118 lines
3.9 KiB
C++
118 lines
3.9 KiB
C++
// -*- C++ -*-
|
|
|
|
// Copyright (C) 2007, 2008, 2009 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 3, 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.
|
|
|
|
// Under Section 7 of GPL version 3, you are granted additional
|
|
// permissions described in the GCC Runtime Library Exception, version
|
|
// 3.1, as published by the Free Software Foundation.
|
|
|
|
// You should have received a copy of the GNU General Public License and
|
|
// a copy of the GCC Runtime Library Exception along with this program;
|
|
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
// <http://www.gnu.org/licenses/>.
|
|
|
|
/** @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::get().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 /* _GLIBCXX_PARALLEL_OMP_LOOP_STATIC_H */
|