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_STABLE_SORT_HPP
12 #define BOOST_COMPUTE_ALGORITHM_STABLE_SORT_HPP
13
14 #include <iterator>
15
16 #include <boost/static_assert.hpp>
17
18 #include <boost/compute/system.hpp>
19 #include <boost/compute/command_queue.hpp>
20 #include <boost/compute/algorithm/detail/merge_sort_on_cpu.hpp>
21 #include <boost/compute/algorithm/detail/merge_sort_on_gpu.hpp>
22 #include <boost/compute/algorithm/detail/radix_sort.hpp>
23 #include <boost/compute/algorithm/detail/insertion_sort.hpp>
24 #include <boost/compute/algorithm/reverse.hpp>
25 #include <boost/compute/functional/operator.hpp>
26 #include <boost/compute/detail/iterator_range_size.hpp>
27 #include <boost/compute/type_traits/is_device_iterator.hpp>
28
29 namespace boost {
30 namespace compute {
31 namespace detail {
32
33 template<class Iterator, class Compare>
dispatch_gpu_stable_sort(Iterator first,Iterator last,Compare compare,command_queue & queue)34 inline void dispatch_gpu_stable_sort(Iterator first,
35 Iterator last,
36 Compare compare,
37 command_queue &queue)
38 {
39 size_t count = detail::iterator_range_size(first, last);
40
41 if(count < 32){
42 detail::serial_insertion_sort(
43 first, last, compare, queue
44 );
45 } else {
46 detail::merge_sort_on_gpu(
47 first, last, compare, true /* stable */, queue
48 );
49 }
50 }
51
52 template<class T>
53 inline typename boost::enable_if_c<is_radix_sortable<T>::value>::type
dispatch_gpu_stable_sort(buffer_iterator<T> first,buffer_iterator<T> last,less<T>,command_queue & queue)54 dispatch_gpu_stable_sort(buffer_iterator<T> first,
55 buffer_iterator<T> last,
56 less<T>,
57 command_queue &queue)
58 {
59 ::boost::compute::detail::radix_sort(first, last, queue);
60 }
61
62 template<class T>
63 inline typename boost::enable_if_c<is_radix_sortable<T>::value>::type
dispatch_gpu_stable_sort(buffer_iterator<T> first,buffer_iterator<T> last,greater<T>,command_queue & queue)64 dispatch_gpu_stable_sort(buffer_iterator<T> first,
65 buffer_iterator<T> last,
66 greater<T>,
67 command_queue &queue)
68 {
69 // radix sorts in descending order
70 ::boost::compute::detail::radix_sort(first, last, false, queue);
71 }
72
73 } // end detail namespace
74
75 /// Sorts the values in the range [\p first, \p last) according to
76 /// \p compare. The relative order of identical values is preserved.
77 ///
78 /// Space complexity: \Omega(n)
79 ///
80 /// \see sort(), is_sorted()
81 template<class Iterator, class Compare>
stable_sort(Iterator first,Iterator last,Compare compare,command_queue & queue=system::default_queue ())82 inline void stable_sort(Iterator first,
83 Iterator last,
84 Compare compare,
85 command_queue &queue = system::default_queue())
86 {
87 BOOST_STATIC_ASSERT(is_device_iterator<Iterator>::value);
88
89 if(queue.get_device().type() & device::gpu) {
90 ::boost::compute::detail::dispatch_gpu_stable_sort(
91 first, last, compare, queue
92 );
93 return;
94 }
95 ::boost::compute::detail::merge_sort_on_cpu(first, last, compare, queue);
96 }
97
98 /// \overload
99 template<class Iterator>
stable_sort(Iterator first,Iterator last,command_queue & queue=system::default_queue ())100 inline void stable_sort(Iterator first,
101 Iterator last,
102 command_queue &queue = system::default_queue())
103 {
104 BOOST_STATIC_ASSERT(is_device_iterator<Iterator>::value);
105 typedef typename std::iterator_traits<Iterator>::value_type value_type;
106
107 ::boost::compute::less<value_type> less;
108
109 ::boost::compute::stable_sort(first, last, less, queue);
110 }
111
112 } // end compute namespace
113 } // end boost namespace
114
115 #endif // BOOST_COMPUTE_ALGORITHM_STABLE_SORT_HPP
116