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# coding: utf-8 | |
""" | |
This file defines various neural network modules and utility functions, including convolutional and residual blocks, | |
normalizations, and functions for spatial transformation and tensor manipulation. | |
""" | |
from torch import nn | |
import torch.nn.functional as F | |
import torch | |
import torch.nn.utils.spectral_norm as spectral_norm | |
import math | |
import warnings | |
def kp2gaussian(kp, spatial_size, kp_variance): | |
""" | |
Transform a keypoint into gaussian like representation | |
""" | |
mean = kp | |
coordinate_grid = make_coordinate_grid(spatial_size, mean) | |
number_of_leading_dimensions = len(mean.shape) - 1 | |
shape = (1,) * number_of_leading_dimensions + coordinate_grid.shape | |
coordinate_grid = coordinate_grid.view(*shape) | |
repeats = mean.shape[:number_of_leading_dimensions] + (1, 1, 1, 1) | |
coordinate_grid = coordinate_grid.repeat(*repeats) | |
# Preprocess kp shape | |
shape = mean.shape[:number_of_leading_dimensions] + (1, 1, 1, 3) | |
mean = mean.view(*shape) | |
mean_sub = (coordinate_grid - mean) | |
out = torch.exp(-0.5 * (mean_sub ** 2).sum(-1) / kp_variance) | |
return out | |
def make_coordinate_grid(spatial_size, ref, **kwargs): | |
d, h, w = spatial_size | |
x = torch.arange(w).type(ref.dtype).to(ref.device) | |
y = torch.arange(h).type(ref.dtype).to(ref.device) | |
z = torch.arange(d).type(ref.dtype).to(ref.device) | |
# NOTE: must be right-down-in | |
x = (2 * (x / (w - 1)) - 1) # the x axis faces to the right | |
y = (2 * (y / (h - 1)) - 1) # the y axis faces to the bottom | |
z = (2 * (z / (d - 1)) - 1) # the z axis faces to the inner | |
yy = y.view(1, -1, 1).repeat(d, 1, w) | |
xx = x.view(1, 1, -1).repeat(d, h, 1) | |
zz = z.view(-1, 1, 1).repeat(1, h, w) | |
meshed = torch.cat([xx.unsqueeze_(3), yy.unsqueeze_(3), zz.unsqueeze_(3)], 3) | |
return meshed | |
class ConvT2d(nn.Module): | |
""" | |
Upsampling block for use in decoder. | |
""" | |
def __init__(self, in_features, out_features, kernel_size=3, stride=2, padding=1, output_padding=1): | |
super(ConvT2d, self).__init__() | |
self.convT = nn.ConvTranspose2d(in_features, out_features, kernel_size=kernel_size, stride=stride, | |
padding=padding, output_padding=output_padding) | |
self.norm = nn.InstanceNorm2d(out_features) | |
def forward(self, x): | |
out = self.convT(x) | |
out = self.norm(out) | |
out = F.leaky_relu(out) | |
return out | |
class ResBlock3d(nn.Module): | |
""" | |
Res block, preserve spatial resolution. | |
""" | |
def __init__(self, in_features, kernel_size, padding): | |
super(ResBlock3d, self).__init__() | |
self.conv1 = nn.Conv3d(in_channels=in_features, out_channels=in_features, kernel_size=kernel_size, padding=padding) | |
self.conv2 = nn.Conv3d(in_channels=in_features, out_channels=in_features, kernel_size=kernel_size, padding=padding) | |
self.norm1 = nn.BatchNorm3d(in_features, affine=True) | |
self.norm2 = nn.BatchNorm3d(in_features, affine=True) | |
def forward(self, x): | |
out = self.norm1(x) | |
out = F.relu(out) | |
out = self.conv1(out) | |
out = self.norm2(out) | |
out = F.relu(out) | |
out = self.conv2(out) | |
out += x | |
return out | |
class UpBlock3d(nn.Module): | |
""" | |
Upsampling block for use in decoder. | |
""" | |
def __init__(self, in_features, out_features, kernel_size=3, padding=1, groups=1): | |
super(UpBlock3d, self).__init__() | |
self.conv = nn.Conv3d(in_channels=in_features, out_channels=out_features, kernel_size=kernel_size, | |
padding=padding, groups=groups) | |
self.norm = nn.BatchNorm3d(out_features, affine=True) | |
def forward(self, x): | |
out = F.interpolate(x, scale_factor=(1, 2, 2)) | |
out = self.conv(out) | |
out = self.norm(out) | |
out = F.relu(out) | |
return out | |
class DownBlock2d(nn.Module): | |
""" | |
Downsampling block for use in encoder. | |
""" | |
def __init__(self, in_features, out_features, kernel_size=3, padding=1, groups=1): | |
super(DownBlock2d, self).__init__() | |
self.conv = nn.Conv2d(in_channels=in_features, out_channels=out_features, kernel_size=kernel_size, padding=padding, groups=groups) | |
self.norm = nn.BatchNorm2d(out_features, affine=True) | |
self.pool = nn.AvgPool2d(kernel_size=(2, 2)) | |
def forward(self, x): | |
out = self.conv(x) | |
out = self.norm(out) | |
out = F.relu(out) | |
out = self.pool(out) | |
return out | |
class DownBlock3d(nn.Module): | |
""" | |
Downsampling block for use in encoder. | |
""" | |
def __init__(self, in_features, out_features, kernel_size=3, padding=1, groups=1): | |
super(DownBlock3d, self).__init__() | |
''' | |
self.conv = nn.Conv3d(in_channels=in_features, out_channels=out_features, kernel_size=kernel_size, | |
padding=padding, groups=groups, stride=(1, 2, 2)) | |
''' | |
self.conv = nn.Conv3d(in_channels=in_features, out_channels=out_features, kernel_size=kernel_size, | |
padding=padding, groups=groups) | |
self.norm = nn.BatchNorm3d(out_features, affine=True) | |
self.pool = nn.AvgPool3d(kernel_size=(1, 2, 2)) | |
def forward(self, x): | |
out = self.conv(x) | |
out = self.norm(out) | |
out = F.relu(out) | |
out = self.pool(out) | |
return out | |
class SameBlock2d(nn.Module): | |
""" | |
Simple block, preserve spatial resolution. | |
""" | |
def __init__(self, in_features, out_features, groups=1, kernel_size=3, padding=1, lrelu=False): | |
super(SameBlock2d, self).__init__() | |
self.conv = nn.Conv2d(in_channels=in_features, out_channels=out_features, kernel_size=kernel_size, padding=padding, groups=groups) | |
self.norm = nn.BatchNorm2d(out_features, affine=True) | |
if lrelu: | |
self.ac = nn.LeakyReLU() | |
else: | |
self.ac = nn.ReLU() | |
def forward(self, x): | |
out = self.conv(x) | |
out = self.norm(out) | |
out = self.ac(out) | |
return out | |
class Encoder(nn.Module): | |
""" | |
Hourglass Encoder | |
""" | |
def __init__(self, block_expansion, in_features, num_blocks=3, max_features=256): | |
super(Encoder, self).__init__() | |
down_blocks = [] | |
for i in range(num_blocks): | |
down_blocks.append(DownBlock3d(in_features if i == 0 else min(max_features, block_expansion * (2 ** i)), min(max_features, block_expansion * (2 ** (i + 1))), kernel_size=3, padding=1)) | |
self.down_blocks = nn.ModuleList(down_blocks) | |
def forward(self, x): | |
outs = [x] | |
for down_block in self.down_blocks: | |
outs.append(down_block(outs[-1])) | |
return outs | |
class Decoder(nn.Module): | |
""" | |
Hourglass Decoder | |
""" | |
def __init__(self, block_expansion, in_features, num_blocks=3, max_features=256): | |
super(Decoder, self).__init__() | |
up_blocks = [] | |
for i in range(num_blocks)[::-1]: | |
in_filters = (1 if i == num_blocks - 1 else 2) * min(max_features, block_expansion * (2 ** (i + 1))) | |
out_filters = min(max_features, block_expansion * (2 ** i)) | |
up_blocks.append(UpBlock3d(in_filters, out_filters, kernel_size=3, padding=1)) | |
self.up_blocks = nn.ModuleList(up_blocks) | |
self.out_filters = block_expansion + in_features | |
self.conv = nn.Conv3d(in_channels=self.out_filters, out_channels=self.out_filters, kernel_size=3, padding=1) | |
self.norm = nn.BatchNorm3d(self.out_filters, affine=True) | |
def forward(self, x): | |
out = x.pop() | |
for up_block in self.up_blocks: | |
out = up_block(out) | |
skip = x.pop() | |
out = torch.cat([out, skip], dim=1) | |
out = self.conv(out) | |
out = self.norm(out) | |
out = F.relu(out) | |
return out | |
class Hourglass(nn.Module): | |
""" | |
Hourglass architecture. | |
""" | |
def __init__(self, block_expansion, in_features, num_blocks=3, max_features=256): | |
super(Hourglass, self).__init__() | |
self.encoder = Encoder(block_expansion, in_features, num_blocks, max_features) | |
self.decoder = Decoder(block_expansion, in_features, num_blocks, max_features) | |
self.out_filters = self.decoder.out_filters | |
def forward(self, x): | |
return self.decoder(self.encoder(x)) | |
class SPADE(nn.Module): | |
def __init__(self, norm_nc, label_nc): | |
super().__init__() | |
self.param_free_norm = nn.InstanceNorm2d(norm_nc, affine=False) | |
nhidden = 128 | |
self.mlp_shared = nn.Sequential( | |
nn.Conv2d(label_nc, nhidden, kernel_size=3, padding=1), | |
nn.ReLU()) | |
self.mlp_gamma = nn.Conv2d(nhidden, norm_nc, kernel_size=3, padding=1) | |
self.mlp_beta = nn.Conv2d(nhidden, norm_nc, kernel_size=3, padding=1) | |
def forward(self, x, segmap): | |
normalized = self.param_free_norm(x) | |
segmap = F.interpolate(segmap, size=x.size()[2:], mode='nearest') | |
actv = self.mlp_shared(segmap) | |
gamma = self.mlp_gamma(actv) | |
beta = self.mlp_beta(actv) | |
out = normalized * (1 + gamma) + beta | |
return out | |
class SPADEResnetBlock(nn.Module): | |
def __init__(self, fin, fout, norm_G, label_nc, use_se=False, dilation=1): | |
super().__init__() | |
# Attributes | |
self.learned_shortcut = (fin != fout) | |
fmiddle = min(fin, fout) | |
self.use_se = use_se | |
# create conv layers | |
self.conv_0 = nn.Conv2d(fin, fmiddle, kernel_size=3, padding=dilation, dilation=dilation) | |
self.conv_1 = nn.Conv2d(fmiddle, fout, kernel_size=3, padding=dilation, dilation=dilation) | |
if self.learned_shortcut: | |
self.conv_s = nn.Conv2d(fin, fout, kernel_size=1, bias=False) | |
# apply spectral norm if specified | |
if 'spectral' in norm_G: | |
self.conv_0 = spectral_norm(self.conv_0) | |
self.conv_1 = spectral_norm(self.conv_1) | |
if self.learned_shortcut: | |
self.conv_s = spectral_norm(self.conv_s) | |
# define normalization layers | |
self.norm_0 = SPADE(fin, label_nc) | |
self.norm_1 = SPADE(fmiddle, label_nc) | |
if self.learned_shortcut: | |
self.norm_s = SPADE(fin, label_nc) | |
def forward(self, x, seg1): | |
x_s = self.shortcut(x, seg1) | |
dx = self.conv_0(self.actvn(self.norm_0(x, seg1))) | |
dx = self.conv_1(self.actvn(self.norm_1(dx, seg1))) | |
out = x_s + dx | |
return out | |
def shortcut(self, x, seg1): | |
if self.learned_shortcut: | |
x_s = self.conv_s(self.norm_s(x, seg1)) | |
else: | |
x_s = x | |
return x_s | |
def actvn(self, x): | |
return F.leaky_relu(x, 2e-1) | |
def filter_state_dict(state_dict, remove_name='fc'): | |
new_state_dict = {} | |
for key in state_dict: | |
if remove_name in key: | |
continue | |
new_state_dict[key] = state_dict[key] | |
return new_state_dict | |
class GRN(nn.Module): | |
""" GRN (Global Response Normalization) layer | |
""" | |
def __init__(self, dim): | |
super().__init__() | |
self.gamma = nn.Parameter(torch.zeros(1, 1, 1, dim)) | |
self.beta = nn.Parameter(torch.zeros(1, 1, 1, dim)) | |
def forward(self, x): | |
Gx = torch.norm(x, p=2, dim=(1, 2), keepdim=True) | |
Nx = Gx / (Gx.mean(dim=-1, keepdim=True) + 1e-6) | |
return self.gamma * (x * Nx) + self.beta + x | |
class LayerNorm(nn.Module): | |
r""" LayerNorm that supports two data formats: channels_last (default) or channels_first. | |
The ordering of the dimensions in the inputs. channels_last corresponds to inputs with | |
shape (batch_size, height, width, channels) while channels_first corresponds to inputs | |
with shape (batch_size, channels, height, width). | |
""" | |
def __init__(self, normalized_shape, eps=1e-6, data_format="channels_last"): | |
super().__init__() | |
self.weight = nn.Parameter(torch.ones(normalized_shape)) | |
self.bias = nn.Parameter(torch.zeros(normalized_shape)) | |
self.eps = eps | |
self.data_format = data_format | |
if self.data_format not in ["channels_last", "channels_first"]: | |
raise NotImplementedError | |
self.normalized_shape = (normalized_shape, ) | |
def forward(self, x): | |
if self.data_format == "channels_last": | |
return F.layer_norm(x, self.normalized_shape, self.weight, self.bias, self.eps) | |
elif self.data_format == "channels_first": | |
u = x.mean(1, keepdim=True) | |
s = (x - u).pow(2).mean(1, keepdim=True) | |
x = (x - u) / torch.sqrt(s + self.eps) | |
x = self.weight[:, None, None] * x + self.bias[:, None, None] | |
return x | |
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 drop_path(x, drop_prob=0., training=False, scale_by_keep=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, scale_by_keep=True): | |
super(DropPath, self).__init__() | |
self.drop_prob = drop_prob | |
self.scale_by_keep = scale_by_keep | |
def forward(self, x): | |
return drop_path(x, self.drop_prob, self.training, self.scale_by_keep) | |
def trunc_normal_(tensor, mean=0., std=1., a=-2., b=2.): | |
return _no_grad_trunc_normal_(tensor, mean, std, a, b) | |