/******************************************************************************
    Hello World example:

    In this example the rank 0 of MPI::COMM_WORLD waits for messages from the 
    other ranks. When a message is received it is displayed (send to stdout).

    Copyright 2003 (c) Critical Software SA
    . http://www.criticalsoftware.com
    . http://www.criticalsoftware.com/hpc
    . csWMPI II@criticalsoftware.com

 *****************************************************************************/

#include "Hello_World.h"
#include <stdio.h>

#include <mpi.h>

#define MESSAGELENGTH  128  /* The length of the messages that               */
                            /* we are going to transmit                      */
#define TAG            100  /* The tag to use for the transmissions          */

/******************************************************************************
        Constructor
 *****************************************************************************/
CHello_World::CHello_World(int argc, char * argv[])
{
    /* Initialize csWMPI II II:                                                   */
    MPI::Init(argc, argv);

    /* Determine what the world looks like and our own position in it:       */
    m_nCommSize = MPI::COMM_WORLD.Get_size();
    m_nCommRank = MPI::COMM_WORLD.Get_rank();
    printf("I am rank %d of %d in MPI_COMM_WORLD\n", m_nCommRank, m_nCommSize);
}

/******************************************************************************
        Destructor
 *****************************************************************************/
CHello_World::~CHello_World()
{
}

/******************************************************************************
        main
 *****************************************************************************/
int main(int argc, char *argv[])
{
    int              nCounter;
    char             pchMessage[MESSAGELENGTH];
    char             pchNodeName[MPI_MAX_PROCESSOR_NAME];
    int              nNodeNameSize;
    CHello_World*    pcHelloWorld = new CHello_World(argc, argv);

    /* If I am rank 0 I'll receive messages from the other ranks in          */
    /* MPI::COMM_WORLD and send them to stdout:                              */
    if (pcHelloWorld->m_nCommRank == 0) {

        for (nCounter = 1; nCounter < pcHelloWorld->m_nCommSize; nCounter++) {
            /* Receive a message from a process:                             */
            MPI::COMM_WORLD.Recv(pchMessage,
                                 MESSAGELENGTH,
                                 MPI::CHAR,
                                 MPI::ANY_SOURCE,
                                 TAG);

            /* Display the received message:                                 */
            printf ("I received the following message: %s\n", pchMessage);
         fflush(stdout);
        }
    } else /* I am NOT rank 0 */ {

        /* Get my node name                                                  */
      MPI_Get_processor_name(pchNodeName, &nNodeNameSize);

        /* Compose my message:                                               */
        sprintf(pchMessage,
                "Hello world from rank %d at %s",
                pcHelloWorld->m_nCommRank,
                pchNodeName);

        /* Send it:                                                          */
        MPI::COMM_WORLD.Send(pchMessage,
                             MESSAGELENGTH,
                             MPI::CHAR,
                             0,
                             TAG);
    }

    /* Flush the output so it's shown when using mpiexec                     */
    fflush (stdout);

    /* Finalize csWMPI II II:                                                     */
    MPI::Finalize();

    /* Pause rank 0 so that the output can be verified:                      */
    if (pcHelloWorld->m_nCommRank == 0) {
        printf("\nPress ENTER to exit...\n");
        fflush (stdout);
        getchar();
    }

    delete pcHelloWorld;
    return 0;
}