Topology

C | Fortran-2008 | Fortran-90

MPI_Group_rank

Parameters

group

The MPI group to explore.

rank

A pointer on the variable in which write the rank of the calling MPI process in the MPI group given.

Return value

The error code returned from the group rank retrieval.

Example

Copy

Feedback

#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>

/**
 * @brief For each process in the group of the default communicator
 * MPI_COMM_WORLD, show their rank.
 **/
int main(int argc, char* argv[])
{
    MPI_Init(&argc, &argv);

    // Get the group of processes from the default communicator
    MPI_Group group;
    MPI_Comm_group(MPI_COMM_WORLD, &group);

    // Get my rank in that group.
    int my_rank;
    MPI_Group_rank(group, &my_rank);

    // Print my rank in that group.
    printf("I am MPI process %d in the group.\n", my_rank);

    MPI_Finalize();

    return EXIT_SUCCESS;
}