fft1 Calculates the discrete Fourier transform of a matrix using Fast Fourier Transform algorithm. fft (x, n, dim) fft (x, n) fft (x) x: input matrix n: Specifies the number of elements of x to be used dim: Specifies the dimention of the matrix along which the FFT is performed This is an Octave function. The FFT is calculated along the first non-singleton dimension of the array. Thus, FFT is computed for each column of x. n is an integer specifying the number of elements of x to use. If n is larger than dimention along. which the FFT is calculated, then x is resized and padded with zeros. Similarly, if n is smaller, then x is truncated. dim is an integer specifying the dimension of the matrix along which the FFT is performed.