models, test_data=(tr_X, tr_y), output='all')
pp_tst_X = wf_init.transform(tst_X)
if pp_tst_X.empty:
continue
for i, dag in enumerate(self.sub_dags):
wf = Workflow(dag)
wf.fit(preproc_X, preproc_y)
res = wf.predict(pp_tst_X)
preds[i].append(pd.DataFrame(res, index=pp_tst_X.index))
preds = [pd.concat(ps) for ps in preds]
self.train = pd.concat(preds, axis=1)
self.train.columns = ['p' + str(x) for x in range(len(preds))]
return self
def aggregate(self, X, y):
res = pd.DataFrame(index=y[0].index)
for i in range(len(X)):
res["p" + str(i)] = y[i]
return res, y[0]
class Booster(ensemble.AdaBoostClassifier):
def __init__(self, sub_dags=()):
self.sub_dags = sub_dags
self.current_sub_dag = 0
super(Booster, self).__init__(base_estimator=Workflow(), n_estimators=len(sub_dags), algorithm='SAMME')
def _make_estimator(self, append=True, random_state=0):
estimator = Workflow(self.sub_dags[self.current_sub_dag])
self.current_sub_dag += 1
if append:
self.estimators_.append(estimator)
return estimator | mit |
ChanChiChoi/scikit-learn | sklearn/manifold/tests/test_mds.py | 324 | 1862 | import numpy as np
from numpy.testing import assert_array_almost_equal
from nose.tools import assert_raises
from sklearn.manifold import mds
def test_smacof():
# test metric smacof using the data of "Modern Multidimensional Scaling",
# Borg & Groenen, p 154
sim = np.array([[0, 5, 3, 4],
[5, 0, 2, 2],
[3, 2, 0, 1],
[4, 2, 1, 0]])
Z = np.array([[-.266, -.539],
[.451, .252],
[.016, -.238],
[-.200, .524]])
X, _ = mds.smacof(sim, init=Z, n_components=2, max_iter=1, n_init=1)
X_true = np.array([[-1.415, -2.471],
[1.633, 1.107],
[.249, -.067],
[-.468, 1.431]])
assert_array_almost_equal(X, X_true, decimal=3)
def test_smacof_error():
# Not symmetric similarity matrix:
sim = np.array([[0, 5, 9, 4],
[5, 0, 2, 2],
[3, 2, 0, 1],
[4, 2, 1, 0]])
assert_raises(ValueError, mds.smacof, sim)
# Not squared similarity matrix:
sim = np.array([[0, 5, 9, 4],
[5, 0, 2, 2],
[4, 2, 1, 0]])
assert_raises(ValueError, mds.smacof, sim)
# init not None and not correct format:
sim = np.array([[0, 5, 3, 4],
[5, 0, 2, 2],
[3, 2, 0, 1],
[4, 2, 1, 0]])
Z = np.array([[-.266, -.539],
[.016, -.238],
[-.200, .524]])
assert_raises(ValueError, mds.smacof, sim, init=Z, n_init=1)
def test_MDS():
sim = np.array([[0, 5, 3, 4],
[5, 0, 2, 2],
[3, 2, 0, 1],
[4, 2, 1, 0]])
mds_clf = mds.MDS(metric=False, n_jobs=3, dissimilarity="precomputed")
mds_clf.fit(sim)
| bsd-3-clause |
rrohan/scikit-learn | sklearn/pipeline.py | 61 | 21271 | """
The :mod:`sklearn.pipeline` module implements utilities to build a composite
estimator, as a chain of transforms and estimators.
"""
# Author: Edouard Duchesnay
# Gael Varoquaux
# Virgile Fritsch
# Alexandre Gramfort
# Lars Buitinck
# Licence: BSD
from collections import defaultdict
from warnings import warn
import numpy as np
from scipy import sparse
from .base import BaseEstimator, TransformerMixin
from .externals.joblib import Parallel, delayed
from .externals import six
from .utils import tosequence
from .utils.metaestimators import if_delegate_has_method
from .externals.six import iteritems
__all__ = ['Pipeline', 'FeatureUnion']
class Pipeline(BaseEstimator):
"""Pipeline of transforms with a final estimator.
Sequentially apply a list of transforms and a final estimator.
Intermediate steps of the pipeline must be 'transforms', that is, they
must implement fit and transform methods.
The final estimator only needs to implement fit.
The purpose of the pipeline is to assemble several steps that can be
cross-validated together while setting different parameters.
For this, it enables setting parameters of the various steps using their
names and the parameter name separated by a '__', as in the example below.
Read more in the :ref:`User Guide <pipeline>`.
Parameters
----------
steps : list
List of (name, transform) tuples (implementing fit/transform) that are
chained, in the order in which they are chained, with the last object
an estimator.
Attributes
----------
named_steps : dict
Read-only attribute to access any step parameter by user given name.
Keys are step names and values are steps parameters.
Examples
--------
>>> from sklearn import svm
>>> from sklearn.datasets import samples_generator
>>> from sklearn.feature_selection import SelectKBest
>>> from sklearn.feature_selection import f_regression
>>> from sklearn.pipeline import Pipeline
>>> # generate some data to play with
>>> X, y = samples_generator.make_classification(
... n_informative=5, n_redundant=0, random_state=42)
>>> # ANOVA SVM-C
>>> anova_filter = SelectKBest(f_regression, k=5)
>>> clf = svm.SVC(kernel='linear')
>>> anova_svm = Pipeline([('anova', anova_filter), ('svc', clf)])
>>> # You can set the parameters using the names issued
>>> # For instance, fit using a k of 10 in the SelectKBest
>>> # and a parameter 'C' of the svm
>>> anova_svm.set_params(anova__k=10, svc__C=.1).fit(X, y)
... # doctest: +ELLIPSIS
Pipeline(steps=[...])
>>> prediction = anova_svm.predict(X)
>>> anova_svm.score(X, y) # doctest: +ELLIPSIS
0.77...
>>> # getting the selected features chosen by anova_filter
>>> anova_svm.named_steps['anova'].get_support()
... # doctest: +NORMALIZE_WHITESPACE
array([ True, True, True, False, False, True, False, True, True, True,
False, False, True, False, True, False, False, False, False,
True], dtype=bool)
"""
# BaseEstimator interface
def __init__(self, steps):
names, estimators = zip(*steps)
if len(dict(steps)) != len(steps):
raise ValueError("Provided step names are not unique: %s" % (names,))
# shallow copy of steps
self.steps = tosequence(steps)
transforms = estimators[:-1]
estimator = estimators[-1]
for t in transforms:
if (not (hasattr(t, "fit") or hasattr(t, "fit_transform")) or not
hasattr(t, "transform")):
raise TypeError("All intermediate steps of the chain should "
"be transforms and implement fit and transform"
" '%s' (type %s) doesn't)" % (t, type(t)))
if not hasattr(estimator, "fit"):
raise TypeError("Last step of chain should implement fit "
"'%s' (type %s) doesn't)"
% (estimator, type(estimator)))
@property
def _estimator_type(self):
return self.steps[-1][1]._estimator_type
def get_params(self, deep=True):
if not deep:
return super(Pipeline, self).get_params(deep=False)
else:
out = self.named_steps
for name, step in six.iteritems(self.named_steps):
for key, value in six.iteritems(step.get_params(deep=True)):
out['%s__%s' % (name, key)] = value
out.update(super(Pipeline, self).get_params(deep=False))
return out
@property
def named_steps(self):
return dict(self.steps)
@property
def _final_estimator(self):
return self.steps[-1][1]
# Estimator interface
def _pre_transform(self, X, y=None, **fit_params):
fit_params_steps = dict((step, {}) for step, _ in self.steps)
for pname, pval in six.iteritems(fit_params):
step, param = pname.split('__', 1)
fit_params_steps[step][param] = pval
Xt = X
for name, transform in self.steps[:-1]:
if hasattr(transform, "fit_transform"):
Xt = transform.fit_transform(Xt, y, **fit_params_steps[name])
else:
Xt = transform.fit(Xt, y, **fit_params_steps[name]) \
.transform(Xt)
return Xt, fit_params_steps[self.steps[-1][0]]
def fit(self, X, y=None, **fit_params):
"""Fit all the transforms one after the other and transform the
data, then fit the transformed data using the final estimator.
Parameters
----------
X : iterable
Training data. Must fulfill input requirements of first step of the
pipeline.
y : iterable, default=None
Training targets. Must fulfill label requirements for all steps of
the pipeline.
"""
Xt, fit_params = self._pre_transform(X, y, **fit_params)
self.steps[-1][-1].fit(Xt, y, **fit_params)
return self
def fit_transform(self, X, y=None, **fit_params):
"""Fit all the transforms one after the other and transform the
data, then use fit_transform on transformed data using the final
estimator.
Parameters
----------
X : iterable
Training data. Must fulfill input requirements of first step of the
pipeline.
y : iterable, default=None
Training targets. Must fulfill label requirements for all steps of
the pipeline.
"""
Xt, fit_params = self._pre_transform(X, y, **fit_params)
if hasattr(self.steps[-1][-1], 'fit_transform'):
return self.steps[-1][-1].fit_transform(Xt, y, **fit_params)
else:
return self.steps[-1][-1].fit(Xt, y, **fit_params).transform(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def predict(self, X):
"""Applies transforms to the data, and the predict method of the
final estimator. Valid only if the final estimator implements
predict.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].predict(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def fit_predict(self, X, y=None, **fit_params):
"""Applies fit_predict of last step in pipeline after transforms.
Applies fit_transforms of a pipeline to the data, followed by the
fit_predict method of the final estimator in the pipeline. Valid
only if the final estimator implements fit_predict.
Parameters
----------
X : iterable
Training data. Must fulfill input requirements of first step of
the pipeline.
y : iterable, default=None
Training targets. Must fulfill label requirements for all steps
of the pipeline.
"""
Xt, fit_params = self._pre_transform(X, y, **fit_params)
return self.steps[-1][-1].fit_predict(Xt, y, **fit_params)
@if_delegate_has_method(delegate='_final_estimator')
def predict_proba(self, X):
"""Applies transforms to the data, and the predict_proba method of the
final estimator. Valid only if the final estimator implements
predict_proba.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].predict_proba(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def decision_function(self, X):
"""Applies transforms to the data, and the decision_function method of
the final estimator. Valid only if the final estimator implements
decision_function.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].decision_function(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def predict_log_proba(self, X):
"""Applies transforms to the data, and the predict_log_proba method of
the final estimator. Valid only if the final estimator implements
predict_log_proba.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].predict_log_proba(Xt)
@if_delegate_has_method(delegate='_final_estimator')
def transform(self, X):
"""Applies transforms to the data, and the transform method of the
final estimator. Valid only if the final estimator implements
transform.
Parameters
----------
X : iterable
Data to predict on. Must fulfill input requirements of first step of
the pipeline.
"""
Xt = X
for name, transform in self.steps:
Xt = transform.transform(Xt)
return Xt
@if_delegate_has_method(delegate='_final_estimator')
def inverse_transform(self, X):
"""Applies inverse transform to the data.
Starts with the last step of the pipeline and applies ``inverse_transform`` in
inverse order of the pipeline steps.
Valid only if all steps of the pipeline implement inverse_transform.
Parameters
----------
X : iterable
Data to inverse transform. Must fulfill output requirements of the
last step of the pipeline.
"""
if X.ndim == 1:
warn("From version 0.19, a 1d X will not be reshaped in"
" pipeline.inverse_transform any more.", FutureWarning)
X = X[None, :]
Xt = X
for name, step in self.steps[::-1]:
Xt = step.inverse_transform(Xt)
return Xt
@if_delegate_has_method(delegate='_final_estimator')
def score(self, X, y=None):
"""Applies transforms to the data, and the score method of the
final estimator. Valid only if the final estimator implements
score.
Parameters
----------
X : iterable
Data to score. Must fulfill input requirements of first step of the
pipeline.
y : iterable, default=None
Targets used for scoring. Must fulfill label requirements for all steps of
the pipeline.
"""
Xt = X
for name, transform in self.steps[:-1]:
Xt = transform.transform(Xt)
return self.steps[-1][-1].score(Xt, y)
@property
def classes_(self):
return self.steps[-1][-1].classes_
@property
def _pairwise(self):
# check if first estimator expects pairwise input
return getattr(self.steps[0][1], '_pairwise', False)
def _name_estimators(estimators):
"""Generate names for estimators."""
names = [type(estimator).__name__.lower() for estimator in estimators]
namecount = defaultdict(int)
for est, name in zip(estimators, names):
namecount[name] += 1
for k, v in list(six.iteritems(namecount)):
if v == 1:
del namecount[k]
for i in reversed(range(len(estimators))):
name = names[i]
if name in namecount:
names[i] += "-%d" % namecount[name]
namecount[name] -= 1
return list(zip(names, estimators))
def make_pipeline(*steps):
"""Construct a Pipeline from the given estimators.
This is a shorthand for the Pipeline constructor; it does not require, and
does not permit, naming the estimators. Instead, they will be given names
automatically based on their types.
Examples
--------
>>> from sklearn.naive_bayes import GaussianNB
>>> from sklearn.preprocessing import StandardScaler
>>> make_pipeline(StandardScaler(), GaussianNB()) # doctest: +NORMALIZE_WHITESPACE
Pipeline(steps=[('standardscaler',
StandardScaler(copy=True, with_mean=True, with_std=True)),
('gaussiannb', GaussianNB())])
Returns
-------
p : Pipeline
"""
return Pipeline(_name_estimators(steps))
def _fit_one_transformer(transformer, X, y):
return transformer.fit(X, y)
def _transform_one(transformer, name, X, transformer_weights):
if transformer_weights is not None and name in transformer_weights:
# if we have a weight for this transformer, muliply output
return transformer.transform(X) * transformer_weights[name]
return transformer.transform(X)
def _fit_transform_one(transformer, name, X, y, transformer_weights,
**fit_params):
if transformer_weights is not None and name in transformer_weights:
# if we have a weight for this transformer, muliply output
if hasattr(transformer, 'fit_transform'):
X_transformed = transformer.fit_transform(X, y, **fit_params)
return X_transformed * transformer_weights[name], transformer
else:
X_transformed = transformer.fit(X, y, **fit_params).transform(X)
return X_transformed * transformer_weights[name], transformer
if hasattr(transformer, 'fit_transform'):
X_transformed = transformer.fit_transform(X, y, **fit_params)
return X_transformed, transformer
else:
X_transformed = transformer.fit(X, y, **fit_params).transform(X)
return X_transformed, transformer
class FeatureUnion(BaseEstimator, TransformerMixin):
"""Concatenates results of multiple transformer objects.
This estimator applies a list of transformer objects in parallel to the
input data, then concatenates the results. This is useful to combine
several feature extraction mechanisms into a single transformer.
Read more in the :ref:`User Guide <feature_union>`.
Parameters
----------
transformer_list: list of (string, transformer) tuples
List of transformer objects to be applied to the data. The first
half of each tuple is the name of the transformer.
n_jobs: int, optional
Number of jobs to run in parallel (default 1).
transformer_weights: dict, optional
Multiplicative weights for features per transformer.
Keys are transformer names, values the weights.
"""
def __init__(self, transformer_list, n_jobs=1, transformer_weights=None):
self.transformer_list = transformer_list
self.n_jobs = n_jobs
self.transformer_weights = transformer_weights
def get_feature_names(self):
"""Get feature names from all transformers.
Returns
-------
feature_names : list of strings
Names of the features produced by transform.
"""
feature_names = []
for name, trans in self.transformer_list:
if not hasattr(trans, 'get_feature_names'):
raise AttributeError("Transformer %s does not provide"
" get_feature_names." % str(name))
feature_names.extend([name + "__" + f for f in
trans.get_feature_names()])
return feature_names
def fit(self, X, y=None):
"""Fit all transformers using X.
Parameters
----------
X : array-like or sparse matrix, shape (n_samples, n_features)
Input data, used to fit transformers.
"""
transformers = Parallel(n_jobs=self.n_jobs)(
delayed(_fit_one_transformer)(trans, X, y)
for name, trans in self.transformer_list)
self._update_transformer_list(transformers)
return self
def fit_transform(self, X, y=None, **fit_params):
"""Fit all transformers using X, transform the data and concatenate
results.
Parameters
----------
X : array-like or sparse matrix, shape (n_samples, n_features)
Input data to be transformed.
Returns
-------
X_t : array-like or sparse matrix, shape (n_samples, sum_n_components)
hstack of results of transformers. sum_n_components is the
sum of n_components (output dimension) over transformers.
"""
result = Parallel(n_jobs=self.n_jobs)(
delayed(_fit_transform_one)(trans, name, X, y,
self.transformer_weights, **fit_params)
for name, trans in self.transformer_list)
Xs, transformers = zip(*result)
self._update_transformer_list(transformers)
if any(sparse.issparse(f) for f in Xs):
Xs = sparse.hstack(Xs).tocsr()
else:
Xs = np.hstack(Xs)
return Xs
def transform(self, X):
"""Transform X separately by each transformer, concatenate results.
Parameters
----------
X : array-like or sparse matrix, shape (n_samples, n_features)
Input data to be transformed.
Returns
-------
X_t : array-like or sparse matrix, shape (n_samples, sum_n_components)
hstack of results of transformers. sum_n_components is the
sum of n_components (output dimension) over transformers.
"""
Xs = Parallel(n_jobs=self.n_jobs)(
delayed(_transform_one)(trans, name, X, self.transformer_weights)
for name, trans in self.transformer_list)
if any(sparse.issparse(f) for f in Xs):
Xs = sparse.hstack(Xs).tocsr()
else:
Xs = np.hstack(Xs)
return Xs
def get_params(self, deep=True):
if not deep:
return super(FeatureUnion, self).get_params(deep=False)
else:
out = dict(self.transformer_list)
for name, trans in self.transformer_list:
for key, value in iteritems(trans.get_params(deep=True)):
out['%s__%s' % (name, key)] = value
out.update(super(FeatureUnion, self).get_params(deep=False))
return out
def _update_transformer_list(self, transformers):
self.transformer_list[:] = [
(name, new)
for ((name, old), new) in zip(self.transformer_list, transformers)
]
# XXX it would be nice to have a keyword-only n_jobs argument to this function,
# but that's not allowed in Python 2.x.
def make_union(*transformers):
"""Construct a FeatureUnion from the given transformers.
This is a shorthand for the FeatureUnion constructor; it does not require,
and does not permit, naming the transformers. Instead, they will be given
names automatically based on their types. It also does not allow weighting.
Examples
--------
>>> from sklearn.decomposition import PCA, TruncatedSVD
>>> make_union(PCA(), TruncatedSVD()) # doctest: +NORMALIZE_WHITESPACE
FeatureUnion(n_jobs=1,
transformer_list=[('pca', PCA(copy=True, n_components=None,
whiten=False)),
('truncatedsvd',
TruncatedSVD(algorithm='randomized',
n_components=2, n_iter=5,
random_state=None, tol=0.0))],
transformer_weights=None)
Returns
-------
f : FeatureUnion
"""
return FeatureUnion(_name_estimators(transformers))
| bsd-3-clause |
potash/scikit-learn | examples/ensemble/plot_voting_decision_regions.py | 86 | 2386 | """
==================================================
Plot the decision boundaries of a VotingClassifier
==================================================
Plot the decision boundaries of a `VotingClassifier` for
two features of the Iris dataset.
Plot the class probabilities of the first sample in a toy dataset
predicted by three different classifiers and averaged by the
`VotingClassifier`.
First, three exemplary classifiers are initialized (`DecisionTreeClassifier`,
`KNeighborsClassifier`, and `SVC`) and used to initialize a
soft-voting `VotingClassifier` with weights `[2, 1, 2]`, which means that
the predicted probabilities of the `DecisionTreeClassifier` and `SVC`
count 5 times as much as the weights of the `KNeighborsClassifier` classifier
when the averaged probability is calculated.
"""
print(__doc__)
from itertools import product
import numpy as np
import matplotlib.pyplot as plt
from sklearn import datasets
from sklearn.tree import DecisionTreeClassifier
from sklearn.neighbors import KNeighborsClassifier
from sklearn.svm import SVC
from sklearn.ensemble import VotingClassifier
# Loading some example data
iris = datasets.load_iris()
X = iris.data[:, [0, 2]]
y = iris.target
# Training classifiers
clf1 = DecisionTreeClassifier(max_depth=4)
clf2 = KNeighborsClassifier(n_neighbors=7)
clf3 = SVC(kernel='rbf', probability=True)
eclf = VotingClassifier(estimators=[('dt', clf1), ('knn', clf2),
('svc', clf3)],
voting='soft', weights=[2, 1, 2])
clf1.fit(X, y)
clf2.fit(X, y)
clf3.fit(X, y)
eclf.fit(X, y)
# Plotting decision regions
x_min, x_max = X[:, 0].min() - 1, X[:, 0].max() + 1
y_min, y_max = X[:, 1].min() - 1, X[:, 1].max() + 1
xx, yy = np.meshgrid(np.arange(x_min, x_max, 0.1),
np.arange(y_min, y_max, 0.1))
f, axarr = plt.subplots(2, 2, sharex='col', sharey='row', figsize=(10, 8))
for idx, clf, tt in zip(product([0, 1], [0, 1]),
[clf1, clf2, clf3, eclf],
['Decision Tree (depth=4)', 'KNN (k=7)',
'Kernel SVM', 'Soft Voting']):
Z = clf.predict(np.c_[xx.ravel(), yy.ravel()])
Z = Z.reshape(xx.shape)
axarr[idx[0], idx[1]].contourf(xx, yy, Z, alpha=0.4)
axarr[idx[0], idx[1]].scatter(X[:, 0], X[:, 1], c=y, alpha=0.8)
axarr[idx[0], idx[1]].set_title(tt)
plt.show()
| bsd-3-clause |
soulmachine/scikit-learn | sklearn/kernel_approximation.py | 3 | 16954 | """
The :mod:`sklearn.kernel_approximation` module implements several
approximate kernel feature maps base on Fourier transforms.
"""
# Author: Andreas Mueller <[email protected]>
#
# License: BSD 3 clause
import warnings
import numpy as np
import scipy.sparse as sp
from scipy.linalg import svd
from .base import BaseEstimator
from .base import TransformerMixin
from .utils import check_array, check_random_state, as_float_array
from .utils.extmath import safe_sparse_dot
from .metrics.pairwise import pairwise_kernels
class RBFSampler(BaseEstimator, TransformerMixin):
"""Approximates feature map of an RBF kernel by Monte Carlo approximation
of its Fourier transform.
Parameters
----------
gamma : float
Parameter of RBF kernel: exp(-gamma * x^2)
n_components : int
Number of Monte Carlo samples per original feature.
Equals the dimensionality of the computed feature space.
random_state : {int, RandomState}, optional
If int, random_state is the seed used by the random number generator;
if RandomState instance, random_state is the random number generator.
Notes
-----
See "Random Features for Large-Scale Kernel Machines" by A. Rahimi and
Benjamin Recht.
"""
def __init__(self, gamma=1., n_components=100, random_state=None):
self.gamma = gamma
self.n_components = n_components
self.random_state = random_state
def fit(self, X, y=None):
"""Fit the model with X.
Samples random projection according to n_features.
Parameters
----------
X : {array-like, sparse matrix}, shape (n_samples, n_features)
Training data, where n_samples in the number of samples
and n_features is the number of features.
Returns
-------
self : object
Returns the transformer.
"""
X = check_array(X, accept_sparse='csr')
random_state = check_random_state(self.random_state)
n_features = X.shape[1]
self.random_weights_ = (np.sqrt(self.gamma) * random_state.normal(
size=(n_features, self.n_components)))
self.random_offset_ = random_state.uniform(0, 2 * np.pi,
size=self.n_components)
return self
def transform(self, X, y=None):
"""Apply the approximate feature map to X.
Parameters
----------
X : {array-like, sparse matrix}, shape (n_samples, n_features)
New data, where n_samples in the number of samples
and n_features is the number of features.
Returns
-------
X_new : array-like, shape (n_samples, n_components)
"""
X = check_array(X, accept_sparse='csr')
projection = safe_sparse_dot(X, self.random_weights_)
projection += self.random_offset_
np.cos(projection, projection)
projection *= np.sqrt(2.) / np.sqrt(self.n_components)
return projection
class SkewedChi2Sampler(BaseEstimator, TransformerMixin):
"""Approximates feature map of the "skewed chi-squared" kernel by Monte
Carlo approximation of its Fourier transform.
Parameters
----------
skewedness : float
"skewedness" parameter of the kernel. Needs to be cross-validated.
n_components : int
number of Monte Carlo samples per original feature.
Equals the dimensionality of the computed feature space.
random_state : {int, RandomState}, optional
If int, random_state is the seed used by the random number generator;
if RandomState instance, random_state is the random number generator.
References
----------
See "Random Fourier Approximations for Skewed Multiplicative Histogram
Kernels" by Fuxin Li, Catalin Ionescu and Cristian Sminchisescu.
See also
--------
AdditiveChi2Sampler : A different approach for approximating an additive
variant of the chi squared kernel.
sklearn.metrics.pairwise.chi2_kernel : The exact chi squared kernel.
"""
def __init__(self, skewedness=1., n_components=100, random_state=None):
self.skewedness = skewedness
self.n_components = n_components
self.random_state = random_state
def fit(self, X, y=None):
"""Fit the model with X.
Samples random projection according to n_features.
Parameters
----------
X : array-like, shape (n_samples, n_features)
Training data, where n_samples in the number of samples
and n_features is the number of features.
Returns
-------
self : object
Returns the transformer.
"""
X = check_array(X)
random_state = check_random_state(self.random_state)
n_features = X.shape[1]
uniform = random_state.uniform(size=(n_features, self.n_components))
# transform by inverse CDF of sech
self.random_weights_ = (1. / np.pi
* np.log(np.tan(np.pi / 2. * uniform)))
self.random_offset_ = random_state.uniform(0, 2 * np.pi,
size=self.n_components)
return self
def transform(self, X, y=None):
"""Apply the approximate feature map to X.
Parameters
----------
X : array-like, shape (n_samples, n_features)
New data, where n_samples in the number of samples
and n_features is the number of features.
Returns
-------
X_new : array-like, shape (n_samples, n_components)
"""
X = as_float_array(X, copy=True)
X = check_array(X, copy=False)
if (X < 0).any():
raise ValueError("X may not contain entries smaller than zero.")
X += self.skewedness
np.log(X, X)
projection = safe_sparse_dot(X, self.random_weights_)
projection += self.random_offset_
np.cos(projection, projection)
projection *= np.sqrt(2.) / np.sqrt(self.n_components)
return projection
class AdditiveChi2Sampler(BaseEstimator, TransformerMixin):
"""Approximate feature map for additive chi2 kernel.
Uses sampling the fourier transform of the kernel characteristic
at regular intervals.
Since the kernel that is to be approximated is additive, the components of
the input vectors can be treated separately. Each entry in the original
space is transformed into 2*sample_steps+1 features, where sample_steps is
a parameter of the method. Typical values of sample_steps include 1, 2 and
3.
Optimal choices for the sampling interval for certain data ranges can be
computed (see the reference). The default values should be reasonable.
Parameters
----------
sample_steps : int, optional
Gives the number of (complex) sampling points.
sample_interval : float, optional
Sampling interval. Must be specified when sample_steps not in {1,2,3}.
Notes
-----
This estimator approximates a slightly different version of the additive
chi squared kernel then ``metric.additive_chi2`` computes.
See also
--------
SkewedChi2Sampler : A Fourier-approximation to a non-additive variant of
the chi squared kernel.
sklearn.metrics.pairwise.chi2_kernel : The exact chi squared kernel.
sklearn.metrics.pairwise.additive_chi2_kernel : The exact additive chi
squared kernel.
References
----------
See `"Efficient additive kernels via explicit feature maps"
<http://eprints.pascal-network.org/archive/00006964/01/vedaldi10.pdf>`_
Vedaldi, A. and Zisserman, A., Computer Vision and Pattern Recognition 2010
"""
def __init__(self, sample_steps=2, sample_interval=None):
self.sample_steps = sample_steps
self.sample_interval = sample_interval
def fit(self, X, y=None):
"""Set parameters."""
X = check_array(X, accept_sparse='csr')
if self.sample_interval is None:
# See reference, figure 2 c)
if self.sample_steps == 1:
self.sample_interval_ = 0.8
elif self.sample_steps == 2:
self.sample_interval_ = 0.5
elif self.sample_steps == 3:
self.sample_interval_ = 0.4
else:
raise ValueError("If sample_steps is not in [1, 2, 3],"
" you need to provide sample_interval")
else:
self.sample_interval_ = self.sample_interval
return self
def transform(self, X, y=None):
"""Apply approximate feature map to X.
Parameters
----------
X : {array-like, sparse matrix}, shape = (n_samples, n_features)
Returns
-------
X_new : {array, sparse matrix}, \
shape = (n_samples, n_features * (2*sample_steps + 1))
Whether the return value is an array of sparse matrix depends on
the type of the input X.
"""
X = check_array(X, accept_sparse='csr')
sparse = sp.issparse(X)
# check if X has negative values. Doesn't play well with np.log.
if ((X.data if sparse else X) < 0).any():
raise ValueError("Entries of X must be non-negative.")
# zeroth component
# 1/cosh = sech
# cosh(0) = 1.0
transf = self._transform_sparse if sparse else self._transform_dense
return transf(X)
def _transform_dense(self, X):
non_zero = (X != 0.0)
X_nz = X[non_zero]
X_step = np.zeros_like(X)
X_step[non_zero] = np.sqrt(X_nz * self.sample_interval_)
X_new = [X_step]
log_step_nz = self.sample_interval_ * np.log(X_nz)
step_nz = 2 * X_nz * self.sample_interval_
for j in range(1, self.sample_steps):
factor_nz = np.sqrt(step_nz /
np.cosh(np.pi * j * self.sample_interval_))
X_step = np.zeros_like(X)
X_step[non_zero] = factor_nz * np.cos(j * log_step_nz)
X_new.append(X_step)
X_step = np.zeros_like(X)
X_step[non_zero] = factor_nz * np.sin(j * log_step_nz)
X_new.append(X_step)
return np.hstack(X_new)
def _transform_sparse(self, X):
indices = X.indices.copy()
indptr = X.indptr.copy()
data_step = np.sqrt(X.data * self.sample_interval_)
X_step = sp.csr_matrix((data_step, indices, indptr),
shape=X.shape, dtype=X.dtype, copy=False)
X_new = [X_step]
log_step_nz = self.sample_interval_ * np.log(X.data)
step_nz = 2 * X.data * self.sample_interval_
for j in range(1, self.sample_steps):
factor_nz = np.sqrt(step_nz /
np.cosh(np.pi * j * self.sample_interval_))
data_step = factor_nz * np.cos(j * log_step_nz)
X_step = sp.csr_matrix((data_step, indices, indptr),
shape=X.shape, dtype=X.dtype, copy=False)
X_new.append(X_step)
data_step = factor_nz * np.sin(j * log_step_nz)
X_step = sp.csr_matrix((data_step, indices, indptr),
shape=X.shape, dtype=X.dtype, copy=False)
X_new.append(X_step)
return sp.hstack(X_new)
class Nystroem(BaseEstimator, TransformerMixin):
"""Approximate a kernel map using a subset of the training data.
Constructs an approximate feature map for an arbitrary kernel
using a subset of the data as basis.
Parameters
----------
kernel : string or callable, default="rbf"
Kernel map to be approximated. A callable should accept two arguments
and the keyword arguments passed to this object as kernel_params, and
should return a floating point number.
n_components : int
Number of features to construct.
How many data points will be used to construct the mapping.
gamma : float, default=None
Gamma parameter for the RBF, polynomial, exponential chi2 and
sigmoid kernels. Interpretation of the default value is left to
the kernel; see the documentation for sklearn.metrics.pairwise.
Ignored by other kernels.
degree : float, default=3
Degree of the polynomial kernel. Ignored by other kernels.
coef0 : float, default=1
Zero coefficient for polynomial and sigmoid kernels.
Ignored by other kernels.
kernel_params : mapping of string to any, optional
Additional parameters (keyword arguments) for kernel function passed
as callable object.
random_state : {int, RandomState}, optional
If int, random_state is the seed used by the random number generator;
if RandomState instance, random_state is the random number generator.
Attributes
----------
components_ : array, shape (n_components, n_features)
Subset of training points used to construct the feature map.
component_indices_ : array, shape (n_components)
Indices of ``components_`` in the training set.
normalization_ : array, shape (n_components, n_components)
Normalization matrix needed for embedding.
Square root of the kernel matrix on ``components_``.
References
----------
* Williams, C.K.I. and Seeger, M.
"Using the Nystroem method to speed up kernel machines",
Advances in neural information processing systems 2001
* T. Yang, Y. Li, M. Mahdavi, R. Jin and Z. Zhou
"Nystroem Method vs Random Fourier Features: A Theoretical and Empirical
Comparison",
Advances in Neural Information Processing Systems 2012
See also
--------
RBFSampler : An approximation to the RBF kernel using random Fourier
features.
sklearn.metrics.pairwise.kernel_metrics : List of built-in kernels.
"""
def __init__(self, kernel="rbf", gamma=None, coef0=1, degree=3,
kernel_params=None, n_components=100, random_state=None):
self.kernel = kernel
self.gamma = gamma
self.coef0 = coef0
self.degree = degree
self.kernel_params = kernel_params
self.n_components = n_components
self.random_state = random_state
def fit(self, X, y=None):
"""Fit estimator to data.
Samples a subset of training points, computes kernel
on these and computes normalization matrix.
Parameters
----------
X : array-like, shape=(n_samples, n_feature)
Training data.
"""
rnd = check_random_state(self.random_state)
if not sp.issparse(X):
X = np.asarray(X)
n_samples = X.shape[0]
# get basis vectors
if self.n_components > n_samples:
# XXX should we just bail?
n_components = n_samples
warnings.warn("n_components > n_samples. This is not possible.\n"
"n_components was set to n_samples, which results"
" in inefficient evaluation of the full kernel.")
else:
n_components = self.n_components
n_components = min(n_samples, n_components)
inds = rnd.permutation(n_samples)
basis_inds = inds[:n_components]
basis = X[basis_inds]
basis_kernel = pairwise_kernels(basis, metric=self.kernel,
filter_params=True,
**self._get_kernel_params())
# sqrt of kernel matrix on basis vectors
U, S, V = svd(basis_kernel)
self.normalization_ = np.dot(U * 1. / np.sqrt(S), V)
self.components_ = basis
self.component_indices_ = inds
return self
def transform(self, X):
"""Apply feature map to X.
Computes an approximate feature map using the kernel
between some training points and X.
Parameters
----------
X : array-like, shape=(n_samples, n_features)
Data to transform.
Returns
-------
X_transformed : array, shape=(n_samples, n_components)
Transformed data.
"""
embedded = pairwise_kernels(X, self.components_,
metric=self.kernel,
filter_params=True,
**self._get_kernel_params())
return np.dot(embedded, self.normalization_.T)
def _get_kernel_params(self):
params = self.kernel_params
if params is None:
params = {}
if not callable(self.kernel):
params['gamma'] = self.gamma
params['degree'] = self.degree
params['coef0'] = self.coef0
return params
| bsd-3-clause |
hainm/scikit-learn | examples/classification/plot_classifier_comparison.py | 181 | 4699 | #!/usr/bin/python
# -*- coding: utf-8 -*-
"""
=====================
Classifier comparison
=====================
A comparison of a several classifiers in scikit-learn on synthetic datasets.
The point of this example is to illustrate the nature of decision boundaries
of different classifiers.
This should be taken with a grain of salt, as the intuition conveyed by
these examples does not necessarily carry over to real datasets.
Particularly in high-dimensional spaces, data can more easily be separated
linearly and the simplicity of classifiers such as naive Bayes and linear SVMs
might lead to better generalization than is achieved by other classifiers.
The plots show training points in solid colors and testing points
semi-transparent. The lower right shows the classification accuracy on the test
set.
"""
print(__doc__)
# Code source: Gaël Varoquaux
# Andreas Müller
# Modified for documentation by Jaques Grobler
# License: BSD 3 clause
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.colors import ListedColormap
from sklearn.cross_validation import train_test_split
from sklearn.preprocessing import StandardScaler
from sklearn.datasets import make_moons, make_circles, make_classification
from sklearn.neighbors import KNeighborsClassifier
from sklearn.svm import SVC
from sklearn.tree import DecisionTreeClassifier
from sklearn.ensemble import RandomForestClassifier, AdaBoostClassifier
from sklearn.naive_bayes import GaussianNB
from sklearn.lda import LDA
from sklearn.qda import QDA
h = .02 # step size in the mesh
names = ["Nearest Neighbors", "Linear SVM", "RBF SVM", "Decision Tree",
"Random Forest", "AdaBoost", "Naive Bayes", "LDA", "QDA"]
classifiers = [
KNeighborsClassifier(3),
SVC(kernel="linear", C=0.025),
SVC(gamma=2, C=1),
DecisionTreeClassifier(max_depth=5),
RandomForestClassifier(max_depth=5, n_estimators=10, max_features=1),
AdaBoostClassifier(),
GaussianNB(),
LDA(),
QDA()]
X, y = make_classification(n_features=2, n_redundant=0, n_informative=2,
random_state=1, n_clusters_per_class=1)
rng = np.random.RandomState(2)
X += 2 * rng.uniform(size=X.shape)
linearly_separable = (X, y)
datasets = [make_moons(noise=0.3, random_state=0),
make_circles(noise=0.2, factor=0.5, random_state=1),
linearly_separable
]
figure = plt.figure(figsize=(27, 9))
i = 1
# iterate over datasets
for ds in datasets:
# preprocess dataset, split into training and test part
X, y = ds
X = StandardScaler().fit_transform(X)
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=.4)
x_min, x_max = X[:, 0].min() - .5, X[:, 0].max() + .5
y_min, y_max = X[:, 1].min() - .5, X[:, 1].max() + .5
xx, yy = np.meshgrid(np.arange(x_min, x_max, h),
np.arange(y_min, y_max, h))
# just plot the dataset first
cm = plt.cm.RdBu
cm_bright = ListedColormap(['#FF0000', '#0000FF'])
ax = plt.subplot(len(datasets), len(classifiers) + 1, i)
# Plot the training points
ax.scatter(X_train[:, 0], X_train[:, 1], c=y_train, cmap=cm_bright)
# and testing points
ax.scatter(X_test[:, 0], X_test[:, 1], c=y_test, cmap=cm_bright, alpha=0.6)
ax.set_xlim(xx.min(), xx.max())
ax.set_ylim(yy.min(), yy.max())
ax.set_xticks(())
ax.set_yticks(())
i += 1
# iterate over classifiers
for name, clf in zip(names, classifiers):
ax = plt.subplot(len(datasets), len(classifiers) + 1, i)
clf.fit(X_train, y_train)
score = clf.score(X_test, y_test)
# Plot the decision boundary. For that, we will assign a color to each
# point in the mesh [x_min, m_max]x[y_min, y_max].
if hasattr(clf, "decision_function"):
Z = clf.decision_function(np.c_[xx.ravel(), yy.ravel()])
else:
Z = clf.predict_proba(np.c_[xx.ravel(), yy.ravel()])[:, 1]
# Put the result into a color plot
Z = Z.reshape(xx.shape)
ax.contourf(xx, yy, Z, cmap=cm, alpha=.8)
# Plot also the training points
ax.scatter(X_train[:, 0], X_train[:, 1], c=y_train, cmap=cm_bright)
# and testing points
ax.scatter(X_test[:, 0], X_test[:, 1], c=y_test, cmap=cm_bright,
alpha=0.6)
ax.set_xlim(xx.min(), xx.max())
ax.set_ylim(yy.min(), yy.max())
ax.set_xticks(())
ax.set_yticks(())
ax.set_title(name)
ax.text(xx.max() - .3, yy.min() + .3, ('%.2f' % score).lstrip('0'),
size=15, horizontalalignment='right')
i += 1
figure.subplots_adjust(left=.02, right=.98)
plt.show()
| bsd-3-clause |
jaduimstra/nilmtk | nilmtk/metrics.py | 5 | 13373 | '''Metrics to compare disaggregation performance against ground truth
data.
All metrics functions have the same interface. Each function takes
`predictions` and `ground_truth` parameters. Both of which are
nilmtk.MeterGroup objects. Each function returns one of two types:
either a pd.Series or a single float. Most functions return a
pd.Series where each index element is a meter instance int or a tuple
of ints for MeterGroups.
Notation
--------
Below is the notation used to mathematically define each metric.
:math:`T` - number of time slices.
:math:`t` - a time slice.
:math:`N` - number of appliances.
:math:`n` - an appliance.
:math:`y^{(n)}_t` - ground truth power of appliance :math:`n` in time slice :math:`t`.
:math:`\\hat{y}^{(n)}_t` - estimated power of appliance :math:`n` in time slice :math:`t`.
:math:`x^{(n)}_t` - ground truth state of appliance :math:`n` in time slice :math:`t`.
:math:`\\hat{x}^{(n)}_t` - estimated state of appliance :math:`n` in time slice :math:`t`.
Functions
---------
'''
from __future__ import print_function, division
import numpy as np
import pandas as pd
import math
from .metergroup import MeterGroup, iterate_through_submeters_of_two_metergroups
from .electric import align_two_meters
def error_in_assigned_energy(predictions, ground_truth):
"""Compute error in assigned energy.
.. math::
error^{(n)} =
\\left | \\sum_t y^{(n)}_t - \\sum_t \\hat{y}^{(n)}_t \\right |
Parameters
----------
predictions, ground_truth : nilmtk.MeterGroup
Returns
-------
errors : pd.Series
Each index is an meter instance int (or tuple for MeterGroups).
Each value is the absolute error in assigned energy for that appliance,
in kWh.
"""
errors = {}
both_sets_of_meters = iterate_through_submeters_of_two_metergroups(
predictions, ground_truth)
for pred_meter, ground_truth_meter in both_sets_of_meters:
sections = pred_meter.good_sections()
ground_truth_energy = ground_truth_meter.total_energy(sections=sections)
predicted_energy = pred_meter.total_energy(sections=sections)
errors[pred_meter.instance()] = np.abs(ground_truth_energy - predicted_energy)
return pd.Series(errors)
def fraction_energy_assigned_correctly(predictions, ground_truth):
'''Compute fraction of energy assigned correctly
.. math::
fraction =
\\sum_n min \\left (
\\frac{\\sum_n y}{\\sum_{n,t} y},
\\frac{\\sum_n \\hat{y}}{\\sum_{n,t} \\hat{y}}
\\right )
Ignores distinction between different AC types, instead if there are
multiple AC types for each meter then we just take the max value across
the AC types.
Parameters
----------
predictions, ground_truth : nilmtk.MeterGroup
Returns
-------
fraction : float in the range [0,1]
Fraction of Energy Correctly Assigned.
'''
predictions_submeters = MeterGroup(meters=predictions.submeters().meters)
ground_truth_submeters = MeterGroup(meters=ground_truth.submeters().meters)
fraction_per_meter_predictions = predictions_submeters.fraction_per_meter()
fraction_per_meter_ground_truth = ground_truth_submeters.fraction_per_meter()
fraction_per_meter_ground_truth.index = fraction_per_meter_ground_truth.index.map(lambda meter: meter.instance)
fraction_per_meter_predictions.index = fraction_per_meter_predictions.index.map(lambda meter: meter.instance)
fraction = 0
for meter_instance in predictions_submeters.instance():
fraction += min(fraction_per_meter_ground_truth[meter_instance],
fraction_per_meter_predictions[meter_instance])
return fraction
def mean_normalized_error_power(predictions, ground_truth):
'''Compute mean normalized error in assigned power
.. math::
error^{(n)} =
\\frac
{ \\sum_t {\\left | y_t^{(n)} - \\hat{y}_t^{(n)} \\right |} }
{ \\sum_t y_t^{(n)} }
Parameters
----------
predictions, ground_truth : nilmtk.MeterGroup
Returns
-------
mne : pd.Series
Each index is an meter instance int (or tuple for MeterGroups).
Each value is the MNE for that appliance.
'''
mne = {}
both_sets_of_meters = iterate_through_submeters_of_two_metergroups(
predictions, ground_truth)
for pred_meter, ground_truth_meter in both_sets_of_meters:
total_abs_diff = 0.0
sum_of_ground_truth_power = 0.0
for aligned_meters_chunk in align_two_meters(pred_meter,
ground_truth_meter):
diff = aligned_meters_chunk.icol(0) - aligned_meters_chunk.icol(1)
total_abs_diff += sum(abs(diff.dropna()))
sum_of_ground_truth_power += aligned_meters_chunk.icol(1).sum()
mne[pred_meter.instance()] = total_abs_diff / sum_of_ground_truth_power
return pd.Series(mne)
def rms_error_power(predictions, ground_truth):
'''Compute RMS error in assigned power
.. math::
error^{(n)} = \\sqrt{ \\frac{1}{T} \\sum_t{ \\left ( y_t - \\hat{y}_t \\right )^2 } }
Parameters
----------
predictions, ground_truth : nilmtk.MeterGroup
Returns
-------
error : pd.Series
Each index is an meter instance int (or tuple for MeterGroups).
Each value is the RMS error in predicted power for that appliance.
'''
error = {}
both_sets_of_meters = iterate_through_submeters_of_two_metergroups(
predictions, ground_truth)
for pred_meter, ground_truth_meter in both_sets_of_meters:
sum_of_squared_diff = 0.0
n_samples = 0
for aligned_meters_chunk in align_two_meters(pred_meter,
ground_truth_meter):
diff = aligned_meters_chunk.icol(0) - aligned_meters_chunk.icol(1)
diff.dropna(inplace=True)
sum_of_squared_diff += (diff ** 2).sum()
n_samples += len(diff)
error[pred_meter.instance()] = math.sqrt(sum_of_squared_diff / n_samples)
return pd.Series(error)
def f1_score(predictions, ground_truth):
'''Compute F1 scores.
.. math::
F_{score}^{(n)} = \\frac
{2 * Precision * Recall}
{Precision + Recall}
Parameters
----------
predictions, ground_truth : nilmtk.MeterGroup
Returns
-------
f1_scores : pd.Series
Each index is an meter instance int (or tuple for MeterGroups).
Each value is the F1 score for that appliance. If there are multiple
chunks then the value is the weighted mean of the F1 score for
each chunk.
'''
# If we import sklearn at top of file then sphinx breaks.
from sklearn.metrics import f1_score as sklearn_f1_score
# sklearn produces lots of DepreciationWarnings with PyTables
import warnings
warnings.filterwarnings("ignore", category=DeprecationWarning)
f1_scores = {}
both_sets_of_meters = iterate_through_submeters_of_two_metergroups(
predictions, ground_truth)
for pred_meter, ground_truth_meter in both_sets_of_meters:
scores_for_meter = pd.DataFrame(columns=['score', 'n_samples'])
for aligned_states_chunk in align_two_meters(pred_meter,
ground_truth_meter,
'when_on'):
aligned_states_chunk.dropna(inplace=True)
aligned_states_chunk = aligned_states_chunk.astype(int)
score = sklearn_f1_score(aligned_states_chunk.icol(0),
aligned_states_chunk.icol(1))
scores_for_meter = scores_for_meter.append(
{'score': score, 'n_samples': len(aligned_states_chunk)},
ignore_index=True)
# Calculate weighted mean
tot_samples = scores_for_meter['n_samples'].sum()
scores_for_meter['proportion'] = (scores_for_meter['n_samples'] /
tot_samples)
avg_score = (scores_for_meter['score'] *
scores_for_meter['proportion']).sum()
f1_scores[pred_meter.instance()] = avg_score
return pd.Series(f1_scores)
##### FUNCTIONS BELOW THIS LINE HAVE NOT YET BEEN CONVERTED TO NILMTK v0.2 #####
"""
def confusion_matrices(predicted_states, ground_truth_states):
'''Compute confusion matrix between appliance states for each appliance
Parameters
----------
predicted_state: Pandas DataFrame of type {appliance :
[array of predicted states]}
ground_truth_state: Pandas DataFrame of type {appliance :
[array of ground truth states]}
Returns
-------
dict of type {appliance : confusion matrix}
'''
re = {}
for appliance in predicted_states:
matrix = np.zeros([np.max(ground_truth_states[appliance]) + 1,
np.max(ground_truth_states[appliance]) + 1])
for time in predicted_states[appliance]:
matrix[predicted_states.values[time, appliance],
ground_truth_states.values[time, appliance]] += 1
re[appliance] = matrix
return re
def tp_fp_fn_tn(predicted_states, ground_truth_states):
'''Compute counts of True Positives, False Positives, False Negatives, True Negatives
.. math::
TP^{(n)} =
\\sum_{t}
and \\left ( x^{(n)}_t = on, \\hat{x}^{(n)}_t = on \\right )
FP^{(n)} =
\\sum_{t}
and \\left ( x^{(n)}_t = off, \\hat{x}^{(n)}_t = on \\right )
FN^{(n)} =
\\sum_{t}
and \\left ( x^{(n)}_t = on, \\hat{x}^{(n)}_t = off \\right )
TN^{(n)} =
\\sum_{t}
and \\left ( x^{(n)}_t = off, \\hat{x}^{(n)}_t = off \\right )
Parameters
----------
predicted_state: Pandas DataFrame of type {appliance :
[array of predicted states]}
ground_truth_state: Pandas DataFrame of type {appliance :
[array of ground truth states]}
Returns
-------
numpy array where columns represent appliances and rows represent: [TP, FP, FN, TN]
'''
# assumes state 0 = off, all other states = on
predicted_states_on = predicted_states > 0
ground_truth_states_on = ground_truth_states > 0
tp = np.sum(np.logical_and(predicted_states_on.values == True,
ground_truth_states_on.values == True), axis=0)
fp = np.sum(np.logical_and(predicted_states_on.values == True,
ground_truth_states_on.values == False), axis=0)
fn = np.sum(np.logical_and(predicted_states_on.values == False,
ground_truth_states_on.values == True), axis=0)
tn = np.sum(np.logical_and(predicted_states_on.values == False,
ground_truth_states_on.values == False), axis=0)
return np.array([tp, fp, fn, tn]).astype(float)
def tpr_fpr(predicted_states, ground_truth_states):
'''Compute True Positive Rate and False Negative Rate
.. math::
TPR^{(n)} = \\frac{TP}{\\left ( TP + FN \\right )}
FPR^{(n)} = \\frac{FP}{\\left ( FP + TN \\right )}
Parameters
----------
predicted_state: Pandas DataFrame of type {appliance :
[array of predicted states]}
ground_truth_state: Pandas DataFrame of type {appliance :
[array of ground truth states]}
Returns
-------
numpy array where columns represent appliances and rows represent: [TPR, FPR]
'''
tfpn = tp_fp_fn_tn(predicted_states, ground_truth_states)
tpr = tfpn[0, :] / (tfpn[0, :] + tfpn[2, :])
fpr = tfpn[1, :] / (tfpn[1, :] + tfpn[3, :])
return np.array([tpr, fpr])
def precision_recall(predicted_states, ground_truth_states):
'''Compute Precision and Recall
.. math::
Precision^{(n)} = \\frac{TP}{\\left ( TP + FP \\right )}
Recall^{(n)} = \\frac{TP}{\\left ( TP + FN \\right )}
Parameters
----------
predicted_state: Pandas DataFrame of type {appliance :
[array of predicted states]}
ground_truth_state: Pandas DataFrame of type {appliance :
[array of ground truth states]}
Returns
-------
numpy array where columns represent appliances and rows represent: [Precision, Recall]
'''
tfpn = tp_fp_fn_tn(predicted_states, ground_truth_states)
prec = tfpn[0, :] / (tfpn[0, :] + tfpn[1, :])
rec = tfpn[0, :] / (tfpn[0, :] + tfpn[2, :])
return np.array([prec, rec])
def hamming_loss(predicted_state, ground_truth_state):
'''Compute Hamming loss
.. math::
HammingLoss =
\\frac{1}{T} \\sum_{t}
\\frac{1}{N} \\sum_{n}
xor \\left ( x^{(n)}_t, \\hat{x}^{(n)}_t \\right )
Parameters
----------
predicted_state: Pandas DataFrame of type {appliance :
[array of predicted states]}
ground_truth_state: Pandas DataFrame of type {appliance :
[array of ground truth states]}
Returns
-------
float of hamming_loss
'''
num_appliances = np.size(ground_truth_state.values, axis=1)
xors = np.sum((predicted_state.values != ground_truth_state.values),
axis=1) / num_appliances
return np.mean(xors)
"""
| apache-2.0 |
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