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from functools import partial
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
class Upsample2D(nn.Module):
"""
An upsampling layer with an optional convolution.
:param channels: channels in the inputs and outputs. :param use_conv: a bool determining if a convolution is
applied. :param dims: determines if the signal is 1D, 2D, or 3D. If 3D, then
upsampling occurs in the inner-two dimensions.
"""
def __init__(self, channels, use_conv=False, use_conv_transpose=False, out_channels=None, name="conv"):
super().__init__()
self.channels = channels
self.out_channels = out_channels or channels
self.use_conv = use_conv
self.use_conv_transpose = use_conv_transpose
self.name = name
conv = None
if use_conv_transpose:
conv = nn.ConvTranspose2d(channels, self.out_channels, 4, 2, 1)
elif use_conv:
conv = nn.Conv2d(self.channels, self.out_channels, 3, padding=1)
# TODO(Suraj, Patrick) - clean up after weight dicts are correctly renamed
if name == "conv":
self.conv = conv
else:
self.Conv2d_0 = conv
def forward(self, x):
assert x.shape[1] == self.channels
if self.use_conv_transpose:
return self.conv(x)
x = F.interpolate(x, scale_factor=2.0, mode="nearest")
# TODO(Suraj, Patrick) - clean up after weight dicts are correctly renamed
if self.use_conv:
if self.name == "conv":
x = self.conv(x)
else:
x = self.Conv2d_0(x)
return x
class Downsample2D(nn.Module):
"""
A downsampling layer with an optional convolution.
:param channels: channels in the inputs and outputs. :param use_conv: a bool determining if a convolution is
applied. :param dims: determines if the signal is 1D, 2D, or 3D. If 3D, then
downsampling occurs in the inner-two dimensions.
"""
def __init__(self, channels, use_conv=False, out_channels=None, padding=1, name="conv"):
super().__init__()
self.channels = channels
self.out_channels = out_channels or channels
self.use_conv = use_conv
self.padding = padding
stride = 2
self.name = name
if use_conv:
conv = nn.Conv2d(self.channels, self.out_channels, 3, stride=stride, padding=padding)
else:
assert self.channels == self.out_channels
conv = nn.AvgPool2d(kernel_size=stride, stride=stride)
# TODO(Suraj, Patrick) - clean up after weight dicts are correctly renamed
if name == "conv":
self.Conv2d_0 = conv
self.conv = conv
elif name == "Conv2d_0":
self.conv = conv
else:
self.conv = conv
def forward(self, x):
assert x.shape[1] == self.channels
if self.use_conv and self.padding == 0:
pad = (0, 1, 0, 1)
x = F.pad(x, pad, mode="constant", value=0)
assert x.shape[1] == self.channels
x = self.conv(x)
return x
class FirUpsample2D(nn.Module):
def __init__(self, channels=None, out_channels=None, use_conv=False, fir_kernel=(1, 3, 3, 1)):
super().__init__()
out_channels = out_channels if out_channels else channels
if use_conv:
self.Conv2d_0 = nn.Conv2d(channels, out_channels, kernel_size=3, stride=1, padding=1)
self.use_conv = use_conv
self.fir_kernel = fir_kernel
self.out_channels = out_channels
def _upsample_2d(self, x, weight=None, kernel=None, factor=2, gain=1):
"""Fused `upsample_2d()` followed by `Conv2d()`.
Args:
Padding is performed only once at the beginning, not between the operations. The fused op is considerably more
efficient than performing the same calculation using standard TensorFlow ops. It supports gradients of arbitrary:
order.
x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W,
C]`.
weight: Weight tensor of the shape `[filterH, filterW, inChannels,
outChannels]`. Grouped convolution can be performed by `inChannels = x.shape[0] // numGroups`.
kernel: FIR filter of the shape `[firH, firW]` or `[firN]`
(separable). The default is `[1] * factor`, which corresponds to nearest-neighbor upsampling.
factor: Integer upsampling factor (default: 2). gain: Scaling factor for signal magnitude (default: 1.0).
Returns:
Tensor of the shape `[N, C, H * factor, W * factor]` or `[N, H * factor, W * factor, C]`, and same datatype as
`x`.
"""
assert isinstance(factor, int) and factor >= 1
# Setup filter kernel.
if kernel is None:
kernel = [1] * factor
# setup kernel
kernel = np.asarray(kernel, dtype=np.float64)
if kernel.ndim == 1:
kernel = np.outer(kernel, kernel)
kernel /= np.sum(kernel)
kernel = kernel * (gain * (factor**2))
if self.use_conv:
convH = weight.shape[2]
convW = weight.shape[3]
inC = weight.shape[1]
p = (kernel.shape[0] - factor) - (convW - 1)
stride = (factor, factor)
# Determine data dimensions.
stride = [1, 1, factor, factor]
output_shape = ((x.shape[2] - 1) * factor + convH, (x.shape[3] - 1) * factor + convW)
output_padding = (
output_shape[0] - (x.shape[2] - 1) * stride[0] - convH,
output_shape[1] - (x.shape[3] - 1) * stride[1] - convW,
)
assert output_padding[0] >= 0 and output_padding[1] >= 0
inC = weight.shape[1]
num_groups = x.shape[1] // inC
# Transpose weights.
weight = torch.reshape(weight, (num_groups, -1, inC, convH, convW))
weight = weight[..., ::-1, ::-1].permute(0, 2, 1, 3, 4)
weight = torch.reshape(weight, (num_groups * inC, -1, convH, convW))
x = F.conv_transpose2d(x, weight, stride=stride, output_padding=output_padding, padding=0)
x = upfirdn2d_native(x, torch.tensor(kernel, device=x.device), pad=((p + 1) // 2 + factor - 1, p // 2 + 1))
else:
p = kernel.shape[0] - factor
x = upfirdn2d_native(
x, torch.tensor(kernel, device=x.device), up=factor, pad=((p + 1) // 2 + factor - 1, p // 2)
)
return x
def forward(self, x):
if self.use_conv:
height = self._upsample_2d(x, self.Conv2d_0.weight, kernel=self.fir_kernel)
height = height + self.Conv2d_0.bias.reshape(1, -1, 1, 1)
else:
height = self._upsample_2d(x, kernel=self.fir_kernel, factor=2)
return height
class FirDownsample2D(nn.Module):
def __init__(self, channels=None, out_channels=None, use_conv=False, fir_kernel=(1, 3, 3, 1)):
super().__init__()
out_channels = out_channels if out_channels else channels
if use_conv:
self.Conv2d_0 = nn.Conv2d(channels, out_channels, kernel_size=3, stride=1, padding=1)
self.fir_kernel = fir_kernel
self.use_conv = use_conv
self.out_channels = out_channels
def _downsample_2d(self, x, weight=None, kernel=None, factor=2, gain=1):
"""Fused `Conv2d()` followed by `downsample_2d()`.
Args:
Padding is performed only once at the beginning, not between the operations. The fused op is considerably more
efficient than performing the same calculation using standard TensorFlow ops. It supports gradients of arbitrary:
order.
x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W, C]`. w: Weight tensor of the shape `[filterH,
filterW, inChannels, outChannels]`. Grouped convolution can be performed by `inChannels = x.shape[0] //
numGroups`. k: FIR filter of the shape `[firH, firW]` or `[firN]` (separable). The default is `[1] *
factor`, which corresponds to average pooling. factor: Integer downsampling factor (default: 2). gain:
Scaling factor for signal magnitude (default: 1.0).
Returns:
Tensor of the shape `[N, C, H // factor, W // factor]` or `[N, H // factor, W // factor, C]`, and same
datatype as `x`.
"""
assert isinstance(factor, int) and factor >= 1
if kernel is None:
kernel = [1] * factor
# setup kernel
kernel = np.asarray(kernel, dtype=np.float64)
if kernel.ndim == 1:
kernel = np.outer(kernel, kernel)
kernel /= np.sum(kernel)
kernel = kernel * gain
if self.use_conv:
_, _, convH, convW = weight.shape
p = (kernel.shape[0] - factor) + (convW - 1)
s = [factor, factor]
x = upfirdn2d_native(x, torch.tensor(kernel, device=x.device), pad=((p + 1) // 2, p // 2))
x = F.conv2d(x, weight, stride=s, padding=0)
else:
p = kernel.shape[0] - factor
x = upfirdn2d_native(x, torch.tensor(kernel, device=x.device), down=factor, pad=((p + 1) // 2, p // 2))
return x
def forward(self, x):
if self.use_conv:
x = self._downsample_2d(x, weight=self.Conv2d_0.weight, kernel=self.fir_kernel)
x = x + self.Conv2d_0.bias.reshape(1, -1, 1, 1)
else:
x = self._downsample_2d(x, kernel=self.fir_kernel, factor=2)
return x
class ResnetBlock2D(nn.Module):
def __init__(
self,
*,
in_channels,
out_channels=None,
conv_shortcut=False,
dropout=0.0,
temb_channels=512,
groups=32,
groups_out=None,
pre_norm=True,
eps=1e-6,
non_linearity="swish",
time_embedding_norm="default",
kernel=None,
output_scale_factor=1.0,
use_nin_shortcut=None,
up=False,
down=False,
):
super().__init__()
self.pre_norm = pre_norm
self.pre_norm = True
self.in_channels = in_channels
out_channels = in_channels if out_channels is None else out_channels
self.out_channels = out_channels
self.use_conv_shortcut = conv_shortcut
self.time_embedding_norm = time_embedding_norm
self.up = up
self.down = down
self.output_scale_factor = output_scale_factor
if groups_out is None:
groups_out = groups
self.norm1 = torch.nn.GroupNorm(num_groups=groups, num_channels=in_channels, eps=eps, affine=True)
self.conv1 = torch.nn.Conv2d(in_channels, out_channels, kernel_size=3, stride=1, padding=1)
if temb_channels is not None:
self.time_emb_proj = torch.nn.Linear(temb_channels, out_channels)
else:
self.time_emb_proj = None
self.norm2 = torch.nn.GroupNorm(num_groups=groups_out, num_channels=out_channels, eps=eps, affine=True)
self.dropout = torch.nn.Dropout(dropout)
self.conv2 = torch.nn.Conv2d(out_channels, out_channels, kernel_size=3, stride=1, padding=1)
if non_linearity == "swish":
self.nonlinearity = lambda x: F.silu(x)
elif non_linearity == "mish":
self.nonlinearity = Mish()
elif non_linearity == "silu":
self.nonlinearity = nn.SiLU()
self.upsample = self.downsample = None
if self.up:
if kernel == "fir":
fir_kernel = (1, 3, 3, 1)
self.upsample = lambda x: upsample_2d(x, kernel=fir_kernel)
elif kernel == "sde_vp":
self.upsample = partial(F.interpolate, scale_factor=2.0, mode="nearest")
else:
self.upsample = Upsample2D(in_channels, use_conv=False)
elif self.down:
if kernel == "fir":
fir_kernel = (1, 3, 3, 1)
self.downsample = lambda x: downsample_2d(x, kernel=fir_kernel)
elif kernel == "sde_vp":
self.downsample = partial(F.avg_pool2d, kernel_size=2, stride=2)
else:
self.downsample = Downsample2D(in_channels, use_conv=False, padding=1, name="op")
self.use_nin_shortcut = self.in_channels != self.out_channels if use_nin_shortcut is None else use_nin_shortcut
self.conv_shortcut = None
if self.use_nin_shortcut:
self.conv_shortcut = torch.nn.Conv2d(in_channels, out_channels, kernel_size=1, stride=1, padding=0)
def forward(self, x, temb):
hidden_states = x
# make sure hidden states is in float32
# when running in half-precision
hidden_states = self.norm1(hidden_states.double()).type(hidden_states.dtype)
hidden_states = self.nonlinearity(hidden_states)
if self.upsample is not None:
x = self.upsample(x)
hidden_states = self.upsample(hidden_states)
elif self.downsample is not None:
x = self.downsample(x)
hidden_states = self.downsample(hidden_states)
hidden_states = self.conv1(hidden_states)
if temb is not None:
temb = self.time_emb_proj(self.nonlinearity(temb))[:, :, None, None]
hidden_states = hidden_states + temb
# make sure hidden states is in float32
# when running in half-precision
hidden_states = self.norm2(hidden_states.double()).type(hidden_states.dtype)
hidden_states = self.nonlinearity(hidden_states)
hidden_states = self.dropout(hidden_states)
hidden_states = self.conv2(hidden_states)
if self.conv_shortcut is not None:
x = self.conv_shortcut(x)
out = (x + hidden_states) / self.output_scale_factor
return out
class Mish(torch.nn.Module):
def forward(self, x):
return x * torch.tanh(torch.nn.functional.softplus(x))
def upsample_2d(x, kernel=None, factor=2, gain=1):
r"""Upsample2D a batch of 2D images with the given filter.
Args:
Accepts a batch of 2D images of the shape `[N, C, H, W]` or `[N, H, W, C]` and upsamples each image with the given
filter. The filter is normalized so that if the input pixels are constant, they will be scaled by the specified
`gain`. Pixels outside the image are assumed to be zero, and the filter is padded with zeros so that its shape is a:
multiple of the upsampling factor.
x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W,
C]`.
k: FIR filter of the shape `[firH, firW]` or `[firN]`
(separable). The default is `[1] * factor`, which corresponds to nearest-neighbor upsampling.
factor: Integer upsampling factor (default: 2). gain: Scaling factor for signal magnitude (default: 1.0).
Returns:
Tensor of the shape `[N, C, H * factor, W * factor]`
"""
assert isinstance(factor, int) and factor >= 1
if kernel is None:
kernel = [1] * factor
kernel = np.asarray(kernel, dtype=np.float64)
if kernel.ndim == 1:
kernel = np.outer(kernel, kernel)
kernel /= np.sum(kernel)
kernel = kernel * (gain * (factor**2))
p = kernel.shape[0] - factor
return upfirdn2d_native(
x, torch.tensor(kernel, device=x.device), up=factor, pad=((p + 1) // 2 + factor - 1, p // 2)
)
def downsample_2d(x, kernel=None, factor=2, gain=1):
r"""Downsample2D a batch of 2D images with the given filter.
Args:
Accepts a batch of 2D images of the shape `[N, C, H, W]` or `[N, H, W, C]` and downsamples each image with the
given filter. The filter is normalized so that if the input pixels are constant, they will be scaled by the
specified `gain`. Pixels outside the image are assumed to be zero, and the filter is padded with zeros so that its
shape is a multiple of the downsampling factor.
x: Input tensor of the shape `[N, C, H, W]` or `[N, H, W,
C]`.
kernel: FIR filter of the shape `[firH, firW]` or `[firN]`
(separable). The default is `[1] * factor`, which corresponds to average pooling.
factor: Integer downsampling factor (default: 2). gain: Scaling factor for signal magnitude (default: 1.0).
Returns:
Tensor of the shape `[N, C, H // factor, W // factor]`
"""
assert isinstance(factor, int) and factor >= 1
if kernel is None:
kernel = [1] * factor
kernel = np.asarray(kernel, dtype=np.float64)
if kernel.ndim == 1:
kernel = np.outer(kernel, kernel)
kernel /= np.sum(kernel)
kernel = kernel * gain
p = kernel.shape[0] - factor
return upfirdn2d_native(x, torch.tensor(kernel, device=x.device), down=factor, pad=((p + 1) // 2, p // 2))
def upfirdn2d_native(input, kernel, up=1, down=1, pad=(0, 0)):
up_x = up_y = up
down_x = down_y = down
pad_x0 = pad_y0 = pad[0]
pad_x1 = pad_y1 = pad[1]
_, channel, in_h, in_w = input.shape
input = input.reshape(-1, in_h, in_w, 1)
_, in_h, in_w, minor = input.shape
kernel_h, kernel_w = kernel.shape
out = input.view(-1, in_h, 1, in_w, 1, minor)
# Temporary workaround for mps specific issue: https://github.com/pytorch/pytorch/issues/84535
if input.device.type == "mps":
out = out.to("cpu")
out = F.pad(out, [0, 0, 0, up_x - 1, 0, 0, 0, up_y - 1])
out = out.view(-1, in_h * up_y, in_w * up_x, minor)
out = F.pad(out, [0, 0, max(pad_x0, 0), max(pad_x1, 0), max(pad_y0, 0), max(pad_y1, 0)])
out = out.to(input.device) # Move back to mps if necessary
out = out[
:,
max(-pad_y0, 0) : out.shape[1] - max(-pad_y1, 0),
max(-pad_x0, 0) : out.shape[2] - max(-pad_x1, 0),
:,
]
out = out.permute(0, 3, 1, 2)
out = out.reshape([-1, 1, in_h * up_y + pad_y0 + pad_y1, in_w * up_x + pad_x0 + pad_x1])
w = torch.flip(kernel, [0, 1]).view(1, 1, kernel_h, kernel_w)
out = F.conv2d(out, w)
out = out.reshape(
-1,
minor,
in_h * up_y + pad_y0 + pad_y1 - kernel_h + 1,
in_w * up_x + pad_x0 + pad_x1 - kernel_w + 1,
)
out = out.permute(0, 2, 3, 1)
out = out[:, ::down_y, ::down_x, :]
out_h = (in_h * up_y + pad_y0 + pad_y1 - kernel_h) // down_y + 1
out_w = (in_w * up_x + pad_x0 + pad_x1 - kernel_w) // down_x + 1
return out.view(-1, channel, out_h, out_w)