/*      FILE: fmodel.c
 *   PURPOSE: Compute the model 
 *    AUTHOR: Kenneth J. Mighell (mighell@noao.edu)
 *  LANGUAGE: ANSI C
 *      DATE: 2001SEP10
 * COPYRIGHT: (C) 2001 Assoc. of Universities for Research in Astronomy Inc.
 *
 * COMMENT:
 *
 *    MXNPARL=7  
 *  
 *  and
 *
 *    ad[0] is B0 (=B_0      constant value of background )
 *    ad[1] is BX (=B_X      X slope value of background )
 *    ad[2] is BY (=B_Y      Y slope value of background )
 *    ad[3] is S0 (=I_0      intensity of 2-d Gaussian )
 *    ad[4] is SX (=X_0      X coordinate of 2-d Gaussian )
 *    ad[5] is SY (=Y_0      Y coordiante of 2-d Gaussian )
 *    ad[6] is SS (=SIGMA_0  standard deviation of 2-d Gaussian )
 *
 *  where
 *
 *    Z = B_0 + + (X*B_X) + (Y*B_Y) + I_0*Gaussian( X, Y; X_0, Y_0, SIGMA_0)
 *
 *  is a Gaussian centered at (X_0,Y_0) on a tilted background
 *
 */

#include "mx.h"
#include "inc.h"

int fmodel_i7(
  double **matrix,
  double **psfmatrix,
  double **xmatrix,
  double **ymatrix,
  int nx,
  int ny,
  double ad[]
){
  int
    status,
    xi,
    yi;
  const int res=5;
  double 
    xd, 
    yd, 
    psfd,
    md,
    b0,
    bx,
    by,
    s0;

  s0 = ad[3];
  b0 = ad[0];
  bx = ad[1];
  by = ad[2];
  for (yi=0; yi<ny; yi++) {
    for (xi=0; xi<nx; xi++) {
      psfd = psfmatrix[yi][xi],
      xd = xmatrix[yi][xi],
      yd = ymatrix[yi][xi],
      md = s0*psfd + b0 + (bx*xd) + (by*yd);
      matrix[yi][xi] = md;
    }
  }

bye:
  status=0;
error:
  return(status);
}
/* end-of-file */