ifftn (Image Processing Toolbox)

Compute N-dimensional inverse fast Fourier transform

Syntax

B = ifftn(A)
B = ifftn(A,siz)

Description

B = ifftn(A) performs the N-dimensional inverse fast Fourier transform. The result B is the same size as A.

B = ifftn(A,siz) pads A with zeros (or truncates A) to create an N-dimensional array of size siz before doing the inverse transform.

For any A, ifftn(fftn(A)) equals A within roundoff error. If A is real, ifftn(fftn(A)) may have small imaginary parts.

Class Support

The input matrix A can be of class double or of any integer class. The output matrix B is of class double.

Remarks

ifftn is a function in MATLAB.

Algorithm

ifftn(A) is equivalent to

B = A;
for p = 1:length(size(A))
    B = ifft(B,[],p);
end

This code computes the one-dimensional inverse fast Fourier transform along each dimension of A. The time required to compute ifftn(A) depends most on the number of prime factors of the dimensions of A. It is fastest when all of the dimensions are powers of 2.