diff --git a/ResNet.py b/ResNet.py new file mode 100644 index 00000000..b4bf966b --- /dev/null +++ b/ResNet.py @@ -0,0 +1,66 @@ +import torch +from torch import nn + +class BasicBlock(nn.Module): + expansion = 1 + def __init__(self, in_channels, out_channels, stride=1): + super(BasicBlock, self).__init__() + self.conv1 = nn.Conv2d(in_channels, out_channels, kernel_size=3, stride=stride, padding=1, bias=False) + self.bn1 = nn.BatchNorm2d(out_channels) + self.relu = nn.ReLU(inplace=True) + self.conv2 = nn.Conv2d(out_channels, out_channels, kernel_size=3, stride=1, padding=1, bias=False) + self.bn2 = nn.BatchNorm2d(out_channels) + self.stride = stride + self.shortcut_conv = nn.Conv2d(in_channels, out_channels, kernel_size=1, stride=stride, bias=False) + self.shortcut_bn = nn.BatchNorm2d(out_channels) + + def forward(self, x): + identity = x + out = self.conv1(x) + out = self.bn1(out) + out = self.relu(out) + out = self.conv2(out) + out = self.bn2(out) + if self.stride != 1 or identity.size() != out.size(): + identity = self.shortcut_conv(identity) + identity = self.shortcut_bn(identity) + out += identity + out = self.relu(out) + return out + +class ResNet18(nn.Module): + def __init__(self, num_classes=1000): + super(ResNet18, self).__init__() + self.in_channels = 64 + self.conv1 = nn.Conv2d(1, 64, kernel_size=7, stride=2, padding=3, bias=False) + self.bn1 = nn.BatchNorm2d(64) + self.relu = nn.ReLU(inplace=True) + self.maxpool = nn.MaxPool2d(kernel_size=3, stride=2, padding=1) + self.layer1 = self._make_layer(BasicBlock, 64, 2, stride=1) + self.layer2 = self._make_layer(BasicBlock, 128, 2, stride=2) + self.layer3 = self._make_layer(BasicBlock, 256, 2, stride=2) + self.layer4 = self._make_layer(BasicBlock, 512, 2, stride=1) + self.avgpool = nn.AdaptiveAvgPool2d((1, 32)) + self.fc = nn.Linear(512 * 32, num_classes) + + def _make_layer(self, block, out_channels, num_blocks, stride): + strides = [stride] + [1] * (num_blocks - 1) + layers = nn.ModuleList() + for stride in strides: + layers.append(block(self.in_channels, out_channels, stride)) + self.in_channels = out_channels * block.expansion + return layers + + def forward(self, x): + x = self.conv1(x) + x = self.bn1(x) + x = self.relu(x) + x = self.maxpool(x) + for layer in self.layer1: x = layer(x) + for layer in self.layer2: x = layer(x) + for layer in self.layer3: x = layer(x) + for layer in self.layer4: x = layer(x) + x = self.avgpool(x) + x = torch.flatten(x, 1) + x = self.fc(x) + return x