anchor.diff:  !$OMP PARALLEL &
   !$OMP PRIVATE(bvx, actv) &
   !$OMP PRIVATE(b_w, b_e, b_s, b_n, b_b, b_t) &
  +!$OMP PRIVATE(w_w, w_e, w_s, w_n, w_b, w_t) &
   !$OMP PRIVATE(Ue, Uw, Vn, Vs, Wt, Wb) &
   !$OMP PRIVATE(Ue0, Uw0, Up0, Vn0, Vs0, Vp0, Wb0, Wt0, Wp0) &
   !$OMP PRIVATE(c_e, c_w, c_n, c_s, c_t, c_b) &
  
positive.code:       b_b = real( ibits(bv(i  ,j  ,k-1), State, 1) )
        b_t = real( ibits(bv(i  ,j  ,k+1), State, 1) )
  
        Uw = 0.5*( Up0 + Uw0 )*b_w
        Ue = 0.5*( Up0 + Ue0 )*b_e
        Vs = 0.5*( Vp0 + Vs0 )*b_s
        Vn = 0.5*( Vp0 + Vn0 )*b_n
        Wb = 0.5*( Wp0 + Wb0 )*b_b
        Wt = 0.5*( Wp0 + Wt0 )*b_t
  
        ! 各面のVBCフラグ ibits() = 0(Normal) / others(BC) >> c_e = 1.0(Normal) / 0.0(BC)
        c_e = 1.0
  
negative.code:     real                                                      ::  Ue0, Uw0, Up0, Vn0, Vs0, Vp0, Wb0, Wt0, Wp0
      real                                                      ::  c_e, c_w, c_n, c_s, c_t, c_b
      real                                                      ::  b_w, b_e, b_s, b_n, b_b, b_t
      real                                                      ::  w_w, w_e, w_s, w_n, w_b, w_t
      real, dimension(1-g:sz(1)+g, 1-g:sz(2)+g, 1-g:sz(3)+g, 3) ::  v0
      real, dimension(1-g:sz(1)+g, 1-g:sz(2)+g, 1-g:sz(3)+g)    ::  div
      integer, dimension(1-g:sz(1)+g, 1-g:sz(2)+g, 1-g:sz(3)+g) ::  bv
  