text: /*
   *  Mathlib : A C Library of Special Functions
   *  Copyright (C) 1998 Ross Ihaka
   *  Copyright (C) 2000 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
   *  http://www.r-project.org/Licenses/
   *
   *  DESCRIPTION
   *
   *    The density of the Cauchy distribution.
   */
  
  #include "nmath.h"
  #include "dpq.h"
  
  double dcauchy(double x, double location, double scale, int give_log)
  {
      double y;
  #ifdef IEEE_754
      /* NaNs propagated correctly */
      if (ISNAN(x) || ISNAN(location) || ISNAN(scale))
  	return x + location + scale;
  #endif
      if (scale <= 0) ML_ERR_return_NAN;
  
      y = (x - location) / scale;
      return give_log ?
  	- log(M_PI * scale * (1. + y * y)) :
  	1. / (M_PI * scale * (1. + y * y));
  }
  