#include <iostream>
#include <mpi.h>
#define MAX 20
int nprocs = 4;
int myrank;
double a[MAX], b[MAX], c[MAX];
MPI_Status status;
//
//init MPI
int main(int argc, char* argv[])
{
MPI_Init(&argc, &argv);
MPI_Status status;
MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
int value = myrank + 10;
int sum = 0;
MPI_Recv(&sum, 1, MPI_INT, (myrank - 1 + nprocs) / nprocs, 10,
MPI_COMM_WORLD, &status);
sum += value;
MPI_Send(&sum, 1, MPI_INT, (myrank + 1) % nprocs, 10, MPI_COMM_WORLD);
if (myrank == 0)
printf("%d", sum);
MPI_Finalize();
return 0;
}
 

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