1 /* Copyright (c) 2009-2018. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
13 int main(int argc, char *argv[])
21 MPI_Init(&argc, &argv);
22 int maxlen = argc >= 2 ? atoi(argv[1]) : 1;
24 MPI_Comm_rank(MPI_COMM_WORLD, &rank);
25 MPI_Comm_size(MPI_COMM_WORLD, &size);
27 mult = maxlen > size ? size : maxlen;
28 int* sb = xbt_new0(int, size * maxlen);
29 int* rb = xbt_new0(int, size * maxlen);
31 for (i = 0; i < size *maxlen; ++i) {
32 sb[i] = rank*size + i;
36 printf("[%d] sndbuf=[", rank);
37 for (i = 0; i < size *mult; i++)
40 status = MPI_Allreduce(sb, rb, size *maxlen, MPI_INT, MPI_SUM, MPI_COMM_WORLD);
42 printf("[%d] rcvbuf=[", rank);
43 for (i = 0; i < size *mult; i++)//do not print everything
47 if (rank == 0 && status != MPI_SUCCESS) {
48 printf("all_to_all returned %d\n", status);
54 return (EXIT_SUCCESS);