my_mpi.cpp

10 Mpi source examples for begginers

#include "mpi.h"
#include <stdio.h>
#define NPROCS 8
int main(argc,argv)
int argc;
char *argv[]; {

int  rank, new_rank,numtasks;
MPI_Comm comm;

MPI_Init(&argc,&argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_split(MPI_COMM_WORLD,1,numtasks-rank, &comm);
if (numtasks != NPROCS) {
  
	printf("Must specify MP_PROCS= %d. Terminating.\n",NPROCS);
	MPI_Finalize(); 
}

MPI_Comm_rank (comm, &new_rank);
printf("rank= %d newrank= %d\n",rank ,new_rank);
MPI_Comm_free(&comm);
MPI_Finalize();

}