ceph/src/boost/boost/compute/algorithm/count_if.hpp

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