Minimal Example (Blocking Reconfiguration)
===========================================

The following C example demonstrates a blocking reconfiguration using the Dyn_PSets library. Copy and adapt for quick experimentation.

.. code-block:: c

    int main(){
        MPI_Session session;
        dyn_pset_state_t *dyn_pset_state;
        int terminate, reconfigured = 0;
        char msg[256];

        /* Initialize a Session so we can create MPI_Info objects before dyn_pset_init */
        MPI_Session_init(MPI_INFO_NULL, MPI_ERRORS_ARE_FATAL, &session);

        /* Set DynPSet verbosity and stdout as outputstream  
        dyn_pset_set_output(NULL, 0); // Increase to print DynPset debug output */

        /* Initialize the DynPSet state */
        dyn_pset_state = dyn_pset_init("mpi://WORLD", NULL, MPI_INFO_NULL, NULL, NULL, NULL, NULL);

        /* In the general case an expansion might be canceled, so we check for it here */
        if (NULL == dyn_pset_state){
            MPI_Session_finalize(&session);
            return 0;
        }

        /* Code path for dynamically added processes */
        if(dyn_pset_state->dynamic_process){
            /* Receive and print message from existing processes before terminating*/
            MPI_Bcast(msg, 256, MPI_CHAR, 0, dyn_pset_state->mpicomm);
            printf("NEW PROCESS: rank %d/%d received message '%s' from original processes\n",
                                                                dyn_pset_state->mpirank, dyn_pset_state->mpisize, msg);
        
        /* Code path for original processes */
        }else{

            printf("ORIGINAL PROCESS: == BEFORE reconfiguration: Rank %d/%d\n", dyn_pset_state->mpirank, dyn_pset_state->mpisize);

            /* Set the optimization information for the DynPSet state */
            MPI_Info_create(&info);
            MPI_Info_set(info, "mpi_num_procs_add", "2");
            dyn_pset_set_info(dyn_pset_state, info);
            MPI_Info_free(&info);

            /* Reconfigure the DyPSet state */
            dyn_pset_adapt(dyn_pset_state, &terminate, &reconfigured);

            printf("ORIGINAL PROCESS: == AFTER reconfiguration: Rank %d/%d\n", dyn_pset_state->mpirank, dyn_pset_state->mpisize);

            strcpy(msg, "Hello, new processes!");
            MPI_Bcast(msg, 256, MPI_CHAR, 0, dyn_pset_state->mpicomm);
        
        }

        /* Finalize the DynPSet state */
        dyn_pset_finalize(&dyn_pset_state, NULL);

        /* Finalize our MPI Session */
        MPI_Session_finalize(&session);    

        return 0;
    }