FM / parallel

/usr/include/c++/4.4.4/parallel/

/usr/include/c++/4.4.4/parallel

Name	Size	Mode	Actions
algo.h	104807	0644	edit dl rm
algobase.h	11140	0644	edit dl rm
algorithm	1385	0644	edit dl rm
algorithmfwd.h	30167	0644	edit dl rm
balanced_quicksort.h	16157	0644	edit dl rm
base.h	12313	0644	edit dl rm
basic_iterator.h	1606	0644	edit dl rm
checkers.h	4605	0644	edit dl rm
compatibility.h	10301	0644	edit dl rm
compiletime_settings.h	2818	0644	edit dl rm
equally_split.h	3191	0644	edit dl rm
features.h	3580	0644	edit dl rm
find.h	14295	0644	edit dl rm
find_selectors.h	7092	0644	edit dl rm
for_each.h	3666	0644	edit dl rm
for_each_selectors.h	9804	0644	edit dl rm
iterator.h	5270	0644	edit dl rm
list_partition.h	5929	0644	edit dl rm
losertree.h	25725	0644	edit dl rm
merge.h	9549	0644	edit dl rm
multiseq_selection.h	16706	0644	edit dl rm
multiway_merge.h	72745	0644	edit dl rm
multiway_mergesort.h	15478	0644	edit dl rm
numeric	19494	0644	edit dl rm
numericfwd.h	6934	0644	edit dl rm
omp_loop.h	3996	0644	edit dl rm
omp_loop_static.h	4037	0644	edit dl rm
parallel.h	1577	0644	edit dl rm
partial_sum.h	7042	0644	edit dl rm
partition.h	14909	0644	edit dl rm
par_loop.h	4541	0644	edit dl rm
queue.h	4904	0644	edit dl rm
quicksort.h	5914	0644	edit dl rm
random_number.h	3808	0644	edit dl rm
random_shuffle.h	17696	0644	edit dl rm
search.h	5598	0644	edit dl rm
settings.h	10987	0644	edit dl rm
set_operations.h	14472	0644	edit dl rm
sort.h	7421	0644	edit dl rm
tags.h	6103	0644	edit dl rm
types.h	4116	0644	edit dl rm
unique_copy.h	5811	0644	edit dl rm
workstealing.h	10088	0644	edit dl rm

Edit: /usr/include/c++/4.4.4/parallel/find.h (14295B)

// -*- 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/find.h
 *  @brief Parallel implementation base for std::find(), std::equal()
 *  and related functions.
 *  This file is a GNU parallel extension to the Standard C++ Library.
 */

// Written by Felix Putze and Johannes Singler.

#ifndef _GLIBCXX_PARALLEL_FIND_H
#define _GLIBCXX_PARALLEL_FIND_H 1

#include <bits/stl_algobase.h>

#include <parallel/features.h>
#include <parallel/parallel.h>
#include <parallel/compatibility.h>
#include <parallel/equally_split.h>

namespace __gnu_parallel
{
/**
 *  @brief Parallel std::find, switch for different algorithms.
 *  @param begin1 Begin iterator of first sequence.
 *  @param end1 End iterator of first sequence.
 *  @param begin2 Begin iterator of second sequence. Must have same
 *  length as first sequence.
 *  @param pred Find predicate.
 *  @param selector Functionality (e. g. std::find_if (), std::equal(),...)
 *  @return Place of finding in both sequences.
 */
template<typename RandomAccessIterator1,
	 typename RandomAccessIterator2,
	 typename Pred,
	 typename Selector>
  inline std::pair<RandomAccessIterator1, RandomAccessIterator2>
  find_template(RandomAccessIterator1 begin1, RandomAccessIterator1 end1,
                RandomAccessIterator2 begin2, Pred pred, Selector selector)
  {
    switch (_Settings::get().find_algorithm)
      {
      case GROWING_BLOCKS:
        return find_template(begin1, end1, begin2, pred, selector,
			     growing_blocks_tag());
      case CONSTANT_SIZE_BLOCKS:
        return find_template(begin1, end1, begin2, pred, selector,
			     constant_size_blocks_tag());
      case EQUAL_SPLIT:
        return find_template(begin1, end1, begin2, pred, selector,
			     equal_split_tag());
      default:
        _GLIBCXX_PARALLEL_ASSERT(false);
        return std::make_pair(begin1, begin2);
      }
  }

#if _GLIBCXX_FIND_EQUAL_SPLIT

/**
 *  @brief Parallel std::find, equal splitting variant.
 *  @param begin1 Begin iterator of first sequence.
 *  @param end1 End iterator of first sequence.
 *  @param begin2 Begin iterator of second sequence. Second sequence
 *  must have same length as first sequence.
 *  @param pred Find predicate.
 *  @param selector Functionality (e. g. std::find_if (), std::equal(),...)
 *  @return Place of finding in both sequences.
 */
template<typename RandomAccessIterator1,
	 typename RandomAccessIterator2,
	 typename Pred,
	 typename Selector>
  std::pair<RandomAccessIterator1, RandomAccessIterator2>
  find_template(RandomAccessIterator1 begin1,
                RandomAccessIterator1 end1,
                RandomAccessIterator2 begin2,
                Pred pred,
                Selector selector,
                equal_split_tag)
  {
    _GLIBCXX_CALL(end1 - begin1)

typedef std::iterator_traits<RandomAccessIterator1> traits_type;
    typedef typename traits_type::difference_type difference_type;
    typedef typename traits_type::value_type value_type;

difference_type length = end1 - begin1;
    difference_type result = length;
    difference_type* borders;

omp_lock_t result_lock;
    omp_init_lock(&result_lock);

thread_index_t num_threads = get_max_threads();
#   pragma omp parallel num_threads(num_threads)
      {
#       pragma omp single
          {
            num_threads = omp_get_num_threads();
            borders = new difference_type[num_threads + 1];
            equally_split(length, num_threads, borders);
          } //single

thread_index_t iam = omp_get_thread_num();
        difference_type start = borders[iam], stop = borders[iam + 1];

RandomAccessIterator1 i1 = begin1 + start;
        RandomAccessIterator2 i2 = begin2 + start;
        for (difference_type pos = start; pos < stop; ++pos)
          {
            #pragma omp flush(result)
            // Result has been set to something lower.
            if (result < pos)
              break;

if (selector(i1, i2, pred))
              {
                omp_set_lock(&result_lock);
                if (pos < result)
                  result = pos;
                omp_unset_lock(&result_lock);
                break;
              }
            ++i1;
            ++i2;
          }
      } //parallel

omp_destroy_lock(&result_lock);
    delete[] borders;

return
      std::pair<RandomAccessIterator1, RandomAccessIterator2>(begin1 + result,
							      begin2 + result);
  }

#endif

#if _GLIBCXX_FIND_GROWING_BLOCKS

/**
 *  @brief Parallel std::find, growing block size variant.
 *  @param begin1 Begin iterator of first sequence.
 *  @param end1 End iterator of first sequence.
 *  @param begin2 Begin iterator of second sequence. Second sequence
 *  must have same length as first sequence.
 *  @param pred Find predicate.
 *  @param selector Functionality (e. g. std::find_if (), std::equal(),...)
 *  @return Place of finding in both sequences.
 *  @see __gnu_parallel::_Settings::find_sequential_search_size
 *  @see __gnu_parallel::_Settings::find_initial_block_size
 *  @see __gnu_parallel::_Settings::find_maximum_block_size
 *  @see __gnu_parallel::_Settings::find_increasing_factor
 *
 *  There are two main differences between the growing blocks and
 *  the constant-size blocks variants.
 *  1. For GB, the block size grows; for CSB, the block size is fixed.

*  2. For GB, the blocks are allocated dynamically;
 *     for CSB, the blocks are allocated in a predetermined manner,
 *     namely spacial round-robin.
 */
template<typename RandomAccessIterator1,
	 typename RandomAccessIterator2,
	 typename Pred,
	 typename Selector>
  std::pair<RandomAccessIterator1, RandomAccessIterator2>
  find_template(RandomAccessIterator1 begin1, RandomAccessIterator1 end1,
                RandomAccessIterator2 begin2, Pred pred, Selector selector,
                growing_blocks_tag)
  {
    _GLIBCXX_CALL(end1 - begin1)

typedef std::iterator_traits<RandomAccessIterator1> traits_type;
    typedef typename traits_type::difference_type difference_type;
    typedef typename traits_type::value_type value_type;

const _Settings& __s = _Settings::get();

difference_type length = end1 - begin1;

difference_type sequential_search_size =
      std::min<difference_type>(length, __s.find_sequential_search_size);

// Try it sequentially first.
    std::pair<RandomAccessIterator1, RandomAccessIterator2> find_seq_result =
      selector.sequential_algorithm(
          begin1, begin1 + sequential_search_size, begin2, pred);

if (find_seq_result.first != (begin1 + sequential_search_size))
      return find_seq_result;

// Index of beginning of next free block (after sequential find).
    difference_type next_block_start = sequential_search_size;
    difference_type result = length;

omp_lock_t result_lock;
    omp_init_lock(&result_lock);

thread_index_t num_threads = get_max_threads();
#   pragma omp parallel shared(result) num_threads(num_threads)
      {
#       pragma omp single
          num_threads = omp_get_num_threads();

// Not within first k elements -> start parallel.
        thread_index_t iam = omp_get_thread_num();

difference_type block_size = __s.find_initial_block_size;
        difference_type start =
            fetch_and_add<difference_type>(&next_block_start, block_size);

// Get new block, update pointer to next block.
        difference_type stop =
            std::min<difference_type>(length, start + block_size);

std::pair<RandomAccessIterator1, RandomAccessIterator2> local_result;

while (start < length)
          {
#           pragma omp flush(result)
            // Get new value of result.
            if (result < start)
              {
                // No chance to find first element.
                break;
              }

local_result = selector.sequential_algorithm(
                begin1 + start, begin1 + stop, begin2 + start, pred);
            if (local_result.first != (begin1 + stop))
              {
                omp_set_lock(&result_lock);
                if ((local_result.first - begin1) < result)
                  {
                    result = local_result.first - begin1;

// Result cannot be in future blocks, stop algorithm.
                    fetch_and_add<difference_type>(&next_block_start, length);
                  }
                  omp_unset_lock(&result_lock);
              }

block_size =
	      std::min<difference_type>(block_size * __s.find_increasing_factor,
					__s.find_maximum_block_size);

// Get new block, update pointer to next block.
            start =
	      fetch_and_add<difference_type>(&next_block_start, block_size);
            stop = ((length < (start + block_size))
		    ? length : (start + block_size));
          }
      } //parallel

omp_destroy_lock(&result_lock);

// Return iterator on found element.
    return
      std::pair<RandomAccessIterator1, RandomAccessIterator2>(begin1 + result,
							      begin2 + result);
  }

#endif

#if _GLIBCXX_FIND_CONSTANT_SIZE_BLOCKS

/**
 *   @brief Parallel std::find, constant block size variant.
 *  @param begin1 Begin iterator of first sequence.
 *  @param end1 End iterator of first sequence.
 *  @param begin2 Begin iterator of second sequence. Second sequence
 *  must have same length as first sequence.
 *  @param pred Find predicate.
 *  @param selector Functionality (e. g. std::find_if (), std::equal(),...)
 *  @return Place of finding in both sequences.
 *  @see __gnu_parallel::_Settings::find_sequential_search_size
 *  @see __gnu_parallel::_Settings::find_block_size
 *  There are two main differences between the growing blocks and the
 *  constant-size blocks variants.
 *  1. For GB, the block size grows; for CSB, the block size is fixed.
 *  2. For GB, the blocks are allocated dynamically; for CSB, the
 *  blocks are allocated in a predetermined manner, namely spacial
 *  round-robin.
 */
template<typename RandomAccessIterator1,
	 typename RandomAccessIterator2,
	 typename Pred,
	 typename Selector>
  std::pair<RandomAccessIterator1, RandomAccessIterator2>
  find_template(RandomAccessIterator1 begin1, RandomAccessIterator1 end1,
                RandomAccessIterator2 begin2, Pred pred, Selector selector,
                constant_size_blocks_tag)
  {
    _GLIBCXX_CALL(end1 - begin1)
    typedef std::iterator_traits<RandomAccessIterator1> traits_type;
    typedef typename traits_type::difference_type difference_type;
    typedef typename traits_type::value_type value_type;

const _Settings& __s = _Settings::get();

difference_type length = end1 - begin1;

difference_type sequential_search_size = std::min<difference_type>(
        length, __s.find_sequential_search_size);

// Try it sequentially first.
    std::pair<RandomAccessIterator1, RandomAccessIterator2> find_seq_result =
      selector.sequential_algorithm(begin1, begin1 + sequential_search_size,
                                    begin2, pred);

if (find_seq_result.first != (begin1 + sequential_search_size))
      return find_seq_result;

difference_type result = length;
    omp_lock_t result_lock;
    omp_init_lock(&result_lock);

// Not within first sequential_search_size elements -> start parallel.

thread_index_t num_threads = get_max_threads();
#   pragma omp parallel shared(result) num_threads(num_threads)
      {
#       pragma omp single
          num_threads = omp_get_num_threads();

thread_index_t iam = omp_get_thread_num();
        difference_type block_size = __s.find_initial_block_size;

// First element of thread's current iteration.
        difference_type iteration_start = sequential_search_size;

// Where to work (initialization).
        difference_type start = iteration_start + iam * block_size;
        difference_type stop =
            std::min<difference_type>(length, start + block_size);

std::pair<RandomAccessIterator1, RandomAccessIterator2> local_result;

while (start < length)
          {
            // Get new value of result.
#           pragma omp flush(result)
            // No chance to find first element.
            if (result < start)
              break;
            local_result = selector.sequential_algorithm(
                begin1 + start, begin1 + stop,
                begin2 + start, pred);
            if (local_result.first != (begin1 + stop))
              {
                omp_set_lock(&result_lock);
                if ((local_result.first - begin1) < result)
                  result = local_result.first - begin1;
                omp_unset_lock(&result_lock);
                // Will not find better value in its interval.
                break;
              }

iteration_start += num_threads * block_size;

// Where to work.
            start = iteration_start + iam * block_size;
            stop = std::min<difference_type>(length, start + block_size);
          }
      } //parallel

omp_destroy_lock(&result_lock);

// Return iterator on found element.
    return
      std::pair<RandomAccessIterator1, RandomAccessIterator2>(begin1 + result,
							      begin2 + result);
  }
#endif
} // end namespace

#endif /* _GLIBCXX_PARALLEL_FIND_H */

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