include/gsl/gsl_sf_clausen.h

0001 /* specfunc/gsl_sf_clausen.h
0002  *
0003  * Copyright (C) 1996, 1997, 1998, 1999, 2000 Gerard Jungman
0004  *
0005  * This program is free software; you can redistribute it and/or modify
0006  * it under the terms of the GNU General Public License as published by
0007  * the Free Software Foundation; either version 3 of the License, or (at
0008  * your option) any later version.
0009  *
0010  * This program is distributed in the hope that it will be useful, but
0011  * WITHOUT ANY WARRANTY; without even the implied warranty of
0012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
0013  * General Public License for more details.
0014  *
0015  * You should have received a copy of the GNU General Public License
0016  * along with this program; if not, write to the Free Software
0017  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
0018  */
0019
0020 /* Author:  G. Jungman */
0021
0022 #ifndef __GSL_SF_CLAUSEN_H__
0023 #define __GSL_SF_CLAUSEN_H__
0024
0025 #include <gsl/gsl_sf_result.h>
0026
0027 #undef __BEGIN_DECLS
0028 #undef __END_DECLS
0029 #ifdef __cplusplus
0030 # define __BEGIN_DECLS extern "C" {
0031 # define __END_DECLS }
0032 #else
0033 # define __BEGIN_DECLS /* empty */
0034 # define __END_DECLS /* empty */
0035 #endif
0036
0037 __BEGIN_DECLS
0038
0039
0040 /* Calculate the Clausen integral:
0041  *   Cl_2(x) := Integrate[-Log[2 Sin[t/2]], {t,0,x}]
0042  *
0043  * Relation to dilogarithm:
0044  *   Cl_2(theta) = Im[ Li_2(e^(i theta)) ]
0045  */
0046 int gsl_sf_clausen_e(double x, gsl_sf_result * result);
0047 double gsl_sf_clausen(const double x);
0048
0049
0050 __END_DECLS
0051
0052 #endif /* __GSL_SF_CLAUSEN_H__ */