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>
serial_reduce_by_key(InputKeyIterator keys_first,InputKeyIterator keys_last,InputValueIterator values_first,OutputKeyIterator keys_result,OutputValueIterator values_result,BinaryFunction function,BinaryPredicate predicate,command_queue & queue)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 k <<
59 k.decl<result_type>("result") <<
60 " = " << values_first[0] << ";\n" <<
61 k.decl<key_type>("previous_key") << " = " << keys_first[0] << ";\n" <<
62 k.decl<result_type>("value") << ";\n" <<
63 k.decl<key_type>("key") << ";\n" <<
64
65 k.decl<uint_>("size") << " = 1;\n" <<
66
67 keys_result[0] << " = previous_key;\n" <<
68 values_result[0] << " = result;\n" <<
69
70 "for(ulong i = 1; i < count; i++) {\n" <<
71 " value = " << values_first[k.var<uint_>("i")] << ";\n" <<
72 " key = " << keys_first[k.var<uint_>("i")] << ";\n" <<
73 " if (" << predicate(k.var<key_type>("previous_key"),
74 k.var<key_type>("key")) << ") {\n" <<
75
76 " result = " << function(k.var<result_type>("result"),
77 k.var<result_type>("value")) << ";\n" <<
78 " }\n " <<
79 " else { \n" <<
80 keys_result[k.var<uint_>("size - 1")] << " = previous_key;\n" <<
81 values_result[k.var<uint_>("size - 1")] << " = result;\n" <<
82 " result = value;\n" <<
83 " size++;\n" <<
84 " } \n" <<
85 " previous_key = key;\n" <<
86 "}\n" <<
87 keys_result[k.var<uint_>("size - 1")] << " = previous_key;\n" <<
88 values_result[k.var<uint_>("size - 1")] << " = result;\n" <<
89 "*result_size = size;";
90
91 kernel kernel = k.compile(context);
92
93 scalar<uint_> result_size(context);
94 kernel.set_arg(result_size_arg, result_size.get_buffer());
95 kernel.set_arg(count_arg, static_cast<uint_>(count));
96
97 queue.enqueue_task(kernel);
98
99 return static_cast<size_t>(result_size.read(queue));
100 }
101
102 } // end detail namespace
103 } // end compute namespace
104 } // end boost namespace
105
106 #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_BY_KEY_HPP
107