diff options
Diffstat (limited to 'gcc-4.4.3/libstdc++-v3/include/parallel/par_loop.h')
-rw-r--r-- | gcc-4.4.3/libstdc++-v3/include/parallel/par_loop.h | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/gcc-4.4.3/libstdc++-v3/include/parallel/par_loop.h b/gcc-4.4.3/libstdc++-v3/include/parallel/par_loop.h new file mode 100644 index 000000000..be61d4ca2 --- /dev/null +++ b/gcc-4.4.3/libstdc++-v3/include/parallel/par_loop.h @@ -0,0 +1,135 @@ +// -*- 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/par_loop.h + * @brief Parallelization of embarrassingly parallel execution by + * means of equal splitting. + * This file is a GNU parallel extension to the Standard C++ Library. + */ + +// Written by Felix Putze. + +#ifndef _GLIBCXX_PARALLEL_PAR_LOOP_H +#define _GLIBCXX_PARALLEL_PAR_LOOP_H 1 + +#include <omp.h> +#include <parallel/settings.h> +#include <parallel/base.h> +#include <parallel/equally_split.h> + +namespace __gnu_parallel +{ + +/** @brief Embarrassingly parallel algorithm for random access + * iterators, using hand-crafted parallelization by equal splitting + * the work. + * + * @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_ed(RandomAccessIterator begin, + RandomAccessIterator end, + Op o, Fu& f, Red r, Result base, + Result& output, + typename std::iterator_traits + <RandomAccessIterator>:: + difference_type bound) + { + typedef std::iterator_traits<RandomAccessIterator> traits_type; + typedef typename traits_type::difference_type difference_type; + const difference_type length = end - begin; + Result *thread_results; + bool* constructed; + + thread_index_t num_threads = + __gnu_parallel::min<difference_type>(get_max_threads(), length); + +# pragma omp parallel num_threads(num_threads) + { +# pragma omp single + { + num_threads = omp_get_num_threads(); + thread_results = static_cast<Result*>( + ::operator new(num_threads * sizeof(Result))); + constructed = new bool[num_threads]; + } + + thread_index_t iam = omp_get_thread_num(); + + // Neutral element. + Result* reduct = static_cast<Result*>(::operator new(sizeof(Result))); + + difference_type + start = equally_split_point(length, num_threads, iam), + stop = equally_split_point(length, num_threads, iam + 1); + + if (start < stop) + { + new(reduct) Result(f(o, begin + start)); + ++start; + constructed[iam] = true; + } + else + constructed[iam] = false; + + for (; start < stop; ++start) + *reduct = r(*reduct, f(o, begin + start)); + + thread_results[iam] = *reduct; + } //parallel + + for (thread_index_t i = 0; i < num_threads; ++i) + if (constructed[i]) + output = r(output, thread_results[i]); + + // Points to last element processed (needed as return value for + // some algorithms like transform). + f.finish_iterator = begin + length; + + delete[] thread_results; + delete[] constructed; + + return o; + } + +} // end namespace + +#endif /* _GLIBCXX_PARALLEL_PAR_LOOP_H */ |