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_COUNT_IF_HPP
12 #define BOOST_COMPUTE_ALGORITHM_COUNT_IF_HPP
13
14 #include <boost/static_assert.hpp>
15
16 #include <boost/compute/device.hpp>
17 #include <boost/compute/system.hpp>
18 #include <boost/compute/command_queue.hpp>
19 #include <boost/compute/algorithm/detail/count_if_with_ballot.hpp>
20 #include <boost/compute/algorithm/detail/count_if_with_reduce.hpp>
21 #include <boost/compute/algorithm/detail/count_if_with_threads.hpp>
22 #include <boost/compute/algorithm/detail/serial_count_if.hpp>
23 #include <boost/compute/detail/iterator_range_size.hpp>
24 #include <boost/compute/type_traits/is_device_iterator.hpp>
25
26 namespace boost {
27 namespace compute {
28
29 /// Returns the number of elements in the range [\p first, \p last)
30 /// for which \p predicate returns \c true.
31 ///
32 /// Space complexity on CPUs: \Omega(1)<br>
33 /// Space complexity on GPUs: \Omega(n)
34 template<class InputIterator, class Predicate>
count_if(InputIterator first,InputIterator last,Predicate predicate,command_queue & queue=system::default_queue ())35 inline size_t count_if(InputIterator first,
36 InputIterator last,
37 Predicate predicate,
38 command_queue &queue = system::default_queue())
39 {
40 BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value);
41 const device &device = queue.get_device();
42
43 size_t input_size = detail::iterator_range_size(first, last);
44 if(input_size == 0){
45 return 0;
46 }
47
48 if(device.type() & device::cpu){
49 if(input_size < 1024){
50 return detail::serial_count_if(first, last, predicate, queue);
51 }
52 else {
53 return detail::count_if_with_threads(first, last, predicate, queue);
54 }
55 }
56 else {
57 if(input_size < 32){
58 return detail::serial_count_if(first, last, predicate, queue);
59 }
60 else {
61 return detail::count_if_with_reduce(first, last, predicate, queue);
62 }
63 }
64 }
65
66 } // end compute namespace
67 } // end boost namespace
68
69 #endif // BOOST_COMPUTE_ALGORITHM_COUNT_IF_HPP
70