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- //---------------------------------------------------------------------------//
- // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com>
- //
- // Distributed under the Boost Software License, Version 1.0
- // See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt
- //
- // See http://boostorg.github.com/compute for more information.
- //---------------------------------------------------------------------------//
- #ifndef BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_SCAN_HPP
- #define BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_SCAN_HPP
- #include <iterator>
- #include <boost/compute/device.hpp>
- #include <boost/compute/kernel.hpp>
- #include <boost/compute/command_queue.hpp>
- #include <boost/compute/detail/meta_kernel.hpp>
- #include <boost/compute/detail/iterator_range_size.hpp>
- namespace boost {
- namespace compute {
- namespace detail {
- template<class InputIterator, class OutputIterator, class T, class BinaryOperator>
- inline OutputIterator serial_scan(InputIterator first,
- InputIterator last,
- OutputIterator result,
- bool exclusive,
- T init,
- BinaryOperator op,
- command_queue &queue)
- {
- if(first == last){
- return result;
- }
- typedef typename
- std::iterator_traits<InputIterator>::value_type input_type;
- typedef typename
- std::iterator_traits<OutputIterator>::value_type output_type;
- const context &context = queue.get_context();
- // create scan kernel
- meta_kernel k("serial_scan");
- // Arguments
- size_t n_arg = k.add_arg<ulong_>("n");
- size_t init_arg = k.add_arg<output_type>("initial_value");
- if(!exclusive){
- k <<
- k.decl<const ulong_>("start_idx") << " = 1;\n" <<
- k.decl<output_type>("sum") << " = " << first[0] << ";\n" <<
- result[0] << " = sum;\n";
- }
- else {
- k <<
- k.decl<const ulong_>("start_idx") << " = 0;\n" <<
- k.decl<output_type>("sum") << " = initial_value;\n";
- }
- k <<
- "for(ulong i = start_idx; i < n; i++){\n" <<
- k.decl<const input_type>("x") << " = "
- << first[k.var<ulong_>("i")] << ";\n";
- if(exclusive){
- k << result[k.var<ulong_>("i")] << " = sum;\n";
- }
- k << " sum = "
- << op(k.var<output_type>("sum"), k.var<output_type>("x"))
- << ";\n";
- if(!exclusive){
- k << result[k.var<ulong_>("i")] << " = sum;\n";
- }
- k << "}\n";
- // compile scan kernel
- kernel scan_kernel = k.compile(context);
- // setup kernel arguments
- size_t n = detail::iterator_range_size(first, last);
- scan_kernel.set_arg<ulong_>(n_arg, n);
- scan_kernel.set_arg<output_type>(init_arg, static_cast<output_type>(init));
- // execute the kernel
- queue.enqueue_1d_range_kernel(scan_kernel, 0, 1, 1);
- // return iterator pointing to the end of the result range
- return result + n;
- }
- } // end detail namespace
- } // end compute namespace
- } // end boost namespace
- #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_SCAN_HPP
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