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/*
* Copyright (C) by Argonne National Laboratory
* See COPYRIGHT in top-level directory
*/
#include "mpi.h"
#include <stdio.h>
#include "mpitest.h"
#define MAX_PROCESSES 10
int main(int argc, char **argv)
{
int rank, size, i, j;
int table[MAX_PROCESSES][MAX_PROCESSES];
int errors = 0;
int participants;
int displs[MAX_PROCESSES];
int recv_counts[MAX_PROCESSES];
MPI_Comm test_comm;
MTest_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
/* A maximum of MAX_PROCESSES processes can participate */
participants = (size > MAX_PROCESSES) ? MAX_PROCESSES : size;
if (MAX_PROCESSES % participants) {
fprintf(stderr, "Number of processors must divide %d\n", MAX_PROCESSES);
MPI_Abort(MPI_COMM_WORLD, 1);
}
MPI_Comm_split(MPI_COMM_WORLD, rank < participants, rank, &test_comm);
if (rank < participants) {
/* Determine what rows are my responsibility */
int block_size = MAX_PROCESSES / participants;
int begin_row = rank * block_size;
int end_row = (rank + 1) * block_size;
int send_count = block_size * MAX_PROCESSES;
/* Fill in the displacements and recv_counts */
for (i = 0; i < participants; i++) {
displs[i] = i * block_size * MAX_PROCESSES;
recv_counts[i] = send_count;
}
/* Paint my rows my color */
for (i = begin_row; i < end_row; i++)
for (j = 0; j < MAX_PROCESSES; j++)
table[i][j] = rank + 10;
/* Everybody gets the gathered data */
if ((char *) &table[begin_row][0] != (char *) table + displs[rank] * sizeof(int))
MPI_Allgatherv(&table[begin_row][0], send_count, MPI_INT,
&table[0][0], recv_counts, displs, MPI_INT, test_comm);
else
MPI_Allgatherv(MPI_IN_PLACE, send_count, MPI_INT,
&table[0][0], recv_counts, displs, MPI_INT, test_comm);
/* Everybody should have the same table now.
*
* The entries are:
* Table[i][j] = (i/block_size) + 10;
*/
for (i = 0; i < MAX_PROCESSES; i++)
if ((table[i][0] - table[i][MAX_PROCESSES - 1] != 0))
errors++;
for (i = 0; i < MAX_PROCESSES; i++) {
for (j = 0; j < MAX_PROCESSES; j++) {
if (table[i][j] != (i / block_size) + 10)
errors++;
}
}
if (errors) {
/* Print out table if there are any errors */
for (i = 0; i < MAX_PROCESSES; i++) {
printf("\n");
for (j = 0; j < MAX_PROCESSES; j++)
printf(" %d", table[i][j]);
}
printf("\n");
}
}
MPI_Comm_free(&test_comm);
MTest_Finalize(errors);
return MTestReturnValue(errors);
}
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