I am trying to write a FORTRAN code to evaluate the fast Fourier transform of the Gaussian function f(r)=exp(-(r^2)) using FFTW3 library. As everyone knows, the Fourier transform of the Gaussian function is another Gaussian function.
I am looking at some code and there is this:What is the purpose of BLOCK? I tried to google it, but all I found was something about BLOCK DATA and COMMON blocks. I'm not sure whether they are related.