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