Oh! Thanks @KFrank !!
I’m really sorry for ignoring you, can you tell me how I can check the gradient?
Actually, I wrote a code for checking gradient by looking at the change of weight like
         print(self.classifier.fc[0].weight[0:1])
         loss.backward()
         print(self.classifier.fc[0].weight[0:1])

But it is too coarse code.
I would really appreciate it if you could let me know.
Thanks…!