NAME

get_vector_dft - Computes the discrete Fourier transform (DFT) of a vector

SYNOPSIS

#include "wrap_fftw/wrap_fftw.h"

Example compile flags (system dependent):
  -DLINUX_X86_64 -DLINUX_X86_64_OPTERON  -DGNU_COMPILER 
   -I/home/kobus/include
   -L/home/kobus/misc/load/linux_x86_64_opteron -L/usr/lib/x86_64-linux-gnu
  -lKJB                               -lfftw3  -lgsl -lgslcblas -ljpeg  -lSVM -lstdc++                    -lpthread -lSLATEC -lg2c    -lacml -lacml_mv -lblas -lg2c      -lncursesw 


int get_vector_dft
(
	Vector **output_re_vpp,
	Vector **output_im_vpp,
	const Vector *input_re_vp,
	const Vector *input_im_vp
);

DESCRIPTION

This routine computes the discrete Fourier transform (DFT) of a paire of matrices representing a complex vector. The vector representing the imaginary part can be NULL. The first two argument are pointers to matrices for the real and imaginary parts of the result. If they are null, then matrices of the appropriate sizes are created. If they are the wrong size, they are resized. Finally, if they are the right size, then the storage is recycled, as is.

RETURNS

NO_ERROR on success, and ERROR on failure, with an error message being set.

NOTE

This routine simply wraps the appropriate fftw library functions for convenient use with our our data structures. The fftw library can also be used directly in conjunction with the kjb_library by including fftw3.h (the makefile builder should know where to find everthing). This can be preferable in some cases where one wants to exploit the tuning mechanism from that library, and cut down on overhead. However, for ocasional use, the savings won't be very great.

WARNING

The default behaviour of this routine is to inherits fftw's normalization strategy which is to return unnormalized transforms. This means that taking the transform, and then inverting, requires division by N=num_cols*num_rows. This behaviour can be changed using the set_fftw_style() function.

REFERENCES

http://www.fftw.org/

DISCLAIMER

This software is not adequatedly tested. It is recomended that results are checked independantly where appropriate.

AUTHOR

Kobus Barnard

DOCUMENTER