Is the output of FFTW in angular velocity domain?

Hi,

I have a question in FFTW, I need to make the out put data in angular
velocity domain, like 1/2*sqrt(pi)*exp(omiga**2/4) for exp(-x**2). I guess
the FFTW output is in frequency domain, what do I need to do to change it?

Thanks,

Shuangyi