MPI Hello World - 2

This MPI program illustrates the use of MPI_Send and MPI_Recv functions. Basically, the master sends a message, “Hello, world”, to the process whose rank is 1, and then after having received the message, the process prints the message along with its rank.

	#include <stdio.h>
	#include "mpi.h"
	#define FROM_MASTER 1
	int main(int argc, char *argv[])
	{
	int rank, nprocs;
	char message[12] = "Hello, world";
	/* status for MPI_Recv */
	MPI_Status status;
	/* Initialize MPI execution environment */
	MPI_Init(&argc, &argv);
	/* Determines the size of MPI_COMM_WORLD */
	MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
	/* Give each process a unique rank */
	MPI_Comm_rank(MPI_COMM_WORLD, &rank);
	/* If the process is the master */
	if ( rank == 0 )
	/* Send message to process whose rank is 1 in the MPI_COMM_WORLD */
	MPI_Send(&message, 12, MPI_CHAR, 1, FROM_MASTER, MPI_COMM_WORLD);
	/* If the process has rank of 1 */
	else if ( rank == 1 )
	{
	/* Receive message sent from master */
	MPI_Recv(&message, 12, MPI_CHAR, 0, FROM_MASTER, MPI_COMM_WORLD, &status);
	/* Print the rank and message */
	printf("Process %d says : %s\n", rank, message);
	}
	/* Terminate MPI execution environment */
	MPI_Finalize();
	}

view raw hello_send_recv.c hosted with ❤ by GitHub

Compile it using

mpicc hello_send_recv.c

view raw Compile Hello 2 hosted with ❤ by GitHub

Execute it using

mpirun -np 2 ./a.out

view raw execute hello 2 hosted with ❤ by GitHub

MPI Hello World - 1
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