77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <mpi.h>
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#define BUFSIZE 1000 /* Amount of numbers to sum. */
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#define TAG 0 /* Message tag. */
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int main(int argc, char **argv) {
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int size, rank, elems, i, sum = 0;
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/* Start with MPI_Init and get the rank. */
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MPI_Init(&argc, &argv);
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MPI_Comm_size(MPI_COMM_WORLD, &size);
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MPI_Comm_rank(MPI_COMM_WORLD, &rank);
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/***********************************************************************
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* MASTER PROCESS *
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***********************************************************************/
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if(rank == 0) {
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int array[BUFSIZE];
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int temp;
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/* Get the number of processes. */
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printf("MASTER: %d processes available.\n", size);
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/* Create the data to send. */
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for(i = 0; i < BUFSIZE; i++) {
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array[i] = 9;
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}
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/* Calculate how much data to send to each slave. */
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elems = BUFSIZE / (size - 1);
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/* Send data to the slaves. */
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for(i = 1; i < size; i++) {
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MPI_Send(&array[(i - 1) * elems], elems, MPI_INT, i, TAG, MPI_COMM_WORLD);
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}
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/* Receive answers from the slaves. */
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for(i = 1; i < size; i++) {
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MPI_Recv(&temp, 1, MPI_INT, i, TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
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sum += temp;
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}
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printf("MASTER: The sum of the array is: %d.\n", sum);
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/***********************************************************************
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* SLAVE PROCESS *
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***********************************************************************/
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} else {
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int * buffer;
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/* Calculate how much data to receive from the master and allocate memory. */
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elems = BUFSIZE / (size - 1);
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buffer = (int *)malloc(sizeof(int) * elems);
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/* Receive orders from the master. */
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MPI_Recv(buffer, elems, MPI_INT, 0, TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
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/* Calculate. */
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for(i = 0; i < elems; i++)
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sum += buffer[i];
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/* Send answer to the master. */
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MPI_Send(&sum, 1, MPI_INT, 0, TAG, MPI_COMM_WORLD);
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/* Clean up. */
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free(buffer);
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}
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/* End with MPI_Finalize. */
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MPI_Finalize();
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return EXIT_SUCCESS;
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}
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