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Diffstat (limited to 'gsl-1.9/cdf/exponential.c')
-rw-r--r-- | gsl-1.9/cdf/exponential.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/gsl-1.9/cdf/exponential.c b/gsl-1.9/cdf/exponential.c new file mode 100644 index 0000000..e997bb0 --- /dev/null +++ b/gsl-1.9/cdf/exponential.c @@ -0,0 +1,59 @@ +/* cdf/exponential.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> + +/* The exponential distribution has the form + + p(x) dx = exp(-x/mu) dx/mu + + for x = 0 ... +infty */ + +double +gsl_cdf_exponential_P (const double x, const double mu) +{ + if (x < 0) + { + return 0; + } + else + { + double P = -expm1 (-x / mu); + + return P; + } +} + +double +gsl_cdf_exponential_Q (const double x, const double mu) +{ + if (x < 0) + { + return 1; + } + else + { + double Q = exp (-x / mu); + + return Q; + } +} |