NAME
Math::FFTW - Perl interface to parts of the FFTW
SYNOPSIS
use Math::FFTW;
# should be evenly spaced in x
my @ydata = ...; # with noise
my $coefficients = Math::FFTW::fftw_dft_real2complex_1d(\@ydata);
# $coefficients is ary ref. Contains the complex fourier
# coefficients as [c1_real, c1_imaginary, c2_real, ..., cn_imaginary]
# should give us the same data as we put in.
my $same_y_data = Math::FFTW::fftw_idft_complex2real_1d($coefficients);
# set all coefficients beyond the fiftieth to zero
$_=0 for @{$coefficients}[100..$#$coefficients];
# ==> should smooth our data
my $smoothed = Math::FFTW::fftw_idft_complex2real_1d($coefficients);
DESCRIPTION
*The recommended interface of this module may change. In that case,
however, backwards compatible routines will be provided.*
This is an interface to small parts of the FFTW library. Currently, only
the forward and backward Discrete Fourier Transform of one-dimensional
real data is supported.
If you need anything else, let me know. (And send a patch along if you
like.)
INSTALLATION
You can install this module as you would install any other Perl/XS
extension provided that the FFTW library and its headers are available
and can be found by your compiler/linker.
Tested on Linux/x64.
EXPORT
None by default. The "fftw_dft_real2complex_1d" and
"fftw_idft_complex2real_1d" subroutines can be exported on demand.
SUBROUTINES
fftw_dft_real2complex_1d
The forward DFT returns an array of N/2+1 complex fourier coefficients.
The complex coefficients are returned as two reals each. (Real part,
then imaginary part)
The returned array (reference) should have "(N/2+1)*2 = N+2" elements.
fftw_idft_complex2real_1d
The backward, or inverse DFT returns data from a set of coefficients as
returned by "fftw_dft_real2complex_1d".
Given an array reference of N+2 elements as input, you should get an
array (reference) of N elements in return.
SEE ALSO
AUTHOR
Steffen Müller,
COPYRIGHT AND LICENSE
Copyright (C) 2007 by Steffen Müller
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself, either Perl version 5.6 or, at your
option, any later version of Perl 5 you may have available.
The FFTW library is not contained in this package. Its copyright is held
by Matteo Frigo and the MIT. It is distributed under the GNU General
Public License.