/* -*- Mode: C++; c-basic-offset:4 ; -*- */
/*
 *
 *  (C) 2003 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include "mpi.h"
#include "mpitestconf.h"
#ifdef HAVE_IOSTREAM
// Not all C++ compilers have iostream instead of iostream.h
#include <iostream>
#ifdef HAVE_NAMESPACE_STD
// Those that do often need the std namespace; otherwise, a bare "cout"
// is likely to fail to compile
using namespace std;
#endif
#else
#include <iostream.h>
#endif
#include "mpitestcxx.h"

static char MTEST_Descrip[] = "Simple intercomm scatter test";

int main(int argc, char *argv[])
{
    int errs = 0;
    int *buf = 0;
    int leftGroup, i, count, rank;
    MPI::Intercomm comm;
    MPI::Datatype datatype;

    MTest_Init();

    datatype = MPI::INT;
    while (MTestGetIntercomm(comm, leftGroup, 4)) {
        if (comm == MPI::COMM_NULL)
            continue;
        for (count = 1; count < 65000; count = 2 * count) {
            /* Get an intercommunicator */
            buf = 0;
            if (leftGroup) {
                int rsize;

                rsize = comm.Get_remote_size();
                rank = comm.Get_rank();

                buf = new int[count * rsize];
                if (rank == 0) {
                    for (i = 0; i < count * rsize; i++)
                        buf[i] = i;
                } else {
                    for (i = 0; i < count * rsize; i++)
                        buf[i] = -1;
                }
                try {
                    comm.Scatter(buf, count, datatype,
                                 NULL, 0, datatype, (rank == 0) ? MPI::ROOT : MPI::PROC_NULL);

                }
                catch(MPI::Exception e) {
                    errs++;
                    MTestPrintError(e.Get_error_code());
                }
                /* Test that no other process in this group received the
                 * scatter */
                if (rank != 0) {
                    for (i = 0; i < count * rsize; i++) {
                        if (buf[i] != -1) {
                            if (errs < 10) {
                                cout << "Received data on root group!\n";
                            }
                            errs++;
                        }
                    }
                }
            } else {
                int rank, size;

                rank = comm.Get_rank();
                size = comm.Get_size();

                buf = new int[count];
                /* In the right group */
                for (i = 0; i < count; i++)
                    buf[i] = -1;
                try {
                    comm.Scatter(NULL, 0, datatype, buf, count, datatype, 0);
                }
                catch(MPI::Exception e) {
                    errs++;
                    MTestPrintError(e.Get_error_code());
                }
                /* Check that we have received the correct data */
                for (i = 0; i < count; i++) {
                    if (buf[i] != i + rank * count) {
                        if (errs < 10)
                            cout << "buf[" << i << "] = " << buf[i] << " on " << rank << "\n";
                        errs++;
                    }
                }
            }
            delete[]buf;
        }
        MTestFreeComm(comm);
    }

    MTest_Finalize(errs);
    return 0;
}