ceph/src/boost/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/static_assert.hpp>
  17
  18 #include <boost/compute/algorithm/detail/compact.hpp>
  19 #include <boost/compute/algorithm/detail/balanced_path.hpp>
  20 #include <boost/compute/algorithm/exclusive_scan.hpp>
  21 #include <boost/compute/algorithm/fill_n.hpp>
  22 #include <boost/compute/container/vector.hpp>
  23 #include <boost/compute/detail/iterator_range_size.hpp>
  24 #include <boost/compute/detail/meta_kernel.hpp>
  25 #include <boost/compute/system.hpp>
  26 #include <boost/compute/type_traits/is_device_iterator.hpp>
  27
  28 namespace boost {
  29 namespace compute {
  30 namespace detail {
  31
  32 ///
  33 /// \brief Serial set symmetric difference kernel class
  34 ///
  35 /// Subclass of meta_kernel to perform serial set symmetric
  36 /// difference after tiling
  37 ///
  38 class serial_set_symmetric_difference_kernel : meta_kernel
  39 {
  40 public:
  41     unsigned int tile_size;
  42
  43     serial_set_symmetric_difference_kernel() : meta_kernel("set_symmetric_difference")
  44     {
  45         tile_size = 4;
  46     }
  47
  48     template<class InputIterator1, class InputIterator2,
  49              class InputIterator3, class InputIterator4,
  50              class OutputIterator1, class OutputIterator2>
  51     void set_range(InputIterator1 first1,
  52                     InputIterator2 first2,
  53                     InputIterator3 tile_first1,
  54                     InputIterator3 tile_last1,
  55                     InputIterator4 tile_first2,
  56                     OutputIterator1 result,
  57                     OutputIterator2 counts)
  58     {
  59         m_count = iterator_range_size(tile_first1, tile_last1) - 1;
  60
  61         *this <<
  62         "uint i = get_global_id(0);\n" <<
  63         "uint start1 = " << tile_first1[expr<uint_>("i")] << ";\n" <<
  64         "uint end1 = " << tile_first1[expr<uint_>("i+1")] << ";\n" <<
  65         "uint start2 = " << tile_first2[expr<uint_>("i")] << ";\n" <<
  66         "uint end2 = " << tile_first2[expr<uint_>("i+1")] << ";\n" <<
  67         "uint index = i*" << tile_size << ";\n" <<
  68         "uint count = 0;\n" <<
  69         "while(start1<end1 && start2<end2)\n" <<
  70         "{\n" <<
  71         "   if(" << first1[expr<uint_>("start1")] << " == " <<
  72                     first2[expr<uint_>("start2")] << ")\n" <<
  73         "   {\n" <<
  74         "       start1++; start2++;\n" <<
  75         "   }\n" <<
  76         "   else if(" << first1[expr<uint_>("start1")] << " < " <<
  77                         first2[expr<uint_>("start2")] << ")\n" <<
  78         "   {\n" <<
  79                 result[expr<uint_>("index")] <<
  80                     " = " << first1[expr<uint_>("start1")] << ";\n" <<
  81         "       index++; count++;\n" <<
  82         "       start1++;\n" <<
  83         "   }\n" <<
  84         "   else\n" <<
  85         "   {\n" <<
  86                 result[expr<uint_>("index")] <<
  87                     " = " << first2[expr<uint_>("start2")] << ";\n" <<
  88         "       index++; count++;\n" <<
  89         "       start2++;\n" <<
  90         "   }\n" <<
  91         "}\n" <<
  92         "while(start1<end1)\n" <<
  93         "{\n" <<
  94             result[expr<uint_>("index")] <<
  95                 " = " << first1[expr<uint_>("start1")] << ";\n" <<
  96         "   index++; count++;\n" <<
  97         "   start1++;\n" <<
  98         "}\n" <<
  99         "while(start2<end2)\n" <<
 100         "{\n" <<
 101             result[expr<uint_>("index")] <<
 102                 " = " << first2[expr<uint_>("start2")] << ";\n" <<
 103         "   index++; count++;\n" <<
 104         "   start2++;\n" <<
 105         "}\n" <<
 106         counts[expr<uint_>("i")] << " = count;\n";
 107     }
 108
 109     event exec(command_queue &queue)
 110     {
 111         if(m_count == 0) {
 112             return event();
 113         }
 114
 115         return exec_1d(queue, 0, m_count);
 116     }
 117
 118 private:
 119     size_t m_count;
 120 };
 121
 122 } //end detail namespace
 123
 124 ///
 125 /// \brief Set symmetric difference algorithm
 126 ///
 127 /// Finds the symmetric difference of the sorted range [first2, last2) from
 128 /// the sorted range [first1, last1) and stores it in range starting at result
 129 /// \return Iterator pointing to end of symmetric difference
 130 ///
 131 /// \param first1 Iterator pointing to start of first set
 132 /// \param last1 Iterator pointing to end of first set
 133 /// \param first2 Iterator pointing to start of second set
 134 /// \param last2 Iterator pointing to end of second set
 135 /// \param result Iterator pointing to start of range in which the symmetric
 136 /// difference will be stored
 137 /// \param queue Queue on which to execute
 138 ///
 139 /// Space complexity:
 140 /// \Omega(2(distance(\p first1, \p last1) + distance(\p first2, \p last2)))
 141 template<class InputIterator1, class InputIterator2, class OutputIterator>
 142 inline OutputIterator
 143 set_symmetric_difference(InputIterator1 first1,
 144                          InputIterator1 last1,
 145                          InputIterator2 first2,
 146                          InputIterator2 last2,
 147                          OutputIterator result,
 148                          command_queue &queue = system::default_queue())
 149 {
 150     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator1>::value);
 151     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator2>::value);
 152     BOOST_STATIC_ASSERT(is_device_iterator<OutputIterator>::value);
 153
 154     typedef typename std::iterator_traits<InputIterator1>::value_type value_type;
 155
 156     int tile_size = 1024;
 157
 158     int count1 = detail::iterator_range_size(first1, last1);
 159     int count2 = detail::iterator_range_size(first2, last2);
 160
 161     vector<uint_> tile_a((count1+count2+tile_size-1)/tile_size+1, queue.get_context());
 162     vector<uint_> tile_b((count1+count2+tile_size-1)/tile_size+1, queue.get_context());
 163
 164     // Tile the sets
 165     detail::balanced_path_kernel tiling_kernel;
 166     tiling_kernel.tile_size = tile_size;
 167     tiling_kernel.set_range(first1, last1, first2, last2,
 168                             tile_a.begin()+1, tile_b.begin()+1);
 169     fill_n(tile_a.begin(), 1, 0, queue);
 170     fill_n(tile_b.begin(), 1, 0, queue);
 171     tiling_kernel.exec(queue);
 172
 173     fill_n(tile_a.end()-1, 1, count1, queue);
 174     fill_n(tile_b.end()-1, 1, count2, queue);
 175
 176     vector<value_type> temp_result(count1+count2, queue.get_context());
 177     vector<uint_> counts((count1+count2+tile_size-1)/tile_size + 1, queue.get_context());
 178     fill_n(counts.end()-1, 1, 0, queue);
 179
 180     // Find individual symmetric differences
 181     detail::serial_set_symmetric_difference_kernel symmetric_difference_kernel;
 182     symmetric_difference_kernel.tile_size = tile_size;
 183     symmetric_difference_kernel.set_range(first1, first2, tile_a.begin(),
 184                                             tile_a.end(), tile_b.begin(),
 185                                             temp_result.begin(), counts.begin());
 186
 187     symmetric_difference_kernel.exec(queue);
 188
 189     exclusive_scan(counts.begin(), counts.end(), counts.begin(), queue);
 190
 191     // Compact the results
 192     detail::compact_kernel compact_kernel;
 193     compact_kernel.tile_size = tile_size;
 194     compact_kernel.set_range(temp_result.begin(), counts.begin(), counts.end(), result);
 195
 196     compact_kernel.exec(queue);
 197
 198     return result + (counts.end() - 1).read(queue);
 199 }
 200
 201 } //end compute namespace
 202 } //end boost namespace
 203
 204 #endif // BOOST_COMPUTE_ALGORITHM_SET_SYMMETRIC_DIFFERENCE_HPP