//---------------------------------------------------------------------------//
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// Copyright (c) 2015 Jakub Szuppe <j.szuppe@gmail.com>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// See http://boostorg.github.com/compute for more information.
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//---------------------------------------------------------------------------//
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#ifndef BOOST_COMPUTE_ALGORITHM_DETAIL_REDUCE_BY_KEY_HPP
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#define BOOST_COMPUTE_ALGORITHM_DETAIL_REDUCE_BY_KEY_HPP
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#include <algorithm>
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#include <iterator>
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#include <boost/compute/command_queue.hpp>
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#include <boost/compute/functional.hpp>
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#include <boost/compute/container/vector.hpp>
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#include <boost/compute/detail/iterator_range_size.hpp>
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#include <boost/compute/algorithm/detail/serial_reduce_by_key.hpp>
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#include <boost/compute/algorithm/detail/reduce_by_key_with_scan.hpp>
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#include <boost/compute/type_traits.hpp>
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namespace boost {
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namespace compute {
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namespace detail {
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template<class InputKeyIterator, class InputValueIterator,
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class OutputKeyIterator, class OutputValueIterator,
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class BinaryFunction, class BinaryPredicate>
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size_t reduce_by_key_on_gpu(InputKeyIterator keys_first,
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InputKeyIterator keys_last,
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InputValueIterator values_first,
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OutputKeyIterator keys_result,
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OutputValueIterator values_result,
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BinaryFunction function,
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BinaryPredicate predicate,
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command_queue &queue)
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{
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return detail::reduce_by_key_with_scan(keys_first, keys_last, values_first,
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keys_result, values_result, function,
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predicate, queue);
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}
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template<class InputKeyIterator, class InputValueIterator,
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class OutputKeyIterator, class OutputValueIterator>
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bool reduce_by_key_on_gpu_requirements_met(InputKeyIterator keys_first,
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InputValueIterator values_first,
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OutputKeyIterator keys_result,
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OutputValueIterator values_result,
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const size_t count,
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command_queue &queue)
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{
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const device &device = queue.get_device();
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return (count > 256)
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&& !(device.type() & device::cpu)
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&& reduce_by_key_with_scan_requirements_met(keys_first, values_first,
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keys_result,values_result,
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count, queue);
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return true;
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}
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template<class InputKeyIterator, class InputValueIterator,
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class OutputKeyIterator, class OutputValueIterator,
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class BinaryFunction, class BinaryPredicate>
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inline std::pair<OutputKeyIterator, OutputValueIterator>
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dispatch_reduce_by_key(InputKeyIterator keys_first,
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InputKeyIterator keys_last,
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InputValueIterator values_first,
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OutputKeyIterator keys_result,
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OutputValueIterator values_result,
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BinaryFunction function,
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BinaryPredicate predicate,
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command_queue &queue)
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{
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typedef typename
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std::iterator_traits<OutputKeyIterator>::difference_type key_difference_type;
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typedef typename
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std::iterator_traits<OutputValueIterator>::difference_type value_difference_type;
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const size_t count = detail::iterator_range_size(keys_first, keys_last);
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if (count < 2) {
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boost::compute::copy_n(keys_first, count, keys_result, queue);
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boost::compute::copy_n(values_first, count, values_result, queue);
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return
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std::make_pair<OutputKeyIterator, OutputValueIterator>(
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keys_result + static_cast<key_difference_type>(count),
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values_result + static_cast<value_difference_type>(count)
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);
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}
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size_t result_size = 0;
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if(reduce_by_key_on_gpu_requirements_met(keys_first, values_first, keys_result,
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values_result, count, queue)){
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result_size =
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detail::reduce_by_key_on_gpu(keys_first, keys_last, values_first,
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keys_result, values_result, function,
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predicate, queue);
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}
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else {
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result_size =
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detail::serial_reduce_by_key(keys_first, keys_last, values_first,
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keys_result, values_result, function,
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predicate, queue);
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}
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return
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std::make_pair<OutputKeyIterator, OutputValueIterator>(
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keys_result + static_cast<key_difference_type>(result_size),
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values_result + static_cast<value_difference_type>(result_size)
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);
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}
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} // end detail namespace
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} // end compute namespace
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} // end boost namespace
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#endif // BOOST_COMPUTE_ALGORITHM_DETAIL_REDUCE_BY_KEY_HPP
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