anchor.diff:  C----
   C Source and halfspace constants
   C----
  +      rakin = 0.0d0
         call dipvar(dipin)
         call hafspc(vp,vs,dens)
         call moment1vol(Mvol,slip)
  
positive.code: C----
        IMPLICIT NONE
        REAL*8 x,y,stdp,evdp,z,c,d
        REAL*8 dipin,rakin,area,dvol,Mvol
        REAL*8 vp,vs,dens
        INTEGER i,j
        REAL*8 fx(6,3),fy(6,3),fz(6,3),f(6),ux(6,3),uy(6,3),uz(6,3),u(6)
  
negative.code: 
        IMPLICIT none
        REAL*8 x,y,stdp,evdp,z,c,d             ! Coordinates
        REAL*8 dipin,dvol,Mvol      ! Fault parameters
        REAL*8 vp,vs,dens                      ! Half-space parameters
        INTEGER i,j
        REAL*8 u(6,3),f(6,3),ux,uy,uz
  