gsl-1.9/cdf/rayleigh.c


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/* cdf/rayleigh.c
 * 
 * Copyright (C) 2003 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 2 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.
 */

#include <config.h>
#include <math.h>
#include <gsl/gsl_math.h>
#include <gsl/gsl_cdf.h>

double
gsl_cdf_rayleigh_P (const double x, const double sigma)
{
  double u = x / sigma;
  double P = -expm1 (-u*u/2);
  return P;
}

double
gsl_cdf_rayleigh_Q (const double x, const double sigma)
{
  double u = x / sigma;
  double Q = exp (-u*u/2);
  return Q;
}