4.7.1. Examples using MPI_ALLGATHER, MPI_ALLGATHERV

Example

The all-gather version of Example Examples using MPI_GATHER, MPI_GATHERV . Using MPI_ALLGATHER, we will gather 100 ints from every process in the group to every process.

MPI_Comm comm; 
    int gsize,sendarray[100]; 
    int *rbuf; 
    ... 
    MPI_Comm_size( comm, &gsize); 
    rbuf = (int *)malloc(gsize*100*sizeof(int)); 
    MPI_Allgather( sendarray, 100, MPI_INT, rbuf, 100, MPI_INT, comm);