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/*
* Copyright (C) by Argonne National Laboratory
* See COPYRIGHT in top-level directory
*/
/*
* Test of reduce scatter block.
*
* Each process contributes its rank + the index to the reduction,
* then receives the ith sum
*
* Can be called with any number of processes.
*/
#include "mpi.h"
#include "mpitest.h"
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
int err = 0;
int size, rank, i, sumval;
int *sendbuf;
int *recvbuf;
MPI_Comm comm;
MTest_Init(&argc, &argv);
comm = MPI_COMM_WORLD;
MPI_Comm_size(comm, &size);
MPI_Comm_rank(comm, &rank);
#if MTEST_HAVE_MIN_MPI_VERSION(2,2)
/* MPI_Reduce_scatter block was added in MPI-2.2 */
sendbuf = (int *) malloc(size * sizeof(int));
recvbuf = (int *) malloc(size * sizeof(int));
if (!sendbuf || !recvbuf) {
err++;
fprintf(stderr, "unable to allocate send/recv buffers, aborting");
MPI_Abort(MPI_COMM_WORLD, 1);
}
for (i = 0; i < size; i++)
sendbuf[i] = rank + i;
MPI_Reduce_scatter_block(sendbuf, recvbuf, 1, MPI_INT, MPI_SUM, comm);
sumval = size * rank + ((size - 1) * size) / 2;
if (recvbuf[0] != sumval) {
err++;
fprintf(stdout, "Did not get expected value for reduce scatter block\n");
fprintf(stdout, "[%d] Got %d expected %d\n", rank, recvbuf[0], sumval);
}
free(sendbuf);
/* let's try it again with MPI_IN_PLACE this time */
for (i = 0; i < size; i++)
recvbuf[i] = rank + i;
MPI_Reduce_scatter_block(MPI_IN_PLACE, recvbuf, 1, MPI_INT, MPI_SUM, comm);
sumval = size * rank + ((size - 1) * size) / 2;
if (recvbuf[0] != sumval) {
err++;
fprintf(stdout, "Did not get expected value for reduce scatter block\n");
fprintf(stdout, "[%d] Got %d expected %d\n", rank, recvbuf[0], sumval);
}
free(recvbuf);
#endif
MTest_Finalize(err);
return MTestReturnValue(err);
}
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