Aggregated Residual Transformations for Deep Neural Networks
PDF: https://arxiv.org/pdf/1611.05431.pdf
PyTorch代碼: https://github.com/shanglianlm0525/PyTorch-Networks
ResNeXt的三個版本
PyTorch代碼:
class ResNeXtBlock(nn.Module):
def __init__(self,in_places,places, stride=1,downsampling=False, expansion = 2, cardinality=32):
super(ResNeXtBlock,self).__init__()
self.expansion = expansion
self.downsampling = downsampling
self.bottleneck = nn.Sequential(
nn.Conv2d(in_channels=in_places, out_channels=places, kernel_size=1, stride=1, bias=False),
nn.BatchNorm2d(places),
nn.ReLU(inplace=True),
nn.Conv2d(in_channels=places, out_channels=places, kernel_size=3, stride=stride, padding=1, bias=False, groups=cardinality),
nn.BatchNorm2d(places),
nn.ReLU(inplace=True),
nn.Conv2d(in_channels=places, out_channels=places * self.expansion, kernel_size=1, stride=1, bias=False),
nn.BatchNorm2d(places * self.expansion),
)
if self.downsampling:
self.downsample = nn.Sequential(
nn.Conv2d(in_channels=in_places, out_channels=places * self.expansion, kernel_size=1, stride=stride,bias=False),
nn.BatchNorm2d(places * self.expansion)
)
self.relu = nn.ReLU(inplace=True)
def forward(self, x):
residual = x
out = self.bottleneck(x)
if self.downsampling:
residual = self.downsample(x)
out += residual
out = self.relu(out)
return out
可以直接將VGG 和 ResNet中的Block換做 ResNeXt block