gcc/libstdc++-v3/include/parallel/omp_loop_static.h
Johannes Singler e683ee2a20 re PR libstdc++/33893 ([parallel mode] Algorithms rely on omp_set_dynamic(false))
2007-11-22  Johannes Singler  <singler@ira.uka.de>

        PR libstdc++/33893
        * include/parallel/multiway_merge.h: made omp_dynamic-safe
        * include/parallel/workstealing.h: made omp_dynamic-safe
        * include/parallel/base.h: infrastructure, cleanup
        * include/parallel/par_loop.h: made omp_dynamic-safe
        * include/parallel/features.h: activate loser tree variant
        * include/parallel/quicksort.h: made omp_dynamic-safe
        * include/parallel/compiletime_settings.h: settings overridable
        * include/parallel/equally_split.h: made omp_dynamic-safe
        * include/parallel/omp_loop_static.h: made omp_dynamic-safe
        * include/parallel/random_shuffle.h: made omp_dynamic-safe
        * include/parallel/balanced_quicksort.h: made omp_dynamic-safe
        * include/parallel/set_operations.h: made omp_dynamic-safe
        * include/parallel/unique_copy.h: made omp_dynamic-safe
        * include/parallel/multiway_mergesort.h: made omp_dynamic-safe
        * include/parallel/search.h: made omp_dynamic-safe
        * include/parallel/partition.h: made omp_dynamic-safe
        * include/parallel/partial_sum.h: made omp_dynamic-safe
        * include/parallel/find.h: made omp_dynamic-safe
        * include/parallel/omp_loop.h: made omp_dynamic-safe
        * include/parallel/losertree.h: avoid default constructor

From-SVN: r130347
2007-11-22 10:13:08 +00:00

124 lines
4.3 KiB
C++

// -*- C++ -*-
// Copyright (C) 2007 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the terms
// of the GNU General Public License as published by the Free Software
// Foundation; either version 2, or (at your option) any later
// version.
// This library is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this library; see the file COPYING. If not, write to
// the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
// MA 02111-1307, USA.
// As a special exception, you may use this file as part of a free
// software library without restriction. Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to
// produce an executable, this file does not by itself cause the
// resulting executable to be covered by the GNU General Public
// License. This exception does not however invalidate any other
// reasons why the executable file might be covered by the GNU General
// Public License.
/** @file parallel/omp_loop_static.h
* @brief Parallelization of embarrassingly parallel execution by
* means of an OpenMP for loop with static scheduling.
* This file is a GNU parallel extension to the Standard C++ Library.
*/
// Written by Felix Putze.
#ifndef _GLIBCXX_PARALLEL_OMP_LOOP_STATIC_H
#define _GLIBCXX_PARALLEL_OMP_LOOP_STATIC_H 1
#include <omp.h>
#include <parallel/settings.h>
#include <parallel/basic_iterator.h>
namespace __gnu_parallel
{
/** @brief Embarrassingly parallel algorithm for random access
* iterators, using an OpenMP for loop with static scheduling.
*
* @param begin Begin iterator of element sequence.
* @param end End iterator of element sequence.
* @param o User-supplied functor (comparator, predicate, adding
* functor, ...).
* @param f Functor to "process" an element with op (depends on
* desired functionality, e. g. for std::for_each(), ...).
* @param r Functor to "add" a single result to the already processed
* elements (depends on functionality).
* @param base Base value for reduction.
* @param output Pointer to position where final result is written to
* @param bound Maximum number of elements processed (e. g. for
* std::count_n()).
* @return User-supplied functor (that may contain a part of the result).
*/
template<typename RandomAccessIterator,
typename Op,
typename Fu,
typename Red,
typename Result>
Op
for_each_template_random_access_omp_loop_static(
RandomAccessIterator begin,
RandomAccessIterator end,
Op o, Fu& f, Red r, Result base, Result& output,
typename std::iterator_traits<RandomAccessIterator>::
difference_type bound)
{
typedef typename
std::iterator_traits<RandomAccessIterator>::difference_type
difference_type;
difference_type length = end - begin;
thread_index_t num_threads =
std::min<difference_type>(get_max_threads(), length);
Result *thread_results;
# pragma omp parallel num_threads(num_threads)
{
# pragma omp single
{
num_threads = omp_get_num_threads();
thread_results = new Result[num_threads];
for (thread_index_t i = 0; i < num_threads; i++)
thread_results[i] = Result();
}
thread_index_t iam = omp_get_thread_num();
# pragma omp for schedule(static, Settings::workstealing_chunk_size)
for (difference_type pos = 0; pos < length; pos++)
thread_results[iam] =
r(thread_results[iam], f(o, begin+pos));
} //parallel
for (thread_index_t i = 0; i < num_threads; i++)
output = r(output, thread_results[i]);
delete [] thread_results;
// Points to last element processed (needed as return value for
// some algorithms like transform).
f.finish_iterator = begin + length;
return o;
}
} // end namespace
#endif