GlobalLinSysIterative.h

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///////////////////////////////////////////////////////////////////////////////
//
// File GlobalLinSysIterative.h
//
// For more information, please see: http://www.nektar.info
//
// The MIT License
//
// Copyright (c) 2006 Division of Applied Mathematics, Brown University (USA),
// Department of Aeronautics, Imperial College London (UK), and Scientific
// Computing and Imaging Institute, University of Utah (USA).
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
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// Description: GlobalLinSysIterative header
//
///////////////////////////////////////////////////////////////////////////////
#ifndef NEKTAR_LIB_MULTIREGIONS_GLOBALLINSYSITERATIVE_H
#define NEKTAR_LIB_MULTIREGIONS_GLOBALLINSYSITERATIVE_H
 
#include <MultiRegions/MultiRegionsDeclspec.h>
#include <MultiRegions/GlobalLinSys.h>
#include <MultiRegions/Preconditioner.h>
 
#include <boost/circular_buffer.hpp>
 
namespace Nektar
{
    namespace MultiRegions
    {
        // Forward declarations
        class ExpList;
 
        /// A global linear system.
        class GlobalLinSysIterative : virtual public GlobalLinSys
        {
        public:
            /// Constructor for full direct matrix solve.
            MULTI_REGIONS_EXPORT GlobalLinSysIterative(
                    const GlobalLinSysKey                &pKey,
                    const std::weak_ptr<ExpList>         &pExpList,
                    const std::shared_ptr<AssemblyMap>   &pLocToGloMap);
 
            MULTI_REGIONS_EXPORT virtual ~GlobalLinSysIterative();
 
        protected:
            /// Global to universal unique map
            Array<OneD, int>                            m_map;
 
            /// maximum iterations
            int                                         m_maxiter;
 
            /// Tolerance of iterative solver.
            NekDouble                                   m_tolerance;
 
            /// dot product of rhs to normalise stopping criterion
            NekDouble                                   m_rhs_magnitude;
 
            /// cnt to how many times rhs_magnitude is called 
            NekDouble                                   m_rhs_mag_sm; 
            
            PreconditionerSharedPtr                     m_precon;
 
            MultiRegions::PreconditionerType            m_precontype;
            
            int                                         m_totalIterations;
 
            /// Whether to apply projection technique
            bool                                        m_useProjection;
 
            /// Root if parallel
            bool                                        m_root;
 
            /// Storage for solutions to previous linear problems
            boost::circular_buffer<Array<OneD, NekDouble> > m_prevLinSol;
 
            /// Total counter of previous solutions
            int m_numPrevSols;
 
            /// A-conjugate projection technique
            void DoAconjugateProjection(
                    const int pNumRows,
                    const Array<OneD,const NekDouble> &pInput,
                          Array<OneD,      NekDouble> &pOutput,
                    const AssemblyMapSharedPtr &locToGloMap,
                    const int pNumDir);
 
            /// Actual iterative solve
            void DoConjugateGradient(
                    const int pNumRows,
                    const Array<OneD,const NekDouble> &pInput,
                          Array<OneD,      NekDouble> &pOutput,
                    const AssemblyMapSharedPtr &locToGloMap,
                    const int pNumDir);
 
 
            void Set_Rhs_Magnitude(const NekVector<NekDouble> &pIn);
 
            virtual void v_UniqueMap() = 0;
            
        private:
            void UpdateKnownSolutions(
                    const int pGlobalBndDofs,
                    const Array<OneD,const NekDouble> &pSolution,
                    const int pNumDirBndDofs);
 
            NekDouble CalculateAnorm(
                    const int nGlobal,
                    const Array<OneD,const NekDouble> &in,
                    const int nDir);
 
 
            /// Solve the matrix system
            virtual void v_SolveLinearSystem(
                    const int pNumRows,
                    const Array<OneD,const NekDouble> &pInput,
                          Array<OneD,      NekDouble> &pOutput,
                    const AssemblyMapSharedPtr &locToGloMap,
                    const int pNumDir);
 
            virtual void v_DoMatrixMultiply(
                    const Array<OneD, NekDouble>& pInput,
                          Array<OneD, NekDouble>& pOutput) = 0;
        };
    }
}
 
#endif