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| """ | |
| Copyright (C) 2019 NVIDIA Corporation. All rights reserved. | |
| Licensed under the CC BY-NC-SA 4.0 license (https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode). | |
| """ | |
| import torch | |
| import torch.nn as nn | |
| from torchvision import transforms | |
| from typing import Iterable | |
| import numpy as np | |
| class InstanceNorm(nn.Module): | |
| def __init__(self, epsilon=1e-8): | |
| """ | |
| @notice: avoid in-place ops. | |
| https://discuss.pytorch.org/t/encounter-the-runtimeerror-one-of-the-variables-needed-for-gradient-computation-has-been-modified-by-an-inplace-operation/836/3 | |
| """ | |
| super(InstanceNorm, self).__init__() | |
| self.epsilon = epsilon | |
| def forward(self, x): | |
| x = x - torch.mean(x, (2, 3), True) | |
| tmp = torch.mul(x, x) # or x ** 2 | |
| tmp = torch.rsqrt(torch.mean(tmp, (2, 3), True) + self.epsilon) | |
| return x * tmp | |
| class ApplyStyle(nn.Module): | |
| """ | |
| @ref: https://github.com/lernapparat/lernapparat/blob/master/style_gan/pytorch_style_gan.ipynb | |
| """ | |
| def __init__(self, latent_size, channels): | |
| super(ApplyStyle, self).__init__() | |
| self.linear = nn.Linear(latent_size, channels * 2) | |
| def forward(self, x, latent): | |
| style = self.linear(latent) # style => [batch_size, n_channels*2] | |
| shape = [-1, 2, x.size(1), 1, 1] | |
| style = style.view(shape) # [batch_size, 2, n_channels, ...] | |
| # x = x * (style[:, 0] + 1.) + style[:, 1] | |
| x = x * (style[:, 0] * 1 + 1.0) + style[:, 1] * 1 | |
| return x | |
| class ResnetBlock_Adain(nn.Module): | |
| def __init__(self, dim, latent_size, padding_type, activation=nn.ReLU(True)): | |
| super(ResnetBlock_Adain, self).__init__() | |
| p = 0 | |
| conv1 = [] | |
| if padding_type == "reflect": | |
| conv1 += [nn.ReflectionPad2d(1)] | |
| elif padding_type == "replicate": | |
| conv1 += [nn.ReplicationPad2d(1)] | |
| elif padding_type == "zero": | |
| p = 1 | |
| else: | |
| raise NotImplementedError("padding [%s] is not implemented" % padding_type) | |
| conv1 += [nn.Conv2d(dim, dim, kernel_size=3, padding=p), InstanceNorm()] | |
| self.conv1 = nn.Sequential(*conv1) | |
| self.style1 = ApplyStyle(latent_size, dim) | |
| self.act1 = activation | |
| p = 0 | |
| conv2 = [] | |
| if padding_type == "reflect": | |
| conv2 += [nn.ReflectionPad2d(1)] | |
| elif padding_type == "replicate": | |
| conv2 += [nn.ReplicationPad2d(1)] | |
| elif padding_type == "zero": | |
| p = 1 | |
| else: | |
| raise NotImplementedError("padding [%s] is not implemented" % padding_type) | |
| conv2 += [nn.Conv2d(dim, dim, kernel_size=3, padding=p), InstanceNorm()] | |
| self.conv2 = nn.Sequential(*conv2) | |
| self.style2 = ApplyStyle(latent_size, dim) | |
| def forward(self, x, dlatents_in_slice): | |
| y = self.conv1(x) | |
| y = self.style1(y, dlatents_in_slice) | |
| y = self.act1(y) | |
| y = self.conv2(y) | |
| y = self.style2(y, dlatents_in_slice) | |
| out = x + y | |
| return out | |
| class Generator_Adain_Upsample(nn.Module): | |
| def __init__( | |
| self, | |
| input_nc: int, | |
| output_nc: int, | |
| latent_size: int, | |
| n_blocks: int = 6, | |
| deep: bool = False, | |
| use_last_act: bool = True, | |
| norm_layer: torch.nn.Module = nn.BatchNorm2d, | |
| padding_type: str = "reflect", | |
| ): | |
| assert n_blocks >= 0 | |
| super(Generator_Adain_Upsample, self).__init__() | |
| activation = nn.ReLU(True) | |
| self.deep = deep | |
| self.use_last_act = use_last_act | |
| self.to_tensor_normalize = transforms.Compose( | |
| [ | |
| transforms.ToTensor(), | |
| transforms.Normalize([0.485, 0.456, 0.406], [0.229, 0.224, 0.225]), | |
| ] | |
| ) | |
| self.to_tensor = transforms.Compose([transforms.ToTensor()]) | |
| self.imagenet_mean = torch.tensor([0.485, 0.456, 0.406]).view(1, 3, 1, 1) | |
| self.imagenet_std = torch.tensor([0.229, 0.224, 0.225]).view(1, 3, 1, 1) | |
| self.first_layer = nn.Sequential( | |
| nn.ReflectionPad2d(3), | |
| nn.Conv2d(input_nc, 64, kernel_size=7, padding=0), | |
| norm_layer(64), | |
| activation, | |
| ) | |
| # downsample | |
| self.down1 = nn.Sequential( | |
| nn.Conv2d(64, 128, kernel_size=3, stride=2, padding=1), | |
| norm_layer(128), | |
| activation, | |
| ) | |
| self.down2 = nn.Sequential( | |
| nn.Conv2d(128, 256, kernel_size=3, stride=2, padding=1), | |
| norm_layer(256), | |
| activation, | |
| ) | |
| self.down3 = nn.Sequential( | |
| nn.Conv2d(256, 512, kernel_size=3, stride=2, padding=1), | |
| norm_layer(512), | |
| activation, | |
| ) | |
| if self.deep: | |
| self.down4 = nn.Sequential( | |
| nn.Conv2d(512, 512, kernel_size=3, stride=2, padding=1), | |
| norm_layer(512), | |
| activation, | |
| ) | |
| # resnet blocks | |
| BN = [] | |
| for i in range(n_blocks): | |
| BN += [ | |
| ResnetBlock_Adain( | |
| 512, | |
| latent_size=latent_size, | |
| padding_type=padding_type, | |
| activation=activation, | |
| ) | |
| ] | |
| self.BottleNeck = nn.Sequential(*BN) | |
| if self.deep: | |
| self.up4 = nn.Sequential( | |
| nn.Upsample(scale_factor=2, mode="bilinear", align_corners=False), | |
| nn.Conv2d(512, 512, kernel_size=3, stride=1, padding=1), | |
| nn.BatchNorm2d(512), | |
| activation, | |
| ) | |
| self.up3 = nn.Sequential( | |
| nn.Upsample(scale_factor=2, mode="bilinear", align_corners=False), | |
| nn.Conv2d(512, 256, kernel_size=3, stride=1, padding=1), | |
| nn.BatchNorm2d(256), | |
| activation, | |
| ) | |
| self.up2 = nn.Sequential( | |
| nn.Upsample(scale_factor=2, mode="bilinear", align_corners=False), | |
| nn.Conv2d(256, 128, kernel_size=3, stride=1, padding=1), | |
| nn.BatchNorm2d(128), | |
| activation, | |
| ) | |
| self.up1 = nn.Sequential( | |
| nn.Upsample(scale_factor=2, mode="bilinear", align_corners=False), | |
| nn.Conv2d(128, 64, kernel_size=3, stride=1, padding=1), | |
| nn.BatchNorm2d(64), | |
| activation, | |
| ) | |
| if self.use_last_act: | |
| self.last_layer = nn.Sequential( | |
| nn.ReflectionPad2d(3), | |
| nn.Conv2d(64, output_nc, kernel_size=7, padding=0), | |
| torch.nn.Tanh(), | |
| ) | |
| else: | |
| self.last_layer = nn.Sequential( | |
| nn.ReflectionPad2d(3), | |
| nn.Conv2d(64, output_nc, kernel_size=7, padding=0), | |
| ) | |
| def to(self, device): | |
| super().to(device) | |
| self.device = device | |
| self.imagenet_mean = self.imagenet_mean.to(device) | |
| self.imagenet_std = self.imagenet_std.to(device) | |
| return self | |
| def forward(self, x: Iterable[np.ndarray], dlatents: torch.Tensor): | |
| if self.use_last_act: | |
| x = [self.to_tensor(_) for _ in x] | |
| else: | |
| x = [self.to_tensor_normalize(_) for _ in x] | |
| x = torch.stack(x, dim=0) | |
| x = x.to(self.device) | |
| skip1 = self.first_layer(x) | |
| skip2 = self.down1(skip1) | |
| skip3 = self.down2(skip2) | |
| if self.deep: | |
| skip4 = self.down3(skip3) | |
| x = self.down4(skip4) | |
| else: | |
| x = self.down3(skip3) | |
| for i in range(len(self.BottleNeck)): | |
| x = self.BottleNeck[i](x, dlatents) | |
| if self.deep: | |
| x = self.up4(x) | |
| x = self.up3(x) | |
| x = self.up2(x) | |
| x = self.up1(x) | |
| x = self.last_layer(x) | |
| if self.use_last_act: | |
| x = (x + 1) / 2 | |
| else: | |
| x = x * self.imagenet_std + self.imagenet_mean | |
| return x | |