deps/boost_1_63_0/boost/compute/algorithm/scatter_if.hpp

   1 //---------------------------------------------------------------------------//
   2 // Copyright (c) 2015 Jakub Pola <jakub.pola@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_SCATTER_IF_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_SCATTER_IF_HPP
  13
  14 #include <boost/algorithm/string/replace.hpp>
  15
  16 #include <boost/compute/system.hpp>
  17 #include <boost/compute/exception.hpp>
  18 #include <boost/compute/command_queue.hpp>
  19 #include <boost/compute/iterator/buffer_iterator.hpp>
  20 #include <boost/compute/type_traits/type_name.hpp>
  21 #include <boost/compute/detail/iterator_range_size.hpp>
  22 #include <boost/compute/detail/meta_kernel.hpp>
  23
  24 namespace boost {
  25 namespace compute {
  26 namespace detail {
  27
  28 template<class InputIterator, class MapIterator, class StencilIterator, class OutputIterator, class Predicate>
  29 class scatter_if_kernel : meta_kernel
  30 {
  31 public:
  32     scatter_if_kernel() : meta_kernel("scatter_if")
  33     {}
  34
  35     void set_range(InputIterator first,
  36                    InputIterator last,
  37                    MapIterator map,
  38                    StencilIterator stencil,
  39                    OutputIterator result,
  40                    Predicate predicate)
  41     {
  42         m_count = iterator_range_size(first, last);
  43         m_input_offset = first.get_index();
  44         m_output_offset = result.get_index();
  45
  46         m_input_offset_arg = add_arg<uint_>("input_offset");
  47         m_output_offset_arg = add_arg<uint_>("output_offset");
  48
  49         *this <<
  50         "const uint i = get_global_id(0);\n" <<
  51         "uint i1 = " << map[expr<uint_>("i")] <<
  52         " + output_offset;\n" <<
  53         "uint i2 = i + input_offset;\n" <<
  54         if_(predicate(stencil[expr<uint_>("i")])) << "\n" <<
  55             result[expr<uint_>("i1")] << "=" <<
  56             first[expr<uint_>("i2")] << ";\n";
  57     }
  58
  59     event exec(command_queue &queue)
  60     {
  61         if(m_count == 0) {
  62             return event();
  63         }
  64
  65         set_arg(m_input_offset_arg, uint_(m_input_offset));
  66         set_arg(m_output_offset_arg, uint_(m_output_offset));
  67
  68         return exec_1d(queue, 0, m_count);
  69     }
  70
  71 private:
  72     size_t m_count;
  73     size_t m_input_offset;
  74     size_t m_input_offset_arg;
  75     size_t m_output_offset;
  76     size_t m_output_offset_arg;
  77 };
  78
  79 } // end detail namespace
  80
  81 /// Copies the elements from the range [\p first, \p last) to the range
  82 /// beginning at \p result using the output indices from the range beginning
  83 /// at \p map if stencil is resolved to true. By default the predicate is
  84 /// an identity
  85 ///
  86 ///
  87 template<class InputIterator, class MapIterator, class StencilIterator, class OutputIterator,
  88          class Predicate>
  89 inline void scatter_if(InputIterator first,
  90                        InputIterator last,
  91                        MapIterator map,
  92                        StencilIterator stencil,
  93                        OutputIterator result,
  94                        Predicate predicate,
  95                        command_queue &queue = system::default_queue())
  96 {
  97     detail::scatter_if_kernel<InputIterator, MapIterator, StencilIterator, OutputIterator, Predicate> kernel;
  98
  99     kernel.set_range(first, last, map, stencil, result, predicate);
 100     kernel.exec(queue);
 101 }
 102
 103 template<class InputIterator, class MapIterator, class StencilIterator, class OutputIterator>
 104 inline void scatter_if(InputIterator first,
 105                        InputIterator last,
 106                        MapIterator map,
 107                        StencilIterator stencil,
 108                        OutputIterator result,
 109                        command_queue &queue = system::default_queue())
 110 {
 111     typedef typename std::iterator_traits<StencilIterator>::value_type T;
 112
 113     scatter_if(first, last, map, stencil, result, identity<T>(), queue);
 114 }
 115
 116 } // end compute namespace
 117 } // end boost namespace
 118
 119 #endif // BOOST_COMPUTE_ALGORITHM_SCATTER_IF_HPP