anchor.diff:            Real      SRHO1, VRHO1, SRHON, VRHON, RHO1M, RHONP
             Real      RHOT1M, RHOTNP, RHOTD1M, RHOTDNP
             Logical   PBC
  +
             Integer,Parameter :: NPT = 202
  -          Real,Parameter :: BIGNUM = 1.0E38
  +          Real,Parameter :: BIGNUM = Huge(1.)
   c     BIGNUM = Machine Dependent Largest Number - Set By The User!!!!
   
             Real, Intent(IN)  ::   RHOO(NPT)     
  
positive.code: 
            Integer, Intent(IN)  ::     I1, INP, ALPHA
            Real, Intent(IN)     ::     RADHO(INP), RADHN(INP)
            Real     PI, FTPI
  
  c     /FCT_SCRH/ Holds scratch arrays for use by LCPFCT and CNVFCT
            Real     SCRH(NPT),     SCR1(NPT),     DIFF(NPT)
  
negative.code:          case(3)
  c  + D is added to SOURCE in an explicit formulation . . .
  C-----------------------------------------------------------------------
    303    Do I = I1, IN
              SOURCE(I) = SOURCE(I) + DT*LO(I)*D(I)
           End do
        Return
  