ceph/src/boost/boost/compute/algorithm/minmax_element.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_MINMAX_ELEMENT_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_MINMAX_ELEMENT_HPP
  13
  14 #include <utility>
  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/max_element.hpp>
  21 #include <boost/compute/algorithm/min_element.hpp>
  22 #include <boost/compute/type_traits/is_device_iterator.hpp>
  23
  24 namespace boost {
  25 namespace compute {
  26
  27 /// Returns a pair of iterators with the first pointing to the minimum
  28 /// element and the second pointing to the maximum element in the range
  29 /// [\p first, \p last).
  30 ///
  31 /// \param first first element in the input range
  32 /// \param last last element in the input range
  33 /// \param compare comparison function object which returns true if the first
  34 ///        argument is less than (i.e. is ordered before) the second.
  35 /// \param queue command queue to perform the operation
  36 ///
  37 /// Space complexity on CPUs: \Omega(1)<br>
  38 /// Space complexity on GPUs: \Omega(N)
  39 ///
  40 /// \see max_element(), min_element()
  41 template<class InputIterator, class Compare>
  42 inline std::pair<InputIterator, InputIterator>
  43 minmax_element(InputIterator first,
  44                InputIterator last,
  45                Compare compare,
  46                command_queue &queue = system::default_queue())
  47 {
  48     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value);
  49     if(first == last){
  50         // empty range
  51         return std::make_pair(first, first);
  52     }
  53
  54     return std::make_pair(min_element(first, last, compare, queue),
  55                           max_element(first, last, compare, queue));
  56 }
  57
  58 ///\overload
  59 template<class InputIterator>
  60 inline std::pair<InputIterator, InputIterator>
  61 minmax_element(InputIterator first,
  62                InputIterator last,
  63                command_queue &queue = system::default_queue())
  64 {
  65     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value);
  66     if(first == last){
  67         // empty range
  68         return std::make_pair(first, first);
  69     }
  70
  71     return std::make_pair(min_element(first, last, queue),
  72                           max_element(first, last, queue));
  73 }
  74
  75 } // end compute namespace
  76 } // end boost namespace
  77
  78 #endif // BOOST_COMPUTE_ALGORITHM_MINMAX_ELEMENT_HPP