mmcv/cnn/vgg.py
def conv3x3(in_planes, out_planes, dilation=1):
    "3x3 convolution with padding"
    return nn.Conv2d(
        in_planes,
        out_planes,
        kernel_size=3,
        padding=dilation,
        dilation=dilation)
def conv3x3(in_planes, out_planes, dilation=1):
    "3x3 convolution with padding"
    return nn.Conv2d(
        in_planes,
        out_planes,
        kernel_size=3,
        padding=dilation,
        dilation=dilation)
3x3 convolution with padding