/* @(#)fgauss.c	17.1.1.1 (ES0-DMD) 01/25/02 17:26:58 */
/*===========================================================================
  Copyright (C) 1995 European Southern Observatory (ESO)
 
  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, write to the Free 
  Software Foundation, Inc., 675 Massachusetss Ave, Cambridge, 
  MA 02139, USA.
 
  Corresponding concerning ESO-MIDAS should be addressed as follows:
	Internet e-mail: midas@eso.org
	Postal address: European Southern Observatory
			Data Management Division 
			Karl-Schwarzschild-Strasse 2
			D 85748 Garching bei Muenchen 
			GERMANY
===========================================================================*/

/* @(#)fgauss.c	17.1.1.1  (ESO)  01/25/02  17:26:58 */

#include <math.h>

void fgauss(x,a,y,dyda,na)
float x,*y;
double a[],dyda[];
int na;
{
	int i;
	double fac,ex,arg;

	*y=0.0;
	for (i=1;i<=na-1;i+=3)
	{
		arg=(x-a[i+1])/a[i+2];
		ex=exp(-0.5*arg*arg);
		fac=a[i]*ex*2.0*arg;
		*y += (float)a[i]*ex;
		dyda[i]=ex;
		dyda[i+1]=fac/a[i+2];
		dyda[i+2]=fac*arg/a[i+2];
	}
}