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
    <http://www.fftw.org>

AUTHOR
    Steffen Müller, <tsee@>

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.