ceph/src/boost/libs/compute/include/boost/compute/algorithm/transform_reduce.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_TRANSFORM_REDUCE_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_TRANSFORM_REDUCE_HPP
  13
  14 #include <boost/compute/system.hpp>
  15 #include <boost/compute/algorithm/reduce.hpp>
  16 #include <boost/compute/iterator/transform_iterator.hpp>
  17 #include <boost/compute/iterator/zip_iterator.hpp>
  18 #include <boost/compute/functional/detail/unpack.hpp>
  19 #include <boost/compute/detail/iterator_range_size.hpp>
  20
  21 namespace boost {
  22 namespace compute {
  23
  24 /// Transforms each value in the range [\p first, \p last) with the unary
  25 /// \p transform_function and then reduces each transformed value with
  26 /// \p reduce_function.
  27 ///
  28 /// For example, to calculate the sum of the absolute values of a vector
  29 /// of integers:
  30 ///
  31 /// \snippet test/test_transform_reduce.cpp sum_abs_int
  32 ///
  33 /// \see reduce(), inner_product()
  34 template<class InputIterator,
  35          class OutputIterator,
  36          class UnaryTransformFunction,
  37          class BinaryReduceFunction>
  38 inline void transform_reduce(InputIterator first,
  39                              InputIterator last,
  40                              OutputIterator result,
  41                              UnaryTransformFunction transform_function,
  42                              BinaryReduceFunction reduce_function,
  43                              command_queue &queue = system::default_queue())
  44 {
  45     ::boost::compute::reduce(
  46         ::boost::compute::make_transform_iterator(first, transform_function),
  47         ::boost::compute::make_transform_iterator(last, transform_function),
  48         result,
  49         reduce_function,
  50         queue
  51     );
  52 }
  53
  54 /// \overload
  55 template<class InputIterator1,
  56          class InputIterator2,
  57          class OutputIterator,
  58          class BinaryTransformFunction,
  59          class BinaryReduceFunction>
  60 inline void transform_reduce(InputIterator1 first1,
  61                              InputIterator1 last1,
  62                              InputIterator2 first2,
  63                              OutputIterator result,
  64                              BinaryTransformFunction transform_function,
  65                              BinaryReduceFunction reduce_function,
  66                              command_queue &queue = system::default_queue())
  67 {
  68     typedef typename std::iterator_traits<InputIterator1>::difference_type difference_type;
  69
  70     difference_type n = std::distance(first1, last1);
  71
  72     ::boost::compute::transform_reduce(
  73         ::boost::compute::make_zip_iterator(
  74             boost::make_tuple(first1, first2)
  75         ),
  76         ::boost::compute::make_zip_iterator(
  77             boost::make_tuple(last1, first2 + n)
  78         ),
  79         result,
  80         detail::unpack(transform_function),
  81         reduce_function,
  82         queue
  83     );
  84 }
  85
  86 } // end compute namespace
  87 } // end boost namespace
  88
  89 #endif // BOOST_COMPUTE_ALGORITHM_TRANSFORM_REDUCE_HPP