anchor.diff:                else
                    grav_force_S = mass_S / r_S
                 endif
  -              
  +
                 if (grav_force_P > ZERO .and. grav_force_P > grav_force_S) then
                    volp = volp + vol(i,j,k)
                 else if (grav_force_S > ZERO .and. grav_force_S > grav_force_P) then
                    vols = vols + vol(i,j,k)
                 endif
  -             
  +
              endif
   
           enddo
  
positive.code:   double precision :: dQtt(3,3)
  
    dQtt(:,:) = ZERO
    
    do k = lo(3), hi(3)
       r(3) = problo(3) + (k + HALF) * dx(3) - center(3)
       do j = lo(2), hi(2)
          r(2) = problo(2) + (j + HALF) * dx(2) - center(2)
          do i = lo(1), hi(1)
             r(1) = problo(1) + (i + HALF) * dx(1) - center(1)
  
             if (rho(i,j,k) > ZERO) then
                rhoInv = ONE / rho(i,j,k)
  
negative.code:   ! Determine the original location of the center.
  
    if (dim .eq. 3) then
  
       center(1) = problo(1) + center_fracx * (probhi(1) - problo(1))
       center(2) = problo(2) + center_fracy * (probhi(2) - problo(2))
       center(3) = problo(3) + center_fracz * (probhi(3) - problo(3))
  