FFTW ("Fastest Fourier Transform in the West") is a C subroutine library for computing the Discrete Fourier Transform (DFT) in one or more dimensions, of both real and complex data, and of arbitrarily large input size. FFTW also efficiently handles multiple, strided transforms.
FFTW is installed on LC's On LC's TOSS 3 Linux machines, FFTW is installed in /usr/tce/packages/fftw/*.
FFTW is released under the GNU general public license. It works on any platform with a C compiler, and it is also callable from Fortran. Of special interest to LC users is FFTW's support for parallelization. FFTW offers parallelized code for SMP machines with POSIX threads (pthreads), and an MPI version for distributed memory transforms is also available.
For general information on the FFTW math library, background papers on its technical features, and detailed documentation, consult the FFTW website.