#define FT(i,j,k) ((*this)(subseed,i+x,j+y,k+t)*(R((i)-a)*R(b-(j))*R((k)-c)))
#define Z(i,j) ret+=F(i,j)
#define ZT(i,j,k) ret+=FT(i,j,k)
#define FT(i,j,k) ((*this)(subseed,i+x,j+y,k+t)*(R((i)-a)*R(b-(j))*R((k)-c)))
#define Z(i,j) ret+=F(i,j)
#define ZT(i,j,k) ret+=FT(i,j,k)