2 /* Creator: Bronis R. de Supinski (bronis@llnl.gov) Fri Mar 17 2000 */
3 /* no-error.c -- do some MPI calls without any errors */
10 #define INTERCOMM_CREATE_TAG 666
13 main (int argc, char **argv)
17 char processor_name[128];
22 MPI_Comm temp, intercomm;
24 int drank, dnprocs, rleader, rnprocs;
27 MPI_Init (&argc, &argv);
28 MPI_Comm_size (MPI_COMM_WORLD, &nprocs);
29 MPI_Comm_rank (MPI_COMM_WORLD, &rank);
30 MPI_Get_processor_name (processor_name, &namelen);
31 printf ("(%d) is alive on %s\n", rank, processor_name);
34 MPI_Barrier (MPI_COMM_WORLD);
37 printf ("not enough tasks\n");
40 /* need to make split communicator temporarily... */
41 MPI_Comm_split (MPI_COMM_WORLD, rank % 2, nprocs - rank, &temp);
43 if (temp != MPI_COMM_NULL) {
44 MPI_Comm_size (temp, &tnprocs);
45 MPI_Comm_rank (temp, &trank);
47 /* create an intercommunicator temporarily so can merge it... */
48 rleader = ((rank + nprocs) % 2) ? nprocs - 2 : nprocs - 1;
51 MPI_Recv (buf0, buf_size, MPI_INT, 0, 0, temp, &status);
54 MPI_Intercomm_create (temp, 0, MPI_COMM_WORLD, rleader,
55 INTERCOMM_CREATE_TAG, &intercomm);
59 memset (buf0, 0, buf_size*sizeof(int));
61 MPI_Send (buf0, buf_size, MPI_INT, 1, 0, temp);
65 printf ("(%d) Split communicator too small\n", rank);
68 MPI_Comm_free (&temp);
70 if (intercomm != MPI_COMM_NULL) {
71 MPI_Comm_size (intercomm, &dnprocs);
72 MPI_Comm_rank (intercomm, &drank);
73 MPI_Comm_remote_size (intercomm, &rnprocs);
75 if (rnprocs > drank) {
77 memset (buf1, 1, buf_size*sizeof(int));
79 MPI_Recv (buf0, buf_size, MPI_INT, drank, 0, intercomm, &status);
81 MPI_Send (buf1, buf_size, MPI_INT, drank, 0, intercomm);
84 memset (buf0, 0, buf_size*sizeof(int));
86 MPI_Send (buf0, buf_size, MPI_INT, drank, 0, intercomm);
88 MPI_Recv (buf1, buf_size, MPI_INT, drank, 0, intercomm, &status);
92 printf ("(%d) Intercomm too small (lrank = %d; remote size = %d)\n",
93 rank, drank, rnprocs);
96 MPI_Comm_free (&intercomm);
99 printf ("(%d) Got MPI_COMM_NULL\n", rank);
103 printf ("(%d) MPI_Comm_split got MPI_COMM_NULL\n", rank);
107 MPI_Barrier (MPI_COMM_WORLD);
110 printf ("(%d) Finished normally\n", rank);