FFTW is the Faster Fourier Transform in the "West" abbreviation, is a fast C FFT library. It includes complex, real, symmetric, multidimensional, and parallel transformations to efficiently handle the size of any array. Speed is faster than other free FFT installations, even better than vendor-tuned libraries. To achieve this performance, it employs new code generation and Run-time optimization techniques as well as many other techniques.
FFTW generates a plan for any size pattern, through various operations of the program to complete various modes of transformation; internal structure and its complexity are transparent to the user; fast (internal compilers for various machines, code generators use the AST to generate code at runtime and to optimize themselves, without taking up compilation time, Using tiered storage technology).
The FFTW 3.3 version is the final official version of 3.3-beta, and the main update is to support the OpenMP and POSIX thread versions of the sync installation feature.
Download Address: http://www.fftw.org/fftw-3.3.tar.gz