[Octave-bug-tracker] [bug #65298] fft and ifft do not work correctly and do not agree with Matlab

[Nicholas Jankowski]

Follow-up Comment #4, bug#65298 (group octave):

saving the output h as a mat file and loading it into matlab 2023b, it can
confirm that 

matlab2023b:

>> max(imag(ifft(fft(h))))

ans = 

     0

>> isreal(ifft(fft(h)))

ans =

  logical

   1


octave 9.0.1:

>> max(imag(ifft(fft(h))))
ans = 2.276170624955701e-17

>> isreal(ifft(fft(h)))
ans = 0


which as Dmitri said, triggers the alternate plotting method.

Is the 'residual imaginary parts' a known issue with octave's fft/ifft? is the
issue with the fft or the ifft? and assuming this is a new bug, what would be
a better retitle?


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