/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpiimpl.h"

#include "group.h"

/* -- Begin Profiling Symbol Block for routine MPI_Group_union */

#if defined(HAVE_PRAGMA_WEAK)

#pragma weak MPI_Group_union = PMPI_Group_union

#elif defined(HAVE_PRAGMA_HP_SEC_DEF)

#pragma _HP_SECONDARY_DEF PMPI_Group_union  MPI_Group_union

#elif defined(HAVE_PRAGMA_CRI_DUP)

#pragma _CRI duplicate MPI_Group_union as PMPI_Group_union

#elif defined(HAVE_WEAK_ATTRIBUTE)

int MPI_Group_union(MPI_Group group1, MPI_Group group2, MPI_Group * newgroup)

    __attribute__ ((weak, alias("PMPI_Group_union")));

#endif

/* -- End Profiling Symbol Block */

/* Define MPICH_MPI_FROM_PMPI if weak symbols are not supported to build

   the MPI routines */

#ifndef MPICH_MPI_FROM_PMPI

#undef MPI_Group_union

#define MPI_Group_union PMPI_Group_union

#undef FUNCNAME

#define FUNCNAME MPIR_Group_union_impl

#undef FCNAME

#define FCNAME MPL_QUOTE(FUNCNAME)

int MPIR_Group_union_impl(MPIR_Group * group_ptr1, MPIR_Group * group_ptr2,

                          MPIR_Group ** new_group_ptr)

{

    int mpi_errno = MPI_SUCCESS;

    int g1_idx, g2_idx, nnew, i, k, size1, size2, mylpid;

    MPIR_FUNC_TERSE_STATE_DECL(MPID_STATE_MPIR_GROUP_UNION_IMPL);

    MPIR_FUNC_TERSE_ENTER(MPID_STATE_MPIR_GROUP_UNION_IMPL);

    /* Determine the size of the new group.  The new group consists of all

     * members of group1 plus the members of group2 that are not in group1.

     */

    g1_idx = group_ptr1->idx_of_first_lpid;

    g2_idx = group_ptr2->idx_of_first_lpid;

    /* If the lpid list hasn't been created, do it now */

    if (g1_idx < 0) {

        MPII_Group_setup_lpid_list(group_ptr1);

        g1_idx = group_ptr1->idx_of_first_lpid;

    }

    if (g2_idx < 0) {

        MPII_Group_setup_lpid_list(group_ptr2);

        g2_idx = group_ptr2->idx_of_first_lpid;

    }

    nnew = group_ptr1->size;

    /* Clear the flag bits on the second group.  The flag is set if

     * a member of the second group belongs to the union */

    size2 = group_ptr2->size;

    for (i = 0; i < size2; i++) {

        group_ptr2->lrank_to_lpid[i].flag = 0;

    }

    /* Loop through the lists that are ordered by lpid (local process

     * id) to detect which processes in group 2 are not in group 1

     */

    while (g1_idx >= 0 && g2_idx >= 0) {

        int l1_pid, l2_pid;

        l1_pid = group_ptr1->lrank_to_lpid[g1_idx].lpid;

        l2_pid = group_ptr2->lrank_to_lpid[g2_idx].lpid;

        if (l1_pid > l2_pid) {

            nnew++;

            group_ptr2->lrank_to_lpid[g2_idx].flag = 1;

            g2_idx = group_ptr2->lrank_to_lpid[g2_idx].next_lpid;

        } else if (l1_pid == l2_pid) {

            g1_idx = group_ptr1->lrank_to_lpid[g1_idx].next_lpid;

            g2_idx = group_ptr2->lrank_to_lpid[g2_idx].next_lpid;

        } else {

            /* l1 < l2 */

            g1_idx = group_ptr1->lrank_to_lpid[g1_idx].next_lpid;

        }

    }

    /* If we hit the end of group1, add the remaining members of group 2 */

    while (g2_idx >= 0) {

        nnew++;

        group_ptr2->lrank_to_lpid[g2_idx].flag = 1;

        g2_idx = group_ptr2->lrank_to_lpid[g2_idx].next_lpid;

    }

    if (nnew == 0) {

        *new_group_ptr = MPIR_Group_empty;

        goto fn_exit;

    }

    /* Allocate a new group and lrank_to_lpid array */

    mpi_errno = MPIR_Group_create(nnew, new_group_ptr);

    if (mpi_errno)

        MPIR_ERR_POP(mpi_errno);

    /* If this process is in group1, then we can set the rank now.

     * If we are not in this group, this assignment will set the

     * current rank to MPI_UNDEFINED */

    (*new_group_ptr)->rank = group_ptr1->rank;

    /* Add group1 */

    size1 = group_ptr1->size;

    for (i = 0; i < size1; i++) {

        (*new_group_ptr)->lrank_to_lpid[i].lpid = group_ptr1->lrank_to_lpid[i].lpid;

    }

    /* Add members of group2 that are not in group 1 */

    if (group_ptr1->rank == MPI_UNDEFINED && group_ptr2->rank >= 0) {

        mylpid = group_ptr2->lrank_to_lpid[group_ptr2->rank].lpid;

    } else {

        mylpid = -2;

    }

    k = size1;

    for (i = 0; i < size2; i++) {

        if (group_ptr2->lrank_to_lpid[i].flag) {

            (*new_group_ptr)->lrank_to_lpid[k].lpid = group_ptr2->lrank_to_lpid[i].lpid;

            if ((*new_group_ptr)->rank == MPI_UNDEFINED &&

                group_ptr2->lrank_to_lpid[i].lpid == mylpid)

                (*new_group_ptr)->rank = k;

            k++;

        }

    }

    /* TODO calculate is_local_dense_monotonic */

  fn_exit:

    MPIR_FUNC_TERSE_EXIT(MPID_STATE_MPIR_GROUP_UNION_IMPL);

    return mpi_errno;

  fn_fail:

    goto fn_exit;

}

#endif

#undef FUNCNAME

#define FUNCNAME MPI_Group_union

#undef FCNAME

#define FCNAME MPL_QUOTE(FUNCNAME)

/*@

MPI_Group_union - Produces a group by combining two groups

Input Parameters:

+ group1 - first group (handle)

- group2 - second group (handle)

Output Parameters:

. newgroup - union group (handle)

.N ThreadSafe

.N Fortran

.N Errors

.N MPI_SUCCESS

.N MPI_ERR_GROUP

.N MPI_ERR_EXHAUSTED

.seealso: MPI_Group_free

@*/

int MPI_Group_union(MPI_Group group1, MPI_Group group2, MPI_Group * newgroup)

{

    int mpi_errno = MPI_SUCCESS;

    MPIR_Group *group_ptr1 = NULL;

    MPIR_Group *group_ptr2 = NULL;

    MPIR_Group *new_group_ptr;

    MPIR_FUNC_TERSE_STATE_DECL(MPID_STATE_MPI_GROUP_UNION);

    MPIR_ERRTEST_INITIALIZED_ORDIE();

    MPID_THREAD_CS_ENTER(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);

    MPIR_FUNC_TERSE_ENTER(MPID_STATE_MPI_GROUP_UNION);

    /* Validate parameters, especially handles needing to be converted */

#ifdef HAVE_ERROR_CHECKING

    {

        MPID_BEGIN_ERROR_CHECKS;

        {

            MPIR_ERRTEST_GROUP(group1, mpi_errno);

            MPIR_ERRTEST_GROUP(group2, mpi_errno);

        }

        MPID_END_ERROR_CHECKS;

    }

#endif

    /* Convert MPI object handles to object pointers */

    MPIR_Group_get_ptr(group1, group_ptr1);

    MPIR_Group_get_ptr(group2, group_ptr2);

    /* Validate parameters and objects (post conversion) */

#ifdef HAVE_ERROR_CHECKING

    {

        MPID_BEGIN_ERROR_CHECKS;

        {

            /* Validate group_ptr */

            MPIR_Group_valid_ptr(group_ptr1, mpi_errno);

            MPIR_Group_valid_ptr(group_ptr2, mpi_errno);

            /* If group_ptr is not valid, it will be reset to null */

            if (mpi_errno)

                goto fn_fail;

            MPIR_ERRTEST_ARGNULL(newgroup, "newgroup", mpi_errno);

        }

        MPID_END_ERROR_CHECKS;

    }

#endif /* HAVE_ERROR_CHECKING */

    /* ... body of routine ...  */

    mpi_errno = MPIR_Group_union_impl(group_ptr1, group_ptr2, &new_group_ptr);

    if (mpi_errno)

        goto fn_fail;

    MPIR_OBJ_PUBLISH_HANDLE(*newgroup, new_group_ptr->handle);

    /* ... end of body of routine ... */

  fn_exit:

    MPIR_FUNC_TERSE_EXIT(MPID_STATE_MPI_GROUP_UNION);

    MPID_THREAD_CS_EXIT(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);

    return mpi_errno;

  fn_fail:

    /* --BEGIN ERROR HANDLING-- */

#ifdef HAVE_ERROR_CHECKING

    {

        mpi_errno =

            MPIR_Err_create_code(mpi_errno, MPIR_ERR_RECOVERABLE, FCNAME, __LINE__, MPI_ERR_OTHER,

                                 "**mpi_group_union", "**mpi_group_union %G %G %p", group1, group2,

                                 newgroup);

    }

#endif

    mpi_errno = MPIR_Err_return_comm(NULL, FCNAME, mpi_errno);

    goto fn_exit;

    /* --END ERROR HANDLING-- */

}