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61 lines
2.1 KiB
61 lines
2.1 KiB
5 years ago
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import torch
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import torch.nn.parallel
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import torch.nn as nn
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import torch.nn.functional as F
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class AntiAliasDownsampleLayer(nn.Module):
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def __init__(self, remove_aa_jit: bool = False, filt_size: int = 3, stride: int = 2,
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channels: int = 0):
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super(AntiAliasDownsampleLayer, self).__init__()
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if not remove_aa_jit:
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self.op = DownsampleJIT(filt_size, stride, channels)
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else:
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self.op = Downsample(filt_size, stride, channels)
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def forward(self, x):
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return self.op(x)
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@torch.jit.script
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class DownsampleJIT(object):
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def __init__(self, filt_size: int = 3, stride: int = 2, channels: int = 0):
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self.stride = stride
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self.filt_size = filt_size
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self.channels = channels
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assert self.filt_size == 3
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assert stride == 2
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a = torch.tensor([1., 2., 1.])
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filt = (a[:, None] * a[None, :]).clone().detach()
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filt = filt / torch.sum(filt)
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self.filt = filt[None, None, :, :].repeat((self.channels, 1, 1, 1)).cuda().half()
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def __call__(self, input: torch.Tensor):
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if input.dtype != self.filt.dtype:
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self.filt = self.filt.float()
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input_pad = F.pad(input, (1, 1, 1, 1), 'reflect')
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return F.conv2d(input_pad, self.filt, stride=2, padding=0, groups=input.shape[1])
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class Downsample(nn.Module):
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def __init__(self, filt_size=3, stride=2, channels=None):
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super(Downsample, self).__init__()
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self.filt_size = filt_size
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self.stride = stride
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self.channels = channels
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assert self.filt_size == 3
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a = torch.tensor([1., 2., 1.])
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filt = (a[:, None] * a[None, :])
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filt = filt / torch.sum(filt)
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# self.filt = filt[None, None, :, :].repeat((self.channels, 1, 1, 1))
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self.register_buffer('filt', filt[None, None, :, :].repeat((self.channels, 1, 1, 1)))
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def forward(self, input):
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input_pad = F.pad(input, (1, 1, 1, 1), 'reflect')
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return F.conv2d(input_pad, self.filt, stride=self.stride, padding=0, groups=input.shape[1])
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