void InvCG2(const LinearOperator<LatticeStaggeredFermion>& M, const LatticeStaggeredFermion& chi, LatticeStaggeredFermion& psi,
void InvCG2(const LinearOperator<LatticeFermion>& M, const LatticeFermion& chi, LatticeFermion& psi,
void InvCG2(const LinearOperator<LatticeStaggeredFermion>& M,	    const LatticeStaggeredFermion& chi,	    LatticeStaggeredFermion& psi,	    const Real& RsdCG, 	    int MaxCG, 	    int& n_count){  InvCG2_a(M, chi, psi, RsdCG, MaxCG, n_count);}