FDMMGPCGSolver2.h

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/*************************************************************************
> File Name: FDMMGPCGSolver2.h
> Project Name: CubbyFlow
> Author: Chan-Ho Chris Ohk
> Purpose: 2-D finite difference-type linear system solver using Multigrid
>          Preconditioned conjugate gradient (MGPCG).
> Created Time: 2017/11/05
> Copyright (c) 2018, Chan-Ho Chris Ohk
*************************************************************************/
#ifndef CUBBYFLOW_FDM_MGPCG_SOLVER2_H
#define CUBBYFLOW_FDM_MGPCG_SOLVER2_H

#include <Core/Solver/FDM/FDMMGSolver2.h>

namespace CubbyFlow
{
    class FDMMGPCGSolver2 final : public FDMMGSolver2
    {
    public:
        FDMMGPCGSolver2(
            unsigned int numberOfCGIter,
            size_t maxNumberOfLevels,
            unsigned int numberOfRestrictionIter = 5,
            unsigned int numberOfCorrectionIter = 5,
            unsigned int numberOfCoarsestIter = 20,
            unsigned int numberOfFinalIter = 20,
            double maxTolerance = 1e-9,
            double sorFactor = 1.5,
            bool useRedBlackOrdering = false);

        bool Solve(FDMMGLinearSystem2* system) override;

        unsigned int GetMaxNumberOfIterations() const;

        unsigned int GetLastNumberOfIterations() const;

        double GetTolerance() const;

        double GetLastResidual() const;

    private:
        struct Preconditioner final
        {
            FDMMGLinearSystem2* system;
            MGParameters<FDMBLAS2> mgParams;

            void Build(FDMMGLinearSystem2* system, MGParameters<FDMBLAS2> mgParams);

            void Solve(const FDMVector2& b, FDMVector2* x) const;
        };

        unsigned int m_maxNumberOfIterations;
        unsigned int m_lastNumberOfIterations;
        double m_tolerance;
        double m_lastResidualNorm;

        FDMVector2 m_r;
        FDMVector2 m_d;
        FDMVector2 m_q;
        FDMVector2 m_s;
        Preconditioner m_precond;
    };

    using FDMMGPCGSolver2Ptr = std::shared_ptr<FDMMGPCGSolver2>;
}

#endif