anchor.diff:  p = 0.d0
   DO g= 1, ng
       DO n= 1, nnod
  -        p(n) = p(n) + f0(n,g) * sigf(n,g)
  +        p(n) = p(n) + f0(n,g) * sigf(n,g) * vdel(n)
       END DO
   END DO
  +
  +!STOP
   
   ! Normalize to 1.0
   tpow = 0.
  
positive.code: IMPLICIT NONE
  
  INTEGER, INTENT(IN) :: gt
  REAL, DIMENSION(:), INTENT(INOUT) :: s, sx1, sy1, sz1
  REAL, DIMENSION(:), INTENT(INOUT) :: sx2, sy2, sz2
  
  INTEGER :: h, n
  
  DO h = 1, ng
      DO n = 1, nnod
  
negative.code:     Keo = Ke
      erro = errn
      DO g = ng,1,-1
  
          !!!Calculate Scattering source
          CALL SSrcAd(g, ss0, ssx1, ssy1, ssz1, ssx2, ssy2, ssz2)
  