// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  TU Dresden                                                            ==
// ==                                                                        ==
// ==  Institut für Wissenschaftliches Rechnen                               ==
// ==  Zellescher Weg 12-14                                                  ==
// ==  01069 Dresden                                                         ==
// ==  germany                                                               ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  https://gforge.zih.tu-dresden.de/projects/amdis/                      ==
// ==                                                                        ==
// ============================================================================

/** \file GlobalMatrixSolver.h */

#ifndef AMDIS_GLOBALMATRIXSOLVER_H
#define AMDIS_GLOBALMATRIXSOLVER_H

#include "AMDiS_fwd.h"
#include "Global.h"
#include "ParallelDomainBase.h"
#include "ProblemVec.h"
#include "ProblemInstat.h"

#include "petsc.h"
#include "petscsys.h"
#include "petscao.h"

namespace AMDiS {
  
  class GlobalMatrixSolver : public ProblemVec
  {
  public:
    GlobalMatrixSolver(std::string nameStr,
		       ProblemIterationInterface *problemIteration = NULL)
      : ProblemVec(nameStr, problemIteration),
	meshDistributor(NULL),
	d_nnz(NULL),
	o_nnz(NULL),
	lastMeshNnz(0)
    {}

    ~GlobalMatrixSolver()
    {}

    void addToMeshDistributor(MeshDistributor&);

    void buildAfterCoarsen(AdaptInfo *adaptInfo, Flag flag,
			   bool assembleMatrix = true,
			   bool assembleVector = true);

    void solve(AdaptInfo *adaptInfo, bool fixedMatrix = false);

  protected:
    /// Creates a new non zero pattern structure for the Petsc matrix. 
    void createPetscNnzStructure(Matrix<DOFMatrix*> *mat);
    
    /** \brief
     * Create a PETSc matrix and PETSc vectors. The given DOF matrices are used to
     * create the nnz structure of the PETSc matrix and the values are transfered to it.
     * The given DOF vectors are used to the the values of the PETSc rhs vector.
     *
     * \param[in] mat
     * \param[in] vec
     */
    void fillPetscMatrix(Matrix<DOFMatrix*> *mat, SystemVector *vec);

    /// Takes a dof matrix and sends the values to the global petsc matrix.
    void setDofMatrix(DOFMatrix* mat, int dispMult = 1, 
		      int dispAddRow = 0, int dispAddCol = 0);

    /// Takes a dof vector and sends its values to a given petsc vector.
    void setDofVector(Vec& petscVec, DOFVector<double>* vec, 
		      int disMult = 1, int dispAdd = 0);

    void solvePetscMatrix(SystemVector &vec);

  protected:
    MeshDistributor *meshDistributor;

    /// Petsc's matrix structure.
    Mat petscMatrix;

    /** \brief
     * Petsc's vector structures for the rhs vector, the solution vector and a
     * temporary vector for calculating the final residuum.
     */
    Vec petscRhsVec, petscSolVec, petscTmpVec;

    /// Arrays definig the non zero pattern of Petsc's matrix.
    int *d_nnz, *o_nnz;

    /** \brief
     * Stores the mesh change index of the mesh the nnz structure was created for.
     * Therefore, if the mesh change index is higher than this value, we have to create
     * a new nnz structure for PETSc matrices, because the mesh has been changed and
     * therefore also the assembled matrix structure.
     */
    int lastMeshNnz;
  };


} //namespace AMDiS

#endif