Fftw

FFTW is a free collection of fast C routines for computing the
Discrete Fourier Transform in one or more dimensions.  It includes
complex, real, symmetric, and parallel transforms, and can handle
arbitrary array sizes efficiently.  FFTW is typically faster than
other publically-available FFT implementations, and is even
competitive with vendor-tuned libraries.  (See our web page for
extensive benchmarks.)  To achieve this performance, FFTW uses novel
code-generation and runtime self-optimization techniques (along with
many other tricks).

The doc/ directory contains the manual in texinfo, PDF, info, and HTML
formats.  Frequently asked questions and answers can be found in the
doc/FAQ/ directory in ASCII and HTML.

For a quick introduction to calling FFTW, see the "Tutorial" section
of the manual.

Installation instructions are provided in the manual (don't worry, it
is straightforward).

CONTACTS
--------

FFTW was written by Matteo Frigo and Steven G. Johnson.  You can
contact them at fftw()fftw.org.  The latest version of FFTW,
benchmarks, links, and other information can be found at the FFTW home
page (http://www.fftw.org).  You can also sign up to the fftw-announce
mailing list to receive (infrequent) updates and information about new
releases; to do so, go to:

 http://www.fftw.org/mailman/listinfo/fftw-announce