-[ Example ]-



torch.fft.rfftfreq(5)
   tensor([0.0000, 0.2000, 0.4000])
torch.fft.rfftfreq(4)
   tensor([0.0000, 0.2500, 0.5000])



Compared to the output from "fftfreq()", we see that the Nyquist
   frequency at "f[2]" has changed sign: >>> torch.fft.fftfreq(4)
   tensor([ 0.0000,  0.2500, -0.5000, -0.2500])