1 /* Copyright (c) 2010-2021. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 /******************** Non-deterministic message ordering *********************/
7 /* Server assumes a fixed order in the reception of messages from its clients */
8 /* which is incorrect because the message ordering is non-deterministic */
9 /******************************************************************************/
13 int main(int argc, char **argv)
20 int err = MPI_Init(&argc, &argv);
21 if (err != MPI_SUCCESS) {
22 printf("MPI initialization failed!\n");
26 MPI_Comm_size(MPI_COMM_WORLD, &size); /* Get nr of tasks */
27 MPI_Comm_rank(MPI_COMM_WORLD, &rank); /* Get id of this process */
29 printf("run this program with exactly 4 processes (-np 4)\n");
36 for (int i = 0; i < size - 1; i++) {
37 MPI_Recv(&recv_buffer, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
38 printf("Message received from %d\n", recv_buffer);
41 if (recv_buffer != 3) {
42 printf("The last received message is not 3 but %d!\n", recv_buffer);
47 MPI_Send(&rank, 1, MPI_INT, 0, 42, MPI_COMM_WORLD);
48 printf("Sent %d to rank 0\n", rank);