  .. versionadded:: 1.5.0

    Returns
    -------
    out : ndarray
        The truncated or zero-padded input, transformed along the axes
        indicated by `axes`, or by a combination of `s` or `x`,
        as explained in the parameters section above.
        The length of each transformed axis is as given by the corresponding
        element of `s`, or the length of the input in every axis except for the
        last one if `s` is not given. In the final transformed axis the length
        of the output when `s` is not given is ``2*(m-1)``, where ``m`` is the
        length of the final transformed axis of the input. To get an odd
        number of output points in the final axis, `s` must be specified.

    Raises
    ------
    ValueError
        If `s` and `axes` have different length.
    IndexError
        If an element of `axes` is larger than the number of axes of `x`.

    See Also
    --------
    rfftn : The forward N-D FFT of real input,
            of which `ifftn` is the inverse.
    fft : The 1-D FFT, with definitions and conventions used.
    irfft : The inverse of the 1-D FFT of real input.
    irfft2 : The inverse of the 2-D FFT of real input.

    Notes
    -----
    See `fft` for definitions and conventions used.

    See `rfft` for definitions and conventions used for real input.

    The default value of `s` assumes an even output length in the final
    transformation axis. When performing the final complex to real
    transformation, the Hermitian symmetry requires that the last imaginary
    component along that axis must be 0 and so it is ignored. To avoid losing
    information, the correct length of the real input *must* be given.

    Examples
    --------
    >>> import scipy.fft
    >>> import numpy as np
    >>> x = np.zeros((3, 2, 2))
    >>> x[0, 0, 0] = 3 * 2 * 2
    >>> scipy.fft.irfftn(x)
    array([[[1.,  1.],
            [1.,  1.]],
           [[1.,  1.],
            [1.,  1.]],
           [[1.,  1.],
            [1.,  1.]]])

    r