gcc/libstdc++-v3/include/parallel/numeric

// -*- 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.

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// 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.

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// 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
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/**
 * @file parallel/numeric
*
 * @brief Parallel STL fucntion calls corresponding to stl_numeric.h.
 * The functions defined here mainly do case switches and
 * call the actual parallelized versions in other files.
 * Inlining policy: Functions that basically only contain one function call,
 * are declared inline.
 *  This file is a GNU parallel extension to the Standard C++ Library.
 */

// Written by Johannes Singler and Felix Putze.

#ifndef _GLIBCXX_PARALLEL_NUMERIC_H
#define _GLIBCXX_PARALLEL_NUMERIC_H 1

#include <numeric>
#include <functional>
#include <parallel/numericfwd.h>
#include <parallel/iterator.h>
#include <parallel/for_each.h>
#include <parallel/for_each_selectors.h>
#include <parallel/partial_sum.h>

namespace std
{
namespace __parallel
{
  // Sequential fallback.
  template<typename InputIterator, typename T>
  inline T
  accumulate(InputIterator begin, InputIterator end, T init, __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::accumulate(begin, end, init); }

  // Sequential fallback.
  template<typename InputIterator, typename T, typename BinaryOperation>
  inline T
  accumulate(InputIterator begin, InputIterator end, T init,
	     BinaryOperation binary_op, __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::accumulate(begin, end, init, binary_op); }

  // Sequential fallback for input iterator case.
  template<typename InputIterator, typename T, typename IteratorTag>
  inline T
  accumulate_switch(InputIterator begin, InputIterator end, T init, IteratorTag, __gnu_parallel::parallelism parallelism_tag)
  { return accumulate(begin, end, init, __gnu_parallel::sequential_tag()); }

  // Public interface.
  template<typename InputIterator, typename T>
  inline T
  accumulate(InputIterator begin, InputIterator end, T init, __gnu_parallel::parallelism parallelism_tag = __gnu_parallel::parallel_unbalanced)
  {
    return accumulate_switch(begin, end, init, std::plus<typename std::iterator_traits<InputIterator>::value_type>(), typename std::iterator_traits<InputIterator>::iterator_category(), parallelism_tag);
  }

  // Sequential fallback for input iterator case.
  template<typename InputIterator, typename T, typename BinaryOperation, typename IteratorTag>
  T
  accumulate_switch(InputIterator begin, InputIterator end, T init, BinaryOperation binary_op, IteratorTag, __gnu_parallel::parallelism parallelism_tag)
  {
    return accumulate(begin, end, init, binary_op, __gnu_parallel::sequential_tag());
  }

  // Parallel algorithm for random access iterators.
  template<typename _RandomAccessIterator, typename T, typename BinaryOperation>
  T
  accumulate_switch(_RandomAccessIterator begin, _RandomAccessIterator end, T init, BinaryOperation binary_op, random_access_iterator_tag, __gnu_parallel::parallelism parallelism_tag)
  {
    if (_GLIBCXX_PARALLEL_CONDITION(static_cast<__gnu_parallel::sequence_index_t>(end - begin) >= __gnu_parallel::Settings::accumulate_minimal_n && __gnu_parallel::is_parallel(parallelism_tag)))
      {
	T res = init;
	__gnu_parallel::accumulate_selector<_RandomAccessIterator> my_selector;
	__gnu_parallel::for_each_template_random_access(begin, end, __gnu_parallel::nothing(), my_selector, __gnu_parallel::accumulate_binop_reduct<BinaryOperation>(binary_op), res, res, -1, parallelism_tag);
	return res;
      }
    else
      return accumulate(begin, end, init, binary_op, __gnu_parallel::sequential_tag());
  }

  // Public interface.
  template<typename InputIterator, typename T, typename BinaryOperation>
  inline T
  accumulate(InputIterator begin, InputIterator end, T init, BinaryOperation binary_op, __gnu_parallel::parallelism parallelism_tag = __gnu_parallel::parallel_unbalanced)
  {
    return accumulate_switch(begin, end, init, binary_op, typename std::iterator_traits<InputIterator>::iterator_category(), parallelism_tag);
  }


  // Sequential fallback.
  template<typename InputIterator1, typename InputIterator2, typename T, typename BinaryFunction1, typename BinaryFunction2>
  inline T
  inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init, BinaryFunction1 binary_op1, BinaryFunction2 binary_op2, __gnu_parallel::sequential_tag)
  {
    return _GLIBCXX_STD_P::inner_product(first1, last1, first2, init, binary_op1, binary_op2);
  }

  // Sequential fallback.
  template<typename InputIterator1, typename InputIterator2, typename T>
  inline T
  inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init, __gnu_parallel::sequential_tag)
  {
    return _GLIBCXX_STD_P::inner_product(first1, last1, first2, init);
  }

  // Parallel algorithm for random access iterators.
  template<typename RandomAccessIterator1, typename RandomAccessIterator2, typename T, typename BinaryFunction1, typename BinaryFunction2>
  T
  inner_product_switch(RandomAccessIterator1 first1, RandomAccessIterator1 last1, RandomAccessIterator2 first2, T init, BinaryFunction1 binary_op1, BinaryFunction2 binary_op2, random_access_iterator_tag, random_access_iterator_tag, __gnu_parallel::parallelism parallelism_tag)
  {
    if (_GLIBCXX_PARALLEL_CONDITION((last1 - first1) >= __gnu_parallel::Settings::accumulate_minimal_n && __gnu_parallel::is_parallel(parallelism_tag)))
      {
	T res = init;
	__gnu_parallel::inner_product_selector<RandomAccessIterator1, RandomAccessIterator2, T> my_selector(first1, first2);
	__gnu_parallel::for_each_template_random_access(first1, last1, binary_op2, my_selector, binary_op1, res, res, -1, parallelism_tag);
	return res;
      }
    else
      return inner_product(first1, last1, first2, init, __gnu_parallel::sequential_tag());
  }

  // No parallelism for input iterators.
  template<typename InputIterator1, typename InputIterator2, typename T, typename BinaryFunction1, typename BinaryFunction2, typename IteratorTag1, typename IteratorTag2>
  inline T
  inner_product_switch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init, BinaryFunction1 binary_op1, BinaryFunction2 binary_op2, IteratorTag1, IteratorTag2, __gnu_parallel::parallelism parallelism_tag)
  {
    return _GLIBCXX_STD_P::inner_product(first1, last1, first2, init, binary_op1, binary_op2);
  }

  template<typename InputIterator1, typename InputIterator2, typename T, typename BinaryFunction1, typename BinaryFunction2>
  inline T
  inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init, BinaryFunction1 binary_op1, BinaryFunction2 binary_op2, __gnu_parallel::parallelism parallelism_tag = __gnu_parallel::parallel_unbalanced)
  {
    typedef iterator_traits<InputIterator1> traits1_type;
    typedef typename traits1_type::iterator_category iterator1_category;

    typedef iterator_traits<InputIterator2> traits2_type;
    typedef typename traits2_type::iterator_category iterator2_category;

    return inner_product_switch(first1, last1, first2, init, binary_op1, binary_op2, iterator1_category(), iterator2_category(), parallelism_tag);
  }

  template<typename InputIterator1, typename InputIterator2, typename T>
  inline T
  inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init, __gnu_parallel::parallelism parallelism_tag = __gnu_parallel::parallel_unbalanced)
  {
    typedef iterator_traits<InputIterator1> traits_type;
    typedef typename traits_type::value_type value_type;

    return inner_product(first1, last1, first2, init, std::plus<value_type>(), 
			 std::multiplies<value_type>(), parallelism_tag);
  }

  // Sequential fallback.
  template<typename InputIterator, typename OutputIterator>
  inline OutputIterator
  partial_sum(InputIterator begin, InputIterator end, OutputIterator result,
	      __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::partial_sum(begin, end, result); }

  // Sequential fallback.
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation>
  inline OutputIterator
  partial_sum(InputIterator begin, InputIterator end, OutputIterator result,
	      BinaryOperation bin_op, __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::partial_sum(begin, end, result, bin_op); }

  // Sequential fallback for input iterator case.
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation, typename IteratorTag1, typename IteratorTag2>
  inline OutputIterator
  partial_sum_switch(InputIterator begin, InputIterator end, OutputIterator result, BinaryOperation bin_op, IteratorTag1, IteratorTag2)
  {
    return _GLIBCXX_STD_P::partial_sum(begin, end, result, bin_op);
  }

  // Parallel algorithm for random access iterators.
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation>
  OutputIterator
  partial_sum_switch(InputIterator begin, InputIterator end,
		     OutputIterator result, BinaryOperation bin_op,
		     random_access_iterator_tag, random_access_iterator_tag)
  {
    if (_GLIBCXX_PARALLEL_CONDITION(static_cast<__gnu_parallel::sequence_index_t>(end - begin) >= __gnu_parallel::Settings::partial_sum_minimal_n))
      return __gnu_parallel::parallel_partial_sum(begin, end, result, bin_op);
    else
      return partial_sum(begin, end, result, bin_op, __gnu_parallel::sequential_tag());
  }

  // Public interface.
  template<typename InputIterator, typename OutputIterator>
  inline OutputIterator
  partial_sum(InputIterator begin, InputIterator end, OutputIterator result)
  {
    typedef typename iterator_traits<InputIterator>::value_type value_type;
    return partial_sum(begin, end, result, std::plus<value_type>());
  }

  // Public interface
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation>
  inline OutputIterator
  partial_sum(InputIterator begin, InputIterator end, OutputIterator result,
	      BinaryOperation binary_op)
  {
    typedef iterator_traits<InputIterator> traitsi_type;
    typedef typename traitsi_type::iterator_category iteratori_category;

    typedef iterator_traits<OutputIterator> traitso_type;
    typedef typename traitso_type::iterator_category iteratoro_category;

    return partial_sum_switch(begin, end, result, binary_op,
				   iteratori_category(), iteratoro_category());
  }

  // Sequential fallback.
  template<typename InputIterator, typename OutputIterator>
  inline OutputIterator
  adjacent_difference(InputIterator begin, InputIterator end,
		      OutputIterator result, __gnu_parallel::sequential_tag)
  { return _GLIBCXX_STD_P::adjacent_difference(begin, end, result); }

  // Sequential fallback.
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation>
  inline OutputIterator
  adjacent_difference(InputIterator begin, InputIterator end,
		      OutputIterator result, BinaryOperation bin_op,
		      __gnu_parallel::sequential_tag)
  {
    return _GLIBCXX_STD_P::adjacent_difference(begin, end, result, bin_op);
  }

  // Sequential fallback for input iterator case.
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation, typename IteratorTag1, typename IteratorTag2>
  inline OutputIterator
  adjacent_difference_switch(InputIterator begin, InputIterator end,
			     OutputIterator result, BinaryOperation bin_op,
			     IteratorTag1, IteratorTag2, __gnu_parallel::parallelism)
  { return adjacent_difference(begin, end, result, bin_op); }

  // Parallel algorithm for random access iterators.
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation>
  OutputIterator
  adjacent_difference_switch(InputIterator begin, InputIterator end,
			     OutputIterator result, BinaryOperation bin_op,
			     random_access_iterator_tag, random_access_iterator_tag,
			     __gnu_parallel::parallelism parallelism_tag)
  {
    if (_GLIBCXX_PARALLEL_CONDITION(static_cast<__gnu_parallel::sequence_index_t>(end - begin) >= __gnu_parallel::Settings::adjacent_difference_minimal_n && __gnu_parallel::is_parallel(parallelism_tag)))
      {
	bool dummy = true;
	typedef __gnu_parallel::iterator_pair<InputIterator, OutputIterator, random_access_iterator_tag> ip;
	*result = *begin;
	ip begin_pair(begin + 1, result + 1), end_pair(end, result + (end - begin));
	__gnu_parallel::adjacent_difference_selector<ip> functionality;
	__gnu_parallel::for_each_template_random_access(begin_pair, end_pair, bin_op, functionality, __gnu_parallel::dummy_reduct(), dummy, dummy, -1, parallelism_tag);
	return functionality.finish_iterator;
      }
    else
      return adjacent_difference(begin, end, result, bin_op, __gnu_parallel::sequential_tag());
  }

  // Public interface.
  template<typename InputIterator, typename OutputIterator>
  inline OutputIterator
  adjacent_difference(InputIterator begin, InputIterator end,
		      OutputIterator result,
		      __gnu_parallel::parallelism parallelism_tag = __gnu_parallel::parallel_balanced)
  {
    typedef iterator_traits<InputIterator> traits_type;
    typedef typename traits_type::value_type value_type;
    return adjacent_difference(begin, end, result, std::minus<value_type>());
  }

  // Public interface.
  template<typename InputIterator, typename OutputIterator, typename BinaryOperation>
  inline OutputIterator
  adjacent_difference(InputIterator begin, InputIterator end,
		      OutputIterator result, BinaryOperation binary_op,
		      __gnu_parallel::parallelism parallelism_tag = __gnu_parallel::parallel_balanced)
  {
    typedef iterator_traits<InputIterator> traitsi_type;
    typedef typename traitsi_type::iterator_category iteratori_category;

    typedef iterator_traits<OutputIterator> traitso_type;
    typedef typename traitso_type::iterator_category iteratoro_category;

    return adjacent_difference_switch(begin, end, result, binary_op,
				      iteratori_category(), 
				      iteratoro_category(), parallelism_tag);
  }
} // end namespace
} // end namespace

#endif /* _GLIBCXX_NUMERIC_H */