chi_mpi_commset.h

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#ifndef CHITECH_CHI_MPI_COMMSET_H
#define CHITECH_CHI_MPI_COMMSET_H
 
#include <mpi.h>
#include "mesh/chi_mesh.h"
#include "chi_runtime.h"
 
namespace chi
{
 
//################################################################### Class def
/**Simple implementation a communicator set.
 * Definitions:
 * P = total amount of processors.
 * locI = process I in [0,P]*/
class ChiMPICommunicatorSet
{
private:
  /**A list of communicators, size P, contains a communicator for
   * only communicating with the neighbors of locI.*/
  std::vector<MPI_Comm>  communicators_;
  /**A list of groupings, size P, allows mapping of the rank of locJ
   * relative to the local communicator.*/
  std::vector<MPI_Group> location_groups_;
  /**Used to translate ranks.*/
  MPI_Group              world_group_;
 
public:
  ChiMPICommunicatorSet(std::vector<MPI_Comm>&  communicators,
                        std::vector<MPI_Group>& location_groups,
                        MPI_Group&               world_group) :
    communicators_(communicators),
    location_groups_(location_groups),
    world_group_(world_group)
  {}
 
  MPI_Comm LocICommunicator(int locI) const
  {
    return communicators_[locI];
  }
 
  int MapIonJ(int locI, int locJ) const
  {
    int group_rank;
    MPI_Group_translate_ranks(world_group_, 1, &locI,
                              location_groups_[locJ], &group_rank);
 
    return group_rank;
  }
};
}//namespace chi_objects
 
 
 
 
#endif //CHITECH_CHI_MPI_COMMSET_H