/*
================================================================================
  RPL/2 (R) version 4.0.21
  Copyright (C) 1989-2011 Dr. BERTRAND Joël

  This file is part of RPL/2.

  RPL/2 is free software; you can redistribute it and/or modify it
  under the terms of the CeCILL V2 License as published by the french
  CEA, CNRS and INRIA.
 
  RPL/2 is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the CeCILL V2 License
  for more details.
 
  You should have received a copy of the CeCILL License
  along with RPL/2. If not, write to info@cecill.info.
================================================================================
*/


#include "rpl-conv.h"


/*
================================================================================
  Fonction de calcul d'une transformée de Fourier discrète
================================================================================
  Entrées : pointeur sur une structure struct_processus
--------------------------------------------------------------------------------
  Sorties :
--------------------------------------------------------------------------------
  Effets de bord : néant
================================================================================
*/

void
dft(complex16 *dft, integer4 *nombre_lignes, integer4 *nombre_colonnes,
		integer4 *inverse, integer4 *erreur)
{
	integer4						i;

	gsl_fft_complex_wavetable		*wavetable;
	gsl_fft_complex_workspace		*workspace;

	wavetable = gsl_fft_complex_wavetable_alloc((size_t) (*nombre_colonnes));
	workspace = gsl_fft_complex_workspace_alloc((size_t) (*nombre_colonnes));

	(*erreur) = 0;

	if ((*inverse) == 0)
	{
		for(i = 0; (i < (*nombre_lignes)) && ((*erreur) == 0); i++)
		{
			(*erreur) = gsl_fft_complex_forward((gsl_complex_packed_array)
					&(dft[i * (*nombre_colonnes)]),
					(size_t) 1, (size_t) (*nombre_colonnes),
					wavetable, workspace);
		}
	}
	else
	{
		for(i = 0; (i < (*nombre_lignes)) && ((*erreur) == 0); i++)
		{
			(*erreur) = gsl_fft_complex_inverse((gsl_complex_packed_array)
					&(dft[i * (*nombre_colonnes)]),
					(size_t) 1, (size_t) (*nombre_colonnes),
					wavetable, workspace);
		}
	}

	gsl_fft_complex_wavetable_free(wavetable);
	gsl_fft_complex_workspace_free(workspace);

	return;
}

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