MeshDistributor.h

// ============================================================================
// ==                                                                        ==
// == 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 MeshDistributor.h */

#ifndef AMDIS_MESHDISTRIBUTOR_H
#define AMDIS_MESHDISTRIBUTOR_H


#include <mpi.h>
#include "parallel/DofComm.h"
#include "parallel/ElementObjectData.h"
#include "parallel/ParallelTypes.h"
#include "parallel/MeshPartitioner.h"
#include "parallel/InteriorBoundary.h"
#include "parallel/StdMpi.h"
#include "AMDiS_fwd.h"
#include "Global.h"
#include "ProblemTimeInterface.h"
#include "ProblemIterationInterface.h"
#include "FiniteElemSpace.h"
#include "Serializer.h"
#include "BoundaryManager.h"
#include "SystemVector.h"

namespace AMDiS {

  using namespace std;


  struct BoundaryDofInfo
  {
    map<GeoIndex, DofContainerSet> geoDofs;
  };


  struct DofData
  {
    /// Number of DOFs in the rank mesh.
    int nRankDofs;

    /// Is the index of the first global DOF index, which is owned by the rank.
    int rStartDofs;

    /// Number of DOFs in the whole domain.
    int nOverallDofs;

    /** \brief
     * Maps all DOFs in ranks partition to a bool value. If it is true, the DOF 
     * is owned by the rank. Otherwise, its an interior boundary DOF that is 
     * owned by another rank.
     */
    DofIndexToBool isRankDof;

    /// Maps local to global dof indices.
    DofMapping mapLocalGlobalDofs;

    /// Maps local dof indices to real dof indices.
    DofMapping mapLocalDofIndex;  
  };


  class MeshDistributor
  {
  private:
    MeshDistributor();
	          
    virtual ~MeshDistributor() {}

  public:
    void initParallelization();

    void exitParallelization();

    /// Adds a DOFVector to the set of \ref interchangeVecs. Thus, this vector 
    /// will be automatically interchanged between ranks when mesh is 
    /// repartitioned.
    void addInterchangeVector(DOFVector<double> *vec)
    {
      interchangeVectors.push_back(vec);
    }

    /// Adds all DOFVectors of a SystemVector to \ref interchangeVecs.
    void addInterchangeVector(SystemVector *vec)
    {
      for (int i = 0; i < vec->getSize(); i++)
	interchangeVectors.push_back(vec->getDOFVector(i));
    }
    
    /** \brief
     * This function checks if the mesh has changed on at least on rank. In 
     * this case, the interior boundaries are adapted on all ranks such that 
     * they fit together on all ranks. Furthermore the function 
     * \ref updateLocalGlobalNumbering() is called to update the DOF numberings 
     * and mappings on all rank due to the new mesh structure.
     *
     * \param[in]  tryRepartition   If this parameter is true, repartitioning 
     *                              may be done. This depends on several other 
     *                              parameters. If the parameter is false, the 
     *                              mesh is only checked and adapted but never 
     *                              repartitioned.
     */
    void checkMeshChange(bool tryRepartition = true);

    /** \brief
     * Checks if is required to repartition the mesh. If this is the case, a new
     * partition will be created and the mesh will be redistributed between the
     * ranks.
     */
    void repartitionMesh();
    
    /// Calculates the imbalancing factor and prints it to screen.
    void printImbalanceFactor();

    /** \brief
     * Test, if the mesh consists of macro elements only. The mesh partitioning 
     * of the parallelization works for macro meshes only and would fail, if the 
     * mesh is already refined in some way. Therefore, this function will exit
     * the program if it finds a non macro element in the mesh.
     */
    void testForMacroMesh();

    /// Set for each element on the partitioning level the number of 
    /// leaf elements.
    void setInitialElementWeights();

    inline virtual string getName() 
    { 
      return name; 
    }

    inline Mesh* getMesh()
    {
      return mesh;
    }

    /// Returns an FE space from \ref feSpaces.
    inline const FiniteElemSpace* getFeSpace(unsigned int i = 0)
    {
      FUNCNAME("MeshDistributor::getFeSpace()");

      TEST_EXIT_DBG(i < feSpaces.size())("Should not happen!\n");

      return feSpaces[i];
    }

    /// Returns all FE spaces, thus \ref feSpaces.
    inline vector<const FiniteElemSpace*>& getFeSpaces()
    {
      return feSpaces;
    }

    /// Returns the number of DOFs in rank's domain for a given FE space.
    inline int getNumberRankDofs(const FiniteElemSpace *feSpace) 
    {
      FUNCNAME("MeshDistributor::getNumberRankDofs()");

      TEST_EXIT_DBG(dofFeData.count(feSpace))("Should not happen!\n");

      return dofFeData[feSpace].nRankDofs;
    }

    /// Returns the number of DOFs in rank's domain for a set of FE spaces.
    inline int getNumberRankDofs(vector<const FiniteElemSpace*>& feSpaces)
    {
      FUNCNAME("MeshDistributor::getNumberRankDofs()");

      int result = 0;
      for (unsigned int i = 0; i < feSpaces.size(); i++) {
	TEST_EXIT_DBG(dofFeData.count(feSpaces[i]))("Should not happen!\n");
	result += dofFeData[feSpaces[i]].nRankDofs;
      }

      return result;
    }
    
    /// Returns the first global DOF index of an FE space, owned by rank.
    inline int getStartDofs(const FiniteElemSpace *feSpace)
    {
      FUNCNAME("MeshDistributor::getStartDofs()");

      TEST_EXIT_DBG(dofFeData.count(feSpace))("Should not happen!\n");

      return dofFeData[feSpace].rStartDofs;
    }

    /// Returns the first global DOF index for a set of FE spaces, owned by rank.
    inline int getStartDofs(vector<const FiniteElemSpace*>& feSpaces)
    {
      FUNCNAME("MeshDistributor::getStartDofs()");

      int result = 0;
      for (unsigned int i = 0; i < feSpaces.size(); i++) {
	TEST_EXIT_DBG(dofFeData.count(feSpaces[i]))("Should not happen!\n");

	result += dofFeData[feSpaces[i]].rStartDofs;
      }

      return result;
    }

    /// Returns the global number of DOFs for a given FE space.
    inline int getNumberOverallDofs(const FiniteElemSpace *feSpace)
    {
      FUNCNAME("MeshDistributor::getNumberOverallDofs()");

      TEST_EXIT_DBG(dofFeData.count(feSpace))("Should not happen!\n");

      return dofFeData[feSpace].nOverallDofs;
    }

    /// Returns the global number of DOFs for a set of FE spaces.
    inline int getNumberOverallDofs(vector<const FiniteElemSpace*>& feSpaces)
    {
      FUNCNAME("MeshDistributor::getNumberOverallDofs()");

      int result = 0;
      for (unsigned int i = 0; i < feSpaces.size(); i++) {
	TEST_EXIT_DBG(dofFeData.count(feSpaces[i]))("Should not happen!\n");

	result += dofFeData[feSpaces[i]].nOverallDofs;
      }

      return result;
    }

    inline DofMapping& getMapLocalGlobalDofs(const FiniteElemSpace *feSpace)
    {
      FUNCNAME("MeshDistributor::getMapLocalGlobalDofs()");

      TEST_EXIT_DBG(dofFeData.count(feSpace))("Should not happen!\n");

      return dofFeData[feSpace].mapLocalGlobalDofs;
    }

    /// Maps a local DOF to its global index.
    inline DegreeOfFreedom mapLocalToGlobal(const FiniteElemSpace *feSpace,
					    DegreeOfFreedom dof)
    {
      FUNCNAME("MeshDistributor::mapLocalToGlobal()");

      TEST_EXIT_DBG(dofFeData.count(feSpace))
	("No DOF data for FE space at addr %p!\n", feSpace);

      return dofFeData[feSpace].mapLocalGlobalDofs[dof];
    }

    DegreeOfFreedom mapGlobalToLocal(const FiniteElemSpace *feSpace,
				     DegreeOfFreedom dof);

    /// Maps a local DOF to its local index.
    inline DegreeOfFreedom mapLocalToDofIndex(const FiniteElemSpace *feSpace,
					      DegreeOfFreedom dof)
    {
      FUNCNAME("MeshDistributor::mapLocalToDofIndex()");

      TEST_EXIT_DBG(dofFeData.count(feSpace))
	("No DOF data for FE space at addr %p!\n", feSpace);

      return dofFeData[feSpace].mapLocalDofIndex[dof];
    }

    /// Returns the periodic mapping for all boundary DOFs in rank.
    inline PeriodicDofMap& getPeriodicMapping(const FiniteElemSpace *feSpace)
    {
      return periodicDofMap[feSpace];
    }

    /// Returns for a global DOF index of a given FE space its periodic mapping
    /// for a given  boundary type.
    inline int getPeriodicMapping(const FiniteElemSpace *feSpace,
				  BoundaryType type,
				  int globalDofIndex) 
    {
      FUNCNAME("MeshDistributor::getPeriodicMapping()");

      TEST_EXIT_DBG(periodicDofMap.count(feSpace))("Should not happen!\n");
      TEST_EXIT_DBG(periodicDofMap[feSpace][type].count(globalDofIndex) == 1)
	("There is no periodic association for global DOF %d for boundary type %d!\n",
	 globalDofIndex, type);

      return periodicDofMap[feSpace][type][globalDofIndex];
    }

    /// For a given global DOF index, this function returns the set of periodic
    /// associations, i.e., the boundary types the DOF is associated to, for 
    /// this DOF.
    inline std::set<BoundaryType>& getPerDofAssociations(const FiniteElemSpace* feSpace,
							 int globalDofIndex)
    {
      FUNCNAME("MeshDistributor::getPerDofAssociations()");

      TEST_EXIT_DBG(periodicDofAssociations.count(feSpace))
	("Should not happen!\n");
      TEST_EXIT_DBG(periodicDofAssociations[feSpace].count(globalDofIndex)) 
 	("Should not happen!\n"); 

      return periodicDofAssociations[feSpace][globalDofIndex];
    }

    /// Returns true, if the DOF (global index) is a periodic DOF.
    inline bool isPeriodicDof(const FiniteElemSpace *feSpace, int globalDofIndex)
    {
      return (periodicDofAssociations[feSpace].count(globalDofIndex) > 0 &&
	       periodicDofAssociations[feSpace][globalDofIndex].size() > 0);
    }

    /// Returns true, if the DOF (global index) of a given FE space is a 
    /// periodic DOF for the given boundary type.
    inline bool isPeriodicDof(const FiniteElemSpace *feSpace,
			      BoundaryType type,
			      int globalDofIndex)
    {
      return (periodicDofMap[feSpace][type].count(globalDofIndex) > 0);
    }

    DofComm& getSendDofs()
    {
      return sendDofs;
    }

    DofComm& getRecvDofs()
    {
      return recvDofs;
    }

    DofComm& getPeriodicDofs()
    {
      return periodicDofs;
    }

    /// Return true, if the given DOF is owned by the rank. If false, the DOF
    /// is in rank's partition, but is owned by some other rank.
    inline bool getIsRankDof(const FiniteElemSpace *feSpace, DegreeOfFreedom dof)
    {
      if (dofFeData[feSpace].isRankDof.count(dof))
	return dofFeData[feSpace].isRankDof[dof];

      return false;
    }

    inline DofIndexToBool& getIsRankDof(const FiniteElemSpace *feSpace)
    {
      return dofFeData[feSpace].isRankDof;
    }

    inline long getLastMeshChangeIndex()
    {
      return lastMeshChangeIndex;
    }

    inline int getMpiRank()
    {
      return mpiRank;
    }

    inline int getMpiSize()
    {
      return mpiSize;
    }

    inline MPI::Intracomm& getMpiComm()
    {
      return mpiComm;
    }

    /// Creates a set of all DOFs that are on interior boundaries of rank's
    /// domain. Thus, it creates the union of \ref sendDofs and \ref recvDofs.
    void createBoundaryDofs(const FiniteElemSpace *feSpace,
			    std::set<DegreeOfFreedom> &boundaryDofs);

    // Writes all data of this object to an output stream.
    void serialize(ostream &out);

    // Reads the object data from an input stream.
    void deserialize(istream &in);

    /** \brief
     * This function must be used if the values of a DOFVector must be 
     * synchronised over all ranks. That means, that each rank sends the 
     * values of the DOFs, which are owned by the rank and lie on an interior 
     * bounday, to all other ranks also having these DOFs.
     *
     * This function must be used, for example, after the lineary system is 
     * solved, or after the DOFVector is set by some user defined functions, 
     * e.g., initial solution functions.
     */    
    template<typename T>
    void synchVector(DOFVector<T> &vec) 
    {
      StdMpi<vector<T> > stdMpi(mpiComm);

      const FiniteElemSpace *fe = vec.getFeSpace();

      for (DofComm::Iterator it(sendDofs, fe); !it.end(); it.nextRank()) {
	vector<T> dofs;
	dofs.reserve(it.getDofs().size());
	
	for (; !it.endDofIter(); it.nextDof())
	  dofs.push_back(vec[it.getDofIndex()]);
	
	stdMpi.send(it.getRank(), dofs);
      }
	     
      for (DofComm::Iterator it(recvDofs); !it.end(); it.nextRank())
        stdMpi.recv(it.getRank());
	     
      stdMpi.startCommunication();

      for (DofComm::Iterator it(recvDofs, fe); !it.end(); it.nextRank())
	for (; !it.endDofIter(); it.nextDof())
	  vec[it.getDofIndex()] = 
	     stdMpi.getRecvData(it.getRank())[it.getDofCounter()];
    }
    
    /** \brief
     * Works in the same way as the function above defined for DOFVectors. Due
     * to performance, this function does not call \ref synchVector for each 
     * DOFVector, but instead sends all values of all DOFVectors all at once.
     */
    void synchVector(SystemVector &vec);

    void check3dValidMesh();

    void setBoundaryDofRequirement(Flag flag)
    {
      createBoundaryDofFlag = flag;
    }

    BoundaryDofInfo& getBoundaryDofInfo(const FiniteElemSpace *feSpace)
    {
      return boundaryDofInfo[feSpace];
    }

    void getAllBoundaryDofs(const FiniteElemSpace *feSpace,
			    DofContainer& dofs);


  public:
    /// Adds a stationary problem to the global mesh distributor objects.
    static void addProblemStatGlobal(ProblemStatSeq *probStat);

    
  protected:
    void addProblemStat(ProblemStatSeq *probStat);

    /// Determines the interior boundaries, i.e. boundaries between ranks, and
    /// stores all information about them in \ref interiorBoundary.
    void createInteriorBoundaryInfo();

    void updateInteriorBoundaryInfo();

    void createMeshElementData();

    void createBoundaryData();

    void createBoundaryDofs();

    void createBoundaryDofs(const FiniteElemSpace *feSpace);

    /// Removes all macro elements from the mesh that are not part of ranks 
    /// partition.
    void removeMacroElements();

    void updateLocalGlobalNumbering();

    /// Updates the local and global DOF numbering after the mesh has been 
    /// changed.
    void updateLocalGlobalNumbering(const FiniteElemSpace *feSpace);

    /// Calls \ref createPeriodicMap(feSpace) for all FE spaces that are
    /// handled by the mesh distributor.
    void createPeriodicMap();

    /** \brief
     * Creates, for a specific FE space, to all DOFs in rank's partition that 
     * are on a periodic boundary the mapping from dof index to the other 
     * periodic dof indices. This information is stored in \ref periodicDofMap.
     */    
    void createPeriodicMap(const FiniteElemSpace *feSpace);

    /** \brief
     * This function is called only once during the initialization when the
     * whole macro mesh is available on all cores. It copies the pointers of all
     * macro elements to \ref allMacroElements and stores all neighbour 
     * information based on macro element indices (and not pointer based) in 
     * \ref macroElementNeighbours. These information are then used to 
     * reconstruct macro elements during mesh redistribution.
     */
    void createMacroElementInfo();

    void updateMacroElementInfo();

    /** \brief
     * Checks for all given interior boundaries if the elements fit together on
     * both sides of the boundaries. If this is not the case, the mesh is 
     * adapted. Because refinement of a certain element may forces the 
     * refinement of other elements, it is not guaranteed that all rank's meshes
     * fit together after this function terminates. Hence, it must be called 
     * until a stable mesh refinement is reached.
     *
     * \param[in] allBound   Defines a map from rank to interior boundaries 
     *                       which should be checked.
     *
     * \return    If the mesh has  been changed by this function, it returns 
     *            true. Otherwise, it returns false, i.e., the given interior 
     *            boundaries fit together on both sides.
     */
    bool checkAndAdaptBoundary(RankToBoundMap &allBound);
  
    /// Sets \ref isRankDof to all matrices and rhs vectors in a given 
    /// stationary problem.
    void setRankDofs(ProblemStatSeq *probStat);

    /// Sets \ref isRankDof to all matrices and rhs vectors in all 
    /// stationary problems.
    void setRankDofs();

    /// Removes all periodic boundary condition information from all matrices and
    /// vectors of all stationary problems and from the mesh itself.
    void removePeriodicBoundaryConditions();

    // Removes all periodic boundaries from a given boundary map.
    void removePeriodicBoundaryConditions(BoundaryIndexMap& boundaryMap);

    /// Writes a vector of dof pointers to an output stream.
    void serialize(ostream &out, DofContainer &data);

    /// Writes a \ref RankToDofContainer to an output stream.
    void serialize(ostream &out, 
		   map<int, map<const FiniteElemSpace*, DofContainer> > &data);

    /// Reads a vector of dof pointers from an input stream.
    void deserialize(istream &in, DofContainer &data,
		     map<int, const DegreeOfFreedom*> &dofMap);

    /// Reads a \ref RankToDofContainer from an input stream.
    void deserialize(istream &in, 
		     map<int, map<const FiniteElemSpace*, DofContainer> > &data,
		     map<const FiniteElemSpace*, map<int, const DegreeOfFreedom*> > &dofMap);

    /// Writes a periodic dof mapping to an output stream.
    void serialize(ostream &out, PeriodicDofMap &data);

    void serialize(ostream &out, map<int, std::set<int> >& data);

    /// Reads a periodic dof mapping from an input stream.
    void deserialize(istream &in, PeriodicDofMap &data);

    void deserialize(istream &in, map<int, std::set<int> >& data);

    /// Writes a mapping from dof pointers to some values to an output stream.
    template<typename T>
    void serialize(ostream &out, map<const DegreeOfFreedom*, T> &data)
    {
      FUNCNAME("ParallelDomainBase::serialize()");

      int mapSize = data.size();
      SerUtil::serialize(out, mapSize);
      for (typename map<const DegreeOfFreedom*, T>::iterator it = data.begin();
	   it != data.end(); ++it) {
	int v1 = (*(it->first));
	T v2 = it->second;
	SerUtil::serialize(out, v1);
	SerUtil::serialize(out, v2);
      }
    }

    /// Reads a mapping from dof pointer to some values from an input stream.
    template<typename T>
    void deserialize(istream &in, map<const DegreeOfFreedom*, T> &data,
		     map<int, const DegreeOfFreedom*> &dofMap)
    {
      FUNCNAME("ParallelDomainBase::deserialize()");

      int mapSize = 0;
      SerUtil::deserialize(in, mapSize);
      for (int i = 0; i < mapSize; i++) {
	int v1 = 0;
	T v2;
	SerUtil::deserialize(in, v1);
	SerUtil::deserialize(in, v2);

	TEST_EXIT_DBG(dofMap.count(v1) != 0)("Cannot find DOF %d in map!\n", v1);

	data[dofMap[v1]] = v2;
      }
    }

  protected:
    /// List of all stationary problems that are managed by this mesh 
    /// distributor.
    vector<ProblemStatSeq*> problemStat;

    /// If true, the mesh distributor is already initialized;
    bool initialized;

    /// The rank of the current process.
    int mpiRank;

    /// Overall number of processes.
    int mpiSize;

    /// MPI communicator collected all processes, which should be used for
    /// calculation. The Debug procces is not included in this communicator.
    MPI::Intracomm mpiComm;

    /// Name of the problem (as used in the init files)
    string name;

    /// Finite element spaces of the problem.
    vector<const FiniteElemSpace*> feSpaces;

    /// Mesh of the problem.
    Mesh *mesh;

    /** \brief
     * A refinement manager that should be used on the mesh. It is used to 
     * refine elements at interior boundaries in order to fit together with 
     * elements on the other side of the interior boundary.
     */    
    RefinementManager *refineManager;

    /// Info level.
    int info;

    /// Pointer to a mesh partitioner that is used to partition the mesh to 
    /// the ranks.
    MeshPartitioner *partitioner;

    /// Weights for the elements, i.e., the number of leaf elements within 
    /// this element.
    map<int, double> elemWeights;

    /** \brief
     * Stores to every macro element index the number of the rank that owns this
     * macro element.
     */
    map<int, int> partitionMap;

    map<const FiniteElemSpace*, DofData> dofFeData;

    /// Data structure to store all sub-objects of all elements of the 
    /// macro mesh.
    ElementObjects elObjects;

    /// Maps to each macro element index a pointer to the corresponding element.
    map<int, Element*> macroElIndexMap;
    
    /// Maps to each macro element index the type of this element.
    map<int, int> macroElIndexTypeMap;

    /** \brief 
     * Defines the interior boundaries of the domain that result from 
     * partitioning the whole mesh. Contains only the boundaries, which are 
     * owned by the rank, i.e., the object gives for every neighbour rank i 
     * the boundaries this rank owns and shares with rank i.
     */
    InteriorBoundary myIntBoundary;
    
    /** \brief
     * Defines the interior boundaries of the domain that result from 
     * partitioning the whole mesh. Contains only the boundaries, which are 
     * not owned by the rank, i.e., the object gives for every neighbour rank 
     * i the boundaries that are owned by rank i and are shared with this rank.
     */
    InteriorBoundary otherIntBoundary;

    /** \brief
     * Defines the periodic boundaries with other ranks. Periodic boundaries
     * have no owner, as it is the case of interior boundaries.
     */
    InteriorBoundary periodicBoundary;

    /** \brief
     * This map contains for each rank the list of DOFs the current rank must 
     * send to exchange solution DOFs at the interior boundaries.
     */
    DofComm sendDofs;

    /** \brief
     * This map contains on each rank the list of DOFs from which the current 
     * rank will receive DOF values (i.e., this are all DOFs at an interior 
     * boundary). The DOF indices are given in rank's local numbering.
     */
    DofComm recvDofs;

    /** \brief
     * This map contains on each rank a list of DOFs along the interior bound-
     * aries to communicate with other ranks. The DOF indices are given in rank's
     * local numbering. Periodic boundaries within one subdomain are not 
     * considered here. 
     */
    DofComm periodicDofs;

    /** \brief
     * If periodic boundaries are used, this map stores, for each periodic 
     * boundary type, for all DOFs in rank's partition (that are on periodic 
     * boundaries), the corresponding mapped periodic DOFs. The mapping is 
     * defined by using global DOF indices.
     */
    PeriodicDofMapFeSpace periodicDofMap;
    
    /** \brief
     * If periodic boundaries are used, this map stores to each periodic DOF in 
     * rank's partition the set of periodic boundaries the DOF is associated to.
     * In 2D, most DOFs are only on one periodic boundary. Only, e.g., in a box 
     * with all boundaries being periodic, the four corners are associated by 
     * two different boundaries.
     */
    map<const FiniteElemSpace*, map<DegreeOfFreedom, std::set<BoundaryType> > > periodicDofAssociations;

    
    /// This set of values must be interchanged between ranks when the mesh is 
    /// repartitioned.
    vector<DOFVector<double>*> interchangeVectors;
		        
    /** \brief
     * If the problem definition has been read from a serialization file, this 
     * variable is true, otherwise it is false. This variable is used to stop the
     * initialization function, if the problem definition has already been read
     * from a serialization file.
     */
    bool deserialized;

    /// Denotes whether there exists a filewriter for this object.
    bool writeSerializationFile;

    /// If true, it is possible to repartition the mesh during computations.
    bool repartitioningAllowed;

    /// Stores the number of mesh changes that must lie in between to 
    /// repartitionings.
    int repartitionIthChange;

    /// Counts the number of mesh changes after the last mesh repartitioning 
    /// was done.
    int nMeshChangesAfterLastRepartitioning;

    /// Countes the number of mesh repartitions that were done. Till now, this 
    /// variable is used only for debug outputs.
    int repartitioningCounter;

    /// Directory name where all debug output files should be written to.
    string debugOutputDir;

    /** \brief
     * Stores the mesh change index. This is used to recognize changes in the
     * mesh structure (e.g. through refinement or coarsening managers).
     */
    long lastMeshChangeIndex;

    /// Stores for all macro elements of the original macro mesh the
    /// neighbourhood information based on element indices. Thus, each macro
    /// element index is mapped to a vector containing all indices of 
    /// neighbouring macro elements.
    map<int, vector<int> > macroElementNeighbours;

    /// Store all macro elements of the overall mesh, i.e., before the
    /// mesh is redistributed for the first time.
    vector<MacroElement*> allMacroElements;

    Flag createBoundaryDofFlag;

    map<const FiniteElemSpace*, BoundaryDofInfo> boundaryDofInfo;

  public:
    /// The boundary DOFs are sorted by subobject entities, i.e., first all
    /// face DOFs, edge DOFs and to the last vertex DOFs will be set to
    /// communication structure vectors, \ref sendDofs and \ref recvDofs.
    static const Flag BOUNDARY_SUBOBJ_SORTED;

    /// When boundary DOFs are created, \ref boundaryDofInfo is filled for
    /// all DOFs that this rank will send to other ranks (thus, rank 
    /// owned DOFs.
    static const Flag BOUNDARY_FILL_INFO_SEND_DOFS;

    /// When boundary DOFs are created, \ref boundaryDofInfo is filled for
    /// all DOFs that this rank will receive from other ranks (thus, DOFs
    /// that are owned by another rank).
    static const Flag BOUNDARY_FILL_INFO_RECV_DOFS;

    static MeshDistributor *globalMeshDistributor;

    friend class ParallelDebug;
  };
}

#endif // AMDIS_MESHDISTRIBUTOR_H