--- /dev/null
+/* -*- Mode: C; -*- */
+/* Creator: Bronis R. de Supinski (bronis@llnl.gov) Fri Mar 17 2000 */
+/* no-error.c -- do some MPI calls without any errors */
+
+#include <stdio.h>
+#include "mpi.h"
+
+#define buf_size 128
+
+#define INTERCOMM_CREATE_TAG 666
+
+int
+main (int argc, char **argv)
+{
+ int nprocs = -1;
+ int rank = -1;
+ char processor_name[128];
+ int namelen = 128;
+ int buf0[buf_size];
+ int buf1[buf_size];
+ MPI_Status status;
+ MPI_Comm temp, intercomm;
+ int drank, dnprocs, rleader, rnprocs;
+
+ /* init */
+ MPI_Init (&argc, &argv);
+ MPI_Comm_size (MPI_COMM_WORLD, &nprocs);
+ MPI_Comm_rank (MPI_COMM_WORLD, &rank);
+ MPI_Get_processor_name (processor_name, &namelen);
+ printf ("(%d) is alive on %s\n", rank, processor_name);
+ fflush (stdout);
+
+ MPI_Barrier (MPI_COMM_WORLD);
+
+ if (nprocs < 3) {
+ printf ("not enough tasks\n");
+ }
+ else {
+ /* need to make split communicator temporarily... */
+ MPI_Comm_split (MPI_COMM_WORLD, rank % 2, nprocs - rank, &temp);
+
+ if (temp != MPI_COMM_NULL) {
+ /* create an intercommunicator temporarily so can merge it... */
+ rleader = ((rank + nprocs) % 2) ? nprocs - 2 : nprocs - 1;
+ MPI_Intercomm_create (temp, 0, MPI_COMM_WORLD, rleader,
+ INTERCOMM_CREATE_TAG, &intercomm);
+
+ MPI_Comm_free (&temp);
+
+ if (intercomm != MPI_COMM_NULL) {
+ MPI_Comm_size (intercomm, &dnprocs);
+ MPI_Comm_rank (intercomm, &drank);
+ MPI_Comm_remote_size (intercomm, &rnprocs);
+
+ if (rnprocs > drank) {
+ if (rank % 2) {
+ memset (buf1, 1, buf_size);
+
+ MPI_Recv (buf0, buf_size, MPI_INT, drank, 0, intercomm, &status);
+
+ MPI_Send (buf1, buf_size, MPI_INT, drank, 0, intercomm);
+ }
+ else {
+ memset (buf0, 0, buf_size);
+
+ MPI_Recv (buf1, buf_size, MPI_INT, drank, 0, intercomm, &status);
+
+ MPI_Send (buf0, buf_size, MPI_INT, drank, 0, intercomm);
+ }
+ }
+ else {
+ printf ("(%d) Intercomm too small (lrank = %d; remote size = %d)\n",
+ rank, drank, rnprocs);
+ }
+
+ MPI_Comm_free (&intercomm);
+ }
+ else {
+ printf ("(%d) Got MPI_COMM_NULL\n", rank);
+ }
+ }
+ else {
+ printf ("(%d) MPI_Comm_split got MPI_COMM_NULL\n", rank);
+ }
+ }
+
+ MPI_Barrier (MPI_COMM_WORLD);
+
+ MPI_Finalize ();
+ printf ("(%d) Finished normally\n", rank);
+}
+
+/* EOF */