ceph/src/boost/boost/compute/algorithm/inner_product.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_INNER_PRODUCT_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_INNER_PRODUCT_HPP
  13
  14 #include <boost/static_assert.hpp>
  15
  16 #include <boost/compute/system.hpp>
  17 #include <boost/compute/functional.hpp>
  18 #include <boost/compute/command_queue.hpp>
  19 #include <boost/compute/algorithm/accumulate.hpp>
  20 #include <boost/compute/container/vector.hpp>
  21 #include <boost/compute/iterator/transform_iterator.hpp>
  22 #include <boost/compute/iterator/zip_iterator.hpp>
  23 #include <boost/compute/functional/detail/unpack.hpp>
  24 #include <boost/compute/type_traits/is_device_iterator.hpp>
  25
  26 namespace boost {
  27 namespace compute {
  28
  29 /// Returns the inner product of the elements in the range
  30 /// [\p first1, \p last1) with the elements in the range beginning
  31 /// at \p first2.
  32 ///
  33 /// Space complexity: \Omega(1)<br>
  34 /// Space complexity when binary operator is recognized as associative: \Omega(n)
  35 template<class InputIterator1, class InputIterator2, class T>
  36 inline T inner_product(InputIterator1 first1,
  37                        InputIterator1 last1,
  38                        InputIterator2 first2,
  39                        T init,
  40                        command_queue &queue = system::default_queue())
  41 {
  42     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator1>::value);
  43     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator2>::value);
  44     typedef typename std::iterator_traits<InputIterator1>::value_type input_type;
  45
  46     ptrdiff_t n = std::distance(first1, last1);
  47
  48     return ::boost::compute::accumulate(
  49         ::boost::compute::make_transform_iterator(
  50             ::boost::compute::make_zip_iterator(
  51                 boost::make_tuple(first1, first2)
  52             ),
  53             detail::unpack(multiplies<input_type>())
  54         ),
  55         ::boost::compute::make_transform_iterator(
  56             ::boost::compute::make_zip_iterator(
  57                 boost::make_tuple(last1, first2 + n)
  58             ),
  59             detail::unpack(multiplies<input_type>())
  60         ),
  61         init,
  62         queue
  63     );
  64 }
  65
  66 /// \overload
  67 template<class InputIterator1,
  68          class InputIterator2,
  69          class T,
  70          class BinaryAccumulateFunction,
  71          class BinaryTransformFunction>
  72 inline T inner_product(InputIterator1 first1,
  73                        InputIterator1 last1,
  74                        InputIterator2 first2,
  75                        T init,
  76                        BinaryAccumulateFunction accumulate_function,
  77                        BinaryTransformFunction transform_function,
  78                        command_queue &queue = system::default_queue())
  79 {
  80     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator1>::value);
  81     BOOST_STATIC_ASSERT(is_device_iterator<InputIterator2>::value);
  82     typedef typename std::iterator_traits<InputIterator1>::value_type value_type;
  83
  84     size_t count = detail::iterator_range_size(first1, last1);
  85     vector<value_type> result(count, queue.get_context());
  86     transform(first1,
  87               last1,
  88               first2,
  89               result.begin(),
  90               transform_function,
  91               queue);
  92
  93     return ::boost::compute::accumulate(result.begin(),
  94                                         result.end(),
  95                                         init,
  96                                         accumulate_function,
  97                                         queue);
  98 }
  99
 100 } // end compute namespace
 101 } // end boost namespace
 102
 103 #endif // BOOST_COMPUTE_ALGORITHM_INNER_PRODUCT_HPP