libstdc++
tags.h
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00001 // -*- C++ -*-
00002 
00003 // Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the terms
00007 // of the GNU General Public License as published by the Free Software
00008 // Foundation; either version 3, or (at your option) any later
00009 // version.
00010 
00011 // This library is distributed in the hope that it will be useful, but
00012 // WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014 // General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /**
00026  * @file parallel/tags.h
00027  * @brief Tags for compile-time selection.
00028  *  This file is a GNU parallel extension to the Standard C++ Library.
00029  */
00030 
00031 // Written by Johannes Singler and Felix Putze.
00032 
00033 #ifndef _GLIBCXX_PARALLEL_TAGS_H
00034 #define _GLIBCXX_PARALLEL_TAGS_H 1
00035 
00036 #include <omp.h>
00037 #include <parallel/types.h>
00038 
00039 namespace __gnu_parallel
00040 {
00041   /** @brief Forces sequential execution at compile time. */
00042   struct sequential_tag { };
00043 
00044   /** @brief Recommends parallel execution at compile time,
00045    *  optionally using a user-specified number of threads. */
00046   struct parallel_tag
00047   {
00048     private:
00049       _ThreadIndex _M_num_threads;
00050 
00051     public:
00052       /** @brief Default constructor. Use default number of threads. */
00053       parallel_tag()
00054       { _M_num_threads = 0; }
00055 
00056       /** @brief Default constructor. Recommend number of threads to use.
00057        *  @param __num_threads Desired number of threads. */
00058       parallel_tag(_ThreadIndex __num_threads)
00059       { _M_num_threads = __num_threads; }
00060 
00061       /** @brief Find out desired number of threads.
00062        *  @return Desired number of threads. */
00063       _ThreadIndex __get_num_threads()
00064       {
00065         if(_M_num_threads == 0)
00066           return omp_get_max_threads();
00067         else
00068           return _M_num_threads;
00069       }
00070 
00071       /** @brief Set the desired number of threads.
00072        *  @param __num_threads Desired number of threads. */
00073       void set_num_threads(_ThreadIndex __num_threads)
00074       { _M_num_threads = __num_threads; }
00075   };
00076 
00077   /** @brief Recommends parallel execution using the
00078       default parallel algorithm. */
00079   struct default_parallel_tag : public parallel_tag
00080   {
00081     default_parallel_tag() { }
00082     default_parallel_tag(_ThreadIndex __num_threads)
00083     : parallel_tag(__num_threads) { }
00084   };
00085 
00086   /** @brief Recommends parallel execution using dynamic
00087       load-balancing at compile time. */
00088   struct balanced_tag : public parallel_tag { };
00089 
00090   /** @brief Recommends parallel execution using static
00091       load-balancing at compile time. */
00092   struct unbalanced_tag : public parallel_tag { };
00093 
00094   /** @brief Recommends parallel execution using OpenMP dynamic
00095       load-balancing at compile time. */
00096   struct omp_loop_tag : public parallel_tag { };
00097 
00098   /** @brief Recommends parallel execution using OpenMP static
00099       load-balancing at compile time. */
00100   struct omp_loop_static_tag : public parallel_tag { };
00101 
00102 
00103   /** @brief Base class for for std::find() variants. */
00104   struct find_tag { };
00105 
00106 
00107   /** @brief Forces parallel merging
00108    *  with exact splitting, at compile time. */
00109   struct exact_tag : public parallel_tag
00110   {
00111     exact_tag() { }
00112     exact_tag(_ThreadIndex __num_threads)
00113     : parallel_tag(__num_threads) { }
00114   };
00115 
00116   /** @brief Forces parallel merging
00117    *  with exact splitting, at compile time. */
00118   struct sampling_tag : public parallel_tag
00119   {
00120     sampling_tag() { }
00121     sampling_tag(_ThreadIndex __num_threads)
00122     : parallel_tag(__num_threads) { }
00123   };
00124 
00125 
00126   /** @brief Forces parallel sorting using multiway mergesort
00127    *  at compile time. */
00128   struct multiway_mergesort_tag : public parallel_tag
00129   {
00130     multiway_mergesort_tag() { }
00131     multiway_mergesort_tag(_ThreadIndex __num_threads)
00132     : parallel_tag(__num_threads) { }
00133   };
00134 
00135   /** @brief Forces parallel sorting using multiway mergesort
00136    *  with exact splitting at compile time. */
00137   struct multiway_mergesort_exact_tag : public parallel_tag
00138   {
00139     multiway_mergesort_exact_tag() { }
00140     multiway_mergesort_exact_tag(_ThreadIndex __num_threads)
00141     : parallel_tag(__num_threads) { }
00142   };
00143 
00144   /** @brief Forces parallel sorting using multiway mergesort
00145    *  with splitting by sampling at compile time. */
00146   struct multiway_mergesort_sampling_tag : public parallel_tag
00147   {
00148     multiway_mergesort_sampling_tag() { }
00149     multiway_mergesort_sampling_tag(_ThreadIndex __num_threads)
00150     : parallel_tag(__num_threads) { }
00151   };
00152 
00153   /** @brief Forces parallel sorting using unbalanced quicksort
00154    *  at compile time. */
00155   struct quicksort_tag : public parallel_tag
00156   {
00157     quicksort_tag() { }
00158     quicksort_tag(_ThreadIndex __num_threads)
00159     : parallel_tag(__num_threads) { }
00160   };
00161 
00162   /** @brief Forces parallel sorting using balanced quicksort
00163    *  at compile time. */
00164   struct balanced_quicksort_tag : public parallel_tag
00165   {
00166     balanced_quicksort_tag() { }
00167     balanced_quicksort_tag(_ThreadIndex __num_threads)
00168     : parallel_tag(__num_threads) { }
00169   };
00170 
00171 
00172   /** @brief Selects the growing block size variant for std::find().
00173       @see _GLIBCXX_FIND_GROWING_BLOCKS */
00174   struct growing_blocks_tag : public find_tag { };
00175 
00176   /** @brief Selects the constant block size variant for std::find().
00177       @see _GLIBCXX_FIND_CONSTANT_SIZE_BLOCKS */
00178   struct constant_size_blocks_tag : public find_tag { };
00179 
00180   /** @brief Selects the equal splitting variant for std::find().
00181       @see _GLIBCXX_FIND_EQUAL_SPLIT */
00182   struct equal_split_tag : public find_tag { };
00183 }
00184 
00185 #endif /* _GLIBCXX_PARALLEL_TAGS_H */