matlab compatible fft
y=moc_fft(x,n)
This funcion is much (100x) faster then mtlb_fft
Compute the FFT of A using subroutines from FFTW. The FFT is calculated along the first non-singleton dimension of the array. Thus if A is a matrix, `fft (A)' computes the FFT for each column of A.
If called with two arguments, N is expected to be an integer specifying the number of elements of A to use, or an empty matrix to specify that its value should be ignored. If N is larger than the dimension along which the FFT is calculated, then A is resized and padded with zeros. Otherwise, if N is smaller than the dimension along which the FFT is calculated, then A is truncated.