source: XIOS/dev/branch_openmp/extern/remap/src/mpi_cascade.cpp @ 1328

#include "mpi_cascade.hpp"
#include <iostream>
using namespace ep_lib;

namespace sphereRemap {

CMPICascade::CMPICascade(int nodes_per_level, MPI_Comm comm)
{
        int remaining_levels;
        MPI_Comm intraComm;
        int l = 0; // current level
        do {
                level.push_back(comm);
                remaining_levels = ilog(nodes_per_level /*base*/, level[l].size /*arg*/) + 1;
                level[l].group_size = iroot(remaining_levels, level[l].size); // group_size^remaining_levels <= size
                level[l].p_grp_size = level[l].size/level[l].group_size;
        
                MPI_Comm_split(comm, level[l].colour(), level[l].key(), &intraComm);
                MPI_Comm_split(comm, level[l].p_colour(), level[l].p_key(), &(level[l].pg_comm));
                comm = intraComm;
                l++;
        } while (--remaining_levels);
        num_levels = l;
}

}