copy_site(RScalar<T>& d, int isite, const RScalar<T1>& s1)
copy_site(RComplex<T>& d, int isite, const RComplex<T1>& s1)
copy_site(RScalar<T>& d, int isite, const RScalar<T1>& s1){  copy_site(d.elem(), isite, s1.elem());}