ceph/src/boost/boost/compute/algorithm/detail/find_extrema.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_DETAIL_FIND_EXTREMA_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_DETAIL_FIND_EXTREMA_HPP
  13
  14 #include <boost/compute/detail/iterator_range_size.hpp>
  15 #include <boost/compute/algorithm/detail/find_extrema_on_cpu.hpp>
  16 #include <boost/compute/algorithm/detail/find_extrema_with_reduce.hpp>
  17 #include <boost/compute/algorithm/detail/find_extrema_with_atomics.hpp>
  18 #include <boost/compute/algorithm/detail/serial_find_extrema.hpp>
  19
  20 namespace boost {
  21 namespace compute {
  22 namespace detail {
  23
  24 template<class InputIterator, class Compare>
  25 inline InputIterator find_extrema(InputIterator first,
  26                                   InputIterator last,
  27                                   Compare compare,
  28                                   const bool find_minimum,
  29                                   command_queue &queue)
  30 {
  31     size_t count = iterator_range_size(first, last);
  32
  33     // handle trivial cases
  34     if(count == 0 || count == 1){
  35         return first;
  36     }
  37
  38     const device &device = queue.get_device();
  39
  40     // CPU
  41     if(device.type() & device::cpu) {
  42         return find_extrema_on_cpu(first, last, compare, find_minimum, queue);
  43     }
  44
  45     // GPU
  46     // use serial method for small inputs
  47     if(count < 512)
  48     {
  49         return serial_find_extrema(first, last, compare, find_minimum, queue);
  50     }
  51     // find_extrema_with_reduce() is used only if requirements are met
  52     if(find_extrema_with_reduce_requirements_met(first, last, queue))
  53     {
  54         return find_extrema_with_reduce(first, last, compare, find_minimum, queue);
  55     }
  56
  57     // use serial method for OpenCL version 1.0 due to
  58     // problems with atomic_cmpxchg()
  59     #ifndef BOOST_COMPUTE_CL_VERSION_1_1
  60         return serial_find_extrema(first, last, compare, find_minimum, queue);
  61     #endif
  62
  63     return find_extrema_with_atomics(first, last, compare, find_minimum, queue);
  64 }
  65
  66 } // end detail namespace
  67 } // end compute namespace
  68 } // end boost namespace
  69
  70 #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_FIND_EXTREMA_HPP