1 /* cdf/rayleigh.c
2 *
3 * Copyright (C) 2003, 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 #include "gsl__config.h"
21 #include <math.h>
22 #include "gsl_math.h"
23 #include "gsl_cdf.h"
24
25 double
gsl_cdf_rayleigh_P(const double x,const double sigma)26 gsl_cdf_rayleigh_P (const double x, const double sigma)
27 {
28 double u = x / sigma;
29 double P = -expm1 (-u*u/2);
30 return P;
31 }
32
33 double
gsl_cdf_rayleigh_Q(const double x,const double sigma)34 gsl_cdf_rayleigh_Q (const double x, const double sigma)
35 {
36 double u = x / sigma;
37 double Q = exp (-u*u/2);
38 return Q;
39 }
40