Compute the Ndimensional Fast Fourier Transform.
Parameters:  a : array_like
s : sequence of ints
axes : tuple of int


Notes
Analogously to fft, the term for zero frequency in all axes is in the loworder corner, while the term for the Nyquist frequency in all axes is in the middle.
If neither s nor axes is specified, the transform is taken along all axes. If s is specified and axes is not, the last len(s) axes are used. If axes is specified and s is not, the input shape along the specified axes is used. If s and axes are both specified and are not the same length, an exception is raised.