ffti

Purpose

Computes an inverse 1- or 2-D Fast Fourier transform.

Format

y = ffti(x)

Parameters:

x (NxK matrix) – The values used to compute the inverse Fast Fourier transform.

Returns:

y (LxM matrix) – where L and M are the smallest prime factor products greater than or equal to N and K, respectively.

Examples

x = { 8 1 6,
      3 5 7,
      4 9 2 };

x_ffti = ffti(fft(x));

print real(x_ffti);

After the code:

8.0000   1.0000   6.0000   0.0000
3.0000   5.0000   7.0000   0.0000
4.0000   9.0000   2.0000   0.0000
0.0000   0.0000   0.0000   0.0000

Remarks

Computes the inverse Fourier Fast transform of x, scaled by \(1/N\).

This uses a Temperton prime factor Fast Fourier algorithm.

See also

Functions fft(), rfft(), rffti()