225 lines
8.7 KiB
Python
225 lines
8.7 KiB
Python
import torch
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import torch.nn as nn
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import numpy as np
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__all__ = ['FixupResNet', 'fixup_resnet18', 'fixup_resnet34', 'fixup_resnet50', 'fixup_resnet101', 'fixup_resnet152']
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def conv3x3(in_planes, out_planes, stride=1):
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"""3x3 convolution with padding"""
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return nn.Conv2d(in_planes, out_planes, kernel_size=3, stride=stride,
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padding=1, bias=False)
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def conv5x5(in_planes, out_planes, stride=1):
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"""3x3 convolution with padding"""
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return nn.Conv2d(in_planes, out_planes, kernel_size=5, stride=stride,
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padding=2, bias=False)
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def conv1x1(in_planes, out_planes, stride=1):
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"""1x1 convolution"""
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return nn.Conv2d(in_planes, out_planes, kernel_size=1, stride=stride, bias=False)
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class FixupBasicBlock(nn.Module):
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expansion = 1
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def __init__(self, inplanes, planes, stride=1, downsample=None, use_bn=False, conv_create=conv3x3):
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super(FixupBasicBlock, self).__init__()
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# Both self.conv1 and self.downsample layers downsample the input when stride != 1
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self.bias1a = nn.Parameter(torch.zeros(1))
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self.conv1 = conv_create(inplanes, planes, stride)
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self.bias1b = nn.Parameter(torch.zeros(1))
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self.lrelu = nn.LeakyReLU(negative_slope=0.1, inplace=True)
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self.bias2a = nn.Parameter(torch.zeros(1))
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self.conv2 = conv_create(planes, planes)
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self.scale = nn.Parameter(torch.ones(1))
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self.bias2b = nn.Parameter(torch.zeros(1))
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self.downsample = downsample
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self.stride = stride
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self.use_bn = use_bn
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if use_bn:
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self.bn1 = nn.BatchNorm2d(planes)
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self.bn2 = nn.BatchNorm2d(planes)
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def forward(self, x):
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identity = x
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out = self.conv1(x + self.bias1a)
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if self.use_bn:
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out = self.bn1(out)
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out = self.lrelu(out + self.bias1b)
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out = self.conv2(out + self.bias2a)
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if self.use_bn:
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out = self.bn2(out)
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out = out * self.scale + self.bias2b
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if self.downsample is not None:
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identity = self.downsample(x + self.bias1a)
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out += identity
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out = self.lrelu(out)
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return out
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class FixupBottleneck(nn.Module):
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expansion = 4
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def __init__(self, inplanes, planes, stride=1, downsample=None):
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super(FixupBottleneck, self).__init__()
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# Both self.conv2 and self.downsample layers downsample the input when stride != 1
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self.bias1a = nn.Parameter(torch.zeros(1))
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self.conv1 = conv1x1(inplanes, planes)
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self.bias1b = nn.Parameter(torch.zeros(1))
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self.bias2a = nn.Parameter(torch.zeros(1))
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self.conv2 = conv3x3(planes, planes, stride)
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self.bias2b = nn.Parameter(torch.zeros(1))
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self.bias3a = nn.Parameter(torch.zeros(1))
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self.conv3 = conv1x1(planes, planes * self.expansion)
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self.scale = nn.Parameter(torch.ones(1))
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self.bias3b = nn.Parameter(torch.zeros(1))
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self.lrelu = nn.LeakyReLU(negative_slope=0.1, inplace=True)
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self.downsample = downsample
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self.stride = stride
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def forward(self, x):
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identity = x
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out = self.conv1(x + self.bias1a)
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out = self.lrelu(out + self.bias1b)
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out = self.conv2(out + self.bias2a)
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out = self.lrelu(out + self.bias2b)
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out = self.conv3(out + self.bias3a)
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out = out * self.scale + self.bias3b
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if self.downsample is not None:
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identity = self.downsample(x + self.bias1a)
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out += identity
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out = self.lrelu(out)
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return out
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class FixupResNet(nn.Module):
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def __init__(self, block, layers, num_filters=64, num_classes=1000, input_img_size=64, number_skips=2, use_bn=False,
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disable_passthrough=False):
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super(FixupResNet, self).__init__()
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self.num_layers = sum(layers)
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self.inplanes = 3
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self.number_skips = number_skips
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self.disable_passthrough = disable_passthrough
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self.lrelu = nn.LeakyReLU(negative_slope=0.2, inplace=True)
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self.layer0 = self._make_layer(block, num_filters*2, layers[0], stride=2, use_bn=use_bn, conv_type=conv5x5)
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if number_skips > 0:
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self.inplanes = self.inplanes + 3 # Accomodate a skip connection from the generator.
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self.layer1 = self._make_layer(block, num_filters*4, layers[1], stride=2, use_bn=use_bn, conv_type=conv5x5)
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if number_skips > 1:
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self.inplanes = self.inplanes + 3 # Accomodate a second skip connection from the generator.
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self.layer2 = self._make_layer(block, num_filters*8, layers[2], stride=2, use_bn=use_bn)
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# SRGAN already has a feature loss tied to a separate VGG discriminator. We really don't care about features.
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# Therefore, level off the filter count from this block forwards.
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self.layer3 = self._make_layer(block, num_filters*8, layers[3], stride=2, use_bn=use_bn)
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self.layer4 = self._make_layer(block, num_filters*8, layers[4], stride=2, use_bn=use_bn)
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self.bias2 = nn.Parameter(torch.zeros(1))
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reduced_img_sz = int(input_img_size / 32)
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self.fc1 = nn.Linear(num_filters * 8 * reduced_img_sz * reduced_img_sz, 100)
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self.fc2 = nn.Linear(100, num_classes)
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for m in self.modules():
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if isinstance(m, FixupBasicBlock):
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nn.init.normal_(m.conv1.weight, mean=0, std=np.sqrt(2 / (m.conv1.weight.shape[0] * np.prod(m.conv1.weight.shape[2:]))) * self.num_layers ** (-0.5))
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nn.init.constant_(m.conv2.weight, 0)
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if m.downsample is not None:
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nn.init.normal_(m.downsample.weight, mean=0, std=np.sqrt(2 / (m.downsample.weight.shape[0] * np.prod(m.downsample.weight.shape[2:]))))
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elif isinstance(m, FixupBottleneck):
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nn.init.normal_(m.conv1.weight, mean=0, std=np.sqrt(2 / (m.conv1.weight.shape[0] * np.prod(m.conv1.weight.shape[2:]))) * self.num_layers ** (-0.25))
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nn.init.normal_(m.conv2.weight, mean=0, std=np.sqrt(2 / (m.conv2.weight.shape[0] * np.prod(m.conv2.weight.shape[2:]))) * self.num_layers ** (-0.25))
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nn.init.constant_(m.conv3.weight, 0)
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if m.downsample is not None:
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nn.init.normal_(m.downsample.weight, mean=0, std=np.sqrt(2 / (m.downsample.weight.shape[0] * np.prod(m.downsample.weight.shape[2:]))))
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def _make_layer(self, block, outplanes, blocks, stride=1, use_bn=False, conv_type=conv3x3):
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layers = []
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for _ in range(1, blocks):
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layers.append(block(self.inplanes, self.inplanes))
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downsample = None
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if stride != 1 or self.inplanes != outplanes * block.expansion:
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downsample = conv1x1(self.inplanes, outplanes * block.expansion, stride)
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layers.append(block(self.inplanes, outplanes, stride, downsample, use_bn=use_bn, conv_create=conv_type))
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self.inplanes = outplanes * block.expansion
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return nn.Sequential(*layers)
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def forward(self, x):
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if len(x) == 3:
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# This class can take a medium skip (half-res) and low skip (quarter-res) provided as a tuple in the input.
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x, med_skip, lo_skip = x
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else:
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# Or just a tuple with only the high res input (this assumes number_skips was set right).
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x = x[0]
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if self.disable_passthrough:
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if self.number_skips > 0:
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med_skip = torch.zeros_like(med_skip)
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if self.number_skips > 1:
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lo_skip = torch.zeros_like(lo_skip)
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x = self.layer0(x)
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if self.number_skips > 0:
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x = torch.cat([x, med_skip], dim=1)
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x = self.layer1(x)
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if self.number_skips > 1:
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x = torch.cat([x, lo_skip], dim=1)
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x = self.layer2(x)
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x = self.layer3(x)
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x = self.layer4(x)
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x = x.view(x.size(0), -1)
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x = self.lrelu(self.fc1(x))
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x = self.fc2(x + self.bias2)
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return x
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def fixup_resnet18(**kwargs):
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"""Constructs a Fixup-ResNet-18 model.2
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"""
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model = FixupResNet(FixupBasicBlock, [2, 2, 2, 2, 2], **kwargs)
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return model
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def fixup_resnet34(**kwargs):
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"""Constructs a Fixup-ResNet-34 model.
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"""
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model = FixupResNet(FixupBasicBlock, [5, 5, 3, 3, 3], **kwargs)
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return model
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def fixup_resnet50(**kwargs):
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"""Constructs a Fixup-ResNet-50 model.
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"""
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model = FixupResNet(FixupBottleneck, [3, 4, 6, 3, 2], **kwargs)
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return model
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def fixup_resnet101(**kwargs):
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"""Constructs a Fixup-ResNet-101 model.
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"""
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model = FixupResNet(FixupBottleneck, [3, 4, 23, 3, 2], **kwargs)
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return model
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def fixup_resnet152(**kwargs):
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"""Constructs a Fixup-ResNet-152 model.
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"""
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model = FixupResNet(FixupBottleneck, [3, 8, 36, 3, 2], **kwargs)
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return model
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__all__ = ['FixupResNet', 'fixup_resnet18', 'fixup_resnet34', 'fixup_resnet50', 'fixup_resnet101', 'fixup_resnet152'] |