# 18.11.2.2 Algorithms (Inverse 2D FFT)

2D IFFT is a fast algorithm for two-dimensional discrete Fourier transform (2D IDFT), which can be defined as follows:

$f(x,y)=\sum_{u=0}^{M-1}\sum_{v=0}^{N-1} F(u,v)e^{j2\pi(ux/M+vy/N)}$

The algorithm for 2D IFFT is very similar to the algorithm for 2D FFT in that it is broken down into a series of 1D IFFTs to accelerate the computation.

Origin uses the FFTW library for Fast Fourier Transforms.