climategan / climategan /blocks.py
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"""File for all blocks which are parts of decoders
"""
import torch
import torch.nn as nn
import torch.nn.functional as F
import climategan.strings as strings
from climategan.norms import SPADE, AdaptiveInstanceNorm2d, LayerNorm, SpectralNorm
class InterpolateNearest2d(nn.Module):
"""
Custom implementation of nn.Upsample because pytorch/xla
does not yet support scale_factor and needs to be provided with
the output_size
"""
def __init__(self, scale_factor=2):
"""
Create an InterpolateNearest2d module
Args:
scale_factor (int, optional): Output size multiplier. Defaults to 2.
"""
super().__init__()
self.scale_factor = scale_factor
def forward(self, x):
"""
Interpolate x in "nearest" mode on its last 2 dimensions
Args:
x (torch.Tensor): input to interpolate
Returns:
torch.Tensor: upsampled tensor with shape
(...x.shape, x.shape[-2] * scale_factor, x.shape[-1] * scale_factor)
"""
return F.interpolate(
x,
size=(x.shape[-2] * self.scale_factor, x.shape[-1] * self.scale_factor),
mode="nearest",
)
# -----------------------------------------
# ----- Generic Convolutional Block -----
# -----------------------------------------
class Conv2dBlock(nn.Module):
def __init__(
self,
input_dim,
output_dim,
kernel_size,
stride=1,
padding=0,
dilation=1,
norm="none",
activation="relu",
pad_type="zero",
bias=True,
):
super().__init__()
self.use_bias = bias
# initialize padding
if pad_type == "reflect":
self.pad = nn.ReflectionPad2d(padding)
elif pad_type == "replicate":
self.pad = nn.ReplicationPad2d(padding)
elif pad_type == "zero":
self.pad = nn.ZeroPad2d(padding)
else:
assert 0, "Unsupported padding type: {}".format(pad_type)
# initialize normalization
use_spectral_norm = False
if norm.startswith("spectral_"):
norm = norm.replace("spectral_", "")
use_spectral_norm = True
norm_dim = output_dim
if norm == "batch":
self.norm = nn.BatchNorm2d(norm_dim)
elif norm == "instance":
# self.norm = nn.InstanceNorm2d(norm_dim, track_running_stats=True)
self.norm = nn.InstanceNorm2d(norm_dim)
elif norm == "layer":
self.norm = LayerNorm(norm_dim)
elif norm == "adain":
self.norm = AdaptiveInstanceNorm2d(norm_dim)
elif norm == "spectral" or norm.startswith("spectral_"):
self.norm = None # dealt with later in the code
elif norm == "none":
self.norm = None
else:
raise ValueError("Unsupported normalization: {}".format(norm))
# initialize activation
if activation == "relu":
self.activation = nn.ReLU(inplace=False)
elif activation == "lrelu":
self.activation = nn.LeakyReLU(0.2, inplace=False)
elif activation == "prelu":
self.activation = nn.PReLU()
elif activation == "selu":
self.activation = nn.SELU(inplace=False)
elif activation == "tanh":
self.activation = nn.Tanh()
elif activation == "sigmoid":
self.activation = nn.Sigmoid()
elif activation == "none":
self.activation = None
else:
raise ValueError("Unsupported activation: {}".format(activation))
# initialize convolution
if norm == "spectral" or use_spectral_norm:
self.conv = SpectralNorm(
nn.Conv2d(
input_dim,
output_dim,
kernel_size,
stride,
dilation=dilation,
bias=self.use_bias,
)
)
else:
self.conv = nn.Conv2d(
input_dim,
output_dim,
kernel_size,
stride,
dilation=dilation,
bias=self.use_bias if norm != "batch" else False,
)
def forward(self, x):
x = self.conv(self.pad(x))
if self.norm is not None:
x = self.norm(x)
if self.activation is not None:
x = self.activation(x)
return x
def __str__(self):
return strings.conv2dblock(self)
# -----------------------------
# ----- Residual Blocks -----
# -----------------------------
class ResBlocks(nn.Module):
"""
From https://github.com/NVlabs/MUNIT/blob/master/networks.py
"""
def __init__(self, num_blocks, dim, norm="in", activation="relu", pad_type="zero"):
super().__init__()
self.model = nn.Sequential(
*[
ResBlock(dim, norm=norm, activation=activation, pad_type=pad_type)
for _ in range(num_blocks)
]
)
def forward(self, x):
return self.model(x)
def __str__(self):
return strings.resblocks(self)
class ResBlock(nn.Module):
def __init__(self, dim, norm="in", activation="relu", pad_type="zero"):
super().__init__()
self.dim = dim
self.norm = norm
self.activation = activation
model = []
model += [
Conv2dBlock(
dim, dim, 3, 1, 1, norm=norm, activation=activation, pad_type=pad_type
)
]
model += [
Conv2dBlock(
dim, dim, 3, 1, 1, norm=norm, activation="none", pad_type=pad_type
)
]
self.model = nn.Sequential(*model)
def forward(self, x):
residual = x
out = self.model(x)
out += residual
return out
def __str__(self):
return strings.resblock(self)
# --------------------------
# ----- Base Decoder -----
# --------------------------
class BaseDecoder(nn.Module):
def __init__(
self,
n_upsample=4,
n_res=4,
input_dim=2048,
proj_dim=64,
output_dim=3,
norm="batch",
activ="relu",
pad_type="zero",
output_activ="tanh",
low_level_feats_dim=-1,
use_dada=False,
):
super().__init__()
self.low_level_feats_dim = low_level_feats_dim
self.use_dada = use_dada
self.model = []
if proj_dim != -1:
self.proj_conv = Conv2dBlock(
input_dim, proj_dim, 1, 1, 0, norm=norm, activation=activ
)
else:
self.proj_conv = None
proj_dim = input_dim
if low_level_feats_dim > 0:
self.low_level_conv = Conv2dBlock(
input_dim=low_level_feats_dim,
output_dim=proj_dim,
kernel_size=3,
stride=1,
padding=1,
pad_type=pad_type,
norm=norm,
activation=activ,
)
self.merge_feats_conv = Conv2dBlock(
input_dim=2 * proj_dim,
output_dim=proj_dim,
kernel_size=1,
stride=1,
padding=0,
pad_type=pad_type,
norm=norm,
activation=activ,
)
else:
self.low_level_conv = None
self.model += [ResBlocks(n_res, proj_dim, norm, activ, pad_type=pad_type)]
dim = proj_dim
# upsampling blocks
for i in range(n_upsample):
self.model += [
InterpolateNearest2d(scale_factor=2),
Conv2dBlock(
input_dim=dim,
output_dim=dim // 2,
kernel_size=3,
stride=1,
padding=1,
pad_type=pad_type,
norm=norm,
activation=activ,
),
]
dim //= 2
# use reflection padding in the last conv layer
self.model += [
Conv2dBlock(
input_dim=dim,
output_dim=output_dim,
kernel_size=3,
stride=1,
padding=1,
pad_type=pad_type,
norm="none",
activation=output_activ,
)
]
self.model = nn.Sequential(*self.model)
def forward(self, z, cond=None, z_depth=None):
low_level_feat = None
if isinstance(z, (list, tuple)):
if self.low_level_conv is None:
z = z[0]
else:
z, low_level_feat = z
low_level_feat = self.low_level_conv(low_level_feat)
low_level_feat = F.interpolate(
low_level_feat, size=z.shape[-2:], mode="bilinear"
)
if z_depth is not None and self.use_dada:
z = z * z_depth
if self.proj_conv is not None:
z = self.proj_conv(z)
if low_level_feat is not None:
z = self.merge_feats_conv(torch.cat([low_level_feat, z], dim=1))
return self.model(z)
def __str__(self):
return strings.basedecoder(self)
# --------------------------
# ----- SPADE Blocks -----
# --------------------------
# https://github.com/NVlabs/SPADE/blob/0ff661e70131c9b85091d11a66e019c0f2062d4c
# /models/networks/generator.py
# 0ff661e on 13 Apr 2019
class SPADEResnetBlock(nn.Module):
def __init__(
self,
fin,
fout,
cond_nc,
spade_use_spectral_norm,
spade_param_free_norm,
spade_kernel_size,
last_activation=None,
):
super().__init__()
# Attributes
self.fin = fin
self.fout = fout
self.use_spectral_norm = spade_use_spectral_norm
self.param_free_norm = spade_param_free_norm
self.kernel_size = spade_kernel_size
self.learned_shortcut = fin != fout
self.last_activation = last_activation
fmiddle = min(fin, fout)
# create conv layers
self.conv_0 = nn.Conv2d(fin, fmiddle, kernel_size=3, padding=1)
self.conv_1 = nn.Conv2d(fmiddle, fout, kernel_size=3, padding=1)
if self.learned_shortcut:
self.conv_s = nn.Conv2d(fin, fout, kernel_size=1, bias=False)
# apply spectral norm if specified
if spade_use_spectral_norm:
self.conv_0 = SpectralNorm(self.conv_0)
self.conv_1 = SpectralNorm(self.conv_1)
if self.learned_shortcut:
self.conv_s = SpectralNorm(self.conv_s)
self.norm_0 = SPADE(spade_param_free_norm, spade_kernel_size, fin, cond_nc)
self.norm_1 = SPADE(spade_param_free_norm, spade_kernel_size, fmiddle, cond_nc)
if self.learned_shortcut:
self.norm_s = SPADE(spade_param_free_norm, spade_kernel_size, fin, cond_nc)
# note the resnet block with SPADE also takes in |seg|,
# the semantic segmentation map as input
def forward(self, x, seg):
x_s = self.shortcut(x, seg)
dx = self.conv_0(self.activation(self.norm_0(x, seg)))
dx = self.conv_1(self.activation(self.norm_1(dx, seg)))
out = x_s + dx
if self.last_activation == "lrelu":
return self.activation(out)
elif self.last_activation is None:
return out
else:
raise NotImplementedError(
"The type of activation is not supported: {}".format(
self.last_activation
)
)
def shortcut(self, x, seg):
if self.learned_shortcut:
x_s = self.conv_s(self.norm_s(x, seg))
else:
x_s = x
return x_s
def activation(self, x):
return F.leaky_relu(x, 2e-1)
def __str__(self):
return strings.spaderesblock(self)