ceph/src/boost/libs/compute/include/boost/compute/algorithm/detail/serial_reduce_by_key.hpp

   1 //---------------------------------------------------------------------------//
   2 // Copyright (c) 2015 Jakub Szuppe <j.szuppe@gmail.com>
   3 //
   4 // Distributed under the Boost Software License, Version 1.0
   5 // See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt
   7 //
   8 // See http://boostorg.github.com/compute for more information.
   9 //---------------------------------------------------------------------------//
  10
  11 #ifndef BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_BY_KEY_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_BY_KEY_HPP
  13
  14 #include <iterator>
  15
  16 #include <boost/compute/command_queue.hpp>
  17 #include <boost/compute/functional.hpp>
  18 #include <boost/compute/container/vector.hpp>
  19 #include <boost/compute/container/detail/scalar.hpp>
  20 #include <boost/compute/detail/meta_kernel.hpp>
  21 #include <boost/compute/detail/iterator_range_size.hpp>
  22 #include <boost/compute/type_traits/result_of.hpp>
  23
  24 namespace boost {
  25 namespace compute {
  26 namespace detail {
  27
  28 template<class InputKeyIterator, class InputValueIterator,
  29          class OutputKeyIterator, class OutputValueIterator,
  30          class BinaryFunction, class BinaryPredicate>
  31 inline size_t serial_reduce_by_key(InputKeyIterator keys_first,
  32                                    InputKeyIterator keys_last,
  33                                    InputValueIterator values_first,
  34                                    OutputKeyIterator keys_result,
  35                                    OutputValueIterator values_result,
  36                                    BinaryFunction function,
  37                                    BinaryPredicate predicate,
  38                                    command_queue &queue)
  39 {
  40     typedef typename
  41         std::iterator_traits<InputValueIterator>::value_type value_type;
  42     typedef typename
  43         std::iterator_traits<InputKeyIterator>::value_type key_type;
  44     typedef typename
  45         ::boost::compute::result_of<BinaryFunction(value_type, value_type)>::type result_type;
  46
  47     const context &context = queue.get_context();
  48     size_t count = detail::iterator_range_size(keys_first, keys_last);
  49     if(count < 1){
  50         return count;
  51     }
  52
  53     meta_kernel k("serial_reduce_by_key");
  54     size_t count_arg = k.add_arg<uint_>("count");
  55     size_t result_size_arg = k.add_arg<uint_ *>(memory_object::global_memory,
  56                                                 "result_size");
  57
  58     convert<result_type> to_result_type;
  59
  60     k <<
  61         k.decl<result_type>("result") <<
  62             " = " << to_result_type(values_first[0]) << ";\n" <<
  63         k.decl<key_type>("previous_key") << " = " << keys_first[0] << ";\n" <<
  64         k.decl<result_type>("value") << ";\n" <<
  65         k.decl<key_type>("key") << ";\n" <<
  66
  67         k.decl<uint_>("size") << " = 1;\n" <<
  68
  69         keys_result[0] << " = previous_key;\n" <<
  70         values_result[0] << " = result;\n" <<
  71
  72         "for(ulong i = 1; i < count; i++) {\n" <<
  73         "    value = " << to_result_type(values_first[k.var<uint_>("i")]) << ";\n" <<
  74         "    key = " << keys_first[k.var<uint_>("i")] << ";\n" <<
  75         "    if (" << predicate(k.var<key_type>("previous_key"),
  76                                 k.var<key_type>("key")) << ") {\n" <<
  77
  78         "        result = " << function(k.var<result_type>("result"),
  79                                         k.var<result_type>("value")) << ";\n" <<
  80         "    }\n " <<
  81         "    else { \n" <<
  82                  keys_result[k.var<uint_>("size - 1")] << " = previous_key;\n" <<
  83                  values_result[k.var<uint_>("size - 1")] << " = result;\n" <<
  84         "        result = value;\n" <<
  85         "        size++;\n" <<
  86         "    } \n" <<
  87         "    previous_key = key;\n" <<
  88         "}\n" <<
  89         keys_result[k.var<uint_>("size - 1")] << " = previous_key;\n" <<
  90         values_result[k.var<uint_>("size - 1")] << " = result;\n" <<
  91         "*result_size = size;";
  92
  93     kernel kernel = k.compile(context);
  94
  95     scalar<uint_> result_size(context);
  96     kernel.set_arg(result_size_arg, result_size.get_buffer());
  97     kernel.set_arg(count_arg, static_cast<uint_>(count));
  98
  99     queue.enqueue_task(kernel);
 100
 101     return static_cast<size_t>(result_size.read(queue));
 102 }
 103
 104 } // end detail namespace
 105 } // end compute namespace
 106 } // end boost namespace
 107
 108 #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_BY_KEY_HPP