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