1 /* fft/gsl_fft.h
2  *
3  * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 3 of the License, or (at
8  * your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18  */
19 
20 #ifndef __GSL_FFT_H__
21 #define __GSL_FFT_H__
22 
23 #include "gsl_complex.h"
24 
25 #undef __BEGIN_DECLS
26 #undef __END_DECLS
27 #ifdef __cplusplus
28 # define __BEGIN_DECLS extern "C" {
29 # define __END_DECLS }
30 #else
31 # define __BEGIN_DECLS /* empty */
32 # define __END_DECLS /* empty */
33 #endif
34 
35 __BEGIN_DECLS
36 
37 #ifndef GSL_DISABLE_DEPRECATED
38 typedef enum
39   {
40     forward = -1, backward = +1,
41     gsl_fft_forward = -1, gsl_fft_backward = +1
42   }
43 gsl_fft_direction;
44 #else
45 typedef enum
46   {
47     gsl_fft_forward = -1, gsl_fft_backward = +1
48   }
49 gsl_fft_direction;
50 #endif
51 
52 /* this gives the sign in the formula
53 
54    h(f) = \sum x(t) exp(+/- 2 pi i f t)
55 
56    where - is the forward transform direction and + the inverse direction */
57 
58 __END_DECLS
59 
60 #endif /* __GSL_FFT_H__ */
61