Dear all; I need a subroutine of Fortran90 about "Fast Fourier Transform of a Step-function in 3-dimonsional." I read the related subroutines in Numerical Recipes Book, but I couldn't match it for a 3D step function. Whould you please let me to have access to a subroutine for the mentioned goal? I'm anxiously looking forward your reply. Kind Regards, Fatemeh -- +------------------------------------------------------------------------------+ |Fatemeh Mirjani | Email: f_mirjani@xxxxxxxxxxxx | |Computational Condensed Matter Research Lab. | Tel/Fax Office: +98311-3913746 | |ICTP Affiliated Center in Isfahan, | Tel Lab.: +98311-3913731 | +----------Physics Department, Isfahan University of Technology, Iran----------+