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- from collections import abc
- import os
-
- import torch
- from torch.nn import functional as F
- from torch.autograd import Function
- from torch.utils.cpp_extension import load
-
-
- module_path = os.path.dirname(__file__)
- upfirdn2d_op = load(
- "upfirdn2d",
- sources=[
- os.path.join(module_path, "upfirdn2d.cpp"),
- os.path.join(module_path, "upfirdn2d_kernel.cu"),
- ],
- )
-
-
- class UpFirDn2dBackward(Function):
- @staticmethod
- def forward(
- ctx, grad_output, kernel, grad_kernel, up, down, pad, g_pad, in_size, out_size
- ):
-
- up_x, up_y = up
- down_x, down_y = down
- g_pad_x0, g_pad_x1, g_pad_y0, g_pad_y1 = g_pad
-
- grad_output = grad_output.reshape(-1, out_size[0], out_size[1], 1)
-
- grad_input = upfirdn2d_op.upfirdn2d(
- grad_output,
- grad_kernel,
- down_x,
- down_y,
- up_x,
- up_y,
- g_pad_x0,
- g_pad_x1,
- g_pad_y0,
- g_pad_y1,
- )
- grad_input = grad_input.view(in_size[0], in_size[1], in_size[2], in_size[3])
-
- ctx.save_for_backward(kernel)
-
- pad_x0, pad_x1, pad_y0, pad_y1 = pad
-
- ctx.up_x = up_x
- ctx.up_y = up_y
- ctx.down_x = down_x
- ctx.down_y = down_y
- ctx.pad_x0 = pad_x0
- ctx.pad_x1 = pad_x1
- ctx.pad_y0 = pad_y0
- ctx.pad_y1 = pad_y1
- ctx.in_size = in_size
- ctx.out_size = out_size
-
- return grad_input
-
- @staticmethod
- def backward(ctx, gradgrad_input):
- kernel, = ctx.saved_tensors
-
- gradgrad_input = gradgrad_input.reshape(-1, ctx.in_size[2], ctx.in_size[3], 1)
-
- gradgrad_out = upfirdn2d_op.upfirdn2d(
- gradgrad_input,
- kernel,
- ctx.up_x,
- ctx.up_y,
- ctx.down_x,
- ctx.down_y,
- ctx.pad_x0,
- ctx.pad_x1,
- ctx.pad_y0,
- ctx.pad_y1,
- )
- # gradgrad_out = gradgrad_out.view(ctx.in_size[0], ctx.out_size[0], ctx.out_size[1], ctx.in_size[3])
- gradgrad_out = gradgrad_out.view(
- ctx.in_size[0], ctx.in_size[1], ctx.out_size[0], ctx.out_size[1]
- )
-
- return gradgrad_out, None, None, None, None, None, None, None, None
-
-
- class UpFirDn2d(Function):
- @staticmethod
- def forward(ctx, input, kernel, up, down, pad):
- up_x, up_y = up
- down_x, down_y = down
- pad_x0, pad_x1, pad_y0, pad_y1 = pad
-
- kernel_h, kernel_w = kernel.shape
- batch, channel, in_h, in_w = input.shape
- ctx.in_size = input.shape
-
- input = input.reshape(-1, in_h, in_w, 1)
-
- ctx.save_for_backward(kernel, torch.flip(kernel, [0, 1]))
-
- out_h = (in_h * up_y + pad_y0 + pad_y1 - kernel_h + down_y) // down_y
- out_w = (in_w * up_x + pad_x0 + pad_x1 - kernel_w + down_x) // down_x
- ctx.out_size = (out_h, out_w)
-
- ctx.up = (up_x, up_y)
- ctx.down = (down_x, down_y)
- ctx.pad = (pad_x0, pad_x1, pad_y0, pad_y1)
-
- g_pad_x0 = kernel_w - pad_x0 - 1
- g_pad_y0 = kernel_h - pad_y0 - 1
- g_pad_x1 = in_w * up_x - out_w * down_x + pad_x0 - up_x + 1
- g_pad_y1 = in_h * up_y - out_h * down_y + pad_y0 - up_y + 1
-
- ctx.g_pad = (g_pad_x0, g_pad_x1, g_pad_y0, g_pad_y1)
-
- out = upfirdn2d_op.upfirdn2d(
- input, kernel, up_x, up_y, down_x, down_y, pad_x0, pad_x1, pad_y0, pad_y1
- )
- # out = out.view(major, out_h, out_w, minor)
- out = out.view(-1, channel, out_h, out_w)
-
- return out
-
- @staticmethod
- def backward(ctx, grad_output):
- kernel, grad_kernel = ctx.saved_tensors
-
- grad_input = None
-
- if ctx.needs_input_grad[0]:
- grad_input = UpFirDn2dBackward.apply(
- grad_output,
- kernel,
- grad_kernel,
- ctx.up,
- ctx.down,
- ctx.pad,
- ctx.g_pad,
- ctx.in_size,
- ctx.out_size,
- )
-
- return grad_input, None, None, None, None
-
-
- def upfirdn2d(input, kernel, up=1, down=1, pad=(0, 0)):
- if not isinstance(up, abc.Iterable):
- up = (up, up)
-
- if not isinstance(down, abc.Iterable):
- down = (down, down)
-
- if len(pad) == 2:
- pad = (pad[0], pad[1], pad[0], pad[1])
-
- if input.device.type == "cpu":
- out = upfirdn2d_native(input, kernel, *up, *down, *pad)
-
- else:
- out = UpFirDn2d.apply(input, kernel, up, down, pad)
-
- return out
-
-
- def upfirdn2d_native(
- input, kernel, up_x, up_y, down_x, down_y, pad_x0, pad_x1, pad_y0, pad_y1
- ):
- _, 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)
- 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[
- :,
- 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) // down_y
- out_w = (in_w * up_x + pad_x0 + pad_x1 - kernel_w + down_x) // down_x
-
- return out.view(-1, channel, out_h, out_w)
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