FFTW is a C subroutine library for computing the discrete Fourier transform (DFT) in one or more dimensions, of arbitrary input size, and of both real and complex data (as well as of even/odd data, i.e. the discrete cosine/sine transforms or DCT/DST).
Log into tork.ncifcrf.gov, and the library files can be found in /opt/nasapps/stow/fftw-3.1.2/lib