81 lines
2.5 KiB
Python
81 lines
2.5 KiB
Python
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from typing import Type, List, Union
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import torch
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from torch import nn as nn
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from torch.nn import init as init
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from torch.nn.modules.batchnorm import _BatchNorm
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@torch.no_grad()
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def default_init_weights(
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module_list: Union[List[nn.Module], nn.Module],
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scale: float = 1,
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bias_fill: float = 0,
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**kwargs,
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) -> None:
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"""Initialize network weights.
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Args:
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module_list (list[nn.Module] | nn.Module): Modules to be initialized.
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scale (float): Scale initialized weights, especially for residual
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blocks. Default: 1.
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bias_fill (float): The value to fill bias. Default: 0
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kwargs (dict): Other arguments for initialization function.
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"""
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if not isinstance(module_list, list):
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module_list = [module_list]
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for module in module_list:
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for m in module.modules():
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if isinstance(m, nn.Conv2d):
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init.kaiming_normal_(m.weight, **kwargs)
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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.fill_(bias_fill)
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elif isinstance(m, nn.Linear):
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init.kaiming_normal_(m.weight, **kwargs)
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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.fill_(bias_fill)
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elif isinstance(m, _BatchNorm):
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init.constant_(m.weight, 1)
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if m.bias is not None:
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m.bias.data.fill_(bias_fill)
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def make_layer(
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basic_block: Type[nn.Module], num_basic_block: int, **kwarg
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) -> nn.Sequential:
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"""Make layers by stacking the same blocks.
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Args:
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basic_block (Type[nn.Module]): nn.Module class for basic block.
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num_basic_block (int): number of blocks.
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Returns:
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nn.Sequential: Stacked blocks in nn.Sequential.
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"""
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layers = []
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for _ in range(num_basic_block):
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layers.append(basic_block(**kwarg))
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return nn.Sequential(*layers)
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# TODO: may write a cpp file
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def pixel_unshuffle(x: torch.Tensor, scale: int) -> torch.Tensor:
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"""Pixel unshuffle.
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Args:
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x (Tensor): Input feature with shape (b, c, hh, hw).
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scale (int): Downsample ratio.
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Returns:
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Tensor: the pixel unshuffled feature.
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"""
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b, c, hh, hw = x.size()
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out_channel = c * (scale**2)
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assert hh % scale == 0 and hw % scale == 0
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h = hh // scale
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w = hw // scale
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x_view = x.view(b, c, h, scale, w, scale)
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return x_view.permute(0, 1, 3, 5, 2, 4).reshape(b, out_channel, h, w)
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