anchor.diff:    IF (bcrod == 1) CALL crod_updt(xbpos)
     CALL Dsigr_updt()
   
  +  call check_xs()
  +
     fn = get_time()
     xs_time = xs_time + (fn-st)
   
  
positive.code:   IF (bcrod == 1) CALL crod_tab_updt(xbpos)
    CALL Dsigr_updt()
  
    fn = get_time()
    xs_time = xs_time + (fn-st)
  
  
    END SUBROUTINE XStab_updt
  
    !******************************************************************************!
  
  
negative.code: 
               dum = dum + zdel(k)
             END DO
             ! if negative CX found, Surpress CX to zero and calculate D and sigr
             DO k = nzz, 1, -1
               DO g = 1, ng
                  IF (siga(xyz(i,j,k),g) < 0.) siga(xyz(i,j,k),g) = 0.
  