+/* Copyright (c) 2007, 2009, 2010. The SimGrid Team.
+ * All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
#include <stdio.h>
-#include <stdlib.h>
#include <mpi.h>
-int main(int argc, char *argv[]) {
- int rank, size;
- int i;
- int *sendbuf, *recvbuf;
+int main(int argc, char **argv)
+{
+ int size, rank;
+ int root = 0;
+ int value = 1;
+ int sum = -99;
+
+ double start_timer;
+
+
MPI_Init(&argc, &argv);
- MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
- sendbuf = malloc(sizeof(int) * size);
- recvbuf = malloc(sizeof(int) * size);
- for (i = 0; i < size; i++) {
- sendbuf[i] = 0;
- recvbuf[i] = 0;
- }
- sendbuf[rank] = rank + 1;
- MPI_Reduce(sendbuf, recvbuf, size, MPI_INT, MPI_SUM, 0, MPI_COMM_WORLD);
- if (0 == rank) {
- printf("nodes: ", rank);
- for (i = 0; i < size; i++) {
- printf("%d ", recvbuf[i]);
- }
- printf("\n");
+ MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+
+ start_timer = MPI_Wtime();
+
+ printf("rank %d has value %d\n", rank, value);
+ MPI_Reduce(&value, &sum, 1, MPI_INT, MPI_SUM, root, MPI_COMM_WORLD);
+ if (rank == root) {
+ printf("On root: sum=%d\n", sum);
+ printf("Elapsed time=%lf s\n", MPI_Wtime() - start_timer);
}
- free(sendbuf);
- free(recvbuf);
MPI_Finalize();
return 0;
}
