.OUTPUT FILE: MAC001
[Enter name of the file which will contain AC coeffs.]
.MASK RADIUS: 25
[Enter radius of the circular mask which will be centered at NX/2+1, NY/2+1]
.(F)ULL OR (H)ALF OUTPUT FILE: F
[F results in a autocorrelation function file with dimensions 2*NX,2*NY (useful for mask radius =>MAX(NX/4,NY/4).
H results in a autocorrelation function file with dimensions NX, NY (enough if one is interested only in lower order ACF coeffs. or mask radius is small)]