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/compute/system.hpp>
  17 #include <boost/compute/command_queue.hpp>
  18 #include <boost/compute/algorithm/max_element.hpp>
  19 #include <boost/compute/algorithm/min_element.hpp>
  20
  21 namespace boost {
  22 namespace compute {
  23
  24 /// Returns a pair of iterators with the first pointing to the minimum
  25 /// element and the second pointing to the maximum element in the range
  26 /// [\p first, \p last).
  27 ///
  28 /// \param first first element in the input range
  29 /// \param last last element in the input range
  30 /// \param compare comparison function object which returns true if the first
  31 ///        argument is less than (i.e. is ordered before) the second.
  32 /// \param queue command queue to perform the operation
  33 ///
  34 /// Space complexity on CPUs: \Omega(1)<br>
  35 /// Space complexity on GPUs: \Omega(N)
  36 ///
  37 /// \see max_element(), min_element()
  38 template<class InputIterator, class Compare>
  39 inline std::pair<InputIterator, InputIterator>
  40 minmax_element(InputIterator first,
  41                InputIterator last,
  42                Compare compare,
  43                command_queue &queue = system::default_queue())
  44 {
  45     if(first == last){
  46         // empty range
  47         return std::make_pair(first, first);
  48     }
  49
  50     return std::make_pair(min_element(first, last, compare, queue),
  51                           max_element(first, last, compare, queue));
  52 }
  53
  54 ///\overload
  55 template<class InputIterator>
  56 inline std::pair<InputIterator, InputIterator>
  57 minmax_element(InputIterator first,
  58                InputIterator last,
  59                command_queue &queue = system::default_queue())
  60 {
  61     if(first == last){
  62         // empty range
  63         return std::make_pair(first, first);
  64     }
  65
  66     return std::make_pair(min_element(first, last, queue),
  67                           max_element(first, last, queue));
  68 }
  69
  70 } // end compute namespace
  71 } // end boost namespace
  72
  73 #endif // BOOST_COMPUTE_ALGORITHM_MINMAX_ELEMENT_HPP