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/* Copyright (c) 2013-2018. 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. */
/*
* Test of reduce scatter.
* Each processor contributes its rank + the index to the reduction, then receives the ith sum
* Can be called with any number of processors.
*/
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
int main( int argc, char **argv )
{
int err = 0;
int toterr;
int size;
int rank;
int i;
MPI_Comm comm;
MPI_Init( &argc, &argv );
comm = MPI_COMM_WORLD;
MPI_Comm_size( comm, &size );
MPI_Comm_rank( comm, &rank );
int* sendbuf = (int *) malloc( size * sizeof(int) );
for (i=0; i<size; i++)
sendbuf[i] = rank + i;
int* recvcounts = (int*) malloc (size * sizeof(int));
int* recvbuf = (int*) malloc (size * sizeof(int));
for (i=0; i<size; i++)
recvcounts[i] = 1;
MPI_Reduce_scatter( sendbuf, recvbuf, recvcounts, MPI_INT, MPI_SUM, comm );
int sumval = size * rank + ((size - 1) * size)/2;
/* recvbuf should be size * (rank + i) */
if (recvbuf[0] != sumval) {
err++;
fprintf( stdout, "Did not get expected value for reduce scatter\n" );
fprintf( stdout, "[%d] Got %d expected %d\n", rank, recvbuf[0], sumval );
}
MPI_Allreduce( &err, &toterr, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD );
if (rank == 0 && toterr == 0) {
printf( " No Errors\n" );
}
free(sendbuf);
free(recvcounts);
free(recvbuf);
MPI_Finalize();
return toterr;
}
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