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/*
 * MueLu_BlockedGaussSeidelSmoother_decl.hpp
 *
 *  Created on: 30.01.2012
 *      Author: tobias
 */

#ifndef MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_DECL_HPP_
#define MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_DECL_HPP_

#include "MueLu_ConfigDefs.hpp"

#include <Teuchos_ParameterList.hpp>

#include <Xpetra_MapExtractor_fwd.hpp>

#include "MueLu_BlockedGaussSeidelSmoother_fwd.hpp"

#include "MueLu_SmootherPrototype.hpp"
#include "MueLu_FactoryBase_fwd.hpp"
#include "MueLu_FactoryManagerBase_fwd.hpp"
#include "MueLu_SmootherBase_fwd.hpp"
#include "MueLu_Utilities_fwd.hpp"

namespace MueLu {

  /*!
    @class BlockedGaussSeidelSmoother
    @brief block Gauss-Seidel method for blocked matrices

    Implementation of a block Gauss-Seidel methods for blocked matrices
    @param LocalOrdinal sweeps = 1: number of BGS sweeps
    @param Scalar omega = 1.0: damping parameter
    @param RCP<FactoryBase> AFact = Teuchos::null: factory for blocked "A" operator

    Use the AddFactoryManager routine to declare the subsmoothers/subsolvers for the block Gauss-Seidel method for
    the block rows. The corresponding factory manager has to provide a variable "A" (pointing to the subblock of the blocked A operator)
    and a smoother object (variable: "PreSmoother").

    Example
    \code

    // prototypes for direct solvers for blocks 1 and 2
    RCP<SmootherPrototype> smoProto11     = rcp( new DirectSolver("", Teuchos::ParameterList(), A11Fact) );
    RCP<SmootherPrototype> smoProto22     = rcp( new DirectSolver("", Teuchos::ParameterList(), A22Fact) );
    RCP<SmootherFactory> Smoo11Fact = rcp( new SmootherFactory(smoProto11) );
    RCP<SmootherFactory> Smoo22Fact = rcp( new SmootherFactory(smoProto22) );

    // define factory manager objects for sublocks
    RCP<FactoryManager> M11 = rcp(new FactoryManager());
    M11->SetFactory("A", A11Fact);
    M11->SetFactory("Smoother", Smoo11Fact);

    RCP<FactoryManager> M22 = rcp(new FactoryManager());
    M22->SetFactory("A", A22Fact);
    M22->SetFactory("Smoother", Smoo22Fact);

    // create blocked Gauss-Seidel smoother for 2x2 blocked matrix
    RCP<BlockedGaussSeidelSmoother> smootherPrototype     = rcp( new BlockedGaussSeidelSmoother(2,1.0) );
    smootherPrototype->AddFactoryManager(M11);
    smootherPrototype->AddFactoryManager(M22);
    RCP<SmootherFactory>   smootherFact          = rcp( new SmootherFactory(smootherPrototype) );

    // use smootherFact in main-factory manager
    \endcode
  */

  template <class Scalar = SmootherPrototype<>::scalar_type,
            class LocalOrdinal = typename SmootherPrototype<Scalar>::local_ordinal_type,
            class GlobalOrdinal = typename SmootherPrototype<Scalar, LocalOrdinal>::global_ordinal_type,
            class Node = typename SmootherPrototype<Scalar, LocalOrdinal, GlobalOrdinal>::node_type>
  class BlockedGaussSeidelSmoother :
    public SmootherPrototype<Scalar,LocalOrdinal,GlobalOrdinal,Node>
  {
    typedef Xpetra::MapExtractor<Scalar, LocalOrdinal, GlobalOrdinal, Node> MapExtractorClass;

#undef MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_SHORT
#include "MueLu_UseShortNames.hpp"

  public:

    //! @name Constructors / destructors
    //@{

    /*! @brief Constructor
    */
    BlockedGaussSeidelSmoother();

    //! Destructor
    virtual ~BlockedGaussSeidelSmoother();
    //@}

    //! Input
    //@{
    RCP<const ParameterList> GetValidParameterList() const;

    void DeclareInput(Level &currentLevel) const;

    //! Add a factory manager
    //void AddFactoryManager(RCP<const FactoryManagerBase> FactManager);

    //! Add a factory manager at a specific position
    void AddFactoryManager(RCP<const FactoryManagerBase> FactManager, int pos);


    //@}

    //! @name Setup and Apply methods.
    //@{

    /*! @brief Setup routine
     * In the Setup method the Inverse_ vector is filled with the corresponding
     * SmootherBase objects. Without the Inverse_ vector being filled we cannot call
     * BlockedGaussSeidelSmoother::Apply.
    */
    void Setup(Level &currentLevel);

    /*! @brief Apply the direct solver.
    Solves the linear system <tt>AX=B</tt> using the constructed solver.
    @param X initial guess
    @param B right-hand side
    @param InitialGuessIsZero This option has no effect.
    */
    void Apply(MultiVector& X, const MultiVector& B, bool InitialGuessIsZero = false) const;
    //@}

    RCP<SmootherPrototype> Copy() const;

    //! @name Overridden from Teuchos::Describable
    //@{

    //! Return a simple one-line description of this object.
    std::string description() const;

    //! Print the object with some verbosity level to an FancyOStream object.
    //using MueLu::Describable::describe; // overloading, not hiding
    void print(Teuchos::FancyOStream &out, const VerbLevel verbLevel = Default) const;

    //@}

  private:

    //! smoother type
    std::string type_;

    //! vector of factory managers
    std::vector<Teuchos::RCP<const FactoryManagerBase> > FactManager_;

    //! vector of smoother/solver factories
    std::vector<Teuchos::RCP<const SmootherBase> > Inverse_;

    //! A Factory
    RCP<FactoryBase> AFact_;

    //! block operator
    RCP<Matrix> A_;                  // < ! internal blocked operator "A" generated by AFact_

    RCP<const MapExtractorClass> rangeMapExtractor_;  //!< range  map extractor (from A_ generated by AFact)
    RCP<const MapExtractorClass> domainMapExtractor_; //!< domain map extractor (from A_ generated by AFact)

    std::map<size_t,size_t> bgsOrderingIndex2blockRowIndex_; //!< map: block GaussSeidel ordering to block row ordering
  }; // class Amesos2Smoother

} // namespace MueLu

#define MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_SHORT

#endif /* MUELU_BLOCKEDGAUSSSEIDELSMOOTHER_DECL_HPP_ */
