group_rank       1106 ompi/communicator/comm_cid.c     const int group_rank = ompi_group_rank (group);
group_rank       1133 ompi/communicator/comm_cid.c     peers_group[0] = group_rank ? ((group_rank - 1) >> 1) : MPI_PROC_NULL;
group_rank       1134 ompi/communicator/comm_cid.c     peers_group[1] = (group_rank * 2 + 1) < group_size ? group_rank * 2 + 1: MPI_PROC_NULL;
group_rank       1135 ompi/communicator/comm_cid.c     peers_group[2] = (group_rank * 2 + 2) < group_size ? group_rank * 2 + 2 : MPI_PROC_NULL;