ceph/src/boost/libs/compute/include/boost/compute/algorithm/set_symmetric_difference.hpp

   1 //---------------------------------------------------------------------------//
   2 // Copyright (c) 2014 Roshan <thisisroshansmail@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_SET_SYMMETRIC_DIFFERENCE_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_SET_SYMMETRIC_DIFFERENCE_HPP
  13
  14 #include <iterator>
  15
  16 #include <boost/compute/algorithm/detail/compact.hpp>
  17 #include <boost/compute/algorithm/detail/balanced_path.hpp>
  18 #include <boost/compute/algorithm/exclusive_scan.hpp>
  19 #include <boost/compute/algorithm/fill_n.hpp>
  20 #include <boost/compute/container/vector.hpp>
  21 #include <boost/compute/detail/iterator_range_size.hpp>
  22 #include <boost/compute/detail/meta_kernel.hpp>
  23 #include <boost/compute/system.hpp>
  24
  25 namespace boost {
  26 namespace compute {
  27 namespace detail {
  28
  29 ///
  30 /// \brief Serial set symmetric difference kernel class
  31 ///
  32 /// Subclass of meta_kernel to perform serial set symmetric
  33 /// difference after tiling
  34 ///
  35 class serial_set_symmetric_difference_kernel : meta_kernel
  36 {
  37 public:
  38     unsigned int tile_size;
  39
  40     serial_set_symmetric_difference_kernel() : meta_kernel("set_symmetric_difference")
  41     {
  42         tile_size = 4;
  43     }
  44
  45     template<class InputIterator1, class InputIterator2,
  46              class InputIterator3, class InputIterator4,
  47              class OutputIterator1, class OutputIterator2>
  48     void set_range(InputIterator1 first1,
  49                     InputIterator2 first2,
  50                     InputIterator3 tile_first1,
  51                     InputIterator3 tile_last1,
  52                     InputIterator4 tile_first2,
  53                     OutputIterator1 result,
  54                     OutputIterator2 counts)
  55     {
  56         m_count = iterator_range_size(tile_first1, tile_last1) - 1;
  57
  58         *this <<
  59         "uint i = get_global_id(0);\n" <<
  60         "uint start1 = " << tile_first1[expr<uint_>("i")] << ";\n" <<
  61         "uint end1 = " << tile_first1[expr<uint_>("i+1")] << ";\n" <<
  62         "uint start2 = " << tile_first2[expr<uint_>("i")] << ";\n" <<
  63         "uint end2 = " << tile_first2[expr<uint_>("i+1")] << ";\n" <<
  64         "uint index = i*" << tile_size << ";\n" <<
  65         "uint count = 0;\n" <<
  66         "while(start1<end1 && start2<end2)\n" <<
  67         "{\n" <<
  68         "   if(" << first1[expr<uint_>("start1")] << " == " <<
  69                     first2[expr<uint_>("start2")] << ")\n" <<
  70         "   {\n" <<
  71         "       start1++; start2++;\n" <<
  72         "   }\n" <<
  73         "   else if(" << first1[expr<uint_>("start1")] << " < " <<
  74                         first2[expr<uint_>("start2")] << ")\n" <<
  75         "   {\n" <<
  76                 result[expr<uint_>("index")] <<
  77                     " = " << first1[expr<uint_>("start1")] << ";\n" <<
  78         "       index++; count++;\n" <<
  79         "       start1++;\n" <<
  80         "   }\n" <<
  81         "   else\n" <<
  82         "   {\n" <<
  83                 result[expr<uint_>("index")] <<
  84                     " = " << first2[expr<uint_>("start2")] << ";\n" <<
  85         "       index++; count++;\n" <<
  86         "       start2++;\n" <<
  87         "   }\n" <<
  88         "}\n" <<
  89         "while(start1<end1)\n" <<
  90         "{\n" <<
  91             result[expr<uint_>("index")] <<
  92                 " = " << first1[expr<uint_>("start1")] << ";\n" <<
  93         "   index++; count++;\n" <<
  94         "   start1++;\n" <<
  95         "}\n" <<
  96         "while(start2<end2)\n" <<
  97         "{\n" <<
  98             result[expr<uint_>("index")] <<
  99                 " = " << first2[expr<uint_>("start2")] << ";\n" <<
 100         "   index++; count++;\n" <<
 101         "   start2++;\n" <<
 102         "}\n" <<
 103         counts[expr<uint_>("i")] << " = count;\n";
 104     }
 105
 106     event exec(command_queue &queue)
 107     {
 108         if(m_count == 0) {
 109             return event();
 110         }
 111
 112         return exec_1d(queue, 0, m_count);
 113     }
 114
 115 private:
 116     size_t m_count;
 117 };
 118
 119 } //end detail namespace
 120
 121 ///
 122 /// \brief Set symmetric difference algorithm
 123 ///
 124 /// Finds the symmetric difference of the sorted range [first2, last2) from
 125 /// the sorted range [first1, last1) and stores it in range starting at result
 126 /// \return Iterator pointing to end of symmetric difference
 127 ///
 128 /// \param first1 Iterator pointing to start of first set
 129 /// \param last1 Iterator pointing to end of first set
 130 /// \param first2 Iterator pointing to start of second set
 131 /// \param last2 Iterator pointing to end of second set
 132 /// \param result Iterator pointing to start of range in which the symmetric
 133 /// difference will be stored
 134 /// \param queue Queue on which to execute
 135 ///
 136 template<class InputIterator1, class InputIterator2, class OutputIterator>
 137 inline OutputIterator set_symmetric_difference(InputIterator1 first1,
 138                                      InputIterator1 last1,
 139                                      InputIterator2 first2,
 140                                      InputIterator2 last2,
 141                                      OutputIterator result,
 142                                      command_queue &queue = system::default_queue())
 143 {
 144     typedef typename std::iterator_traits<InputIterator1>::value_type value_type;
 145
 146     int tile_size = 1024;
 147
 148     int count1 = detail::iterator_range_size(first1, last1);
 149     int count2 = detail::iterator_range_size(first2, last2);
 150
 151     vector<uint_> tile_a((count1+count2+tile_size-1)/tile_size+1, queue.get_context());
 152     vector<uint_> tile_b((count1+count2+tile_size-1)/tile_size+1, queue.get_context());
 153
 154     // Tile the sets
 155     detail::balanced_path_kernel tiling_kernel;
 156     tiling_kernel.tile_size = tile_size;
 157     tiling_kernel.set_range(first1, last1, first2, last2,
 158                             tile_a.begin()+1, tile_b.begin()+1);
 159     fill_n(tile_a.begin(), 1, 0, queue);
 160     fill_n(tile_b.begin(), 1, 0, queue);
 161     tiling_kernel.exec(queue);
 162
 163     fill_n(tile_a.end()-1, 1, count1, queue);
 164     fill_n(tile_b.end()-1, 1, count2, queue);
 165
 166     vector<value_type> temp_result(count1+count2, queue.get_context());
 167     vector<uint_> counts((count1+count2+tile_size-1)/tile_size + 1, queue.get_context());
 168     fill_n(counts.end()-1, 1, 0, queue);
 169
 170     // Find individual symmetric differences
 171     detail::serial_set_symmetric_difference_kernel symmetric_difference_kernel;
 172     symmetric_difference_kernel.tile_size = tile_size;
 173     symmetric_difference_kernel.set_range(first1, first2, tile_a.begin(),
 174                                             tile_a.end(), tile_b.begin(),
 175                                             temp_result.begin(), counts.begin());
 176
 177     symmetric_difference_kernel.exec(queue);
 178
 179     exclusive_scan(counts.begin(), counts.end(), counts.begin(), queue);
 180
 181     // Compact the results
 182     detail::compact_kernel compact_kernel;
 183     compact_kernel.tile_size = tile_size;
 184     compact_kernel.set_range(temp_result.begin(), counts.begin(), counts.end(), result);
 185
 186     compact_kernel.exec(queue);
 187
 188     return result + (counts.end() - 1).read(queue);
 189 }
 190
 191 } //end compute namespace
 192 } //end boost namespace
 193
 194 #endif // BOOST_COMPUTE_ALGORITHM_SET_SYMMETRIC_DIFFERENCE_HPP