** Discrete Fourier transform. **

** FFT(X) is the discrete Fourier transform of vector X. If the **

** length of X is a power of two, a fast radix-2 fast-Fourier **

** transform algorithm is used. If the length of X is not a **

** power of two, a slower non-power-of-two algorithm is employed. **

** FFT(X,N) is the N-point FFT, padded with zeros if X has less **

** than N points and truncated if it has more. **

** If X is a matrix, the FFT operation is applied to each column. **

** **

** **

** See also IFFT , FFT2 , IFFT2 , FFTSHIFT . **

** **