/* @(#)mo_getoff.c	17.1.1.1 (ES0-DMD) 01/25/02 17:49:06 */
/*===========================================================================
  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
===========================================================================*/

/* @(#)mo_getoff.c	17.1.1.1 (ESO-DAG) 01/25/02 17:49:06 */

#include <math.h>

void MO_GETOFF(x,a,y,dyda,na)
float x,a[],*y,dyda[];
int na;
{
	int i,j,k,ii,jj;
	float fac,ex,arg,cnt;
	double xd;
	for (k=1;k<=na;k++) {
	  dyda[k]=0;
	}
	if (x==0){
	  *y=0.0;}
	else{
	xd=x;
	cnt=0.0;
	for (ii=1;ii<=na;ii++){
	  for (jj=ii+1;jj<=na;jj++){
	    cnt=cnt+1;
	    if (cnt==x){
	      i=ii;
	      j=jj;
	    }}}
	*y = a[j]-a[i];
	dyda[i] = -1;
	dyda[j] = 1;
      }

}