
    Return inverse multi-dimensional discrete Fourier transform of
    arbitrary type sequence x.

    The returned array contains::

      y[j_1,..,j_d] = 1/p * sum[k_1=0..n_1-1, ..., k_d=0..n_d-1]
         x[k_1,..,k_d] * prod[i=1..d] exp(sqrt(-1)*2*pi/n_i * j_i * k_i)

    where ``d = len(x.shape)``, ``n = x.shape``, and ``p = prod[i=1..d] n_i``.

    For description of parameters see `fftn`.

    See Also
    --------
    fftn : for detailed information.

    