|
from operator import gt, lt |
|
|
|
from .libmp.backend import xrange |
|
|
|
from .functions.functions import SpecialFunctions |
|
from .functions.rszeta import RSCache |
|
from .calculus.quadrature import QuadratureMethods |
|
from .calculus.inverselaplace import LaplaceTransformInversionMethods |
|
from .calculus.calculus import CalculusMethods |
|
from .calculus.optimization import OptimizationMethods |
|
from .calculus.odes import ODEMethods |
|
from .matrices.matrices import MatrixMethods |
|
from .matrices.calculus import MatrixCalculusMethods |
|
from .matrices.linalg import LinearAlgebraMethods |
|
from .matrices.eigen import Eigen |
|
from .identification import IdentificationMethods |
|
from .visualization import VisualizationMethods |
|
|
|
from . import libmp |
|
|
|
class Context(object): |
|
pass |
|
|
|
class StandardBaseContext(Context, |
|
SpecialFunctions, |
|
RSCache, |
|
QuadratureMethods, |
|
LaplaceTransformInversionMethods, |
|
CalculusMethods, |
|
MatrixMethods, |
|
MatrixCalculusMethods, |
|
LinearAlgebraMethods, |
|
Eigen, |
|
IdentificationMethods, |
|
OptimizationMethods, |
|
ODEMethods, |
|
VisualizationMethods): |
|
|
|
NoConvergence = libmp.NoConvergence |
|
ComplexResult = libmp.ComplexResult |
|
|
|
def __init__(ctx): |
|
ctx._aliases = {} |
|
|
|
SpecialFunctions.__init__(ctx) |
|
RSCache.__init__(ctx) |
|
QuadratureMethods.__init__(ctx) |
|
LaplaceTransformInversionMethods.__init__(ctx) |
|
CalculusMethods.__init__(ctx) |
|
MatrixMethods.__init__(ctx) |
|
|
|
def _init_aliases(ctx): |
|
for alias, value in ctx._aliases.items(): |
|
try: |
|
setattr(ctx, alias, getattr(ctx, value)) |
|
except AttributeError: |
|
pass |
|
|
|
_fixed_precision = False |
|
|
|
|
|
verbose = False |
|
|
|
def warn(ctx, msg): |
|
print("Warning:", msg) |
|
|
|
def bad_domain(ctx, msg): |
|
raise ValueError(msg) |
|
|
|
def _re(ctx, x): |
|
if hasattr(x, "real"): |
|
return x.real |
|
return x |
|
|
|
def _im(ctx, x): |
|
if hasattr(x, "imag"): |
|
return x.imag |
|
return ctx.zero |
|
|
|
def _as_points(ctx, x): |
|
return x |
|
|
|
def fneg(ctx, x, **kwargs): |
|
return -ctx.convert(x) |
|
|
|
def fadd(ctx, x, y, **kwargs): |
|
return ctx.convert(x)+ctx.convert(y) |
|
|
|
def fsub(ctx, x, y, **kwargs): |
|
return ctx.convert(x)-ctx.convert(y) |
|
|
|
def fmul(ctx, x, y, **kwargs): |
|
return ctx.convert(x)*ctx.convert(y) |
|
|
|
def fdiv(ctx, x, y, **kwargs): |
|
return ctx.convert(x)/ctx.convert(y) |
|
|
|
def fsum(ctx, args, absolute=False, squared=False): |
|
if absolute: |
|
if squared: |
|
return sum((abs(x)**2 for x in args), ctx.zero) |
|
return sum((abs(x) for x in args), ctx.zero) |
|
if squared: |
|
return sum((x**2 for x in args), ctx.zero) |
|
return sum(args, ctx.zero) |
|
|
|
def fdot(ctx, xs, ys=None, conjugate=False): |
|
if ys is not None: |
|
xs = zip(xs, ys) |
|
if conjugate: |
|
cf = ctx.conj |
|
return sum((x*cf(y) for (x,y) in xs), ctx.zero) |
|
else: |
|
return sum((x*y for (x,y) in xs), ctx.zero) |
|
|
|
def fprod(ctx, args): |
|
prod = ctx.one |
|
for arg in args: |
|
prod *= arg |
|
return prod |
|
|
|
def nprint(ctx, x, n=6, **kwargs): |
|
""" |
|
Equivalent to ``print(nstr(x, n))``. |
|
""" |
|
print(ctx.nstr(x, n, **kwargs)) |
|
|
|
def chop(ctx, x, tol=None): |
|
""" |
|
Chops off small real or imaginary parts, or converts |
|
numbers close to zero to exact zeros. The input can be a |
|
single number or an iterable:: |
|
|
|
>>> from mpmath import * |
|
>>> mp.dps = 15; mp.pretty = False |
|
>>> chop(5+1e-10j, tol=1e-9) |
|
mpf('5.0') |
|
>>> nprint(chop([1.0, 1e-20, 3+1e-18j, -4, 2])) |
|
[1.0, 0.0, 3.0, -4.0, 2.0] |
|
|
|
The tolerance defaults to ``100*eps``. |
|
""" |
|
if tol is None: |
|
tol = 100*ctx.eps |
|
try: |
|
x = ctx.convert(x) |
|
absx = abs(x) |
|
if abs(x) < tol: |
|
return ctx.zero |
|
if ctx._is_complex_type(x): |
|
|
|
part_tol = max(tol, absx*tol) |
|
if abs(x.imag) < part_tol: |
|
return x.real |
|
if abs(x.real) < part_tol: |
|
return ctx.mpc(0, x.imag) |
|
except TypeError: |
|
if isinstance(x, ctx.matrix): |
|
return x.apply(lambda a: ctx.chop(a, tol)) |
|
if hasattr(x, "__iter__"): |
|
return [ctx.chop(a, tol) for a in x] |
|
return x |
|
|
|
def almosteq(ctx, s, t, rel_eps=None, abs_eps=None): |
|
r""" |
|
Determine whether the difference between `s` and `t` is smaller |
|
than a given epsilon, either relatively or absolutely. |
|
|
|
Both a maximum relative difference and a maximum difference |
|
('epsilons') may be specified. The absolute difference is |
|
defined as `|s-t|` and the relative difference is defined |
|
as `|s-t|/\max(|s|, |t|)`. |
|
|
|
If only one epsilon is given, both are set to the same value. |
|
If none is given, both epsilons are set to `2^{-p+m}` where |
|
`p` is the current working precision and `m` is a small |
|
integer. The default setting typically allows :func:`~mpmath.almosteq` |
|
to be used to check for mathematical equality |
|
in the presence of small rounding errors. |
|
|
|
**Examples** |
|
|
|
>>> from mpmath import * |
|
>>> mp.dps = 15 |
|
>>> almosteq(3.141592653589793, 3.141592653589790) |
|
True |
|
>>> almosteq(3.141592653589793, 3.141592653589700) |
|
False |
|
>>> almosteq(3.141592653589793, 3.141592653589700, 1e-10) |
|
True |
|
>>> almosteq(1e-20, 2e-20) |
|
True |
|
>>> almosteq(1e-20, 2e-20, rel_eps=0, abs_eps=0) |
|
False |
|
|
|
""" |
|
t = ctx.convert(t) |
|
if abs_eps is None and rel_eps is None: |
|
rel_eps = abs_eps = ctx.ldexp(1, -ctx.prec+4) |
|
if abs_eps is None: |
|
abs_eps = rel_eps |
|
elif rel_eps is None: |
|
rel_eps = abs_eps |
|
diff = abs(s-t) |
|
if diff <= abs_eps: |
|
return True |
|
abss = abs(s) |
|
abst = abs(t) |
|
if abss < abst: |
|
err = diff/abst |
|
else: |
|
err = diff/abss |
|
return err <= rel_eps |
|
|
|
def arange(ctx, *args): |
|
r""" |
|
This is a generalized version of Python's :func:`~mpmath.range` function |
|
that accepts fractional endpoints and step sizes and |
|
returns a list of ``mpf`` instances. Like :func:`~mpmath.range`, |
|
:func:`~mpmath.arange` can be called with 1, 2 or 3 arguments: |
|
|
|
``arange(b)`` |
|
`[0, 1, 2, \ldots, x]` |
|
``arange(a, b)`` |
|
`[a, a+1, a+2, \ldots, x]` |
|
``arange(a, b, h)`` |
|
`[a, a+h, a+h, \ldots, x]` |
|
|
|
where `b-1 \le x < b` (in the third case, `b-h \le x < b`). |
|
|
|
Like Python's :func:`~mpmath.range`, the endpoint is not included. To |
|
produce ranges where the endpoint is included, :func:`~mpmath.linspace` |
|
is more convenient. |
|
|
|
**Examples** |
|
|
|
>>> from mpmath import * |
|
>>> mp.dps = 15; mp.pretty = False |
|
>>> arange(4) |
|
[mpf('0.0'), mpf('1.0'), mpf('2.0'), mpf('3.0')] |
|
>>> arange(1, 2, 0.25) |
|
[mpf('1.0'), mpf('1.25'), mpf('1.5'), mpf('1.75')] |
|
>>> arange(1, -1, -0.75) |
|
[mpf('1.0'), mpf('0.25'), mpf('-0.5')] |
|
|
|
""" |
|
if not len(args) <= 3: |
|
raise TypeError('arange expected at most 3 arguments, got %i' |
|
% len(args)) |
|
if not len(args) >= 1: |
|
raise TypeError('arange expected at least 1 argument, got %i' |
|
% len(args)) |
|
|
|
a = 0 |
|
dt = 1 |
|
|
|
if len(args) == 1: |
|
b = args[0] |
|
elif len(args) >= 2: |
|
a = args[0] |
|
b = args[1] |
|
if len(args) == 3: |
|
dt = args[2] |
|
a, b, dt = ctx.mpf(a), ctx.mpf(b), ctx.mpf(dt) |
|
assert a + dt != a, 'dt is too small and would cause an infinite loop' |
|
|
|
if a > b: |
|
if dt > 0: |
|
return [] |
|
op = gt |
|
else: |
|
if dt < 0: |
|
return [] |
|
op = lt |
|
|
|
result = [] |
|
i = 0 |
|
t = a |
|
while 1: |
|
t = a + dt*i |
|
i += 1 |
|
if op(t, b): |
|
result.append(t) |
|
else: |
|
break |
|
return result |
|
|
|
def linspace(ctx, *args, **kwargs): |
|
""" |
|
``linspace(a, b, n)`` returns a list of `n` evenly spaced |
|
samples from `a` to `b`. The syntax ``linspace(mpi(a,b), n)`` |
|
is also valid. |
|
|
|
This function is often more convenient than :func:`~mpmath.arange` |
|
for partitioning an interval into subintervals, since |
|
the endpoint is included:: |
|
|
|
>>> from mpmath import * |
|
>>> mp.dps = 15; mp.pretty = False |
|
>>> linspace(1, 4, 4) |
|
[mpf('1.0'), mpf('2.0'), mpf('3.0'), mpf('4.0')] |
|
|
|
You may also provide the keyword argument ``endpoint=False``:: |
|
|
|
>>> linspace(1, 4, 4, endpoint=False) |
|
[mpf('1.0'), mpf('1.75'), mpf('2.5'), mpf('3.25')] |
|
|
|
""" |
|
if len(args) == 3: |
|
a = ctx.mpf(args[0]) |
|
b = ctx.mpf(args[1]) |
|
n = int(args[2]) |
|
elif len(args) == 2: |
|
assert hasattr(args[0], '_mpi_') |
|
a = args[0].a |
|
b = args[0].b |
|
n = int(args[1]) |
|
else: |
|
raise TypeError('linspace expected 2 or 3 arguments, got %i' \ |
|
% len(args)) |
|
if n < 1: |
|
raise ValueError('n must be greater than 0') |
|
if not 'endpoint' in kwargs or kwargs['endpoint']: |
|
if n == 1: |
|
return [ctx.mpf(a)] |
|
step = (b - a) / ctx.mpf(n - 1) |
|
y = [i*step + a for i in xrange(n)] |
|
y[-1] = b |
|
else: |
|
step = (b - a) / ctx.mpf(n) |
|
y = [i*step + a for i in xrange(n)] |
|
return y |
|
|
|
def cos_sin(ctx, z, **kwargs): |
|
return ctx.cos(z, **kwargs), ctx.sin(z, **kwargs) |
|
|
|
def cospi_sinpi(ctx, z, **kwargs): |
|
return ctx.cospi(z, **kwargs), ctx.sinpi(z, **kwargs) |
|
|
|
def _default_hyper_maxprec(ctx, p): |
|
return int(1000 * p**0.25 + 4*p) |
|
|
|
_gcd = staticmethod(libmp.gcd) |
|
list_primes = staticmethod(libmp.list_primes) |
|
isprime = staticmethod(libmp.isprime) |
|
bernfrac = staticmethod(libmp.bernfrac) |
|
moebius = staticmethod(libmp.moebius) |
|
_ifac = staticmethod(libmp.ifac) |
|
_eulernum = staticmethod(libmp.eulernum) |
|
_stirling1 = staticmethod(libmp.stirling1) |
|
_stirling2 = staticmethod(libmp.stirling2) |
|
|
|
def sum_accurately(ctx, terms, check_step=1): |
|
prec = ctx.prec |
|
try: |
|
extraprec = 10 |
|
while 1: |
|
ctx.prec = prec + extraprec + 5 |
|
max_mag = ctx.ninf |
|
s = ctx.zero |
|
k = 0 |
|
for term in terms(): |
|
s += term |
|
if (not k % check_step) and term: |
|
term_mag = ctx.mag(term) |
|
max_mag = max(max_mag, term_mag) |
|
sum_mag = ctx.mag(s) |
|
if sum_mag - term_mag > ctx.prec: |
|
break |
|
k += 1 |
|
cancellation = max_mag - sum_mag |
|
if cancellation != cancellation: |
|
break |
|
if cancellation < extraprec or ctx._fixed_precision: |
|
break |
|
extraprec += min(ctx.prec, cancellation) |
|
return s |
|
finally: |
|
ctx.prec = prec |
|
|
|
def mul_accurately(ctx, factors, check_step=1): |
|
prec = ctx.prec |
|
try: |
|
extraprec = 10 |
|
while 1: |
|
ctx.prec = prec + extraprec + 5 |
|
max_mag = ctx.ninf |
|
one = ctx.one |
|
s = one |
|
k = 0 |
|
for factor in factors(): |
|
s *= factor |
|
term = factor - one |
|
if (not k % check_step): |
|
term_mag = ctx.mag(term) |
|
max_mag = max(max_mag, term_mag) |
|
sum_mag = ctx.mag(s-one) |
|
|
|
|
|
if -term_mag > ctx.prec: |
|
break |
|
k += 1 |
|
cancellation = max_mag - sum_mag |
|
if cancellation != cancellation: |
|
break |
|
if cancellation < extraprec or ctx._fixed_precision: |
|
break |
|
extraprec += min(ctx.prec, cancellation) |
|
return s |
|
finally: |
|
ctx.prec = prec |
|
|
|
def power(ctx, x, y): |
|
r"""Converts `x` and `y` to mpmath numbers and evaluates |
|
`x^y = \exp(y \log(x))`:: |
|
|
|
>>> from mpmath import * |
|
>>> mp.dps = 30; mp.pretty = True |
|
>>> power(2, 0.5) |
|
1.41421356237309504880168872421 |
|
|
|
This shows the leading few digits of a large Mersenne prime |
|
(performing the exact calculation ``2**43112609-1`` and |
|
displaying the result in Python would be very slow):: |
|
|
|
>>> power(2, 43112609)-1 |
|
3.16470269330255923143453723949e+12978188 |
|
""" |
|
return ctx.convert(x) ** ctx.convert(y) |
|
|
|
def _zeta_int(ctx, n): |
|
return ctx.zeta(n) |
|
|
|
def maxcalls(ctx, f, N): |
|
""" |
|
Return a wrapped copy of *f* that raises ``NoConvergence`` when *f* |
|
has been called more than *N* times:: |
|
|
|
>>> from mpmath import * |
|
>>> mp.dps = 15 |
|
>>> f = maxcalls(sin, 10) |
|
>>> print(sum(f(n) for n in range(10))) |
|
1.95520948210738 |
|
>>> f(10) # doctest: +IGNORE_EXCEPTION_DETAIL |
|
Traceback (most recent call last): |
|
... |
|
NoConvergence: maxcalls: function evaluated 10 times |
|
|
|
""" |
|
counter = [0] |
|
def f_maxcalls_wrapped(*args, **kwargs): |
|
counter[0] += 1 |
|
if counter[0] > N: |
|
raise ctx.NoConvergence("maxcalls: function evaluated %i times" % N) |
|
return f(*args, **kwargs) |
|
return f_maxcalls_wrapped |
|
|
|
def memoize(ctx, f): |
|
""" |
|
Return a wrapped copy of *f* that caches computed values, i.e. |
|
a memoized copy of *f*. Values are only reused if the cached precision |
|
is equal to or higher than the working precision:: |
|
|
|
>>> from mpmath import * |
|
>>> mp.dps = 15; mp.pretty = True |
|
>>> f = memoize(maxcalls(sin, 1)) |
|
>>> f(2) |
|
0.909297426825682 |
|
>>> f(2) |
|
0.909297426825682 |
|
>>> mp.dps = 25 |
|
>>> f(2) # doctest: +IGNORE_EXCEPTION_DETAIL |
|
Traceback (most recent call last): |
|
... |
|
NoConvergence: maxcalls: function evaluated 1 times |
|
|
|
""" |
|
f_cache = {} |
|
def f_cached(*args, **kwargs): |
|
if kwargs: |
|
key = args, tuple(kwargs.items()) |
|
else: |
|
key = args |
|
prec = ctx.prec |
|
if key in f_cache: |
|
cprec, cvalue = f_cache[key] |
|
if cprec >= prec: |
|
return +cvalue |
|
value = f(*args, **kwargs) |
|
f_cache[key] = (prec, value) |
|
return value |
|
f_cached.__name__ = f.__name__ |
|
f_cached.__doc__ = f.__doc__ |
|
return f_cached |
|
|