/* @(#)mo_mrqmin.c	17.1.1.1 (ESO-SDAG) 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
===========================================================================*/
void MO_MRQMIN(x,y,sig,ndata,a,ma,lista,mfit,covar,alpha,chisq,funcs,alamda)

float x[],y[],sig[],a[],**covar,**alpha,*chisq,*alamda;
int ndata,ma,lista[],mfit;
void (*funcs)();
{
	int k,kk,j,ihit;
	static float *da,*atry,**oneda,*beta,ochisq;
	float *vector(),**matrix();
	void free_matrix(),free_vector();

	if (*alamda < 0.0) {
	   oneda = matrix(1,mfit,1,1);
	   atry  = vector(1,ma);
	   da    = vector(1,ma);
	   beta  = vector(1,ma);
	   /*
           atry = (float *) osmmget( ma * sizeof(float));
	   da   = (float *) osmmget( ma * sizeof(float));
	   beta = (float *) osmmget( ma * sizeof(float));
	   */
	   kk=mfit+1;
	   for (j=1;j<=ma;j++) {
	       ihit=0;
	       for (k=1;k<=mfit;k++)
	           if (lista[k] == j) ihit++;
	       if (ihit == 0)
	          lista[kk++]=j;
               else if (ihit > 1)
                  SCETER(2, "FATAL: Bad LISTA permutation in MRQMIN-1");
	       }
	   if (kk != ma+1) 
              SCETER(2, "FATAL: Bad LISTA permutation in MRQMIN-2");
	   *alamda=0.001;
	   MO_MRQCOF(x,y,sig,ndata,a,ma,lista,mfit,alpha,beta,chisq,funcs);
		     ochisq=(*chisq);
	}
	for (j=1;j<=mfit;j++) {
	    for (k=1;k<=mfit;k++) covar[j][k]=alpha[j][k];
	    covar[j][j]=alpha[j][j]*(1.0+(*alamda));
	    oneda[j][1]=beta[j];
	}
	MO_GAUSSJ(covar,mfit,oneda,1);
	for (j=1;j<=mfit;j++)
	    da[j]=oneda[j][1];
	if (*alamda == 0.0) {
	   MO_COVSRT(covar,ma,lista,mfit);
	   free_vector(beta,1,ma);
	   free_vector(da,1,ma);
	   free_vector(atry,1,ma);
	   free_matrix(oneda,1,mfit,1,1);
	   /*
           osmmfree((char *) beta);
           osmmfree((char *) da);
           osmmfree((char *) atry);
	   */

	   return;
	}
	for (j=1;j<=ma;j++) atry[j]=a[j];
	for (j=1;j<=mfit;j++)
	    atry[lista[j]] = a[lista[j]]+da[j];
	MO_MRQCOF(x,y,sig,ndata,atry,ma,lista,mfit,covar,da,chisq,funcs);
	if (*chisq < ochisq) {
	   *alamda *= 0.1;
	   ochisq=(*chisq);
	   for (j=1;j<=mfit;j++) {
	       for (k=1;k<=mfit;k++) alpha[j][k]=covar[j][k];
	       beta[j]=da[j];
	       a[lista[j]]=atry[lista[j]];
	   }
	} else {
	   *alamda *= 10.0;
	   *chisq=ochisq;
	}
	return;
}