time-space signal takes up only half the space.



fftn = torch.fft.ifft2(t)
torch.allclose(fftn[..., :6], rfftn)
   True



The discrete Fourier transform is separable, so "ihfft2()" here is
   equivalent to a combination of "ifft()" and "ihfft()":



two_ffts = torch.fft.ifft(torch.fft.ihfft(t, dim=1), dim=0)
torch.allclose(t, two_ffts)
   True


