praat/external/gsl/gsl_fft.h

/* fft/gsl_fft.h
 * 
 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or (at
 * your option) any later version.
 * 
 * This program 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 GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#ifndef __GSL_FFT_H__
#define __GSL_FFT_H__

#include "gsl_complex.h"

#undef __BEGIN_DECLS
#undef __END_DECLS
#ifdef __cplusplus
# define __BEGIN_DECLS extern "C" {
# define __END_DECLS }
#else
# define __BEGIN_DECLS /* empty */
# define __END_DECLS /* empty */
#endif

__BEGIN_DECLS

#ifndef GSL_DISABLE_DEPRECATED
typedef enum
  {
    forward = -1, backward = +1,
    gsl_fft_forward = -1, gsl_fft_backward = +1      
  }
gsl_fft_direction;
#else
typedef enum
  {
    gsl_fft_forward = -1, gsl_fft_backward = +1   
  }
gsl_fft_direction;
#endif

/* this gives the sign in the formula

   h(f) = \sum x(t) exp(+/- 2 pi i f t) 
       
   where - is the forward transform direction and + the inverse direction */

__END_DECLS

#endif /* __GSL_FFT_H__ */