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/*
* Copyright (C) by Argonne National Laboratory
* See COPYRIGHT in top-level directory
*/
/** PGROUP Creation (Connect/Accept Method)
* James Dinan <dinan@mcs.anl.gov>
* May, 2011
*
* In this test, processes create an intracommunicator and creation is
* collective only on the members of the new communicator, not on the parent
* communicator. This is accomplished by building up and merging
* intercommunicators using Connect/Accept to merge with a controller
* process.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <mpi.h>
#include "mpitest.h"
const int verbose = 0;
void PGroup_create(int count, int members[], MPI_Comm * group);
void PGroup_create(int count, int members[], MPI_Comm * group)
{
int i, me, nproc, is_member;
char *port;
MPI_Comm pgroup;
MPI_Comm_rank(MPI_COMM_WORLD, &me);
MPI_Comm_size(MPI_COMM_WORLD, &nproc);
if (count == 0) {
*group = MPI_COMM_NULL;
return;
} else if (count == 1 && members[0] == me) {
*group = MPI_COMM_SELF;
return;
}
for (i = 0, is_member = 0; i < count; i++) {
if (members[i] == me) {
is_member = 1;
break;
}
}
if (!is_member) {
*group = MPI_COMM_NULL;
return;
}
port = malloc(MPI_MAX_PORT_NAME);
/* NOTE: Assume members list is identical and sorted on all processes */
/* I am the leader */
if (me == members[0]) {
MPI_Comm pgroup_new;
pgroup = MPI_COMM_SELF;
MPI_Open_port(MPI_INFO_NULL, port);
for (i = 1; i < count; i++) {
MPI_Comm pgroup_old = pgroup;
MPI_Send(port, MPI_MAX_PORT_NAME, MPI_CHAR, members[i], 0, MPI_COMM_WORLD);
MPI_Comm_accept(port, MPI_INFO_NULL, 0, pgroup, &pgroup_new);
MPI_Intercomm_merge(pgroup_new, 0 /* LOW */ , &pgroup);
MPI_Comm_free(&pgroup_new);
if (pgroup_old != MPI_COMM_SELF)
MPI_Comm_free(&pgroup_old);
}
MPI_Close_port(port);
}
/* I am not the leader */
else {
int merged = 0;
MPI_Comm pgroup_new;
for (i = 0; i < count; i++) {
if (members[i] == me) {
MPI_Recv(port, MPI_MAX_PORT_NAME, MPI_CHAR, members[0], 0, MPI_COMM_WORLD,
MPI_STATUS_IGNORE);
MPI_Comm_connect(port, MPI_INFO_NULL, 0, MPI_COMM_SELF, &pgroup_new);
MPI_Intercomm_merge(pgroup_new, 1 /* HIGH */ , &pgroup);
MPI_Comm_free(&pgroup_new);
merged = 1;
} else if (merged) {
MPI_Comm pgroup_old = pgroup;
MPI_Comm_connect(port, MPI_INFO_NULL, 0, pgroup, &pgroup_new);
MPI_Intercomm_merge(pgroup_new, 0 /* HIGH */ , &pgroup);
MPI_Comm_free(&pgroup_new);
MPI_Comm_free(&pgroup_old);
}
/* else => !merged */
}
}
free(port);
*group = pgroup;
}
int main(int argc, char **argv)
{
int me, nproc, i;
int gsize, *glist;
MPI_Comm group;
MTest_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &me);
MPI_Comm_size(MPI_COMM_WORLD, &nproc);
gsize = nproc / 2 + (nproc % 2);
glist = malloc(gsize * sizeof(int));
for (i = 0; i < nproc; i += 2)
glist[i / 2] = i;
if (me % 2 == 0) {
int gme, gnproc;
PGroup_create(gsize, glist, &group);
MPI_Barrier(group);
MPI_Comm_rank(group, &gme);
MPI_Comm_size(group, &gnproc);
if (verbose)
printf("[%d] Group rank = %d, size = %d\n", me, gme, gnproc);
if (group != MPI_COMM_SELF)
MPI_Comm_free(&group);
}
free(glist);
MTest_Finalize(0);
return MTestReturnValue(0);
}
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