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algo.h	78.15 KB	-rw-r--r--
algobase.h	16.75 KB	-rw-r--r--
algorithm	1.35 KB	-rw-r--r--
algorithmfwd.h	31.45 KB	-rw-r--r--
balanced_quicksort.h	16.55 KB	-rw-r--r--
base.h	12.08 KB	-rw-r--r--
basic_iterator.h	1.55 KB	-rw-r--r--
checkers.h	2.25 KB	-rw-r--r--
compatibility.h	3.7 KB	-rw-r--r--
compiletime_settings.h	2.8 KB	-rw-r--r--
equally_split.h	3.28 KB	-rw-r--r--
features.h	3.46 KB	-rw-r--r--
find.h	13.27 KB	-rw-r--r--
find_selectors.h	6.83 KB	-rw-r--r--
for_each.h	3.85 KB	-rw-r--r--
for_each_selectors.h	10.32 KB	-rw-r--r--
iterator.h	5.54 KB	-rw-r--r--
list_partition.h	6.39 KB	-rw-r--r--
losertree.h	27.92 KB	-rw-r--r--
merge.h	9.35 KB	-rw-r--r--
multiseq_selection.h	21.56 KB	-rw-r--r--
multiway_merge.h	68.88 KB	-rw-r--r--
multiway_mergesort.h	14.91 KB	-rw-r--r--
numeric	20.23 KB	-rw-r--r--
numericfwd.h	7.32 KB	-rw-r--r--
omp_loop.h	3.94 KB	-rw-r--r--
omp_loop_static.h	4.01 KB	-rw-r--r--
par_loop.h	4.45 KB	-rw-r--r--
parallel.h	1.54 KB	-rw-r--r--
partial_sum.h	7.3 KB	-rw-r--r--
partition.h	14.61 KB	-rw-r--r--
queue.h	5.41 KB	-rw-r--r--
quicksort.h	5.98 KB	-rw-r--r--
random_number.h	4.13 KB	-rw-r--r--
random_shuffle.h	18.24 KB	-rw-r--r--
search.h	5.26 KB	-rw-r--r--
set_operations.h	14.25 KB	-rw-r--r--
settings.h	12.17 KB	-rw-r--r--
sort.h	7.53 KB	-rw-r--r--
tags.h	5.84 KB	-rw-r--r--
types.h	3.63 KB	-rw-r--r--
unique_copy.h	6.02 KB	-rw-r--r--
workstealing.h	9.38 KB	-rw-r--r--

Code Editor : quicksort.h

// -*- C++ -*-

// Copyright (C) 2007-2019 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/quicksort.h
 *  @brief Implementation of a unbalanced parallel quicksort (in-place).
 *  This file is a GNU parallel extension to the Standard C++ Library.
 */

// Written by Johannes Singler.

#ifndef _GLIBCXX_PARALLEL_QUICKSORT_H
#define _GLIBCXX_PARALLEL_QUICKSORT_H 1

#include <parallel/parallel.h>
#include <parallel/partition.h>

namespace __gnu_parallel
{
  /** @brief Unbalanced quicksort divide step.
   *  @param __begin Begin iterator of subsequence.
   *  @param __end End iterator of subsequence.
   *  @param __comp Comparator.
   *  @param __pivot_rank Desired __rank of the pivot.
   *  @param __num_samples Choose pivot from that many samples.
   *  @param __num_threads Number of threads that are allowed to work on
   *  this part.
   */
  template<typename _RAIter, typename _Compare>
    typename std::iterator_traits<_RAIter>::difference_type
    __parallel_sort_qs_divide(_RAIter __begin, _RAIter __end,
			      _Compare __comp, typename std::iterator_traits
			      <_RAIter>::difference_type __pivot_rank,
			      typename std::iterator_traits
			      <_RAIter>::difference_type
			      __num_samples, _ThreadIndex __num_threads)
    {
      typedef std::iterator_traits<_RAIter> _TraitsType;
      typedef typename _TraitsType::value_type _ValueType;
      typedef typename _TraitsType::difference_type _DifferenceType;

_DifferenceType __n = __end - __begin;
      __num_samples = std::min(__num_samples, __n);

// Allocate uninitialized, to avoid default constructor.
      _ValueType* __samples = static_cast<_ValueType*>
	(::operator new(__num_samples * sizeof(_ValueType)));

for (_DifferenceType __s = 0; __s < __num_samples; ++__s)
        {
          const unsigned long long __index = static_cast<unsigned long long>
	    (__s) * __n / __num_samples;
          ::new(&(__samples[__s])) _ValueType(__begin[__index]);
        }

__gnu_sequential::sort(__samples, __samples + __num_samples, __comp);

_ValueType& __pivot = __samples[__pivot_rank * __num_samples / __n];

__gnu_parallel::__binder2nd<_Compare, _ValueType, _ValueType, bool>
        __pred(__comp, __pivot);
      _DifferenceType __split = __parallel_partition(__begin, __end,
						     __pred, __num_threads);

for (_DifferenceType __s = 0; __s < __num_samples; ++__s)
	__samples[__s].~_ValueType();
      ::operator delete(__samples);

return __split;
    }

/** @brief Unbalanced quicksort conquer step.
   *  @param __begin Begin iterator of subsequence.
   *  @param __end End iterator of subsequence.
   *  @param __comp Comparator.
   *  @param __num_threads Number of threads that are allowed to work on
   *  this part.
   */
  template<typename _RAIter, typename _Compare>
    void
    __parallel_sort_qs_conquer(_RAIter __begin, _RAIter __end,
			       _Compare __comp,
			       _ThreadIndex __num_threads)
    {
      typedef std::iterator_traits<_RAIter> _TraitsType;
      typedef typename _TraitsType::value_type _ValueType;
      typedef typename _TraitsType::difference_type _DifferenceType;

if (__num_threads <= 1)
        {
          __gnu_sequential::sort(__begin, __end, __comp);
          return;
        }

_DifferenceType __n = __end - __begin, __pivot_rank;

if (__n <= 1)
        return;

_ThreadIndex __num_threads_left;

if ((__num_threads % 2) == 1)
        __num_threads_left = __num_threads / 2 + 1;
      else
        __num_threads_left = __num_threads / 2;

__pivot_rank = __n * __num_threads_left / __num_threads;

_DifferenceType __split = __parallel_sort_qs_divide
	(__begin, __end, __comp, __pivot_rank,
	 _Settings::get().sort_qs_num_samples_preset, __num_threads);

#pragma omp parallel sections num_threads(2)
      {
#pragma omp section
        __parallel_sort_qs_conquer(__begin, __begin + __split,
				   __comp, __num_threads_left);
#pragma omp section
        __parallel_sort_qs_conquer(__begin + __split, __end,
				   __comp, __num_threads - __num_threads_left);
      }
    }

/** @brief Unbalanced quicksort main call.
   *  @param __begin Begin iterator of input sequence.
   *  @param __end End iterator input sequence, ignored.
   *  @param __comp Comparator.
   *  @param __num_threads Number of threads that are allowed to work on
   *  this part.
   */
  template<typename _RAIter, typename _Compare>
    void
    __parallel_sort_qs(_RAIter __begin, _RAIter __end,
		       _Compare __comp,
		       _ThreadIndex __num_threads)
    {
      _GLIBCXX_CALL(__n)

typedef std::iterator_traits<_RAIter> _TraitsType;
      typedef typename _TraitsType::value_type _ValueType;
      typedef typename _TraitsType::difference_type _DifferenceType;

_DifferenceType __n = __end - __begin;

// At least one element per processor.
      if (__num_threads > __n)
        __num_threads = static_cast<_ThreadIndex>(__n);

__parallel_sort_qs_conquer(
        __begin, __begin + __n, __comp, __num_threads);
    }

} //namespace __gnu_parallel

#endif /* _GLIBCXX_PARALLEL_QUICKSORT_H */

${this.title}

Code Editor : quicksort.h