Message-Passing-Interface/mpi_testing_various_p2p_communication_methods.c at master · mijapa/Message-Passing-Interface · GitHub

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/*
  "Hello World" MPI Test Program
*/
#include <stdlib.h>
#include <stdio.h>
#include <mpi.h>

int main(int argc, char **argv) {
    MPI_Init(NULL, NULL);
    int world_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
    int world_size;
    MPI_Comm_size(MPI_COMM_WORLD, &world_size);

    // We are assuming at least 2 processes for this task
    if (world_size < 2) {
        fprintf(stderr, "World size must be greater than 1 for %s\n", argv[0]);
        MPI_Abort(MPI_COMM_WORLD, 1);
    }

    int number;

    //Send
    if (world_rank == 0) {
        // If we are rank 0, set the number to -1 and send it to process 1
        number = -1;
        MPI_Send(&number, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
    } else if (world_rank == 1) {
        MPI_Recv(&number, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
        printf("Send: Process 1 received number %d from process 0\n", number);
    }

    //Ssend
    if (world_rank == 0) {
        // If we are rank 0, set the number to -1 and send it to process 1
        number = -1;
        MPI_Ssend(&number, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
    } else if (world_rank == 1) {
        MPI_Recv(&number, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
        printf("Ssend: Process 1 received number %d from process 0\n", number);
    }

    //Bsend
    if (world_rank == 0) {
        // Declare the buffer and attach it
        int buffer_attached_size = MPI_BSEND_OVERHEAD + sizeof(int);
        char *buffer_attached = (char *) malloc(buffer_attached_size);
        MPI_Buffer_attach(buffer_attached, buffer_attached_size);
        // If we are rank 0, set the number to -1 and send it to process 1
        number = -1;
        MPI_Bsend(&number, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
    } else if (world_rank == 1) {
        MPI_Recv(&number, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
        printf("Bsend: Process 1 received number %d from process 0\n", number);
    }

    //Rsend
    if (world_rank == 0) {
        // If we are rank 0, set the number to -1 and send it to process 1
        number = -1;
        MPI_Rsend(&number, 1, MPI_INT, 1, 0, MPI_COMM_WORLD);
    } else if (world_rank == 1) {
        MPI_Recv(&number, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
        printf("Rsend: Process 1 received number %d from process 0\n", number);
    }

    //Isend
    if (world_rank == 0) {
        // If we are rank 0, set the number to -1 and send it to process 1
        number = -1;
        MPI_Request request;
        MPI_Isend(&number, 1, MPI_INT, 1, 0, MPI_COMM_WORLD, &request);
        MPI_Wait(&request, MPI_STATUS_IGNORE);
    } else if (world_rank == 1) {
        MPI_Recv(&number, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
        printf("Isend: Process 1 received number %d from process 0\n", number);
    }

    //Irecv
    if (world_rank == 0) {
        // If we are rank 0, set the number to -1 and send it to process 1
        number = -1;
        MPI_Request request;
        MPI_Isend(&number, 1, MPI_INT, 1, 0, MPI_COMM_WORLD, &request);
        MPI_Wait(&request, MPI_STATUS_IGNORE);
    } else if (world_rank == 1) {
        MPI_Request request;
        MPI_Irecv(&number, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, &request);
        MPI_Wait(&request, MPI_STATUS_IGNORE);
        printf("Irecv: Process 1 received number %d from process 0\n", number);
    }

    MPI_Finalize();
}