// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ==  http://www.amdis-fem.org                                              ==
// ==                                                                        ==
// ============================================================================
//
// Software License for AMDiS
//
// Copyright (c) 2010 Dresden University of Technology 
// All rights reserved.
// Authors: Simon Vey, Thomas Witkowski et al.
//
// This file is part of AMDiS
//
// See also license.opensource.txt in the distribution.



/** \file PetscSolverFeti.h */

#include <map>
#include "parallel/MpiHelper.h"
#include "parallel/PetscSolver.h"
#include "parallel/PetscSolverFetiStructs.h"
#include "parallel/ParallelDofMapping.h"
#include "parallel/ParallelTypes.h"
#include "parallel/SubDomainSolver.h"

#ifndef AMDIS_PETSC_SOLVER_FETI_H
#define AMDIS_PETSC_SOLVER_FETI_H

namespace AMDiS {

  using namespace std;

  /** \brief
   * FETI-DP implementation based on PETSc.
   */
  class PetscSolverFeti : public PetscSolver
  {
  public:
    PetscSolverFeti();

    /// Assemble the sequentially created matrices to the global matrices
    /// required by the FETI-DP method.
    void fillPetscMatrix(Matrix<DOFMatrix*> *mat);

    /// Assembles the global rhs vectors from the sequentially created ones.
    void fillPetscRhs(SystemVector *vec);

    /// Solve the system using FETI-DP method.
    void solvePetscMatrix(SystemVector &vec, AdaptInfo *adaptInfo);

    /// Destroys all matrix data structures.
    void destroyMatrixData();

    /// Detroys all vector data structures.
    void destroyVectorData();

    /// Returns flags to denote which information of the boundary DOFs are 
    /// required by the FETI-DP solver.
    Flag getBoundaryDofRequirement()
    {
      return 
	MeshDistributor::BOUNDARY_SUBOBJ_SORTED |
	MeshDistributor::BOUNDARY_FILL_INFO_SEND_DOFS |
	MeshDistributor::BOUNDARY_FILL_INFO_RECV_DOFS;
    }

    /// Initialization of the data structures with a given list of the FE 
    /// spaces of all components.
    void initialize(vector<const FiniteElemSpace*> feSpaces);

    /// After mesh changes, or if the solver is called the first time, this
    /// function creates all information about primal nodes, dual nodes and
    /// lagrange constraints.    
    void createFetiData();

    int getNumberOfPrimals()
    {
      return primalDofMap.getOverallDofs();
    }

    int getNumberOfDuals()
    {
      return dualDofMap.getOverallDofs();
    }

  protected:
    /// Defines which boundary nodes are primal. Creates global index of
    /// the primal variables.
    void createPrimals(const FiniteElemSpace *feSpace);

    /// Defines the set of dual variables and creates the global index of
    // dual variables.
    void createDuals(const FiniteElemSpace *feSpace);

    /// Create Lagrange multiplier variables corresponding to the dual 
    /// variables.
    void createLagrange(const FiniteElemSpace *feSpace);

    /// Creates a global index of the B variables.
    void createIndexB(const FiniteElemSpace *feSpace);

    /// Creates the Lagrange multiplier constraints and assembles them 
    /// to \ref mat_lagrange.
    void createMatLagrange(vector<const FiniteElemSpace*> &feSpaces);

    /// Creates PETSc KSP solver object for solving the Schur complement
    /// system on the primal variables, \ref ksp_schur_primal
    void createSchurPrimalKsp(vector<const FiniteElemSpace*> &feSpaces);

    /// Destroys PETSc KSP solver object \ref ksp_schur_primal
    void destroySchurPrimalKsp();

    /// Creates PETSc KSP solver object for the FETI-DP operator, \ref ksp_feti
    void createFetiKsp(vector<const FiniteElemSpace*> &feSpaces);

    /// Destroys FETI-DP operator, \ref ksp_feti
    void destroyFetiKsp();

    /** \brief
     * Recovers AMDiS solution vector from PETSc's solution vectors of the
     * FETI-DP system. First, the B variables can locally be copied to the
     * corresponding entries in the DOF vectors. The primal variable must
     * be communicated such that all ranks sharing a primal get a copy of
     * the corresponding value.
     *
     * \param[in]   vec_sol_b        Global PETSc vector of the solution of
     *                               the B variables.
     * \param[in]   vec_sol_primal   Global PETSc vector of the solution of
     *                               the primal variables.
     * \param[out]  vec              SystemVector containing all solution 
     *                               DOF vectors.
     */
    void recoverSolution(Vec &vec_sol_b,
			 Vec &vec_sol_primal,
			 SystemVector &vec);

    /** \brief
     * Solves the FETI-DP system globally, thus without reducing it to the 
     * Lagrange multipliers. This should be used for debugging only to test
     * if the FETI-DP system is setup correctly.
     *
     * \param[out]  vec    Solution DOF vectors.
     */
    void solveFetiMatrix(SystemVector &vec);

    /** \brief
     * Solves the FETI-DP system with reducing it first to the Lagrange
     * multipliers. This is what one expects when using the FETI-DP methid :)
     *
     * \param[out]  vec    Solution DOF vectors.
     */
    void solveReducedFetiMatrix(SystemVector &vec);

    void resetStatistics();

    void printStatistics();

    /// Checks whether a given DOF in a given FE space is a primal DOF.
    inline bool isPrimal(const FiniteElemSpace *feSpace, DegreeOfFreedom dof)
    {
      return primalDofMap[feSpace].isSet(dof);
    }

    /// Checks whether a given DOF in a give FE space is a dual DOF.
    inline bool isDual(const FiniteElemSpace *feSpace, DegreeOfFreedom dof)
    {
      return dualDofMap[feSpace].isSet(dof);
    }

  protected:
    /// Mapping from primal DOF indices to a global index of primals.
    ParallelDofMapping primalDofMap;

    /// Mapping from dual DOF indices to a global index of duals.
    ParallelDofMapping dualDofMap;

    /// Stores to each dual DOF index the index of the first Lagrange
    /// constraint that is assigned to this DOF.
    ParallelDofMapping lagrangeMap;
    
    /// Index for each non primal DOF to the global index of B variables.
    ParallelDofMapping localDofMap;

    /// Mapping of pure local DOF indices, thus no primal and no dual DOFs are
    /// in this map. Is used for the Dirichlet preconditioner only.
    ParallelDofMapping interiorDofMap;

    /// Stores to each dual boundary DOF in each finite elment space the set of
    /// ranks in which the DOF is contained in.
    map<const FiniteElemSpace*, DofIndexToPartitions> boundaryDofRanks;

    /// Global PETSc matrix of Lagrange variables.
    Mat mat_lagrange;

    /// 0: Solve the Schur complement on primal variables with iterative solver.
    /// 1: Create the Schur complement matrix explicitly and solve it with a
    ///    direct solver.
    int schurPrimalSolver;

    /// PETSc solver object to solve the Schur complement on the 
    /// primal variables.
    KSP ksp_schur_primal;

    /// Matrix object that defines a matrix-free implementation for the action
    /// of the Schur complement on the primal variables.
    Mat mat_schur_primal;

    /// Data for MatMult operation in matrix \ref mat_schur_primal
    SchurPrimalData schurPrimalData;

    /// PETSc solver object to solve a system with FETI-DP.    
    KSP ksp_feti;

    /// Matrix object that defines a matrix-free implementation for the action
    /// of the FETI-DP operator.
    Mat mat_feti;

    /// Data for MatMult operation in matrix \ref mat_feti
    FetiData fetiData;

    /// Defines which preconditioner should be used to solve the reduced
    /// FETI-DP system.
    FetiPreconditioner fetiPreconditioner;

    /// Preconditioner object for the reduced FETI-DP system.
    PC precon_feti;

    Mat mat_lagrange_scaled;
   
    FetiDirichletPreconData fetiDirichletPreconData;

    FetiLumpedPreconData fetiLumpedPreconData;

    Mat mat_interior_interior, mat_duals_duals, mat_interior_duals, mat_duals_interior;

    KSP ksp_interior;

    bool multiLevelTest;

    SubDomainSolver *subDomainSolver;
  };

}

#endif