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327 lines
12 KiB
327 lines
12 KiB
"""Pytorch ResNet implementation w/ tweaks
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This file is a copy of https://github.com/pytorch/vision 'resnet.py' (BSD-3-Clause) with
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additional dropout and dynamic global avg/max pool.
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ResNext additions added by Ross Wightman
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"""
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import torch
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import torch.nn as nn
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import torch.nn.functional as F
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import math
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from models.helpers import load_pretrained
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from models.adaptive_avgmax_pool import SelectAdaptivePool2d
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from data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
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_models = ['resnet18', 'resnet34', 'resnet50', 'resnet101', 'resnet152',
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'resnext50_32x4d', 'resnext101_32x4d', 'resnext101_64x4d', 'resnext152_32x4d']
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__all__ = ['ResNet'] + _models
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def _cfg(url='', **kwargs):
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return {
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'url': url,
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'num_classes': 1000, 'input_size': (3, 224, 224), 'pool_size': (7, 7),
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'crop_pct': 0.875, 'interpolation': 'bilinear',
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'mean': IMAGENET_DEFAULT_MEAN, 'std': IMAGENET_DEFAULT_STD,
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'first_conv': 'conv1', 'classifier': 'fc',
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**kwargs
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}
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default_cfgs = {
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'resnet18': _cfg(url='https://download.pytorch.org/models/resnet18-5c106cde.pth'),
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'resnet34': _cfg(url='https://download.pytorch.org/models/resnet34-333f7ec4.pth'),
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'resnet50': _cfg(url='https://download.pytorch.org/models/resnet50-19c8e357.pth'),
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'resnet101': _cfg(url='https://download.pytorch.org/models/resnet101-5d3b4d8f.pth'),
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'resnet152': _cfg(url='https://download.pytorch.org/models/resnet152-b121ed2d.pth'),
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'resnext50_32x4d': _cfg(url='https://www.dropbox.com/s/yxci33lfew51p6a/resnext50_32x4d-068914d1.pth?dl=1',
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interpolation='bicubic'),
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'resnext101_32x4d': _cfg(url=''),
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'resnext101_64x4d': _cfg(url=''),
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'resnext152_32x4d': _cfg(url=''),
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}
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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(
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in_planes, out_planes, kernel_size=3, stride=stride, padding=1, bias=False)
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class BasicBlock(nn.Module):
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expansion = 1
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def __init__(self, inplanes, planes, stride=1, downsample=None,
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cardinality=1, base_width=64, drop_rate=0.0):
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super(BasicBlock, self).__init__()
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assert cardinality == 1, 'BasicBlock only supports cardinality of 1'
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assert base_width == 64, 'BasicBlock doest not support changing base width'
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self.conv1 = conv3x3(inplanes, planes, stride)
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self.bn1 = nn.BatchNorm2d(planes)
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self.relu = nn.ReLU(inplace=True)
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self.conv2 = conv3x3(planes, planes)
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self.bn2 = nn.BatchNorm2d(planes)
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self.downsample = downsample
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self.stride = stride
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self.drop_rate = drop_rate
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def forward(self, x):
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residual = x
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out = self.conv1(x)
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out = self.bn1(out)
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out = self.relu(out)
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if self.drop_rate > 0.:
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out = F.dropout(out, p=self.drop_rate, training=self.training)
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out = self.conv2(out)
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out = self.bn2(out)
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if self.downsample is not None:
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residual = self.downsample(x)
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out += residual
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out = self.relu(out)
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return out
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class Bottleneck(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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cardinality=1, base_width=64, drop_rate=0.0):
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super(Bottleneck, self).__init__()
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width = int(math.floor(planes * (base_width / 64)) * cardinality)
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self.conv1 = nn.Conv2d(inplanes, width, kernel_size=1, bias=False)
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self.bn1 = nn.BatchNorm2d(width)
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self.conv2 = nn.Conv2d(width, width, kernel_size=3, stride=stride,
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padding=1, groups=cardinality, bias=False)
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self.bn2 = nn.BatchNorm2d(width)
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self.conv3 = nn.Conv2d(width, planes * 4, kernel_size=1, bias=False)
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self.bn3 = nn.BatchNorm2d(planes * 4)
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self.relu = nn.ReLU(inplace=True)
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self.downsample = downsample
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self.stride = stride
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self.drop_rate = drop_rate
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def forward(self, x):
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residual = x
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out = self.conv1(x)
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out = self.bn1(out)
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out = self.relu(out)
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if self.drop_rate > 0.:
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out = F.dropout(out, p=self.drop_rate, training=self.training)
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out = self.conv2(out)
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out = self.bn2(out)
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out = self.relu(out)
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out = self.conv3(out)
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out = self.bn3(out)
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if self.downsample is not None:
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residual = self.downsample(x)
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out += residual
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out = self.relu(out)
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return out
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class ResNet(nn.Module):
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def __init__(self, block, layers, num_classes=1000, in_chans=3,
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cardinality=1, base_width=64,
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drop_rate=0.0, block_drop_rate=0.0,
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global_pool='avg'):
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self.num_classes = num_classes
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self.inplanes = 64
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self.cardinality = cardinality
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self.base_width = base_width
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self.drop_rate = drop_rate
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self.expansion = block.expansion
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super(ResNet, self).__init__()
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self.conv1 = nn.Conv2d(in_chans, 64, kernel_size=7, stride=2, padding=3, bias=False)
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self.bn1 = nn.BatchNorm2d(64)
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self.relu = nn.ReLU(inplace=True)
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self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1)
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self.layer1 = self._make_layer(block, 64, layers[0], drop_rate=block_drop_rate)
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self.layer2 = self._make_layer(block, 128, layers[1], stride=2, drop_rate=block_drop_rate)
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self.layer3 = self._make_layer(block, 256, layers[2], stride=2, drop_rate=block_drop_rate)
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self.layer4 = self._make_layer(block, 512, layers[3], stride=2, drop_rate=block_drop_rate)
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self.global_pool = SelectAdaptivePool2d(pool_type=global_pool)
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self.num_features = 512 * block.expansion
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self.fc = nn.Linear(self.num_features * self.global_pool.feat_mult(), num_classes)
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for m in self.modules():
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if isinstance(m, nn.Conv2d):
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nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
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elif isinstance(m, nn.BatchNorm2d):
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nn.init.constant_(m.weight, 1.)
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nn.init.constant_(m.bias, 0.)
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def _make_layer(self, block, planes, blocks, stride=1, drop_rate=0.):
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downsample = None
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if stride != 1 or self.inplanes != planes * block.expansion:
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downsample = nn.Sequential(
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nn.Conv2d(self.inplanes, planes * block.expansion, kernel_size=1, stride=stride, bias=False),
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nn.BatchNorm2d(planes * block.expansion),
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)
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layers = [block(self.inplanes, planes, stride, downsample, self.cardinality, self.base_width, drop_rate)]
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self.inplanes = planes * block.expansion
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for i in range(1, blocks):
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layers.append(block(self.inplanes, planes, cardinality=self.cardinality, base_width=self.base_width))
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return nn.Sequential(*layers)
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def get_classifier(self):
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return self.fc
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def reset_classifier(self, num_classes, global_pool='avg'):
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self.global_pool = SelectAdaptivePool2d(pool_type=global_pool)
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self.num_classes = num_classes
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del self.fc
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if num_classes:
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self.fc = nn.Linear(self.num_features * self.global_pool.feat_mult(), num_classes)
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else:
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self.fc = None
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def forward_features(self, x, pool=True):
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x = self.conv1(x)
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x = self.bn1(x)
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x = self.relu(x)
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x = self.maxpool(x)
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x = self.layer1(x)
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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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if pool:
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x = self.global_pool(x)
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x = x.view(x.size(0), -1)
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return x
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def forward(self, x):
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x = self.forward_features(x)
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if self.drop_rate > 0.:
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x = F.dropout(x, p=self.drop_rate, training=self.training)
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x = self.fc(x)
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return x
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def resnet18(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNet-18 model.
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"""
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default_cfg = default_cfgs['resnet18']
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model = ResNet(BasicBlock, [2, 2, 2, 2], num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnet34(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNet-34 model.
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"""
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default_cfg = default_cfgs['resnet34']
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model = ResNet(BasicBlock, [3, 4, 6, 3], num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnet50(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNet-50 model.
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"""
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default_cfg = default_cfgs['resnet50']
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model = ResNet(Bottleneck, [3, 4, 6, 3], num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnet101(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNet-101 model.
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"""
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default_cfg = default_cfgs['resnet101']
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model = ResNet(Bottleneck, [3, 4, 23, 3], num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnet152(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNet-152 model.
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"""
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default_cfg = default_cfgs['resnet152']
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model = ResNet(Bottleneck, [3, 8, 36, 3], num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnext50_32x4d(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNeXt50-32x4d model.
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"""
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default_cfg = default_cfgs['resnext50_32x4d']
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model = ResNet(
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Bottleneck, [3, 4, 6, 3], cardinality=32, base_width=4,
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num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnext101_32x4d(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNeXt-101 model.
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"""
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default_cfg = default_cfgs['resnext101_32x4d']
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model = ResNet(
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Bottleneck, [3, 4, 23, 3], cardinality=32, base_width=4,
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num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnext101_64x4d(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNeXt101-64x4d model.
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"""
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default_cfg = default_cfgs['resnext101_32x4d']
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model = ResNet(
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Bottleneck, [3, 4, 23, 3], cardinality=64, base_width=4,
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num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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def resnext152_32x4d(num_classes=1000, in_chans=3, pretrained=False, **kwargs):
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"""Constructs a ResNeXt152-32x4d model.
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"""
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default_cfg = default_cfgs['resnext152_32x4d']
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model = ResNet(
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Bottleneck, [3, 8, 36, 3], cardinality=32, base_width=4,
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num_classes=num_classes, in_chans=in_chans, **kwargs)
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model.default_cfg = default_cfg
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if pretrained:
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load_pretrained(model, default_cfg, num_classes, in_chans)
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return model
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