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import torch | |
from functools import reduce | |
import torch.nn as nn | |
import torch.nn.functional as F | |
from functools import partial | |
class FeedForward(nn.Module): | |
def __init__(self, frame_hidden, mlp_ratio, n_vecs, t2t_params, p): | |
""" | |
Args: | |
frame_hidden: hidden size of frame features | |
mlp_ratio: mlp ratio in the middle layer of the transformers | |
n_vecs: number of vectors in the transformer | |
t2t_params: dictionary -> {'kernel_size': kernel_size, 'stride': stride, 'padding': padding, 'output_size': output_shape} | |
p: dropout rate, 0 by default | |
""" | |
super(FeedForward, self).__init__() | |
self.conv = nn.Sequential( | |
nn.Linear(frame_hidden, frame_hidden * mlp_ratio), | |
nn.ReLU(inplace=True), | |
nn.Dropout(p), | |
nn.Linear(frame_hidden * mlp_ratio, frame_hidden), | |
nn.Dropout(p) | |
) | |
def forward(self, x, n_vecs=0, output_h=0, output_w=0): | |
x = self.conv(x) | |
return x | |
class FusionFeedForward(nn.Module): | |
def __init__(self, frame_hidden, mlp_ratio, n_vecs, t2t_params, p): | |
super(FusionFeedForward, self).__init__() | |
self.kernel_shape = reduce((lambda x, y: x * y), t2t_params['kernel_size']) | |
self.t2t_params = t2t_params | |
hidden_size = self.kernel_shape * mlp_ratio | |
self.conv1 = nn.Linear(frame_hidden, hidden_size) | |
self.conv2 = nn.Sequential( | |
nn.ReLU(inplace=True), | |
nn.Dropout(p), | |
nn.Linear(hidden_size, frame_hidden), | |
nn.Dropout(p) | |
) | |
assert t2t_params is not None and n_vecs is not None | |
tp = t2t_params.copy() | |
self.fold = nn.Fold(**tp) | |
del tp['output_size'] | |
self.unfold = nn.Unfold(**tp) | |
self.n_vecs = n_vecs | |
def forward(self, x, n_vecs=0, output_h=0, output_w=0): | |
x = self.conv1(x) | |
b, n, c = x.size() | |
if n_vecs != 0: | |
normalizer = x.new_ones(b, n, self.kernel_shape).view(-1, n_vecs, self.kernel_shape).permute(0, 2, 1) | |
x = self.unfold(F.fold(x.view(-1, n_vecs, c).permute(0, 2, 1), output_size=(output_h, output_w), | |
kernel_size=self.t2t_params['kernel_size'], stride=self.t2t_params['stride'], | |
padding=self.t2t_params['padding']) / F.fold(normalizer, | |
output_size=(output_h, output_w), | |
kernel_size=self.t2t_params[ | |
'kernel_size'], | |
stride=self.t2t_params['stride'], | |
padding=self.t2t_params[ | |
'padding'])).permute(0, | |
2, | |
1).contiguous().view( | |
b, n, c) | |
else: | |
normalizer = x.new_ones(b, n, self.kernel_shape).view(-1, self.n_vecs, self.kernel_shape).permute(0, 2, 1) | |
x = self.unfold(self.fold(x.view(-1, self.n_vecs, c).permute(0, 2, 1)) / self.fold(normalizer)).permute(0, | |
2, | |
1).contiguous().view( | |
b, n, c) | |
x = self.conv2(x) | |
return x | |
class ResidualBlock_noBN(nn.Module): | |
"""Residual block w/o BN | |
---Conv-ReLU-Conv-+- | |
|________________| | |
""" | |
def __init__(self, nf=64): | |
super(ResidualBlock_noBN, self).__init__() | |
self.conv1 = nn.Conv2d(nf, nf, kernel_size=3, stride=1, padding=1, bias=True) | |
self.conv2 = nn.Conv2d(nf, nf, kernel_size=3, stride=1, padding=1, bias=True) | |
self.lrelu = nn.LeakyReLU(negative_slope=0.2, inplace=True) | |
def forward(self, x): | |
""" | |
Args: | |
x: with shape of [b, c, t, h, w] | |
Returns: processed features with shape [b, c, t, h, w] | |
""" | |
identity = x | |
out = self.lrelu(self.conv1(x)) | |
out = self.conv2(out) | |
out = identity + out | |
# Remove ReLU at the end of the residual block | |
# http://torch.ch/blog/2016/02/04/resnets.html | |
return out | |
def make_layer(block, n_layers): | |
layers = [] | |
for _ in range(n_layers): | |
layers.append(block()) | |
return nn.Sequential(*layers) | |