3 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 James Theiler, Brian Gough
5 * This program is free software; you can redistribute it and/or modify
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13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
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17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
22 #include <gsl/gsl_rng.h>
23 #include <gsl/gsl_randist.h>
25 /* The Weibull distribution has the form,
27 p(x) dx = (b/a) (x/a)^(b-1) exp(-(x/a)^b) dx
32 gsl_ran_weibull (const gsl_rng * r, const double a, const double b)
34 double x = gsl_rng_uniform_pos (r);
36 double z = pow (-log (x), 1 / b);
42 gsl_ran_weibull_pdf (const double x, const double a, const double b)
61 double p = (b/a) * exp (-pow (x/a, b) + (b - 1) * log (x/a));