anchor.diff:           case(3)
   c  + D is added to SOURCE in an explicit formulation . . .
   C-----------------------------------------------------------------------
  -  303    Do  I = I1, IN
  +  303    Do I = I1, IN
               SOURCE(I) = SOURCE(I) + DT*LO(I)*D(I)
            End do
         Return
  
positive.code:           Do I = I1, INP
               HADUDTH(I) = DT*AH(I)*UH(I) - ADUGTH(I)
               EPSH(I) = HADUDTH(I)*RLH(I)
               SCRH(I) = MIN ( ONE6TH, ABS(EPSH(I)) )           
               SCRH(I) = ONE3RD*SCRH(I)**2
               HADUDTH(I) = 0.5*HADUDTH(I)
               NULH(I) =  ONE6TH + ONE3RD*(EPSH(I) + SCRH(I))*
  
negative.code: 
            Integer, Intent(IN)  ::     I1, INP, ALPHA
            Real, Intent(IN)     ::     RADHO(INP), RADHN(INP)
  
  c     /FCT_SCRH/ Holds scratch arrays for use by LCPFCT and CNVFCT
            Real     SCRH(NPT),     SCR1(NPT),     DIFF(NPT)
  