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import torch | |
import torch.nn as nn | |
import math | |
from collections import OrderedDict | |
################## AlexNet ################## | |
def bn_relu(inplanes): | |
return nn.Sequential(nn.BatchNorm2d(inplanes), nn.ReLU(inplace=True)) | |
def bn_relu_pool(inplanes, kernel_size=3, stride=2): | |
return nn.Sequential(nn.BatchNorm2d(inplanes), nn.ReLU(inplace=True), nn.MaxPool2d(kernel_size=kernel_size, stride=stride)) | |
class AlexNet(nn.Module): | |
def __init__(self, num_classes=1): | |
super(AlexNet, self).__init__() | |
self.conv1 = nn.Conv2d(3, 96, kernel_size=11, stride=4, bias=False) | |
self.relu_pool1 = bn_relu_pool(inplanes=96) | |
self.conv2 = nn.Conv2d(96, 192, kernel_size=5, padding=2, groups=2, bias=False) | |
self.relu_pool2 = bn_relu_pool(inplanes=192) | |
self.conv3 = nn.Conv2d(192, 384, kernel_size=3, padding=1, groups=2, bias=False) | |
self.relu3 = bn_relu(inplanes=384) | |
self.conv4 = nn.Conv2d(384, 384, kernel_size=3, padding=1, groups=2, bias=False) | |
self.relu4 = bn_relu(inplanes=384) | |
self.conv5 = nn.Conv2d(384, 256, kernel_size=3, padding=1, groups=2, bias=False) | |
self.relu_pool5 = bn_relu_pool(inplanes=256) | |
# classifier | |
self.conv6 = nn.Conv2d(256, 256, kernel_size=5, groups=2, bias=False) | |
self.relu6 = bn_relu(inplanes=256) | |
self.conv7 = nn.Conv2d(256, num_classes, kernel_size=1, bias=False) | |
def forward(self, x): | |
x = self.conv1(x) | |
x = self.relu_pool1(x) | |
x = self.conv2(x) | |
x = self.relu_pool2(x) | |
x = self.conv3(x) | |
x = self.relu3(x) | |
x = self.conv4(x) | |
x = self.relu4(x) | |
x = self.conv5(x) | |
x = self.relu_pool5(x) | |
x = self.conv6(x) | |
x = self.relu6(x) | |
x = self.conv7(x) | |
x = x.view(x.size(0), -1) | |
return x | |
################## ResNet ################## | |
def conv3x3(in_planes, out_planes, stride=1): | |
# 3x3 convolution with padding | |
return nn.Conv2d(in_planes, out_planes, kernel_size=3, stride=stride, padding=1, bias=False) | |
class BasicBlock(nn.Module): | |
expansion = 1 | |
def __init__(self, inplanes, planes, stride=1, downsample=None): | |
super(BasicBlock, self).__init__() | |
m = OrderedDict() | |
m['conv1'] = conv3x3(inplanes, planes, stride) | |
m['bn1'] = nn.BatchNorm2d(planes) | |
m['relu1'] = nn.ReLU(inplace=True) | |
m['conv2'] = conv3x3(planes, planes) | |
m['bn2'] = nn.BatchNorm2d(planes) | |
self.group1 = nn.Sequential(m) | |
self.relu = nn.Sequential(nn.ReLU(inplace=True)) | |
self.downsample = downsample | |
def forward(self, x): | |
if self.downsample is not None: | |
residual = self.downsample(x) | |
else: | |
residual = x | |
out = self.group1(x) + residual | |
out = self.relu(out) | |
return out | |
class ResNet(nn.Module): | |
def __init__(self, block, layers, num_classes=1000): | |
self.inplanes = 64 | |
super(ResNet, self).__init__() | |
m = OrderedDict() | |
m['conv1'] = nn.Conv2d(3, 64, kernel_size=7, stride=2, padding=3, bias=False) | |
m['bn1'] = nn.BatchNorm2d(64) | |
m['relu1'] = nn.ReLU(inplace=True) | |
m['maxpool'] = nn.MaxPool2d(kernel_size=3, stride=2, padding=1) | |
self.group1= nn.Sequential(m) | |
self.layer1 = self._make_layer(block, 64, layers[0]) | |
self.layer2 = self._make_layer(block, 128, layers[1], stride=2) | |
self.layer3 = self._make_layer(block, 256, layers[2], stride=2) | |
self.layer4 = self._make_layer(block, 512, layers[3], stride=2) | |
self.avgpool = nn.Sequential(nn.AvgPool2d(7)) | |
self.group2 = nn.Sequential( | |
OrderedDict([ | |
('fullyconnected', nn.Linear(512 * block.expansion, num_classes)) | |
]) | |
) | |
for m in self.modules(): | |
if isinstance(m, nn.Conv2d): | |
n = m.kernel_size[0] * m.kernel_size[1] * m.out_channels | |
m.weight.data.normal_(0, math.sqrt(2. / n)) | |
elif isinstance(m, nn.BatchNorm2d): | |
m.weight.data.fill_(1) | |
m.bias.data.zero_() | |
elif isinstance(m, nn.Linear): | |
torch.nn.init.xavier_uniform_(m.weight.data) | |
torch.nn.init.constant_(m.bias.data, 0) | |
def _make_layer(self, block, planes, blocks, stride=1): | |
downsample = None | |
if stride != 1 or self.inplanes != planes * block.expansion: | |
downsample = nn.Sequential( | |
nn.Conv2d(self.inplanes, planes * block.expansion, kernel_size=1, stride=stride, bias=False), | |
nn.BatchNorm2d(planes * block.expansion), | |
) | |
layers = [] | |
layers.append(block(self.inplanes, planes, stride, downsample)) | |
self.inplanes = planes * block.expansion | |
for i in range(1, blocks): | |
layers.append(block(self.inplanes, planes)) | |
return nn.Sequential(*layers) | |
def forward(self, x): | |
x = self.group1(x) | |
x = self.layer1(x) | |
x = self.layer2(x) | |
x = self.layer3(x) | |
x = self.layer4(x) | |
x = self.avgpool(x) | |
x = x.view(x.size(0), -1) | |
x = self.group2(x) | |
return x | |