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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2007-2016 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 3, or (at your option) any later
   9 // version.
  10
  11 // This library is distributed in the hope that it will be useful, but
  12 // WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /**
  26  * @file parallel/tags.h
  27  * @brief Tags for compile-time selection.
  28  *  This file is a GNU parallel extension to the Standard C++ Library.
  29  */
  30
  31 // Written by Johannes Singler and Felix Putze.
  32
  33 #ifndef _GLIBCXX_PARALLEL_TAGS_H
  34 #define _GLIBCXX_PARALLEL_TAGS_H 1
  35
  36 #include <omp.h>
  37 #include <parallel/types.h>
  38
  39 namespace __gnu_parallel
  40 {
  41   /** @brief Forces sequential execution at compile time. */
  42   struct sequential_tag { };
  43
  44   /** @brief Recommends parallel execution at compile time,
  45    *  optionally using a user-specified number of threads. */
  46   struct parallel_tag
  47   {
  48     private:
  49       _ThreadIndex _M_num_threads;
  50
  51     public:
  52       /** @brief Default constructor. Use default number of threads. */
  53       parallel_tag()
  54       { _M_num_threads = 0; }
  55
  56       /** @brief Default constructor. Recommend number of threads to use.
  57        *  @param __num_threads Desired number of threads. */
  58       parallel_tag(_ThreadIndex __num_threads)
  59       { _M_num_threads = __num_threads; }
  60
  61       /** @brief Find out desired number of threads.
  62        *  @return Desired number of threads. */
  63       _ThreadIndex __get_num_threads()
  64       {
  65         if(_M_num_threads == 0)
  66           return omp_get_max_threads();
  67         else
  68           return _M_num_threads;
  69       }
  70
  71       /** @brief Set the desired number of threads.
  72        *  @param __num_threads Desired number of threads. */
  73       void set_num_threads(_ThreadIndex __num_threads)
  74       { _M_num_threads = __num_threads; }
  75   };
  76
  77   /** @brief Recommends parallel execution using the
  78       default parallel algorithm. */
  79   struct default_parallel_tag : public parallel_tag
  80   {
  81     default_parallel_tag() { }
  82     default_parallel_tag(_ThreadIndex __num_threads)
  83     : parallel_tag(__num_threads) { }
  84   };
  85
  86   /** @brief Recommends parallel execution using dynamic
  87       load-balancing at compile time. */
  88   struct balanced_tag : public parallel_tag { };
  89
  90   /** @brief Recommends parallel execution using static
  91       load-balancing at compile time. */
  92   struct unbalanced_tag : public parallel_tag { };
  93
  94   /** @brief Recommends parallel execution using OpenMP dynamic
  95       load-balancing at compile time. */
  96   struct omp_loop_tag : public parallel_tag { };
  97
  98   /** @brief Recommends parallel execution using OpenMP static
  99       load-balancing at compile time. */
 100   struct omp_loop_static_tag : public parallel_tag { };
 101
 102
 103   /** @brief Base class for for std::find() variants. */
 104   struct find_tag { };
 105
 106
 107   /** @brief Forces parallel merging
 108    *  with exact splitting, at compile time. */
 109   struct exact_tag : public parallel_tag
 110   {
 111     exact_tag() { }
 112     exact_tag(_ThreadIndex __num_threads)
 113     : parallel_tag(__num_threads) { }
 114   };
 115
 116   /** @brief Forces parallel merging
 117    *  with exact splitting, at compile time. */
 118   struct sampling_tag : public parallel_tag
 119   {
 120     sampling_tag() { }
 121     sampling_tag(_ThreadIndex __num_threads)
 122     : parallel_tag(__num_threads) { }
 123   };
 124
 125
 126   /** @brief Forces parallel sorting using multiway mergesort
 127    *  at compile time. */
 128   struct multiway_mergesort_tag : public parallel_tag
 129   {
 130     multiway_mergesort_tag() { }
 131     multiway_mergesort_tag(_ThreadIndex __num_threads)
 132     : parallel_tag(__num_threads) { }
 133   };
 134
 135   /** @brief Forces parallel sorting using multiway mergesort
 136    *  with exact splitting at compile time. */
 137   struct multiway_mergesort_exact_tag : public parallel_tag
 138   {
 139     multiway_mergesort_exact_tag() { }
 140     multiway_mergesort_exact_tag(_ThreadIndex __num_threads)
 141     : parallel_tag(__num_threads) { }
 142   };
 143
 144   /** @brief Forces parallel sorting using multiway mergesort
 145    *  with splitting by sampling at compile time. */
 146   struct multiway_mergesort_sampling_tag : public parallel_tag
 147   {
 148     multiway_mergesort_sampling_tag() { }
 149     multiway_mergesort_sampling_tag(_ThreadIndex __num_threads)
 150     : parallel_tag(__num_threads) { }
 151   };
 152
 153   /** @brief Forces parallel sorting using unbalanced quicksort
 154    *  at compile time. */
 155   struct quicksort_tag : public parallel_tag
 156   {
 157     quicksort_tag() { }
 158     quicksort_tag(_ThreadIndex __num_threads)
 159     : parallel_tag(__num_threads) { }
 160   };
 161
 162   /** @brief Forces parallel sorting using balanced quicksort
 163    *  at compile time. */
 164   struct balanced_quicksort_tag : public parallel_tag
 165   {
 166     balanced_quicksort_tag() { }
 167     balanced_quicksort_tag(_ThreadIndex __num_threads)
 168     : parallel_tag(__num_threads) { }
 169   };
 170
 171
 172   /** @brief Selects the growing block size variant for std::find().
 173       @see _GLIBCXX_FIND_GROWING_BLOCKS */
 174   struct growing_blocks_tag : public find_tag { };
 175
 176   /** @brief Selects the constant block size variant for std::find().
 177       @see _GLIBCXX_FIND_CONSTANT_SIZE_BLOCKS */
 178   struct constant_size_blocks_tag : public find_tag { };
 179
 180   /** @brief Selects the equal splitting variant for std::find().
 181       @see _GLIBCXX_FIND_EQUAL_SPLIT */
 182   struct equal_split_tag : public find_tag { };
 183 }
 184
 185 #endif /* _GLIBCXX_PARALLEL_TAGS_H */