The Math::FFT module provides an interface to various Fast Fourier
Transform (FFT) routines of the C routine of fft4g.c; The one-dimensional
data sets, of size 2^n, are assumed to be sampled at a constant
rate.

The FFT methods available are
- cdft: Complex Discrete Fourier Transform
- rdft: Real Discrete Fourier Transform
- ddct: Discrete Cosine Transform
- ddst: Discrete Sine Transform
- dfct:  Cosine Transform of RDFT (Real Symmetric DFT)
- dfst:  Sine Transform of RDFT (Real Symmetric DFT)
as well as their inverses.

The C code for the FFT routines of fft4g.c is copyrighted 1996-99
by Takuya OOURA. The file arrays.c included here to handle passing
arrays to and from C comes from the PGPLOT module of Karl Glazebrook
<kgb@aaoepp.aao.gov.au>. The perl interface of the Math::FTT module
is Copyright 2000 by Randy Kobes <randy@theoryx5.uwinnipeg.ca>,
and may be distributed under the same terms as Perl itself.