imstkNonLinearSolver.h

/*
** This file is part of the Interactive Medical Simulation Toolkit (iMSTK)
** iMSTK is distributed under the Apache License, Version 2.0.
** See accompanying NOTICE for details.
*/

#pragma once

#include "imstkNonLinearSystem.h"
#include "imstkMath.h"
#include "imstkSolverBase.h"

#include <array>
#include <functional>

namespace imstk
{
template<typename SystemMatrix>
class NonLinearSolver : public SolverBase
{
public:
    using JacobianType      = std::function<const SystemMatrix& (const Vectord&)>;
    using UpdateIterateType = std::function<void (const Vectord&, Vectord&)>;
    using FunctionType      = NonLinearSystem<SparseMatrixd>::VectorFunctionType;

    NonLinearSolver();
    ~NonLinearSolver() override = default;

    virtual void solveGivenState(Vectord& x) = 0;
    virtual void solve() override = 0;

    double armijo(const Vectord& dx, Vectord& x, const double previousFnorm);

    void parabolicModel(const std::array<double, 3>& fnorm,
                        std::array<double, 3>& lambda);

    void setSigma(const std::array<double, 2>& newSigma);
    const std::array<double, 2>& getSigma() const;

    void setAlpha(const double newAlpha);
    double getAlpha() const;

    void setArmijoMax(const size_t newArmijoMax);
    size_t getArmijoMax() const;

    void setSystem(std::shared_ptr<NonLinearSystem<SystemMatrix>> newSystem);
    std::shared_ptr<NonLinearSystem<SystemMatrix>> getSystem() const;

    void setUpdateIterate(const UpdateIterateType& newUpdateIterate)
    {
        m_updateIterate = newUpdateIterate;
    }

    virtual void setToFullyImplicit()
    {
        m_isSemiImplicit = false;
    }

    virtual void setToSemiImplicit()
    {
        m_isSemiImplicit = true;
    }

protected:
    std::array<double, 2> m_sigma;                                    
    double m_alpha;                                                   
    size_t m_armijoMax;                                               

    std::shared_ptr<NonLinearSystem<SystemMatrix>> m_nonLinearSystem; 
    UpdateIterateType m_updateIterate;                                
    bool m_isSemiImplicit = false;                                    
};
} // namespace imstk