DiagonalRHFFockMatrixObjective.hpp

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// This file is part of GQCG-GQCP.
//
// Copyright (C) 2017-2020  the GQCG developers
//
// GQCG-GQCP is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GQCG-GQCP is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with GQCG-GQCP.  If not, see <http://www.gnu.org/licenses/>.
 
#pragma once
 
 
#include "QCModel/HF/RHF.hpp"
 
 
namespace GQCP {
 
 
template <typename _Scalar>
class DiagonalRHFFockMatrixObjective {
 
public:
    using Scalar = _Scalar;
 
 
private:
    double precision;                       // The precision with which the diagonality of the Fock matrix should be checked.
    RSQHamiltonian<Scalar> sq_hamiltonian;  // The Hamiltonian expressed in a scalar basis.
 
 
public:
    /*
     *  CONSTRUCTORS
     */
 
    DiagonalRHFFockMatrixObjective(const RSQHamiltonian<Scalar>& sq_hamiltonian, const double precision = 1.0e-08) :
        precision {precision},
        sq_hamiltonian {sq_hamiltonian} {}
 
 
    /*
     *  PUBLIC METHODS
     */
 
    bool isSatisfiedWith(const QCModel::RHF<Scalar>& rhf_parameters) const {
 
        // Prepare the calculation of the Fock matrix in the spinor basis.
        const auto N_P = rhf_parameters.numberOfElectronPairs();
        const auto C = rhf_parameters.expansion();
        const auto D = QCModel::RHF<Scalar>::calculateScalarBasis1DM(C, 2 * N_P);
 
        // Calculate the Fock matrix in the orthonormal spinor and check if it is diagonal.
        auto F_orthonormal = QCModel::RHF<Scalar>::calculateScalarBasisFockMatrix(D, this->sq_hamiltonian);  // The converged Fock matrix (expressed in the scalar orbital basis).
        F_orthonormal.transform(C);                                                                          // Now in the orthonormal spinor basis.
        return F_orthonormal.parameters().isDiagonal(this->precision);
    }
};
 
 
}  // namespace GQCP