libstdc++-v3/include/parallel/tags.h

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2007, 2008 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the terms
   7 // of the GNU General Public License as published by the Free Software
   8 // Foundation; either version 2, or (at your option) any later
   9 // version.
  10
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  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
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  16 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  19 // MA 02111-1307, USA.
  20
  21 // As a special exception, you may use this file as part of a free
  22 // software library without restriction.  Specifically, if other files
  23 // instantiate templates or use macros or inline functions from this
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  26 // resulting executable to be covered by the GNU General Public
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  29 // Public License.
  30
  31 /**
  32  * @file parallel/tags.h
  33  * @brief Tags for compile-time selection.
  34  *  This file is a GNU parallel extension to the Standard C++ Library.
  35  */
  36
  37 // Written by Johannes Singler and Felix Putze.
  38
  39 #ifndef _GLIBCXX_PARALLEL_TAGS_H
  40 #define _GLIBCXX_PARALLEL_TAGS_H 1
  41
  42 #include <omp.h>
  43 #include <parallel/types.h>
  44
  45 namespace __gnu_parallel
  46 {
  47   /** @brief Forces sequential execution at compile time. */
  48   struct sequential_tag { };
  49
  50   /** @brief Recommends parallel execution at compile time,
  51    *  optionally using a user-specified number of threads. */
  52   struct parallel_tag
  53   {
  54     private:
  55       thread_index_t num_threads;
  56
  57     public:
  58       /** @brief Default constructor. Use default number of threads. */
  59       parallel_tag()
  60       {
  61         this->num_threads = 0;
  62       }
  63
  64       /** @brief Default constructor. Recommend number of threads to use.
  65        *  @param num_threads Desired number of threads. */
  66       parallel_tag(thread_index_t num_threads)
  67       {
  68         this->num_threads = num_threads;
  69       }
  70
  71       /** @brief Find out desired number of threads.
  72        *  @return Desired number of threads. */
  73       inline thread_index_t get_num_threads()
  74       {
  75         if(num_threads == 0)
  76           return omp_get_max_threads();
  77         else
  78           return num_threads;
  79       }
  80
  81       /** @brief Set the desired number of threads.
  82        *  @param num_threads Desired number of threads. */
  83       inline void set_num_threads(thread_index_t num_threads)
  84       {
  85         this->num_threads = num_threads;
  86       }
  87   };
  88
  89   /** @brief Recommends parallel execution using the
  90       default parallel algorithm. */
  91   struct default_parallel_tag : public parallel_tag
  92   {
  93       default_parallel_tag() { }
  94       default_parallel_tag(thread_index_t num_threads)
  95           : parallel_tag(num_threads) { }
  96   };
  97
  98   /** @brief Recommends parallel execution using dynamic
  99       load-balancing at compile time. */
 100   struct balanced_tag : public parallel_tag { };
 101
 102   /** @brief Recommends parallel execution using static
 103       load-balancing at compile time. */
 104   struct unbalanced_tag : public parallel_tag { };
 105
 106   /** @brief Recommends parallel execution using OpenMP dynamic
 107       load-balancing at compile time. */
 108   struct omp_loop_tag : public parallel_tag { };
 109
 110   /** @brief Recommends parallel execution using OpenMP static
 111       load-balancing at compile time. */
 112   struct omp_loop_static_tag : public parallel_tag { };
 113
 114
 115   /** @brief Base class for for std::find() variants. */
 116   struct find_tag { };
 117
 118
 119   /** @brief Forces parallel merging
 120    *  with exact splitting, at compile time. */
 121   struct exact_tag : public parallel_tag
 122   {
 123       exact_tag() { }
 124       exact_tag(thread_index_t num_threads)
 125           : parallel_tag(num_threads) { }
 126   };
 127
 128   /** @brief Forces parallel merging
 129    *  with exact splitting, at compile time. */
 130   struct sampling_tag : public parallel_tag
 131   {
 132       sampling_tag() { }
 133       sampling_tag(thread_index_t num_threads)
 134           : parallel_tag(num_threads) { }
 135   };
 136
 137
 138   /** @brief Forces parallel sorting using multiway mergesort
 139    *  at compile time. */
 140   struct multiway_mergesort_tag : public parallel_tag
 141   {
 142       multiway_mergesort_tag() { }
 143       multiway_mergesort_tag(thread_index_t num_threads)
 144           : parallel_tag(num_threads) { }
 145   };
 146
 147   /** @brief Forces parallel sorting using multiway mergesort
 148    *  with exact splitting at compile time. */
 149   struct multiway_mergesort_exact_tag : public parallel_tag
 150   {
 151       multiway_mergesort_exact_tag() { }
 152       multiway_mergesort_exact_tag(thread_index_t num_threads)
 153           : parallel_tag(num_threads) { }
 154   };
 155
 156   /** @brief Forces parallel sorting using multiway mergesort
 157    *  with splitting by sampling at compile time. */
 158   struct multiway_mergesort_sampling_tag : public parallel_tag
 159   {
 160       multiway_mergesort_sampling_tag() { }
 161       multiway_mergesort_sampling_tag(thread_index_t num_threads)
 162           : parallel_tag(num_threads) { }
 163   };
 164
 165   /** @brief Forces parallel sorting using unbalanced quicksort
 166    *  at compile time. */
 167   struct quicksort_tag : public parallel_tag
 168   {
 169       quicksort_tag() { }
 170       quicksort_tag(thread_index_t num_threads)
 171           : parallel_tag(num_threads) { }
 172   };
 173
 174   /** @brief Forces parallel sorting using balanced quicksort
 175    *  at compile time. */
 176   struct balanced_quicksort_tag : public parallel_tag
 177   {
 178       balanced_quicksort_tag() { }
 179       balanced_quicksort_tag(thread_index_t num_threads)
 180           : parallel_tag(num_threads) { }
 181   };
 182
 183
 184   /** @brief Selects the growing block size variant for std::find().
 185       @see _GLIBCXX_FIND_GROWING_BLOCKS */
 186   struct growing_blocks_tag : public find_tag { };
 187
 188   /** @brief Selects the constant block size variant for std::find().
 189       @see _GLIBCXX_FIND_CONSTANT_SIZE_BLOCKS */
 190   struct constant_size_blocks_tag : public find_tag { };
 191
 192   /** @brief Selects the equal splitting variant for std::find().
 193       @see _GLIBCXX_FIND_EQUAL_SPLIT */
 194   struct equal_split_tag : public find_tag { };
 195 }
 196
 197 #endif /* _GLIBCXX_PARALLEL_TAGS_H */