323 lines
11 KiB
Python
323 lines
11 KiB
Python
import torch
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import torch.nn as nn
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import torch.nn.init as init
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import torch.nn.functional as F
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import torch.nn.utils.spectral_norm as SpectralNorm
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from math import sqrt
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def pixel_norm(x, epsilon=1e-8):
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return x * torch.rsqrt(torch.mean(torch.pow(x, 2), dim=1, keepdims=True) + epsilon)
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def initialize_weights(net_l, scale=1):
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if not isinstance(net_l, list):
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net_l = [net_l]
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for net in net_l:
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for m in net.modules():
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if isinstance(m, nn.Conv2d) or isinstance(m, nn.Conv3d):
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init.kaiming_normal_(m.weight, a=0, mode='fan_in')
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m.weight.data *= scale # for residual block
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if m.bias is not None:
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m.bias.data.zero_()
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elif isinstance(m, nn.Linear):
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init.kaiming_normal_(m.weight, a=0, mode='fan_in')
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m.weight.data *= scale
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if m.bias is not None:
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m.bias.data.zero_()
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elif isinstance(m, nn.BatchNorm2d):
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init.constant_(m.weight, 1)
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init.constant_(m.bias.data, 0.0)
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def make_layer(block, n_layers, return_layers=False):
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layers = []
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for _ in range(n_layers):
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layers.append(block())
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if return_layers:
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return nn.Sequential(*layers), layers
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else:
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return nn.Sequential(*layers)
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class ResidualBlock(nn.Module):
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'''Residual block with BN
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---Conv-BN-ReLU-Conv-+-
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'''
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def __init__(self, nf=64):
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super(ResidualBlock, self).__init__()
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self.lrelu = nn.LeakyReLU(negative_slope=0.1, inplace=True)
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self.conv1 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True)
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self.BN1 = nn.BatchNorm2d(nf)
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self.conv2 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True)
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self.BN2 = nn.BatchNorm2d(nf)
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# initialization
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initialize_weights([self.conv1, self.conv2], 0.1)
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def forward(self, x):
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identity = x
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out = self.lrelu(self.BN1(self.conv1(x)))
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out = self.BN2(self.conv2(out))
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return identity + out
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class ResidualBlockSpectralNorm(nn.Module):
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'''Residual block with Spectral Normalization.
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---SpecConv-ReLU-SpecConv-+-
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'''
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def __init__(self, nf, total_residual_blocks):
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super(ResidualBlockSpectralNorm, self).__init__()
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self.lrelu = nn.LeakyReLU(negative_slope=0.1, inplace=True)
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self.conv1 = SpectralNorm(nn.Conv2d(nf, nf, 3, 1, 1, bias=True))
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self.conv2 = SpectralNorm(nn.Conv2d(nf, nf, 3, 1, 1, bias=True))
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initialize_weights([self.conv1, self.conv2], 1)
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def forward(self, x):
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identity = x
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out = self.lrelu(self.conv1(x))
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out = self.conv2(out)
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return identity + out
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class ResidualBlock_noBN(nn.Module):
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'''Residual block w/o BN
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---Conv-ReLU-Conv-+-
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'''
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def __init__(self, nf=64):
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super(ResidualBlock_noBN, self).__init__()
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self.lrelu = nn.LeakyReLU(negative_slope=0.1, inplace=True)
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self.conv1 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True)
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self.conv2 = nn.Conv2d(nf, nf, 3, 1, 1, bias=True)
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# initialization
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initialize_weights([self.conv1, self.conv2], 0.1)
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def forward(self, x):
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identity = x
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out = self.lrelu(self.conv1(x))
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out = self.conv2(out)
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return identity + out
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def flow_warp(x, flow, interp_mode='bilinear', padding_mode='zeros'):
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"""Warp an image or feature map with optical flow
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Args:
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x (Tensor): size (N, C, H, W)
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flow (Tensor): size (N, H, W, 2), normal value
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interp_mode (str): 'nearest' or 'bilinear'
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padding_mode (str): 'zeros' or 'border' or 'reflection'
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Returns:
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Tensor: warped image or feature map
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"""
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assert x.size()[-2:] == flow.size()[1:3]
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B, C, H, W = x.size()
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# mesh grid
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grid_y, grid_x = torch.meshgrid(torch.arange(0, H), torch.arange(0, W))
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grid = torch.stack((grid_x, grid_y), 2).float() # W(x), H(y), 2
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grid.requires_grad = False
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grid = grid.type_as(x)
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vgrid = grid + flow
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# scale grid to [-1,1]
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vgrid_x = 2.0 * vgrid[:, :, :, 0] / max(W - 1, 1) - 1.0
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vgrid_y = 2.0 * vgrid[:, :, :, 1] / max(H - 1, 1) - 1.0
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vgrid_scaled = torch.stack((vgrid_x, vgrid_y), dim=3)
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output = F.grid_sample(x, vgrid_scaled, mode=interp_mode, padding_mode=padding_mode)
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return output
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class PixelUnshuffle(nn.Module):
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def __init__(self, reduction_factor):
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super(PixelUnshuffle, self).__init__()
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self.r = reduction_factor
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def forward(self, x):
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(b, f, w, h) = x.shape
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x = x.contiguous().view(b, f, w // self.r, self.r, h // self.r, self.r)
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x = x.permute(0, 1, 3, 5, 2, 4).contiguous().view(b, f * (self.r ** 2), w // self.r, h // self.r)
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return x
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# simply define a silu function
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def silu(input):
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'''
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Applies the Sigmoid Linear Unit (SiLU) function element-wise:
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SiLU(x) = x * sigmoid(x)
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'''
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return input * torch.sigmoid(input)
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# create a class wrapper from PyTorch nn.Module, so
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# the function now can be easily used in models
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class SiLU(nn.Module):
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'''
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Applies the Sigmoid Linear Unit (SiLU) function element-wise:
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SiLU(x) = x * sigmoid(x)
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Shape:
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- Input: (N, *) where * means, any number of additional
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dimensions
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- Output: (N, *), same shape as the input
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References:
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- Related paper:
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https://arxiv.org/pdf/1606.08415.pdf
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Examples:
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>>> m = silu()
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>>> input = torch.randn(2)
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>>> output = m(input)
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'''
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def __init__(self):
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'''
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Init method.
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'''
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super().__init__() # init the base class
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def forward(self, input):
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'''
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Forward pass of the function.
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'''
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return silu(input)
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''' Convenience class with Conv->BN->ReLU. Includes weight initialization and auto-padding for standard
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kernel sizes. '''
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class ConvBnRelu(nn.Module):
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def __init__(self, filters_in, filters_out, kernel_size=3, stride=1, relu=True, bn=True, bias=True):
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super(ConvBnRelu, self).__init__()
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padding_map = {1: 0, 3: 1, 5: 2, 7: 3}
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assert kernel_size in padding_map.keys()
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self.conv = nn.Conv2d(filters_in, filters_out, kernel_size, stride, padding_map[kernel_size], bias=bias)
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if bn:
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self.bn = nn.BatchNorm2d(filters_out)
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else:
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self.bn = None
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if relu:
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self.relu = nn.ReLU()
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else:
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self.relu = None
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# Init params.
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for m in self.modules():
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if isinstance(m, nn.Conv2d):
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nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu' if self.relu else 'linear')
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elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
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nn.init.constant_(m.weight, 1)
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nn.init.constant_(m.bias, 0)
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def forward(self, x):
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x = self.conv(x)
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if self.bn:
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x = self.bn(x)
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if self.relu:
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return self.relu(x)
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else:
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return x
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''' Convenience class with Conv->BN->SiLU. Includes weight initialization and auto-padding for standard
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kernel sizes. '''
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class ConvBnSilu(nn.Module):
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def __init__(self, filters_in, filters_out, kernel_size=3, stride=1, silu=True, bn=True, bias=True):
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super(ConvBnSilu, self).__init__()
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padding_map = {1: 0, 3: 1, 5: 2, 7: 3}
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assert kernel_size in padding_map.keys()
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self.conv = nn.Conv2d(filters_in, filters_out, kernel_size, stride, padding_map[kernel_size], bias=bias)
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if bn:
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self.bn = nn.BatchNorm2d(filters_out)
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else:
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self.bn = None
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if silu:
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self.silu = SiLU()
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else:
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self.silu = None
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# Init params.
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for m in self.modules():
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if isinstance(m, nn.Conv2d):
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nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu' if self.silu else 'linear')
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elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
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nn.init.constant_(m.weight, 1)
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nn.init.constant_(m.bias, 0)
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def forward(self, x):
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x = self.conv(x)
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if self.bn:
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x = self.bn(x)
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if self.silu:
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return self.silu(x)
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else:
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return x
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''' Convenience class with Conv->BN->LeakyReLU. Includes weight initialization and auto-padding for standard
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kernel sizes. '''
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class ConvBnLelu(nn.Module):
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def __init__(self, filters_in, filters_out, kernel_size=3, stride=1, lelu=True, bn=True, bias=True):
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super(ConvBnLelu, self).__init__()
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padding_map = {1: 0, 3: 1, 5: 2, 7: 3}
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assert kernel_size in padding_map.keys()
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self.conv = nn.Conv2d(filters_in, filters_out, kernel_size, stride, padding_map[kernel_size], bias=bias)
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if bn:
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self.bn = nn.BatchNorm2d(filters_out)
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else:
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self.bn = None
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if lelu:
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self.lelu = nn.LeakyReLU(negative_slope=.1)
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else:
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self.lelu = None
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# Init params.
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for m in self.modules():
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if isinstance(m, nn.Conv2d):
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nn.init.kaiming_normal_(m.weight, a=.1, mode='fan_out',
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nonlinearity='leaky_relu' if self.lelu else 'linear')
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elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
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nn.init.constant_(m.weight, 1)
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nn.init.constant_(m.bias, 0)
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def forward(self, x):
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x = self.conv(x)
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if self.bn:
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x = self.bn(x)
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if self.lelu:
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return self.lelu(x)
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else:
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return x
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''' Convenience class with Conv->GroupNorm->LeakyReLU. Includes weight initialization and auto-padding for standard
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kernel sizes. '''
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class ConvGnLelu(nn.Module):
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def __init__(self, filters_in, filters_out, kernel_size=3, stride=1, lelu=True, gn=True, bias=True, num_groups=8):
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super(ConvGnLelu, self).__init__()
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padding_map = {1: 0, 3: 1, 5: 2, 7: 3}
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assert kernel_size in padding_map.keys()
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self.conv = nn.Conv2d(filters_in, filters_out, kernel_size, stride, padding_map[kernel_size], bias=bias)
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if gn:
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self.gn = nn.GroupNorm(num_groups, filters_out)
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else:
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self.gn = None
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if lelu:
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self.lelu = nn.LeakyReLU(negative_slope=.1)
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else:
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self.lelu = None
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# Init params.
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for m in self.modules():
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if isinstance(m, nn.Conv2d):
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nn.init.kaiming_normal_(m.weight, a=.1, mode='fan_out',
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nonlinearity='leaky_relu' if self.lelu else 'linear')
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elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
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nn.init.constant_(m.weight, 1)
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nn.init.constant_(m.bias, 0)
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def forward(self, x):
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x = self.conv(x)
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if self.gn:
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x = self.gn(x)
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if self.lelu:
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return self.lelu(x)
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else:
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return x |