ceph/src/boost/boost/compute/algorithm/detail/serial_reduce.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_SERIAL_REDUCE_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_HPP
  13
  14 #include <boost/compute/command_queue.hpp>
  15 #include <boost/compute/detail/meta_kernel.hpp>
  16 #include <boost/compute/detail/iterator_range_size.hpp>
  17 #include <boost/compute/type_traits/result_of.hpp>
  18
  19 namespace boost {
  20 namespace compute {
  21 namespace detail {
  22
  23 // Space complexity: O(1)
  24 template<class InputIterator, class OutputIterator, class BinaryFunction>
  25 inline void serial_reduce(InputIterator first,
  26                           InputIterator last,
  27                           OutputIterator result,
  28                           BinaryFunction function,
  29                           command_queue &queue)
  30 {
  31     typedef typename
  32         std::iterator_traits<InputIterator>::value_type T;
  33     typedef typename
  34         ::boost::compute::result_of<BinaryFunction(T, T)>::type result_type;
  35
  36     const context &context = queue.get_context();
  37     size_t count = detail::iterator_range_size(first, last);
  38     if(count == 0){
  39         return;
  40     }
  41
  42     meta_kernel k("serial_reduce");
  43     size_t count_arg = k.add_arg<cl_uint>("count");
  44
  45     k <<
  46         k.decl<result_type>("result") << " = " << first[0] << ";\n" <<
  47         "for(uint i = 1; i < count; i++)\n" <<
  48         "    result = " << function(k.var<T>("result"),
  49                                     first[k.var<uint_>("i")]) << ";\n" <<
  50         result[0] << " = result;\n";
  51
  52     kernel kernel = k.compile(context);
  53
  54     kernel.set_arg(count_arg, static_cast<uint_>(count));
  55
  56     queue.enqueue_task(kernel);
  57 }
  58
  59 } // end detail namespace
  60 } // end compute namespace
  61 } // end boost namespace
  62
  63 #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_REDUCE_HPP