PuLID-FLUX / eva_clip /eva_vit_model.py
邬彦泽
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# --------------------------------------------------------
# Adapted from https://github.com/microsoft/unilm/tree/master/beit
# --------------------------------------------------------
import math
import os
from functools import partial
from itertools import repeat
import collections.abc
import torch
import torch.nn as nn
import warnings
import torch.nn.functional as F
from .transformer import PatchDropout
from .rope import VisionRotaryEmbedding, VisionRotaryEmbeddingFast
if os.getenv('ENV_TYPE') == 'deepspeed':
try:
from deepspeed.runtime.activation_checkpointing.checkpointing import checkpoint
except:
from torch.utils.checkpoint import checkpoint
else:
from torch.utils.checkpoint import checkpoint
try:
import xformers
import xformers.ops as xops
XFORMERS_IS_AVAILBLE = True
except:
XFORMERS_IS_AVAILBLE = False
def _ntuple(n):
def parse(x):
if isinstance(x, collections.abc.Iterable):
return x
return tuple(repeat(x, n))
return parse
to_2tuple = _ntuple(2)
def _no_grad_trunc_normal_(tensor, mean, std, a, b):
# Cut & paste from PyTorch official master until it's in a few official releases - RW
# Method based on https://people.sc.fsu.edu/~jburkardt/presentations/truncated_normal.pdf
def norm_cdf(x):
# Computes standard normal cumulative distribution function
return (1. + math.erf(x / math.sqrt(2.))) / 2.
if (mean < a - 2 * std) or (mean > b + 2 * std):
warnings.warn("mean is more than 2 std from [a, b] in nn.init.trunc_normal_. "
"The distribution of values may be incorrect.",
stacklevel=2)
with torch.no_grad():
# Values are generated by using a truncated uniform distribution and
# then using the inverse CDF for the normal distribution.
# Get upper and lower cdf values
l = norm_cdf((a - mean) / std)
u = norm_cdf((b - mean) / std)
# Uniformly fill tensor with values from [l, u], then translate to
# [2l-1, 2u-1].
tensor.uniform_(2 * l - 1, 2 * u - 1)
# Use inverse cdf transform for normal distribution to get truncated
# standard normal
tensor.erfinv_()
# Transform to proper mean, std
tensor.mul_(std * math.sqrt(2.))
tensor.add_(mean)
# Clamp to ensure it's in the proper range
tensor.clamp_(min=a, max=b)
return tensor
def trunc_normal_(tensor, mean=0., std=1., a=-2., b=2.):
# type: (Tensor, float, float, float, float) -> Tensor
r"""Fills the input Tensor with values drawn from a truncated
normal distribution. The values are effectively drawn from the
normal distribution :math:`\mathcal{N}(\text{mean}, \text{std}^2)`
with values outside :math:`[a, b]` redrawn until they are within
the bounds. The method used for generating the random values works
best when :math:`a \leq \text{mean} \leq b`.
Args:
tensor: an n-dimensional `torch.Tensor`
mean: the mean of the normal distribution
std: the standard deviation of the normal distribution
a: the minimum cutoff value
b: the maximum cutoff value
Examples:
>>> w = torch.empty(3, 5)
>>> nn.init.trunc_normal_(w)
"""
return _no_grad_trunc_normal_(tensor, mean, std, a, b)
def drop_path(x, drop_prob: float = 0., training: bool = False, scale_by_keep: bool = True):
"""Drop paths (Stochastic Depth) per sample (when applied in main path of residual blocks).
This is the same as the DropConnect impl I created for EfficientNet, etc networks, however,
the original name is misleading as 'Drop Connect' is a different form of dropout in a separate paper...
See discussion: https://github.com/tensorflow/tpu/issues/494#issuecomment-532968956 ... I've opted for
changing the layer and argument names to 'drop path' rather than mix DropConnect as a layer name and use
'survival rate' as the argument.
"""
if drop_prob == 0. or not training:
return x
keep_prob = 1 - drop_prob
shape = (x.shape[0],) + (1,) * (x.ndim - 1) # work with diff dim tensors, not just 2D ConvNets
random_tensor = x.new_empty(shape).bernoulli_(keep_prob)
if keep_prob > 0.0 and scale_by_keep:
random_tensor.div_(keep_prob)
return x * random_tensor
class DropPath(nn.Module):
"""Drop paths (Stochastic Depth) per sample (when applied in main path of residual blocks).
"""
def __init__(self, drop_prob=None):
super(DropPath, self).__init__()
self.drop_prob = drop_prob
def forward(self, x):
return drop_path(x, self.drop_prob, self.training)
def extra_repr(self) -> str:
return 'p={}'.format(self.drop_prob)
class Mlp(nn.Module):
def __init__(
self,
in_features,
hidden_features=None,
out_features=None,
act_layer=nn.GELU,
norm_layer=nn.LayerNorm,
drop=0.,
subln=False,
):
super().__init__()
out_features = out_features or in_features
hidden_features = hidden_features or in_features
self.fc1 = nn.Linear(in_features, hidden_features)
self.act = act_layer()
self.ffn_ln = norm_layer(hidden_features) if subln else nn.Identity()
self.fc2 = nn.Linear(hidden_features, out_features)
self.drop = nn.Dropout(drop)
def forward(self, x):
x = self.fc1(x)
x = self.act(x)
# x = self.drop(x)
# commit this for the orignal BERT implement
x = self.ffn_ln(x)
x = self.fc2(x)
x = self.drop(x)
return x
class SwiGLU(nn.Module):
def __init__(self, in_features, hidden_features=None, out_features=None, act_layer=nn.SiLU, drop=0.,
norm_layer=nn.LayerNorm, subln=False):
super().__init__()
out_features = out_features or in_features
hidden_features = hidden_features or in_features
self.w1 = nn.Linear(in_features, hidden_features)
self.w2 = nn.Linear(in_features, hidden_features)
self.act = act_layer()
self.ffn_ln = norm_layer(hidden_features) if subln else nn.Identity()
self.w3 = nn.Linear(hidden_features, out_features)
self.drop = nn.Dropout(drop)
def forward(self, x):
x1 = self.w1(x)
x2 = self.w2(x)
hidden = self.act(x1) * x2
x = self.ffn_ln(hidden)
x = self.w3(x)
x = self.drop(x)
return x
class Attention(nn.Module):
def __init__(
self, dim, num_heads=8, qkv_bias=False, qk_scale=None, attn_drop=0.,
proj_drop=0., window_size=None, attn_head_dim=None, xattn=False, rope=None, subln=False, norm_layer=nn.LayerNorm):
super().__init__()
self.num_heads = num_heads
head_dim = dim // num_heads
if attn_head_dim is not None:
head_dim = attn_head_dim
all_head_dim = head_dim * self.num_heads
self.scale = qk_scale or head_dim ** -0.5
self.subln = subln
if self.subln:
self.q_proj = nn.Linear(dim, all_head_dim, bias=False)
self.k_proj = nn.Linear(dim, all_head_dim, bias=False)
self.v_proj = nn.Linear(dim, all_head_dim, bias=False)
else:
self.qkv = nn.Linear(dim, all_head_dim * 3, bias=False)
if qkv_bias:
self.q_bias = nn.Parameter(torch.zeros(all_head_dim))
self.v_bias = nn.Parameter(torch.zeros(all_head_dim))
else:
self.q_bias = None
self.v_bias = None
if window_size:
self.window_size = window_size
self.num_relative_distance = (2 * window_size[0] - 1) * (2 * window_size[1] - 1) + 3
self.relative_position_bias_table = nn.Parameter(
torch.zeros(self.num_relative_distance, num_heads)) # 2*Wh-1 * 2*Ww-1, nH
# cls to token & token 2 cls & cls to cls
# get pair-wise relative position index for each token inside the window
coords_h = torch.arange(window_size[0])
coords_w = torch.arange(window_size[1])
coords = torch.stack(torch.meshgrid([coords_h, coords_w])) # 2, Wh, Ww
coords_flatten = torch.flatten(coords, 1) # 2, Wh*Ww
relative_coords = coords_flatten[:, :, None] - coords_flatten[:, None, :] # 2, Wh*Ww, Wh*Ww
relative_coords = relative_coords.permute(1, 2, 0).contiguous() # Wh*Ww, Wh*Ww, 2
relative_coords[:, :, 0] += window_size[0] - 1 # shift to start from 0
relative_coords[:, :, 1] += window_size[1] - 1
relative_coords[:, :, 0] *= 2 * window_size[1] - 1
relative_position_index = \
torch.zeros(size=(window_size[0] * window_size[1] + 1, ) * 2, dtype=relative_coords.dtype)
relative_position_index[1:, 1:] = relative_coords.sum(-1) # Wh*Ww, Wh*Ww
relative_position_index[0, 0:] = self.num_relative_distance - 3
relative_position_index[0:, 0] = self.num_relative_distance - 2
relative_position_index[0, 0] = self.num_relative_distance - 1
self.register_buffer("relative_position_index", relative_position_index)
else:
self.window_size = None
self.relative_position_bias_table = None
self.relative_position_index = None
self.attn_drop = nn.Dropout(attn_drop)
self.inner_attn_ln = norm_layer(all_head_dim) if subln else nn.Identity()
# self.proj = nn.Linear(all_head_dim, all_head_dim)
self.proj = nn.Linear(all_head_dim, dim)
self.proj_drop = nn.Dropout(proj_drop)
self.xattn = xattn
self.xattn_drop = attn_drop
self.rope = rope
def forward(self, x, rel_pos_bias=None, attn_mask=None):
B, N, C = x.shape
if self.subln:
q = F.linear(input=x, weight=self.q_proj.weight, bias=self.q_bias)
k = F.linear(input=x, weight=self.k_proj.weight, bias=None)
v = F.linear(input=x, weight=self.v_proj.weight, bias=self.v_bias)
q = q.reshape(B, N, self.num_heads, -1).permute(0, 2, 1, 3) # B, num_heads, N, C
k = k.reshape(B, N, self.num_heads, -1).permute(0, 2, 1, 3)
v = v.reshape(B, N, self.num_heads, -1).permute(0, 2, 1, 3)
else:
qkv_bias = None
if self.q_bias is not None:
qkv_bias = torch.cat((self.q_bias, torch.zeros_like(self.v_bias, requires_grad=False), self.v_bias))
qkv = F.linear(input=x, weight=self.qkv.weight, bias=qkv_bias)
qkv = qkv.reshape(B, N, 3, self.num_heads, -1).permute(2, 0, 3, 1, 4) # 3, B, num_heads, N, C
q, k, v = qkv[0], qkv[1], qkv[2]
if self.rope:
# slightly fast impl
q_t = q[:, :, 1:, :]
ro_q_t = self.rope(q_t)
q = torch.cat((q[:, :, :1, :], ro_q_t), -2).type_as(v)
k_t = k[:, :, 1:, :]
ro_k_t = self.rope(k_t)
k = torch.cat((k[:, :, :1, :], ro_k_t), -2).type_as(v)
if self.xattn:
q = q.permute(0, 2, 1, 3) # B, num_heads, N, C -> B, N, num_heads, C
k = k.permute(0, 2, 1, 3)
v = v.permute(0, 2, 1, 3)
x = xops.memory_efficient_attention(
q, k, v,
p=self.xattn_drop,
scale=self.scale,
)
x = x.reshape(B, N, -1)
x = self.inner_attn_ln(x)
x = self.proj(x)
x = self.proj_drop(x)
else:
q = q * self.scale
attn = (q @ k.transpose(-2, -1))
if self.relative_position_bias_table is not None:
relative_position_bias = \
self.relative_position_bias_table[self.relative_position_index.view(-1)].view(
self.window_size[0] * self.window_size[1] + 1,
self.window_size[0] * self.window_size[1] + 1, -1) # Wh*Ww,Wh*Ww,nH
relative_position_bias = relative_position_bias.permute(2, 0, 1).contiguous() # nH, Wh*Ww, Wh*Ww
attn = attn + relative_position_bias.unsqueeze(0).type_as(attn)
if rel_pos_bias is not None:
attn = attn + rel_pos_bias.type_as(attn)
if attn_mask is not None:
attn_mask = attn_mask.bool()
attn = attn.masked_fill(~attn_mask[:, None, None, :], float("-inf"))
attn = attn.softmax(dim=-1)
attn = self.attn_drop(attn)
x = (attn @ v).transpose(1, 2).reshape(B, N, -1)
x = self.inner_attn_ln(x)
x = self.proj(x)
x = self.proj_drop(x)
return x
class Block(nn.Module):
def __init__(self, dim, num_heads, mlp_ratio=4., qkv_bias=False, qk_scale=None, drop=0., attn_drop=0.,
drop_path=0., init_values=None, act_layer=nn.GELU, norm_layer=nn.LayerNorm,
window_size=None, attn_head_dim=None, xattn=False, rope=None, postnorm=False,
subln=False, naiveswiglu=False):
super().__init__()
self.norm1 = norm_layer(dim)
self.attn = Attention(
dim, num_heads=num_heads, qkv_bias=qkv_bias, qk_scale=qk_scale,
attn_drop=attn_drop, proj_drop=drop, window_size=window_size, attn_head_dim=attn_head_dim,
xattn=xattn, rope=rope, subln=subln, norm_layer=norm_layer)
# NOTE: drop path for stochastic depth, we shall see if this is better than dropout here
self.drop_path = DropPath(drop_path) if drop_path > 0. else nn.Identity()
self.norm2 = norm_layer(dim)
mlp_hidden_dim = int(dim * mlp_ratio)
if naiveswiglu:
self.mlp = SwiGLU(
in_features=dim,
hidden_features=mlp_hidden_dim,
subln=subln,
norm_layer=norm_layer,
)
else:
self.mlp = Mlp(
in_features=dim,
hidden_features=mlp_hidden_dim,
act_layer=act_layer,
subln=subln,
drop=drop
)
if init_values is not None and init_values > 0:
self.gamma_1 = nn.Parameter(init_values * torch.ones((dim)),requires_grad=True)
self.gamma_2 = nn.Parameter(init_values * torch.ones((dim)),requires_grad=True)
else:
self.gamma_1, self.gamma_2 = None, None
self.postnorm = postnorm
def forward(self, x, rel_pos_bias=None, attn_mask=None):
if self.gamma_1 is None:
if self.postnorm:
x = x + self.drop_path(self.norm1(self.attn(x, rel_pos_bias=rel_pos_bias, attn_mask=attn_mask)))
x = x + self.drop_path(self.norm2(self.mlp(x)))
else:
x = x + self.drop_path(self.attn(self.norm1(x), rel_pos_bias=rel_pos_bias, attn_mask=attn_mask))
x = x + self.drop_path(self.mlp(self.norm2(x)))
else:
if self.postnorm:
x = x + self.drop_path(self.gamma_1 * self.norm1(self.attn(x, rel_pos_bias=rel_pos_bias, attn_mask=attn_mask)))
x = x + self.drop_path(self.gamma_2 * self.norm2(self.mlp(x)))
else:
x = x + self.drop_path(self.gamma_1 * self.attn(self.norm1(x), rel_pos_bias=rel_pos_bias, attn_mask=attn_mask))
x = x + self.drop_path(self.gamma_2 * self.mlp(self.norm2(x)))
return x
class PatchEmbed(nn.Module):
""" Image to Patch Embedding
"""
def __init__(self, img_size=224, patch_size=16, in_chans=3, embed_dim=768):
super().__init__()
img_size = to_2tuple(img_size)
patch_size = to_2tuple(patch_size)
num_patches = (img_size[1] // patch_size[1]) * (img_size[0] // patch_size[0])
self.patch_shape = (img_size[0] // patch_size[0], img_size[1] // patch_size[1])
self.img_size = img_size
self.patch_size = patch_size
self.num_patches = num_patches
self.proj = nn.Conv2d(in_chans, embed_dim, kernel_size=patch_size, stride=patch_size)
def forward(self, x, **kwargs):
B, C, H, W = x.shape
# FIXME look at relaxing size constraints
assert H == self.img_size[0] and W == self.img_size[1], \
f"Input image size ({H}*{W}) doesn't match model ({self.img_size[0]}*{self.img_size[1]})."
x = self.proj(x).flatten(2).transpose(1, 2)
return x
class RelativePositionBias(nn.Module):
def __init__(self, window_size, num_heads):
super().__init__()
self.window_size = window_size
self.num_relative_distance = (2 * window_size[0] - 1) * (2 * window_size[1] - 1) + 3
self.relative_position_bias_table = nn.Parameter(
torch.zeros(self.num_relative_distance, num_heads)) # 2*Wh-1 * 2*Ww-1, nH
# cls to token & token 2 cls & cls to cls
# get pair-wise relative position index for each token inside the window
coords_h = torch.arange(window_size[0])
coords_w = torch.arange(window_size[1])
coords = torch.stack(torch.meshgrid([coords_h, coords_w])) # 2, Wh, Ww
coords_flatten = torch.flatten(coords, 1) # 2, Wh*Ww
relative_coords = coords_flatten[:, :, None] - coords_flatten[:, None, :] # 2, Wh*Ww, Wh*Ww
relative_coords = relative_coords.permute(1, 2, 0).contiguous() # Wh*Ww, Wh*Ww, 2
relative_coords[:, :, 0] += window_size[0] - 1 # shift to start from 0
relative_coords[:, :, 1] += window_size[1] - 1
relative_coords[:, :, 0] *= 2 * window_size[1] - 1
relative_position_index = \
torch.zeros(size=(window_size[0] * window_size[1] + 1,) * 2, dtype=relative_coords.dtype)
relative_position_index[1:, 1:] = relative_coords.sum(-1) # Wh*Ww, Wh*Ww
relative_position_index[0, 0:] = self.num_relative_distance - 3
relative_position_index[0:, 0] = self.num_relative_distance - 2
relative_position_index[0, 0] = self.num_relative_distance - 1
self.register_buffer("relative_position_index", relative_position_index)
def forward(self):
relative_position_bias = \
self.relative_position_bias_table[self.relative_position_index.view(-1)].view(
self.window_size[0] * self.window_size[1] + 1,
self.window_size[0] * self.window_size[1] + 1, -1) # Wh*Ww,Wh*Ww,nH
return relative_position_bias.permute(2, 0, 1).contiguous() # nH, Wh*Ww, Wh*Ww
class EVAVisionTransformer(nn.Module):
""" Vision Transformer with support for patch or hybrid CNN input stage
"""
def __init__(self, img_size=224, patch_size=16, in_chans=3, num_classes=1000, embed_dim=768, depth=12,
num_heads=12, mlp_ratio=4., qkv_bias=False, qk_scale=None, drop_rate=0., attn_drop_rate=0.,
drop_path_rate=0., norm_layer=nn.LayerNorm, init_values=None, patch_dropout=0.,
use_abs_pos_emb=True, use_rel_pos_bias=False, use_shared_rel_pos_bias=False, rope=False,
use_mean_pooling=True, init_scale=0.001, grad_checkpointing=False, xattn=False, postnorm=False,
pt_hw_seq_len=16, intp_freq=False, naiveswiglu=False, subln=False):
super().__init__()
if not XFORMERS_IS_AVAILBLE:
xattn = False
self.image_size = img_size
self.num_classes = num_classes
self.num_features = self.embed_dim = embed_dim # num_features for consistency with other models
self.patch_embed = PatchEmbed(
img_size=img_size, patch_size=patch_size, in_chans=in_chans, embed_dim=embed_dim)
num_patches = self.patch_embed.num_patches
self.cls_token = nn.Parameter(torch.zeros(1, 1, embed_dim))
# self.mask_token = nn.Parameter(torch.zeros(1, 1, embed_dim))
if use_abs_pos_emb:
self.pos_embed = nn.Parameter(torch.zeros(1, num_patches + 1, embed_dim))
else:
self.pos_embed = None
self.pos_drop = nn.Dropout(p=drop_rate)
if use_shared_rel_pos_bias:
self.rel_pos_bias = RelativePositionBias(window_size=self.patch_embed.patch_shape, num_heads=num_heads)
else:
self.rel_pos_bias = None
if rope:
half_head_dim = embed_dim // num_heads // 2
hw_seq_len = img_size // patch_size
self.rope = VisionRotaryEmbeddingFast(
dim=half_head_dim,
pt_seq_len=pt_hw_seq_len,
ft_seq_len=hw_seq_len if intp_freq else None,
# patch_dropout=patch_dropout
)
else:
self.rope = None
self.naiveswiglu = naiveswiglu
dpr = [x.item() for x in torch.linspace(0, drop_path_rate, depth)] # stochastic depth decay rule
self.use_rel_pos_bias = use_rel_pos_bias
self.blocks = nn.ModuleList([
Block(
dim=embed_dim, num_heads=num_heads, mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[i], norm_layer=norm_layer,
init_values=init_values, window_size=self.patch_embed.patch_shape if use_rel_pos_bias else None,
xattn=xattn, rope=self.rope, postnorm=postnorm, subln=subln, naiveswiglu=naiveswiglu)
for i in range(depth)])
self.norm = nn.Identity() if use_mean_pooling else norm_layer(embed_dim)
self.fc_norm = norm_layer(embed_dim) if use_mean_pooling else None
self.head = nn.Linear(embed_dim, num_classes) if num_classes > 0 else nn.Identity()
if self.pos_embed is not None:
trunc_normal_(self.pos_embed, std=.02)
trunc_normal_(self.cls_token, std=.02)
# trunc_normal_(self.mask_token, std=.02)
self.apply(self._init_weights)
self.fix_init_weight()
if isinstance(self.head, nn.Linear):
trunc_normal_(self.head.weight, std=.02)
self.head.weight.data.mul_(init_scale)
self.head.bias.data.mul_(init_scale)
# setting a patch_dropout of 0. would mean it is disabled and this function would be the identity fn
self.patch_dropout = PatchDropout(patch_dropout) if patch_dropout > 0. else nn.Identity()
self.grad_checkpointing = grad_checkpointing
def fix_init_weight(self):
def rescale(param, layer_id):
param.div_(math.sqrt(2.0 * layer_id))
for layer_id, layer in enumerate(self.blocks):
rescale(layer.attn.proj.weight.data, layer_id + 1)
if self.naiveswiglu:
rescale(layer.mlp.w3.weight.data, layer_id + 1)
else:
rescale(layer.mlp.fc2.weight.data, layer_id + 1)
def get_cast_dtype(self) -> torch.dtype:
return self.blocks[0].mlp.fc2.weight.dtype
def _init_weights(self, m):
if isinstance(m, nn.Linear):
trunc_normal_(m.weight, std=.02)
if m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
def get_num_layers(self):
return len(self.blocks)
def lock(self, unlocked_groups=0, freeze_bn_stats=False):
assert unlocked_groups == 0, 'partial locking not currently supported for this model'
for param in self.parameters():
param.requires_grad = False
@torch.jit.ignore
def set_grad_checkpointing(self, enable=True):
self.grad_checkpointing = enable
@torch.jit.ignore
def no_weight_decay(self):
return {'pos_embed', 'cls_token'}
def get_classifier(self):
return self.head
def reset_classifier(self, num_classes, global_pool=''):
self.num_classes = num_classes
self.head = nn.Linear(self.embed_dim, num_classes) if num_classes > 0 else nn.Identity()
def forward_features(self, x, return_all_features=False, return_hidden=False, shuffle=False):
x = self.patch_embed(x)
batch_size, seq_len, _ = x.size()
if shuffle:
idx = torch.randperm(x.shape[1]) + 1
zero = torch.LongTensor([0, ])
idx = torch.cat([zero, idx])
pos_embed = self.pos_embed[:, idx]
cls_tokens = self.cls_token.expand(batch_size, -1, -1) # stole cls_tokens impl from Phil Wang, thanks
x = torch.cat((cls_tokens, x), dim=1)
if shuffle:
x = x + pos_embed
elif self.pos_embed is not None:
x = x + self.pos_embed
x = self.pos_drop(x)
# a patch_dropout of 0. would mean it is disabled and this function would do nothing but return what was passed in
if os.getenv('RoPE') == '1':
if self.training and not isinstance(self.patch_dropout, nn.Identity):
x, patch_indices_keep = self.patch_dropout(x)
self.rope.forward = partial(self.rope.forward, patch_indices_keep=patch_indices_keep)
else:
self.rope.forward = partial(self.rope.forward, patch_indices_keep=None)
x = self.patch_dropout(x)
else:
x = self.patch_dropout(x)
rel_pos_bias = self.rel_pos_bias() if self.rel_pos_bias is not None else None
hidden_states = []
for idx, blk in enumerate(self.blocks):
if (0 < idx <= 20) and (idx % 4 == 0) and return_hidden:
hidden_states.append(x)
if self.grad_checkpointing:
x = checkpoint(blk, x, (rel_pos_bias,))
else:
x = blk(x, rel_pos_bias=rel_pos_bias)
if not return_all_features:
x = self.norm(x)
if self.fc_norm is not None:
return self.fc_norm(x.mean(1)), hidden_states
else:
return x[:, 0], hidden_states
return x
def forward(self, x, return_all_features=False, return_hidden=False, shuffle=False):
if return_all_features:
return self.forward_features(x, return_all_features, return_hidden, shuffle)
x, hidden_states = self.forward_features(x, return_all_features, return_hidden, shuffle)
x = self.head(x)
if return_hidden:
return x, hidden_states
return x