ceph/src/boost/boost/compute/algorithm/inclusive_scan.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_INCLUSIVE_SCAN_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_INCLUSIVE_SCAN_HPP
  13
  14 #include <boost/compute/functional.hpp>
  15 #include <boost/compute/system.hpp>
  16 #include <boost/compute/command_queue.hpp>
  17 #include <boost/compute/algorithm/detail/scan.hpp>
  18
  19 namespace boost {
  20 namespace compute {
  21
  22 /// Performs an inclusive scan of the elements in the range [\p first, \p last)
  23 /// and stores the results in the range beginning at \p result.
  24 ///
  25 /// Each element in the output is assigned to the sum of the current value in
  26 /// the input with the sum of every previous value in the input.
  27 ///
  28 /// \param first first element in the range to scan
  29 /// \param last last element in the range to scan
  30 /// \param result first element in the result range
  31 /// \param binary_op associative binary operator
  32 /// \param queue command queue to perform the operation
  33 ///
  34 /// \return \c OutputIterator to the end of the result range
  35 ///
  36 /// The default operation is to add the elements up.
  37 ///
  38 /// \snippet test/test_scan.cpp inclusive_scan_int
  39 ///
  40 /// But different associative operation can be specified as \p binary_op
  41 /// instead (e.g., multiplication, maximum, minimum).
  42 ///
  43 /// \snippet test/test_scan.cpp inclusive_scan_int_multiplies
  44 ///
  45 /// Space complexity on GPUs: \Omega(n)<br>
  46 /// Space complexity on GPUs when \p first == \p result: \Omega(2n)<br>
  47 /// Space complexity on CPUs: \Omega(1)
  48 ///
  49 /// \see exclusive_scan()
  50 template<class InputIterator, class OutputIterator, class BinaryOperator>
  51 inline OutputIterator
  52 inclusive_scan(InputIterator first,
  53                InputIterator last,
  54                OutputIterator result,
  55                BinaryOperator binary_op,
  56                command_queue &queue = system::default_queue())
  57 {
  58     typedef typename
  59         std::iterator_traits<OutputIterator>::value_type output_type;
  60
  61     return detail::scan(first, last, result, false,
  62                         output_type(0), binary_op,
  63                         queue);
  64 }
  65
  66 /// \overload
  67 template<class InputIterator, class OutputIterator>
  68 inline OutputIterator
  69 inclusive_scan(InputIterator first,
  70                InputIterator last,
  71                OutputIterator result,
  72                command_queue &queue = system::default_queue())
  73 {
  74     typedef typename
  75         std::iterator_traits<OutputIterator>::value_type output_type;
  76
  77     return detail::scan(first, last, result, false,
  78                         output_type(0), boost::compute::plus<output_type>(),
  79                         queue);
  80 }
  81
  82 } // end compute namespace
  83 } // end boost namespace
  84
  85 #endif // BOOST_COMPUTE_ALGORITHM_INCLUSIVE_SCAN_HPP