scan.c

      temp2 = xm2*ym2-xym*xym;
      obj->singuflag = 1;
      }
    else
      obj->singuflag = 0;

    if ((fabs(temp=xm2-ym2)) > 0.0)
      theta = atan2(2.0 * xym,temp) / 2.0;
    else
      theta = PI/4.0;

    temp = sqrt(0.25*temp*temp+xym*xym);
    pmy2 = pmx2 = 0.5*(xm2+ym2);
    pmx2+=temp;
    pmy2-=temp;

    obj->dnpix = (obj->flag & OBJ_OVERFLOW)? obj->fdnpix:(LONG)dnpix;
    obj->dflux = tv;
    obj->mx = xm+xmin;	/* add back xmin */
    obj->my = ym+ymin;	/* add back ymin */
    obj->mx2 = xm2;
    obj->my2 = ym2;
    obj->mxy = xym;
    obj->a = (float)sqrt(pmx2);
    obj->b = (float)sqrt(pmy2);
    obj->theta = theta*180.0/PI;

    obj->cxx = (float)(ym2/temp2);
    obj->cyy = (float)(xm2/temp2);
    obj->cxy = (float)(-2*xym/temp2);

    darea = (double)area2 - dnpix;
    t1t2 = thresh/thresh2;
    if (t1t2>0.0 && !prefs.dweight_flag)
      {
      obj->abcor = (darea<0.0?darea:-1.0)/(2*PI*log(t1t2<1.0?t1t2:0.99)
	*obj->a*obj->b);
      if (obj->abcor>1.0)
        obj->abcor = 1.0;
      }
    else
      obj->abcor = 1.0;
    }

  return;
  }