1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/glprng02.c	Mon Dec 06 13:09:21 2010 +0100
     1.3 @@ -0,0 +1,76 @@
     1.4 +/* glprng02.c */
     1.5 +
     1.6 +/***********************************************************************
     1.7 +*  This code is part of GLPK (GNU Linear Programming Kit).
     1.8 +*
     1.9 +*  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
    1.10 +*  2009, 2010 Andrew Makhorin, Department for Applied Informatics,
    1.11 +*  Moscow Aviation Institute, Moscow, Russia. All rights reserved.
    1.12 +*  E-mail: <mao@gnu.org>.
    1.13 +*
    1.14 +*  GLPK is free software: you can redistribute it and/or modify it
    1.15 +*  under the terms of the GNU General Public License as published by
    1.16 +*  the Free Software Foundation, either version 3 of the License, or
    1.17 +*  (at your option) any later version.
    1.18 +*
    1.19 +*  GLPK is distributed in the hope that it will be useful, but WITHOUT
    1.20 +*  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    1.21 +*  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
    1.22 +*  License for more details.
    1.23 +*
    1.24 +*  You should have received a copy of the GNU General Public License
    1.25 +*  along with GLPK. If not, see <http://www.gnu.org/licenses/>.
    1.26 +***********************************************************************/
    1.27 +
    1.28 +#include "glpenv.h"
    1.29 +#include "glprng.h"
    1.30 +#define xfault xerror
    1.31 +
    1.32 +/***********************************************************************
    1.33 +*  NAME
    1.34 +*
    1.35 +*  rng_unif_01 - obtain pseudo-random number in the range [0, 1]
    1.36 +*
    1.37 +*  SYNOPSIS
    1.38 +*
    1.39 +*  #include "glprng.h"
    1.40 +*  double rng_unif_01(RNG *rand);
    1.41 +*
    1.42 +*  RETURNS
    1.43 +*
    1.44 +*  The routine rng_unif_01 returns a next pseudo-random number which is
    1.45 +*  uniformly distributed in the range [0, 1]. */
    1.46 +
    1.47 +double rng_unif_01(RNG *rand)
    1.48 +{     double x;
    1.49 +      x = (double)rng_next_rand(rand) / 2147483647.0;
    1.50 +      xassert(0.0 <= x && x <= 1.0);
    1.51 +      return x;
    1.52 +}
    1.53 +
    1.54 +/***********************************************************************
    1.55 +*  NAME
    1.56 +*
    1.57 +*  rng_uniform - obtain pseudo-random number in the range [a, b]
    1.58 +*
    1.59 +*  SYNOPSIS
    1.60 +*
    1.61 +*  #include "glprng.h"
    1.62 +*  double rng_uniform(RNG *rand, double a, double b);
    1.63 +*
    1.64 +*  RETURNS
    1.65 +*
    1.66 +*  The routine rng_uniform returns a next pseudo-random number which is
    1.67 +*  uniformly distributed in the range [a, b]. */
    1.68 +
    1.69 +double rng_uniform(RNG *rand, double a, double b)
    1.70 +{     double x;
    1.71 +      if (a >= b)
    1.72 +         xfault("rng_uniform: a = %g, b = %g; invalid range\n", a, b);
    1.73 +      x = rng_unif_01(rand);
    1.74 +      x = a * (1.0 - x) + b * x;
    1.75 +      xassert(a <= x && x <= b);
    1.76 +      return x;
    1.77 +}
    1.78 +
    1.79 +/* eof */