/*=========================================================================

   Library: iMSTK

   Copyright (c) Kitware, Inc. & Center for Modeling, Simulation,
   & Imaging in Medicine, Rensselaer Polytechnic Institute.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0.txt

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

=========================================================================*/

#pragma once

#include "imstkLinearSolver.h"

namespace imstk
{
///
/// \brief Base class for iterative linear solvers.
///
class IterativeLinearSolver : public LinearSolver<SparseMatrixd>
{
public:
    ///
    /// \brief Default constructor/destructor
    ///
    IterativeLinearSolver() = default;
    virtual ~IterativeLinearSolver() override = default;

    ///
    /// \brief Do one iteration of the method.
    ///
    //virtual void iterate(Vectord& x, bool updateResidual = true) = 0;

    ///
    /// \brief set/get the maximum number of iterations for the iterative solver.
    ///
    virtual void setMaxNumIterations(const size_t maxIter);
    virtual size_t getMaxNumIterations() const;

    ///
    /// \brief Return residual vector
    ///
    virtual const Vectord& getResidualVector();
    virtual const Vectord& getResidualVector(const Vectord& x);

    ///
    /// \brief Return residue in 2-norm
    ///
    virtual double getResidual(const Vectord& x);

    ///
    /// \brief Print solver information.
    ///
    void print() const override;

    ///
    /// \brief Solve the linear system using Gauss-Seidel iterations.
    ///
    virtual void solve(Vectord& x) override;

    ///
    /// \brief Returns true if the solver is iterative
    ///
    bool isIterative() const override
    {
        return true;
    };

protected:
    size_t  m_maxIterations = 100;  ///> Maximum number of iterations to be performed.
    Vectord m_residual;             ///> Storage for residual vector.
};
} //imstk
