MPI - Printing in an order

Question

I\'m trying to write a function in C where every processor prints it\'s own data. Here is what i have:

void print_mesh(int p,int myid,int** U0,int X,int Y){
         


        

Answer 1

So, you can do something like this:

MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
if (rank == 0) {
    MPI_Send(&message, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
    printf("1 SIZE = %d RANK = %d MESSAGE = %d \n",size,rank, message);
} else {
    int buffer;
    MPI_Status status;
    MPI_Probe(MPI_ANY_SOURCE, 0, MPI_COMM_WORLD, &status);
    MPI_Get_count(&status, MPI_INT, &buffer);
    if (buffer == 1) {
        printf("2 SIZE = %d RANK = %d MESSAGE = %d \n",size,rank, message);
        MPI_Recv(&message, buffer, MPI_INT, MPI_ANY_SOURCE, 0, MPI_COMM_WORLD, &status);
        if (rank + 1 != size) {
            MPI_Send(&message, 1, MPI_INT, ++rank, 0, MPI_COMM_WORLD);
        }
    };
};
MPI_Finalize();

After execute:

$ mpirun -n 5 ./a.out 
1 SIZE = 5 RANK = 0 MESSAGE = 999 
2 SIZE = 5 RANK = 1 MESSAGE = 999 
2 SIZE = 5 RANK = 2 MESSAGE = 999 
2 SIZE = 5 RANK = 3 MESSAGE = 999 
2 SIZE = 5 RANK = 4 MESSAGE = 999