// ============================================================================
// ==                                                                        ==
// == 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 PetscSolver.h */

#ifndef AMDIS_PETSC_SOLVER_H
#define AMDIS_PETSC_SOLVER_H

#include <set>
#include <map>
#include <mpi.h>

#include "AMDiS_fwd.h"
#include "Global.h"
#include "Initfile.h"
#include "DOFMatrix.h"
#include "parallel/MeshDistributor.h"

#include <petsc.h>
#include <petscsys.h>
#include <petscao.h>
#include <petscksp.h>

namespace AMDiS {

  using namespace std;


  class PetscSolver
  {
  public:
    PetscSolver()
      : meshDistributor(NULL),
	mpiRank(-1)
    {}

    virtual ~PetscSolver() {}

    void setMeshDistributor(MeshDistributor *m)
    {
      meshDistributor = m;
      mpiRank = meshDistributor->getMpiRank();
    }

    /** \brief
     * Create a PETSc matrix. The given DOF matrices are used to create the nnz 
     * structure of the PETSc matrix and the values are transfered to it.
     *
     * \param[in] mat
     */
    virtual void fillPetscMatrix(Matrix<DOFMatrix*> *mat) = 0;

    /** \brief
     * Create a PETSc vector and fills it with the rhs values of the system.
     *
     * \param[in] vec
     */
    virtual void fillPetscRhs(SystemVector *vec) = 0;

    /// Use PETSc to solve the linear system of equations
    virtual void solvePetscMatrix(SystemVector &vec, AdaptInfo *adaptInfo) = 0;

    /// Destroys all matrix data structures.
    virtual void destroyMatrixData() = 0;

    virtual Flag getBoundaryDofRequirement()
    {
      return 0;
    }

    KSP getSolver() { return solver; }

    PC getPc() { return pc; }

  protected:
    void printSolutionInfo(AdaptInfo* adaptInfo,
			   bool iterationCounter = true,
			   bool residual = true);

    /** \brief
     * Copies between to PETSc vectors by using different index sets for the
     * origin and the destination vectors.
     *
     * \param[in]   originVec    The PETSc vector from which we copy from.
     * \param[out]  destVec      The PETSc vector we copy too.
     * \param[in]   originIndex  Set of global indices referring to the 
     *                           origin vector.
     * \param[in]   destIndex    Set of global indices referring to the
     *                           destination vector.
     */
    void copyVec(Vec& originVec, Vec& destVec, 
		 vector<int>& originIndex, vector<int>& destIndex);

    /// Checks if all given FE spaces are handled by the mesh distributor.
    void checkFeSpaces(vector<const FiniteElemSpace*>& feSpaces);

    /// Returns a vector with the FE spaces of each row in the matrix. Thus, the
    /// resulting vector may contain the same FE space multiple times.
    vector<const FiniteElemSpace*> getFeSpaces(Matrix<DOFMatrix*> *mat);

    /// Returns a vector with the FE spaces of all components of a system vector.
    vector<const FiniteElemSpace*> getFeSpaces(SystemVector *vec);

  protected:
    MeshDistributor *meshDistributor;
    
    int mpiRank;

    /// 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;

    KSP solver;

    PC pc;
  };


} // namespace AMDiS

#endif