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C | FORTRAN-legacy | FORTRAN-2008

MPI_Group_rank

Definition

MPI_Group_rank gets the rank of the calling MPI process in the group given.

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int MPI_Group_rank(MPI_Group group,
                   int* 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.

Returned value

The error code returned from the group rank retrieval.

MPI_SUCCESS
The routine successfully completed.

Example

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#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;
}