pokeSpin(PScalar<T1>& l, const PScalar<T2>& r, int row)
pokeSpin(PScalar<T1>& l, const PScalar<T2>& r, int row, int col)
pokeSpin(PScalar<T1>& l, const PScalar<T2>& r, int row){  pokeSpin(l.elem(),r.elem(),row);  return l;}