8. Write a MPI Program demonstration of MPI_Scatter and MPI_Gather.
- How to run Program ?
- Click Build on codeblocks only → Build or press
Ctrl+F9 - This will create an
.exefile inside your projectbin\Debugfolder. - Go to your project folder (e.g.
OneDrive\Desktop\Parallel-programs\Program8\bin\Debug) based on where you saved your program. - You’ll find something like: main.exe or FileName.exe for example (
Program8.exe) - Open Command Prompt.
- Navigate to Your
.exeLocation (eg: cd OneDrive\Desktop\Parallel-programs\Program8\bin\Debug) based on where you saved your program. - Type command to run the program: mpiexec -n 4 FileName.exe for example (
Program8.exe).
- Click Build on codeblocks only → Build or press
PROGRAM:
#include <mpi.h>
#include <stdio.h>
int main(int argc, char *argv[]) {
int rank, size;
int send_data[100], recv_data, gathered_data[100];
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
if (rank == 0) {
for (int i = 0; i < size; i++) {
send_data[i] = i * 10;
}
}
MPI_Scatter(send_data, 1, MPI_INT, &recv_data, 1, MPI_INT, 0, MPI_COMM_WORLD);
recv_data = recv_data + rank;
MPI_Gather(&recv_data, 1, MPI_INT, gathered_data, 1, MPI_INT, 0, MPI_COMM_WORLD);
if (rank == 0) {
printf("Gathered data in root process:\n");
for (int i = 0; i < size; i++) {
printf("gathered_data[%d] = %d\n", i, gathered_data[i]);
}
}
MPI_Finalize();
return 0;
}OUTPUT: