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//        MueLu: A package for multigrid based preconditioning
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// @HEADER
#ifndef MUELU_SHIFTEDLAPLACIAN_DECL_HPP
#define MUELU_SHIFTEDLAPLACIAN_DECL_HPP

// Xpetra
#include <Xpetra_Matrix_fwd.hpp>
#include <Xpetra_VectorFactory_fwd.hpp>
#include <Xpetra_MultiVectorFactory_fwd.hpp>
#include <Xpetra_TpetraMultiVector.hpp>

// MueLu
#include "MueLu.hpp"
#include "MueLu_ConfigDefs.hpp"

#if defined(HAVE_MUELU_IFPACK2) and defined(HAVE_MUELU_TPETRA)

#include <MueLu_BaseClass.hpp>
#include <MueLu_CoalesceDropFactory_fwd.hpp>
#include <MueLu_CoupledAggregationFactory_fwd.hpp>
#include <MueLu_CoupledRBMFactory_fwd.hpp>
#include <MueLu_DirectSolver_fwd.hpp>
#include <MueLu_GenericRFactory_fwd.hpp>
#include <MueLu_Hierarchy_fwd.hpp>
#include <MueLu_Ifpack2Smoother_fwd.hpp>
#include <MueLu_PFactory_fwd.hpp>
#include <MueLu_PgPFactory_fwd.hpp>
#include <MueLu_RAPFactory_fwd.hpp>
#include <MueLu_RAPShiftFactory_fwd.hpp>
#include <MueLu_SaPFactory_fwd.hpp>
#include <MueLu_ShiftedLaplacian_fwd.hpp>
#include <MueLu_ShiftedLaplacianOperator.hpp>
#include <MueLu_SmootherFactory_fwd.hpp>
#include <MueLu_SmootherPrototype_fwd.hpp>
#include <MueLu_TentativePFactory_fwd.hpp>
#include <MueLu_TransPFactory_fwd.hpp>
#include <MueLu_UncoupledAggregationFactory_fwd.hpp>
#include <MueLu_Utilities_fwd.hpp>

// Belos
#ifdef HAVE_MUELU_TPETRA_INST_INT_INT
#include <BelosConfigDefs.hpp>
#include <BelosLinearProblem.hpp>
#include <BelosSolverFactory.hpp>
#include <BelosTpetraAdapter.hpp>
#endif

namespace MueLu {

  /*!
    @brief Shifted Laplacian Helmholtz solver

    This class provides a black box solver for indefinite Helmholtz problems.
    An AMG-Shifted Laplacian is used as a preconditioner for Krylov iterative
    solvers in Belos.

    @ingroup MueLuAdapters
  */
  template <class Scalar        = Xpetra::Matrix<>::scalar_type,
            class LocalOrdinal  = typename Xpetra::Matrix<Scalar>::local_ordinal_type,
            class GlobalOrdinal = typename Xpetra::Matrix<Scalar, LocalOrdinal>::global_ordinal_type,
            class Node          = typename Xpetra::Matrix<Scalar, LocalOrdinal, GlobalOrdinal>::node_type>
  class ShiftedLaplacian : public BaseClass {
#undef MUELU_SHIFTEDLAPLACIAN_SHORT
#include "MueLu_UseShortNames.hpp"

    typedef Tpetra::Vector<SC,LO,GO,NO>                  TVEC;
    typedef Tpetra::MultiVector<SC,LO,GO,NO>             TMV;
    typedef Tpetra::Operator<SC,LO,GO,NO>                OP;
#ifdef HAVE_MUELU_TPETRA_INST_INT_INT
    typedef Belos::LinearProblem<SC,TMV,OP>              LinearProblem;
    typedef Belos::SolverManager<SC,TMV,OP>              SolverManager;
    typedef Belos::SolverFactory<SC,TMV,OP>              SolverFactory;
#endif

  public:

  /*
    FIXME  26-June-2015 JJH:  This contructor is setting numerous defaults.  However, they don't match the defaults
    FIXME  int the method setParameters().  There also isn't any parameter validation that I can see.
  */

    //! Constructors
    ShiftedLaplacian():
      numPDEs_(1),
      Smoother_("schwarz"),
      Aggregation_("uncoupled"),
      Nullspace_("constant"),
      numLevels_(5),
      coarseGridSize_(100),
      omega_(2.0*M_PI),
      iters_(500),
      blksize_(1),
      tol_(1.0e-4),
      nsweeps_(5),
      ncycles_(1),
      cycles_(8),
      subiters_(10),
      option_(1),
      nproblems_(0),
      solverType_(1),
      restart_size_(100),
      recycle_size_(25),
      smoother_sweeps_(4),
      smoother_damping_((SC)1.0),
      krylov_type_(1),
      krylov_iterations_(5),
      krylov_preconditioner_(1),
      ilu_leveloffill_(5.0),
      ilu_abs_thresh_(0.0),
      ilu_rel_thresh_(1.0),
      ilu_diagpivotthresh_(0.1),
      ilu_drop_tol_(0.01),
      ilu_fill_tol_(0.01),
      ilu_relax_val_(1.0),
      ilu_rowperm_("LargeDiag"),
      ilu_colperm_("COLAMD"),
      ilu_drop_rule_("DROP_BASIC"),
      ilu_normtype_("INF_NORM"),
      ilu_milutype_("SILU"),
      schwarz_overlap_(0),
      schwarz_usereorder_(true),
      schwarz_combinemode_(Tpetra::ADD),
      schwarz_ordermethod_("rcm"),
      GridTransfersExist_(false),
      isSymmetric_(true)
    { }

    // Destructor
    virtual ~ShiftedLaplacian();

    // Parameters
    void setParameters(Teuchos::RCP< Teuchos::ParameterList > paramList);

    // Set matrices
    void setProblemMatrix(RCP<Matrix>& A);
    void setProblemMatrix(RCP< Tpetra::CrsMatrix<SC,LO,GO,NO> >& TpetraA);
    void setPreconditioningMatrix(RCP<Matrix>& P);
    void setPreconditioningMatrix(RCP< Tpetra::CrsMatrix<SC,LO,GO,NO> >& TpetraP);
    void setstiff(RCP<Matrix>& K);
    void setstiff(RCP< Tpetra::CrsMatrix<SC,LO,GO,NO> >& TpetraK);
    void setmass(RCP<Matrix>& M);
    void setmass(RCP< Tpetra::CrsMatrix<SC,LO,GO,NO> >& TpetraM);
    void setcoords(RCP<MultiVector>& Coords);
    void setNullSpace(RCP<MultiVector> NullSpace);
    void setLevelShifts(std::vector<Scalar> levelshifts);

    // initialize: set parameters and factories, construct
    // prolongation and restriction matrices
    void initialize();
    // setupFastRAP: setup hierarchy with
    // prolongators of the stiffness matrix
    // constant complex shifts
    void setupFastRAP();
    // setupSlowRAP: setup hierarchy with
    // prolongators of the stiffness matrix
    // variable complex shifts
    void setupSlowRAP();
    // setupNormalRAP: setup hierarchy with
    // prolongators of the preconditioning matrix
    void setupNormalRAP();
    // setupSolver: initialize Belos solver
    void setupSolver();
    // resetLinearProblem: for multiple frequencies;
    // reset the Belos operator if the frequency changes
    void resetLinearProblem();


    // Solve phase
    int solve(const RCP<TMV> B, RCP<TMV>& X);
    void multigrid_apply(const RCP<MultiVector> B,
			 RCP<MultiVector>& X);
    void multigrid_apply(const RCP<Tpetra::MultiVector<SC,LO,GO,NO> > B,
			 RCP<Tpetra::MultiVector<SC,LO,GO,NO> >& X);
    int GetIterations();
    double GetResidual();

    RCP<FactoryManager>               Manager_;

  private:

    // Problem options
    // numPDEs_ -> number of DOFs at each node
    int numPDEs_;

    // Multigrid options
    // numLevels_      -> number of Multigrid levels
    // coarseGridSize_ -> size of coarsest grid (if current level has less DOFs, stop coarsening)
    std::string Smoother_, Aggregation_, Nullspace_;
    int numLevels_, coarseGridSize_;

    // Shifted Laplacian/Helmholtz parameters
    double          omega_;
    std::vector<SC> levelshifts_;

    // Krylov solver inputs
    // iters  -> max number of iterations
    // tol    -> residual tolerance
    int    iters_, blksize_;
    double tol_;
    int    nsweeps_, ncycles_;
    int    cycles_, subiters_, option_, nproblems_, solverType_;
    int    restart_size_, recycle_size_;

    // Smoother parameters
    int    smoother_sweeps_;
    Scalar smoother_damping_;
    int    krylov_type_;
    int    krylov_iterations_;
    int    krylov_preconditioner_;
    double ilu_leveloffill_, ilu_abs_thresh_, ilu_rel_thresh_, ilu_diagpivotthresh_;
    double ilu_drop_tol_, ilu_fill_tol_, ilu_relax_val_;
    std::string ilu_rowperm_, ilu_colperm_, ilu_drop_rule_, ilu_normtype_, ilu_milutype_;
    int    schwarz_overlap_;
    bool   schwarz_usereorder_;
    Tpetra::CombineMode schwarz_combinemode_;
    std::string schwarz_ordermethod_;

    // flags for setup
    bool GridTransfersExist_;
    bool isSymmetric_;

    // Xpetra matrices
    // K_ -> stiffness matrix
    // M_ -> mass matrix
    // A_ -> Problem matrix
    // P_ -> Preconditioning matrix
    RCP<Matrix>                       K_, M_, A_, P_;
    RCP<MultiVector>                  Coords_, NullSpace_;

    // Multigrid Hierarchy
    RCP<Hierarchy>                    Hierarchy_;

    // Factories and prototypes
    RCP<TentativePFactory>            TentPfact_;
    RCP<PFactory>                     Pfact_;
    RCP<PgPFactory>                   PgPfact_;
    RCP<TransPFactory>                TransPfact_;
    RCP<GenericRFactory>              Rfact_;
    RCP<RAPFactory>                   Acfact_;
    RCP<RAPShiftFactory>              Acshift_;
    RCP<CoalesceDropFactory>          Dropfact_;
    RCP<CoupledAggregationFactory>    Aggfact_;
    RCP<UncoupledAggregationFactory>  UCaggfact_;
    RCP<SmootherPrototype>            smooProto_, coarsestSmooProto_;
    RCP<SmootherFactory>              smooFact_,  coarsestSmooFact_;
    Teuchos::ParameterList            coarsestSmooList_;
    std::string                       precType_;
    Teuchos::ParameterList            precList_;

    // Operator and Preconditioner
    RCP< MueLu::ShiftedLaplacianOperator<SC,LO,GO,NO> > MueLuOp_;
    RCP< Tpetra::CrsMatrix<SC,LO,GO,NO> >               TpetraA_;

#ifdef HAVE_MUELU_TPETRA_INST_INT_INT
    // Belos Linear Problem and Solver
    RCP<LinearProblem>                LinearProblem_;
    RCP<SolverManager>                SolverManager_;
    RCP<SolverFactory>                SolverFactory_;
    RCP<Teuchos::ParameterList>       BelosList_;
#endif

  };

}

#define MUELU_SHIFTEDLAPLACIAN_SHORT

#endif //if defined(HAVE_MUELU_IFPACK2) and defined(HAVE_MUELU_TPETRA)

#endif // MUELU_SHIFTEDLAPLACIAN_DECL_HPP
