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1 | //---------------------------------------------------------------------------// |
2 | // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@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_EXCLUSIVE_SCAN_HPP | |
12 | #define BOOST_COMPUTE_ALGORITHM_EXCLUSIVE_SCAN_HPP | |
13 | ||
92f5a8d4 TL |
14 | #include <boost/static_assert.hpp> |
15 | ||
7c673cae FG |
16 | #include <boost/compute/functional.hpp> |
17 | #include <boost/compute/system.hpp> | |
18 | #include <boost/compute/command_queue.hpp> | |
19 | #include <boost/compute/algorithm/detail/scan.hpp> | |
92f5a8d4 | 20 | #include <boost/compute/type_traits/is_device_iterator.hpp> |
7c673cae FG |
21 | |
22 | namespace boost { | |
23 | namespace compute { | |
24 | ||
25 | /// Performs an exclusive scan of the elements in the range [\p first, \p last) | |
26 | /// and stores the results in the range beginning at \p result. | |
27 | /// | |
28 | /// Each element in the output is assigned to the sum of all the previous | |
29 | /// values in the input. | |
30 | /// | |
31 | /// \param first first element in the range to scan | |
32 | /// \param last last element in the range to scan | |
33 | /// \param result first element in the result range | |
34 | /// \param init value used to initialize the scan sequence | |
35 | /// \param binary_op associative binary operator | |
36 | /// \param queue command queue to perform the operation | |
37 | /// | |
38 | /// \return \c OutputIterator to the end of the result range | |
39 | /// | |
40 | /// The default operation is to add the elements up. | |
41 | /// | |
42 | /// \snippet test/test_scan.cpp exclusive_scan_int | |
43 | /// | |
44 | /// But different associative operation can be specified as \p binary_op | |
45 | /// instead (e.g., multiplication, maximum, minimum). Also value used to | |
46 | /// initialized the scan sequence can be specified. | |
47 | /// | |
48 | /// \snippet test/test_scan.cpp exclusive_scan_int_multiplies | |
49 | /// | |
b32b8144 FG |
50 | /// Space complexity on GPUs: \Omega(n)<br> |
51 | /// Space complexity on GPUs when \p first == \p result: \Omega(2n)<br> | |
52 | /// Space complexity on CPUs: \Omega(1) | |
53 | /// | |
7c673cae FG |
54 | /// \see inclusive_scan() |
55 | template<class InputIterator, class OutputIterator, class T, class BinaryOperator> | |
56 | inline OutputIterator | |
57 | exclusive_scan(InputIterator first, | |
58 | InputIterator last, | |
59 | OutputIterator result, | |
60 | T init, | |
61 | BinaryOperator binary_op, | |
62 | command_queue &queue = system::default_queue()) | |
63 | { | |
92f5a8d4 TL |
64 | BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value); |
65 | BOOST_STATIC_ASSERT(is_device_iterator<OutputIterator>::value); | |
7c673cae FG |
66 | return detail::scan(first, last, result, true, init, binary_op, queue); |
67 | } | |
68 | ||
69 | /// \overload | |
70 | template<class InputIterator, class OutputIterator, class T> | |
71 | inline OutputIterator | |
72 | exclusive_scan(InputIterator first, | |
73 | InputIterator last, | |
74 | OutputIterator result, | |
75 | T init, | |
76 | command_queue &queue = system::default_queue()) | |
77 | { | |
92f5a8d4 TL |
78 | BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value); |
79 | BOOST_STATIC_ASSERT(is_device_iterator<OutputIterator>::value); | |
7c673cae FG |
80 | typedef typename |
81 | std::iterator_traits<OutputIterator>::value_type output_type; | |
82 | ||
83 | return detail::scan(first, last, result, true, | |
84 | init, boost::compute::plus<output_type>(), | |
85 | queue); | |
86 | } | |
87 | ||
88 | /// \overload | |
89 | template<class InputIterator, class OutputIterator> | |
90 | inline OutputIterator | |
91 | exclusive_scan(InputIterator first, | |
92 | InputIterator last, | |
93 | OutputIterator result, | |
94 | command_queue &queue = system::default_queue()) | |
95 | { | |
92f5a8d4 TL |
96 | BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value); |
97 | BOOST_STATIC_ASSERT(is_device_iterator<OutputIterator>::value); | |
7c673cae FG |
98 | typedef typename |
99 | std::iterator_traits<OutputIterator>::value_type output_type; | |
100 | ||
101 | return detail::scan(first, last, result, true, | |
102 | output_type(0), boost::compute::plus<output_type>(), | |
103 | queue); | |
104 | } | |
105 | ||
106 | } // end compute namespace | |
107 | } // end boost namespace | |
108 | ||
109 | #endif // BOOST_COMPUTE_ALGORITHM_EXCLUSIVE_SCAN_HPP |