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# numpy.fft.hfft

`numpy.fft.``hfft`(a, n=None, axis=-1)

  Compute the FFT of a signal whose spectrum has Hermitian symmetry.

  Parameters : | a : array_like The input array. n : int, optional The length of the FFT. axis : int, optional The axis over which to compute the FFT, assuming Hermitian symmetry of the spectrum. Default is the last axis.
  Returns : | out : ndarray The transformed input.

  See also

  `rfft`
    Compute the one-dimensional FFT for real input.
  `ihfft`
    The inverse of hfft.

  Notes

  hfft/ihfft are a pair analogous to rfft/irfft, but for the opposite case: here the signal is real in the frequency domain and has Hermite symmetry in the time domain. So here it’s hfft for which you must supply the length of the result if it is to be odd: `ihfft(hfft(a), len(a)) == a`, within numerical accuracy.

  Examples

      >>> signal = np.array([[1, 1.j], [-1.j, 2]])
      >>> np.conj(signal.T) - signal   # check Hermitian symmetry
      array([[ 0.-0.j,  0.+0.j],
             [ 0.+0.j,  0.-0.j]])
      >>> freq_spectrum = np.fft.hfft(signal)
      >>> freq_spectrum
      array([[ 1.,  1.],
             [ 2., -2.]])

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