1 //---------------------------------------------------------------------------//
2 // Copyright (c) 2015 Jakub Szuppe <j.szuppe@gmail.com>
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
8 // See http://boostorg.github.com/compute for more information.
9 //---------------------------------------------------------------------------//
11 #ifndef BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_BY_KEY_HPP
12 #define BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_BY_KEY_HPP
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>
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,
41 std::iterator_traits<InputValueIterator>::value_type value_type;
43 std::iterator_traits<InputKeyIterator>::value_type key_type;
45 ::boost::compute::result_of<BinaryFunction(value_type, value_type)>::type result_type;
47 const context &context = queue.get_context();
48 size_t count = detail::iterator_range_size(keys_first, keys_last);
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,
58 convert<result_type> to_result_type;
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" <<
67 k.decl<uint_>("size") << " = 1;\n" <<
69 keys_result[0] << " = previous_key;\n" <<
70 values_result[0] << " = result;\n" <<
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" <<
78 " result = " << function(k.var<result_type>("result"),
79 k.var<result_type>("value")) << ";\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" <<
87 " previous_key = key;\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;";
93 kernel kernel = k.compile(context);
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));
99 queue.enqueue_task(kernel);
101 return static_cast<size_t>(result_size.read(queue));
104 } // end detail namespace
105 } // end compute namespace
106 } // end boost namespace
108 #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_BY_KEY_HPP