cJ()

function out=cJ(in)

Input:

• in: $d=3$ dimensional data stored as an $\prod_k S_k\,\times\,1$ vector

Global variables:

• gbl_S: dimensions of $d=3$ dimensional data set

Output:

• out: cJ operator applied to in, where cJ$\equiv$cI$^{-1}$

Write a file ``cJ.m'' containing a function of the above specification which uses FFTW to compute the inverse Fourier transform.

Hint: Do not forget the normalization factor $1/\prod_k S_k$.

To test your transforms execute the following commands at the octave prompt:

in=randn(prod(S),1); %# Random input vector
cJ(cI(in))./in %# Check ratio of cJ applied to cI(in) to in