/*

 *  Mathlib : A C Library of Special Functions

 *  Copyright (C) 1998 Ross Ihaka

 *  Copyright (C) 2000--2008 The R Core Team

 *

 *  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, a copy is available at

 *  https://www.R-project.org/Licenses/

 *

 *  SYNOPSIS

 *

 *    #include <Rmath.h>

 *    double rexp(double scale)

 *

 *  DESCRIPTION

 *

 *    Random variates from the exponential distribution.

 *

 */

#include "nmath.h"

double rexp(double scale)

{

    if (!R_FINITE(scale) || scale <= 0.0) {

  if(scale == 0.) return 0.;

  /* else */

  ML_WARN_return_NAN;

    }

    return scale * exp_rand(); // --> in ./sexp.c

}