BackPropagation？

[xwuShirley]

I am a beginner of PyTorch. Don't we need to write something like a backward function, like the last section in your paper https://arxiv.org/abs/1806.10779 (the appendix, equation(6)-(11) )? I thought you need to define backward function in the class SwitchNorm(nn.Module), or it automatically backward through the forward question?