alpar@1: /* glprng02.c */
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  This code is part of GLPK (GNU Linear Programming Kit).
alpar@1: *
alpar@1: *  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
alpar@1: *  2009, 2010 Andrew Makhorin, Department for Applied Informatics,
alpar@1: *  Moscow Aviation Institute, Moscow, Russia. All rights reserved.
alpar@1: *  E-mail: <mao@gnu.org>.
alpar@1: *
alpar@1: *  GLPK is free software: you can redistribute it and/or modify it
alpar@1: *  under the terms of the GNU General Public License as published by
alpar@1: *  the Free Software Foundation, either version 3 of the License, or
alpar@1: *  (at your option) any later version.
alpar@1: *
alpar@1: *  GLPK is distributed in the hope that it will be useful, but WITHOUT
alpar@1: *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
alpar@1: *  or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
alpar@1: *  License for more details.
alpar@1: *
alpar@1: *  You should have received a copy of the GNU General Public License
alpar@1: *  along with GLPK. If not, see <http://www.gnu.org/licenses/>.
alpar@1: ***********************************************************************/
alpar@1: 
alpar@1: #include "glpenv.h"
alpar@1: #include "glprng.h"
alpar@1: #define xfault xerror
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  NAME
alpar@1: *
alpar@1: *  rng_unif_01 - obtain pseudo-random number in the range [0, 1]
alpar@1: *
alpar@1: *  SYNOPSIS
alpar@1: *
alpar@1: *  #include "glprng.h"
alpar@1: *  double rng_unif_01(RNG *rand);
alpar@1: *
alpar@1: *  RETURNS
alpar@1: *
alpar@1: *  The routine rng_unif_01 returns a next pseudo-random number which is
alpar@1: *  uniformly distributed in the range [0, 1]. */
alpar@1: 
alpar@1: double rng_unif_01(RNG *rand)
alpar@1: {     double x;
alpar@1:       x = (double)rng_next_rand(rand) / 2147483647.0;
alpar@1:       xassert(0.0 <= x && x <= 1.0);
alpar@1:       return x;
alpar@1: }
alpar@1: 
alpar@1: /***********************************************************************
alpar@1: *  NAME
alpar@1: *
alpar@1: *  rng_uniform - obtain pseudo-random number in the range [a, b]
alpar@1: *
alpar@1: *  SYNOPSIS
alpar@1: *
alpar@1: *  #include "glprng.h"
alpar@1: *  double rng_uniform(RNG *rand, double a, double b);
alpar@1: *
alpar@1: *  RETURNS
alpar@1: *
alpar@1: *  The routine rng_uniform returns a next pseudo-random number which is
alpar@1: *  uniformly distributed in the range [a, b]. */
alpar@1: 
alpar@1: double rng_uniform(RNG *rand, double a, double b)
alpar@1: {     double x;
alpar@1:       if (a >= b)
alpar@1:          xfault("rng_uniform: a = %g, b = %g; invalid range\n", a, b);
alpar@1:       x = rng_unif_01(rand);
alpar@1:       x = a * (1.0 - x) + b * x;
alpar@1:       xassert(a <= x && x <= b);
alpar@1:       return x;
alpar@1: }
alpar@1: 
alpar@1: /* eof */