1 /* Copyright (c) 2013-2014. 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. */
8 * Test of reduce scatter.
10 * Each processor contributes its rank + the index to the reduction,
11 * then receives the ith sum
13 * Can be called with any number of processors.
20 int main( int argc, char **argv )
23 int *sendbuf, *recvbuf, *recvcounts;
24 int size, rank, i, sumval;
28 MPI_Init( &argc, &argv );
29 comm = MPI_COMM_WORLD;
31 MPI_Comm_size( comm, &size );
32 MPI_Comm_rank( comm, &rank );
33 sendbuf = (int *) malloc( size * sizeof(int) );
34 for (i=0; i<size; i++)
35 sendbuf[i] = rank + i;
36 recvcounts = (int *)malloc( size * sizeof(int) );
37 recvbuf = (int *)malloc( size * sizeof(int) );
38 for (i=0; i<size; i++)
40 MPI_Reduce_scatter( sendbuf, recvbuf, recvcounts, MPI_INT, MPI_SUM, comm );
41 sumval = size * rank + ((size - 1) * size)/2;
42 /* recvbuf should be size * (rank + i) */
43 if (recvbuf[0] != sumval) {
45 fprintf( stdout, "Did not get expected value for reduce scatter\n" );
46 fprintf( stdout, "[%d] Got %d expected %d\n", rank, recvbuf[0], sumval );
49 MPI_Allreduce( &err, &toterr, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD );
50 if (rank == 0 && toterr == 0) {
51 printf( " No Errors\n" );