MPI_Gather: Segmentation fault in Master Slave Program

问题

Following is a simple program where all Slaves process send their rank (as the token) to the Master process.

The program when executed runs correctly most of the times but raises Segmentation Fault the others.

int token = rank;
vector<int> recvData(world_size);

MPI_Gather(&token, 1, MPI_INT, &recvData[0], 1, MPI_INT, 0, MPI_COMM_WORLD);

if(rank == 0)
{
    // Root process
    for (int irank = 1; irank < world_size; irank++)
    {
        cout << "Token received from rank " << irank << " = " << recvData[irank] << endl;
    }
}

Full code here

Following is the error message:

YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Segmentation fault:
11 (signal 11) This typically refers to a problem with your
application. Please see the FAQ page for debugging suggestions

Full Error here

Is there any way to avoid such situations?

Edit 1: Following are the outputs of mpirun when ran in verbose mode (both cases):

i) Success Case

ii) Segmentation Fault Case

P.S.: I asked a similar question to this today, and a suggestion was given to use MPI_Gather() but the problem still persists.

来源：https://stackoverflow.com/questions/46515831/mpi-gather-segmentation-fault-in-master-slave-program

标签

c++