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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2007, 2008 Free Software Foundation, Inc.
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   5 // This file is part of the GNU ISO C++ Library.  This library is free
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   8 // Foundation; either version 2, or (at your option) any later
   9 // version.
  10
  11 // This library is distributed in the hope that it will be useful, but
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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
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  18 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
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  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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  25 // produce an executable, this file does not by itself cause the
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  29 // Public License.
  30
  31 /** @file parallel/for_each.h
  32  *  @brief Main interface for embarrassingly parallel functions.
  33  *
  34  *  The explicit implementation are in other header files, like
  35  *  workstealing.h, par_loop.h, omp_loop.h, and omp_loop_static.h.
  36  *  This file is a GNU parallel extension to the Standard C++ Library.
  37  */
  38
  39 // Written by Felix Putze.
  40
  41 #ifndef _GLIBCXX_PARALLEL_FOR_EACH_H
  42 #define _GLIBCXX_PARALLEL_FOR_EACH_H 1
  43
  44 #include <parallel/settings.h>
  45 #include <parallel/par_loop.h>
  46 #include <parallel/omp_loop.h>
  47 #include <parallel/workstealing.h>
  48
  49 namespace __gnu_parallel
  50 {
  51   /** @brief Chose the desired algorithm by evaluating @c parallelism_tag.
  52    *  @param begin Begin iterator of input sequence.
  53    *  @param end End iterator of input sequence.
  54    *  @param user_op A user-specified functor (comparator, predicate,
  55    *  associative operator,...)
  56    *  @param functionality functor to "process" an element with
  57    *  user_op (depends on desired functionality, e. g. accumulate,
  58    *  for_each,...
  59    *  @param reduction Reduction functor.
  60    *  @param reduction_start Initial value for reduction.
  61    *  @param output Output iterator.
  62    *  @param bound Maximum number of elements processed.
  63    *  @param parallelism_tag Parallelization method */
  64   template<typename InputIterator, typename UserOp,
  65            typename Functionality, typename Red, typename Result>
  66     UserOp
  67     for_each_template_random_access(InputIterator begin, InputIterator end,
  68                                     UserOp user_op,
  69                                     Functionality& functionality,
  70                                     Red reduction, Result reduction_start,
  71                                     Result& output, typename
  72                                     std::iterator_traits<InputIterator>::
  73                                     difference_type bound,
  74                                     parallelism parallelism_tag)
  75     {
  76       if (parallelism_tag == parallel_unbalanced)
  77         return for_each_template_random_access_ed(begin, end, user_op,
  78                                                   functionality, reduction,
  79                                                   reduction_start,
  80                                                   output, bound);
  81       else if (parallelism_tag == parallel_omp_loop)
  82         return for_each_template_random_access_omp_loop(begin, end, user_op,
  83                                                         functionality,
  84                                                         reduction,
  85                                                         reduction_start,
  86                                                         output, bound);
  87       else if (parallelism_tag == parallel_omp_loop_static)
  88         return for_each_template_random_access_omp_loop(begin, end, user_op,
  89                                                         functionality,
  90                                                         reduction,
  91                                                         reduction_start,
  92                                                         output, bound);
  93       else      //e. g. parallel_balanced
  94         return for_each_template_random_access_workstealing(begin, end,
  95                                                             user_op,
  96                                                             functionality,
  97                                                             reduction,
  98                                                             reduction_start,
  99                                                             output, bound);
 100   }
 101 }
 102
 103 #endif