MPS support

[akorzh]

i tried to run it on MPS, and hit some issue in decode that in 1j * y one matrix is complex and other isn't which triggered assert in mps backend: binarygemm. Any ideas how can i solve this?

[akorzh]

---> 70 S = mag * (x + 1j * y)
71 audio = self.istft(S)
72 return audio

RuntimeError: c10::isComplexType(input.scalar_type()) && c10::isComplexType(other.scalar_type()) INTERNAL ASSERT FAILED at "/Users/runner/work/pytorch/pytorch/pytorch/aten/src/ATen/native/mps/operations/BinaryKernel.mm":340, please report a bug to PyTorch.

[kgoba]

Perhaps you can express the line as S = mag * torch.complex(x, y)? As per https://pytorch.org/docs/stable/generated/torch.complex.html