/* glprng02.c */

/***********************************************************************

*  This code is part of GLPK (GNU Linear Programming Kit).

*

*  Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,

*  2009, 2010 Andrew Makhorin, Department for Applied Informatics,

*  Moscow Aviation Institute, Moscow, Russia. All rights reserved.

*  E-mail: <mao@gnu.org>.

*

*  GLPK 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 3 of the License, or

*  (at your option) any later version.

*

*  GLPK 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 GLPK. If not, see <http://www.gnu.org/licenses/>.

***********************************************************************/

#include "glpenv.h"

#include "glprng.h"

#define xfault xerror

/***********************************************************************

*  NAME

*

*  rng_unif_01 - obtain pseudo-random number in the range [0, 1]

*

*  SYNOPSIS

*

*  #include "glprng.h"

*  double rng_unif_01(RNG *rand);

*

*  RETURNS

*

*  The routine rng_unif_01 returns a next pseudo-random number which is

*  uniformly distributed in the range [0, 1]. */

double rng_unif_01(RNG *rand)

{     double x;

      x = (double)rng_next_rand(rand) / 2147483647.0;

      xassert(0.0 <= x && x <= 1.0);

      return x;

}

/***********************************************************************

*  NAME

*

*  rng_uniform - obtain pseudo-random number in the range [a, b]

*

*  SYNOPSIS

*

*  #include "glprng.h"

*  double rng_uniform(RNG *rand, double a, double b);

*

*  RETURNS

*

*  The routine rng_uniform returns a next pseudo-random number which is

*  uniformly distributed in the range [a, b]. */

double rng_uniform(RNG *rand, double a, double b)

{     double x;

      if (a >= b)

         xfault("rng_uniform: a = %g, b = %g; invalid range\n", a, b);

      x = rng_unif_01(rand);

      x = a * (1.0 - x) + b * x;

      xassert(a <= x && x <= b);

      return x;

}

/* eof */