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Diffstat (limited to 'boost/compute/algorithm/detail/balanced_path.hpp')
| -rw-r--r-- | boost/compute/algorithm/detail/balanced_path.hpp | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/boost/compute/algorithm/detail/balanced_path.hpp b/boost/compute/algorithm/detail/balanced_path.hpp new file mode 100644 index 0000000000..e5025532d3 --- /dev/null +++ b/boost/compute/algorithm/detail/balanced_path.hpp @@ -0,0 +1,162 @@ +//---------------------------------------------------------------------------// +// Copyright (c) 2014 Roshan <thisisroshansmail@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_BALANCED_PATH_HPP +#define BOOST_COMPUTE_ALGORITHM_DETAIL_BALANCED_PATH_HPP + +#include <iterator> + +#include <boost/compute/algorithm/find_if.hpp> +#include <boost/compute/container/vector.hpp> +#include <boost/compute/detail/iterator_range_size.hpp> +#include <boost/compute/detail/meta_kernel.hpp> +#include <boost/compute/lambda.hpp> +#include <boost/compute/system.hpp> + +namespace boost { +namespace compute { +namespace detail { + +/// +/// \brief Balanced Path kernel class +/// +/// Subclass of meta_kernel to break two sets into tiles according +/// to their balanced path. +/// +class balanced_path_kernel : public meta_kernel +{ +public: + unsigned int tile_size; + + balanced_path_kernel() : meta_kernel("balanced_path") + { + tile_size = 4; + } + + template<class InputIterator1, class InputIterator2, + class OutputIterator1, class OutputIterator2, + class Compare> + void set_range(InputIterator1 first1, + InputIterator1 last1, + InputIterator2 first2, + InputIterator2 last2, + OutputIterator1 result_a, + OutputIterator2 result_b, + Compare comp) + { + typedef typename std::iterator_traits<InputIterator1>::value_type value_type; + + m_a_count = iterator_range_size(first1, last1); + m_a_count_arg = add_arg<uint_>("a_count"); + + m_b_count = iterator_range_size(first2, last2); + m_b_count_arg = add_arg<uint_>("b_count"); + + *this << + "uint i = get_global_id(0);\n" << + "uint target = (i+1)*" << tile_size << ";\n" << + "uint start = max(convert_int(0),convert_int(target)-convert_int(b_count));\n" << + "uint end = min(target,a_count);\n" << + "uint a_index, b_index;\n" << + "while(start<end)\n" << + "{\n" << + " a_index = (start + end)/2;\n" << + " b_index = target - a_index - 1;\n" << + " if(!(" << comp(first2[expr<uint_>("b_index")], + first1[expr<uint_>("a_index")]) << "))\n" << + " start = a_index + 1;\n" << + " else end = a_index;\n" << + "}\n" << + "a_index = start;\n" << + "b_index = target - start;\n" << + "if(b_index < b_count)\n" << + "{\n" << + " " << decl<const value_type>("x") << " = " << + first2[expr<uint_>("b_index")] << ";\n" << + " uint a_start = 0, a_end = a_index, a_mid;\n" << + " uint b_start = 0, b_end = b_index, b_mid;\n" << + " while(a_start<a_end)\n" << + " {\n" << + " a_mid = (a_start + a_end)/2;\n" << + " if(" << comp(first1[expr<uint_>("a_mid")], expr<value_type>("x")) << ")\n" << + " a_start = a_mid+1;\n" << + " else a_end = a_mid;\n" << + " }\n" << + " while(b_start<b_end)\n" << + " {\n" << + " b_mid = (b_start + b_end)/2;\n" << + " if(" << comp(first2[expr<uint_>("b_mid")], expr<value_type>("x")) << ")\n" << + " b_start = b_mid+1;\n" << + " else b_end = b_mid;\n" << + " }\n" << + " uint a_run = a_index - a_start;\n" << + " uint b_run = b_index - b_start;\n" << + " uint x_count = a_run + b_run;\n" << + " uint b_advance = max(x_count / 2, x_count - a_run);\n" << + " b_end = min(b_count, b_start + b_advance + 1);\n" << + " uint temp_start = b_index, temp_end = b_end, temp_mid;" << + " while(temp_start < temp_end)\n" << + " {\n" << + " temp_mid = (temp_start + temp_end + 1)/2;\n" << + " if(" << comp(expr<value_type>("x"), first2[expr<uint_>("temp_mid")]) << ")\n" << + " temp_end = temp_mid-1;\n" << + " else temp_start = temp_mid;\n" << + " }\n" << + " b_run = temp_start - b_start + 1;\n" << + " b_advance = min(b_advance, b_run);\n" << + " uint a_advance = x_count - b_advance;\n" << + " uint star = convert_uint((a_advance == b_advance + 1) " << + "&& (b_advance < b_run));\n" << + " a_index = a_start + a_advance;\n" << + " b_index = target - a_index + star;\n" << + "}\n" << + result_a[expr<uint_>("i")] << " = a_index;\n" << + result_b[expr<uint_>("i")] << " = b_index;\n"; + + } + + template<class InputIterator1, class InputIterator2, + class OutputIterator1, class OutputIterator2> + void set_range(InputIterator1 first1, + InputIterator1 last1, + InputIterator2 first2, + InputIterator2 last2, + OutputIterator1 result_a, + OutputIterator2 result_b) + { + typedef typename std::iterator_traits<InputIterator1>::value_type value_type; + ::boost::compute::less<value_type> less_than; + set_range(first1, last1, first2, last2, result_a, result_b, less_than); + } + + event exec(command_queue &queue) + { + if((m_a_count + m_b_count)/tile_size == 0) { + return event(); + } + + set_arg(m_a_count_arg, uint_(m_a_count)); + set_arg(m_b_count_arg, uint_(m_b_count)); + + return exec_1d(queue, 0, (m_a_count + m_b_count)/tile_size); + } + +private: + size_t m_a_count; + size_t m_a_count_arg; + size_t m_b_count; + size_t m_b_count_arg; +}; + +} //end detail namespace +} //end compute namespace +} //end boost namespace + +#endif // BOOST_COMPUTE_ALGORITHM_DETAIL_BALANCED_PATH_HPP |