UHFSCFSolver.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 "Mathematical/Algorithm/CompoundConvergenceCriterion.hpp"
#include "Mathematical/Algorithm/IterativeAlgorithm.hpp"
#include "Mathematical/Optimization/ConsecutiveIteratesNormConvergence.hpp"
#include "QCMethod/HF/UHF/UHFDensityMatrixCalculation.hpp"
#include "QCMethod/HF/UHF/UHFElectronicEnergyCalculation.hpp"
#include "QCMethod/HF/UHF/UHFErrorCalculation.hpp"
#include "QCMethod/HF/UHF/UHFFockMatrixCalculation.hpp"
#include "QCMethod/HF/UHF/UHFFockMatrixDIIS.hpp"
#include "QCMethod/HF/UHF/UHFFockMatrixDiagonalization.hpp"
#include "QCMethod/HF/UHF/UHFSCFEnvironment.hpp"
 
 
namespace GQCP {
 
 
template <typename _Scalar>
class UHFSCFSolver {
public:
    using Scalar = _Scalar;
 
 
public:
    /*
     *  PUBLIC STATIC METHODS
     */
 
    static IterativeAlgorithm<UHFSCFEnvironment<Scalar>> DIIS(const size_t minimum_subspace_dimension = 6, const size_t maximum_subspace_dimension = 6, const double threshold = 1.0e-08, const size_t maximum_number_of_iterations = 128) {
 
        // Create the iteration cycle that effectively 'defines' a DIIS UHF SCF solver.
        StepCollection<UHFSCFEnvironment<Scalar>> diis_uhf_scf_cycle {};
        diis_uhf_scf_cycle
            .add(UHFDensityMatrixCalculation<Scalar>())
            .add(UHFFockMatrixCalculation<Scalar>())
            .add(UHFErrorCalculation<Scalar>())
            .add(UHFFockMatrixDIIS<Scalar>(minimum_subspace_dimension, maximum_subspace_dimension))  // This also calculates the next coefficient matrix.
            .add(UHFElectronicEnergyCalculation<Scalar>());
 
        // Create a convergence criterion on the norm of subsequent density matrices.
        const std::function<std::deque<SpinResolved1DM<Scalar>>(const UHFSCFEnvironment<Scalar>&)> density_matrix_extractor = [](const UHFSCFEnvironment<Scalar>& environment) { return environment.density_matrices; };
 
        using ConvergenceType = ConsecutiveIteratesNormConvergence<SpinResolved1DM<Scalar>, UHFSCFEnvironment<Scalar>>;
        const ConvergenceType convergence_criterion {threshold, density_matrix_extractor, "the UHF spin resolved density matrix in AO basis"};
 
        return IterativeAlgorithm<UHFSCFEnvironment<Scalar>>(diis_uhf_scf_cycle, convergence_criterion, maximum_number_of_iterations);
    }
 
 
    static IterativeAlgorithm<UHFSCFEnvironment<Scalar>> Plain(const double threshold = 1.0e-08, const size_t maximum_number_of_iterations = 128) {
 
        // Create the iteration cycle that effectively 'defines' a plain UHF SCF solver.
        StepCollection<UHFSCFEnvironment<Scalar>> plain_uhf_scf_cycle {};
        plain_uhf_scf_cycle
            .add(UHFDensityMatrixCalculation<Scalar>())
            .add(UHFFockMatrixCalculation<Scalar>())
            .add(UHFFockMatrixDiagonalization<Scalar>())
            .add(UHFElectronicEnergyCalculation<Scalar>());
 
        // Create a convergence criterion on the norm of subsequent density matrices.
        const std::function<std::deque<SpinResolved1DM<Scalar>>(const UHFSCFEnvironment<Scalar>&)> density_matrix_extractor = [](const UHFSCFEnvironment<Scalar>& environment) { return environment.density_matrices; };
 
        using ConvergenceType = ConsecutiveIteratesNormConvergence<SpinResolved1DM<Scalar>, UHFSCFEnvironment<Scalar>>;
        const ConvergenceType convergence_criterion {threshold, density_matrix_extractor, "the UHF spin resolved density matrix in AO basis"};
 
        return IterativeAlgorithm<UHFSCFEnvironment<Scalar>>(plain_uhf_scf_cycle, convergence_criterion, maximum_number_of_iterations);
    }
};
 
 
}  // namespace GQCP