    -----
    `hfft`/`ihfft` are a pair analogous to `rfft`/`irfft`, but for the
    opposite case: here, the signal has Hermitian symmetry in the time
    domain and is real in the frequency domain. So, here, it's `hfft`, for
    which you must supply the length of the result if it is to be odd:
    * even: ``ihfft(hfft(a, 2*len(a) - 2) == a``, within roundoff error,
    * odd: ``ihfft(hfft(a, 2*len(a) - 1) == a``, within roundoff error.

    Examples
    --------
    >>> from scipy.fft import ifft, ihfft
    >>> import numpy as np
    >>> spectrum = np.array([ 15, -4, 0, -1, 0, -4])
    >>> ifft(spectrum)
    array([1.+0.j,  2.+0.j,  3.+0.j,  4.+0.j,  3.+0.j,  2.+0.j]) # may vary
    >>> ihfft(spectrum)
    array([ 1.-0.j,  2.-0.j,  3.-0.j,  4.-0.j]) # may vary
    r