1 /*
2 (C) 2001 by Argonne National Laboratory.
3 See COPYRIGHT in top-level directory.
4 */
5 #include <stdio.h>
6 #include <string.h>
7 #include "mpi.h"
8
9 #define REQUESTS_SIZE 10
10 #define STATUSES_SIZE 10
11 #define LOOP_COUNT 200
12
main(int argc,char * argv[])13 int main( int argc, char *argv[] )
14 {
15 MPI_Comm splited_comm, duped_comm, inter_comm, *comm_ptr;
16 MPI_Request world_requests[REQUESTS_SIZE], comm_requests[REQUESTS_SIZE];
17 MPI_Status world_statuses[STATUSES_SIZE], comm_statuses[STATUSES_SIZE];
18 char processor_name[MPI_MAX_PROCESSOR_NAME];
19 int comm_rank, comm_size, comm_neighbor;
20 int world_rank, world_size, world_neighbor;
21 int icolor, namelen, ibuffers[REQUESTS_SIZE];
22 int ii, jj;
23
24 MPI_Init( &argc, &argv );
25 MPI_Comm_size( MPI_COMM_WORLD, &world_size );
26 MPI_Comm_rank( MPI_COMM_WORLD, &world_rank );
27 MPI_Get_processor_name( processor_name, &namelen );
28
29 fprintf( stdout, "world_rank %d on %s\n", world_rank, processor_name );
30 fflush( stdout );
31
32 if ( world_rank == world_size - 1 )
33 world_neighbor = 0;
34 else
35 world_neighbor = world_rank + 1;
36
37 for ( ii = 0; ii < LOOP_COUNT; ii++ ) {
38 for ( jj = 0; jj < REQUESTS_SIZE; jj++ ) {
39 MPI_Irecv( &ibuffers[jj], 1, MPI_INT, MPI_ANY_SOURCE,
40 99, MPI_COMM_WORLD, &world_requests[jj] );
41 MPI_Send( &world_rank, 1, MPI_INT, world_neighbor,
42 99, MPI_COMM_WORLD );
43 }
44 MPI_Waitall( REQUESTS_SIZE, world_requests, world_statuses );
45 }
46
47 /* Split all processes into 2 separate intracommunicators */
48 icolor = world_rank % 2;
49 MPI_Comm_split( MPI_COMM_WORLD, icolor, world_rank, &splited_comm );
50
51 /* Put in a Comm_dup so local comm ID is different in 2 splited comm */
52 if ( icolor == 0 ) {
53 MPI_Comm_dup( splited_comm, &duped_comm );
54 comm_ptr = &duped_comm;
55 }
56 else
57 comm_ptr = &splited_comm;
58
59 MPI_Comm_size( *comm_ptr, &comm_size );
60 MPI_Comm_rank( *comm_ptr, &comm_rank );
61
62 if ( comm_rank == comm_size - 1 )
63 comm_neighbor = 0;
64 else
65 comm_neighbor = comm_rank + 1;
66
67 for ( ii = 0; ii < LOOP_COUNT; ii++ ) {
68 for ( jj = 0; jj < REQUESTS_SIZE; jj++ ) {
69 MPI_Irecv( &ibuffers[jj], 1, MPI_INT, MPI_ANY_SOURCE,
70 999, *comm_ptr, &comm_requests[jj] );
71 MPI_Send( &comm_rank, 1, MPI_INT, comm_neighbor,
72 999, *comm_ptr );
73 }
74 MPI_Waitall( REQUESTS_SIZE, comm_requests, comm_statuses );
75 }
76
77 /* Form an intercomm between the 2 splited intracomm's */
78 if ( icolor == 0 )
79 MPI_Intercomm_create( *comm_ptr, 0, MPI_COMM_WORLD, 1,
80 9090, &inter_comm );
81 else
82 MPI_Intercomm_create( *comm_ptr, 0, MPI_COMM_WORLD, 0,
83 9090, &inter_comm );
84
85 if ( comm_rank == 0 ) {
86 for ( ii = 0; ii < LOOP_COUNT; ii++ ) {
87 for ( jj = 0; jj < REQUESTS_SIZE; jj++ ) {
88 MPI_Irecv( &ibuffers[jj], 1, MPI_INT, 0,
89 9999, inter_comm, &comm_requests[jj] );
90 MPI_Send( &comm_rank, 1, MPI_INT, 0, 9999, inter_comm );
91 }
92 MPI_Waitall( REQUESTS_SIZE, comm_requests, comm_statuses );
93 }
94 }
95
96 /* Free all communicators created */
97 MPI_Comm_free( &inter_comm );
98 if ( icolor == 0 )
99 MPI_Comm_free( &duped_comm );
100 MPI_Comm_free( &splited_comm );
101
102 MPI_Finalize();
103 return( 0 );
104 }
105