OPENMPI播放mpi_bcast问题

Question

我想了解mpi_bcast。更具体地说，在下面的代码中我期望最终结果是buf0-＆gt; 1990和buf1 - ＆gt; 1991.

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

int main(int argc, char** argv) {
        int rank;
        int buf0;
        int buf1;
        const int root=0;

        MPI_Init(&argc, &argv);
        MPI_Comm_rank(MPI_COMM_WORLD, &rank);
        if(rank == 0){
           buf0 = 1990;
        } else {
           buf1 = 1991;
        }

        printf("[%d]: Before Bcast, buf0 is %d\n", rank, buf0);
        printf("[%d]: Before Bcast, buf1 is %d\n", rank, buf1);

        /* everyone calls bcast, data is taken from root and ends up in everyone's buf */
        MPI_Bcast(&buf0, 1, MPI_INT, 0, MPI_COMM_WORLD);
        MPI_Bcast(&buf1, 1, MPI_INT, 1, MPI_COMM_WORLD);

        printf("[%d]: After Bcast, buf0 is %d\n", rank, buf0);
        printf("[%d]: After Bcast, buf1 is %d\n", rank, buf1);

        MPI_Finalize();
        return 0;
}

然而，我得到的输出如下，我期望两个线程都具有buf0的值并且buf1同步但是线程0的buf1是0.我在这里遗漏了一些东西。

mpirun -np 2 mpi_counter_1
[0]: Before Bcast, buf0 is 1990
[0]: Before Bcast, buf1 is 0
[1]: Before Bcast, buf0 is 0
[1]: Before Bcast, buf1 is 1991
[0]: After Bcast, buf0 is 1990
[0]: After Bcast, buf1 is 0
[1]: After Bcast, buf0 is 1990
[1]: After Bcast, buf1 is 1991