anchor.diff:  
   end subroutine cholsl
   
  -!***************************************************************************************************
  +!*******************************************************************************
  
positive.code: 
  end subroutine choldc
  
  !***************************************************************************************************
  
  subroutine cholsl(a,n,np,p,b,x)
    
  
negative.code:         latwgt = dsin(thetag)
          do ilon = 0, nlon-1
  
            !COMPUTE SPHERICAL HARMONICS OF CURRENT GEODETIC LONGITUDE AND
            !LATITUDE
            glon = lonspace*real(ilon) - 180E0
            phig = dble(glon) * dtor
            call shcalc(thetag,phig)
            shg = sh
  
            !COMPUTE REFERENCE (DIPOLE) MAGNETIC LATITUDE AND LONGITUDE OF
            !CURRENT LOCATION
            xq0 = dot_product(coeff0(Rpt,iepoch,0),shg(Rpt))
            yq0 = dot_product(coeff0(Rpt,iepoch,1),shg(Rpt))
            zq0 = dot_product(coeff0(Rpt,iepoch,2),shg(Rpt))
  