anchor.diff:  c     **** other constants ****
         real*8 onethird,fourthird,fivethird,onesixthm
         real*8 twothird,sevensixthm
  -      real*8 onethirdm
  +      real*8 onethirdm,n13
         parameter (onethird=1.0d0/3.0d0)
         parameter (onethirdm=-1.0d0/3.0d0)
         parameter (twothird=2.0d0/3.0d0)
  
positive.code: 
        return
        end
  
   
  
negative.code: *     **** Density cutoff parameter ****
        real*8 DNS_CUT,ETA,ETA2,alpha_zeta,alpha_zeta2
        parameter (DNS_CUT = 1.0d-20)
        parameter (ETA=1.0d-12)
        parameter (ETA2=1.0d-6)
        parameter (alpha_zeta=(1.0d0-ETA2))
        parameter (alpha_zeta2=(1.0d0-ETA2))
  
  