Solved by KFrank in post #4 
              
              
                Hello 성현! 

It looks like the gradient is supported.  Try: 
>>> import torch
>>> t = torch.randn (1, 8, 2)
>>> t.requires_grad = True
>>> torch.fft (t, 1)
tensor([[[-2.7232,  3.8741],
         [-2.9743, -2.1404],
         [ 1.1234,  4.4275],
         [ 1.7661,  1.6113],
         [-3.6401,  3.6872],
…