abs backward function

[qiulinzhang]

Thanks for your great paper. I have one question about the class absol, line 31, https://github.com/cvlab-yonsei/DAQ/blob/main/models/resnet20_DAQ.py,
I don't understand your backward function, there seems a lot of redundant operation after grad_input = torch.sign(input). Is there any specific explanation about this backward function.

[Shape-Kim]

I am sorry to confuse you. As you say, it might be unnecessary operation after ''grad_input = torch.sign(input)''. Thank you!

[qiulinzhang]

I am sorry to confuse you. As you say, it might be unnecessary operation after ''grad_input = torch.sign(input)''. Thank you!

I understand suddenly , for floating point zero, using torch.sign will get 0. However, the derivative at zero for abs function is not differentiable. using this backward function, we will get sign 1 for number 0. I worry about my guess is correct or not.

[Shape-Kim]

Your guess is correct! Thank you!