Examples
x = [1 2 3; 4 5 6; 7 8 9] m = 4 n = 4 fft21 (A, m, n) ans = 45 + 0i -6 - 15i 15 + 0i -6 + 15i -18 - 15i -5 + 8i -6 - 5i 5 - 4i 15 + 0i -2 - 5i 5 + 0i -2 + 5i -18 + 15i 5 + 4i -6 + 5i -5 - 8i |  |  |
Calculates the two-dimensional discrete Fourier transform of A using a Fast Fourier Transform algorithm.
fft2 (A, m, n) fft2 (A)
input matrix
number of rows of A to be used
number of columns of A to be used
This is an Octave function. It performs two-dimentional FFT on the matrix A. m and n may be used specify the number of rows and columns of A to use. If either of these is larger than the size of A, A is resized and padded with zeros. If A is a multi-dimensional matrix, each two-dimensional sub-matrix of A is treated separately.
x = [1 2 3; 4 5 6; 7 8 9] m = 4 n = 4 fft21 (A, m, n) ans = 45 + 0i -6 - 15i 15 + 0i -6 + 15i -18 - 15i -5 + 8i -6 - 5i 5 - 4i 15 + 0i -2 - 5i 5 + 0i -2 + 5i -18 + 15i 5 + 4i -6 + 5i -5 - 8i | | |