ifft Calculates the inverse discrete Fourier transform of a matrix using Fast Fourier Transform algorithm. ifft (x, n, dim) ifft (x, n) ifft (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 inverse FFT is performed This is an Octave function. This is an Octave function. The inverse FFT is calculated along the first non-singleton dimension of the array. Thus, inverse 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 inverse 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 inverse FFT is performed.