//---------------------------------------------------------------------------// // 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_UNIQUE_COPY_HPP #define BOOST_COMPUTE_ALGORITHM_UNIQUE_COPY_HPP #include <boost/compute/command_queue.hpp> #include <boost/compute/lambda.hpp> #include <boost/compute/system.hpp> #include <boost/compute/algorithm/copy_if.hpp> #include <boost/compute/algorithm/transform.hpp> #include <boost/compute/algorithm/gather.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/functional/operator.hpp> namespace boost { namespace compute { namespace detail { template<class InputIterator, class OutputIterator, class BinaryPredicate> inline OutputIterator serial_unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate op, command_queue &queue) { if(first == last){ return result; } typedef typename std::iterator_traits<InputIterator>::value_type value_type; const context &context = queue.get_context(); size_t count = detail::iterator_range_size(first, last); detail::meta_kernel k("serial_unique_copy"); vector<uint_> unique_count_vector(1, context); size_t size_arg = k.add_arg<const uint_>("size"); size_t unique_count_arg = k.add_arg<uint_ *>(memory_object::global_memory, "unique_count"); k << k.decl<uint_>("index") << " = 0;\n" << k.decl<value_type>("current") << " = " << first[k.var<uint_>("0")] << ";\n" << result[k.var<uint_>("0")] << " = current;\n" << "for(uint i = 1; i < size; i++){\n" << " " << k.decl<value_type>("next") << " = " << first[k.var<uint_>("i")] << ";\n" << " if(!" << op(k.var<value_type>("current"), k.var<value_type>("next")) << "){\n" << " " << result[k.var<uint_>("++index")] << " = next;\n" << " " << "current = next;\n" << " }\n" << "}\n" << "*unique_count = index + 1;\n"; k.set_arg<const uint_>(size_arg, count); k.set_arg(unique_count_arg, unique_count_vector.get_buffer()); k.exec_1d(queue, 0, 1, 1); uint_ unique_count; copy_n(unique_count_vector.begin(), 1, &unique_count, queue); return result + unique_count; } template<class InputIterator, class OutputIterator, class BinaryPredicate> inline OutputIterator unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate op, command_queue &queue) { if(first == last){ return result; } const context &context = queue.get_context(); size_t count = detail::iterator_range_size(first, last); // flags marking unique elements vector<uint_> flags(count, context); // find each unique element and mark it with a one transform( first, last - 1, first + 1, flags.begin() + 1, not2(op), queue ); // first element is always unique fill_n(flags.begin(), 1, 1, queue); // storage for desination indices vector<uint_> indices(count, context); // copy indices for each unique element vector<uint_>::iterator last_index = detail::copy_index_if( flags.begin(), flags.end(), indices.begin(), lambda::_1 == 1, queue ); // copy unique values from input to output using the computed indices gather(indices.begin(), last_index, first, result, queue); // return an iterator to the end of the unique output range return result + std::distance(indices.begin(), last_index); } } // end detail namespace /// Makes a copy of the range [first, last) and removes all consecutive /// duplicate elements (determined by \p op) from the copy. If \p op is not /// provided, the equality operator is used. /// /// \param first first element in the input range /// \param last last element in the input range /// \param result first element in the result range /// \param op binary operator used to check for uniqueness /// \param queue command queue to perform the operation /// /// \return \c OutputIterator to the end of the result range /// /// \see unique() template<class InputIterator, class OutputIterator, class BinaryPredicate> inline OutputIterator unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate op, command_queue &queue = system::default_queue()) { size_t count = detail::iterator_range_size(first, last); if(count < 32){ return detail::serial_unique_copy(first, last, result, op, queue); } else { return detail::unique_copy(first, last, result, op, queue); } } /// \overload template<class InputIterator, class OutputIterator> inline OutputIterator unique_copy(InputIterator first, InputIterator last, OutputIterator result, command_queue &queue = system::default_queue()) { typedef typename std::iterator_traits<InputIterator>::value_type value_type; return ::boost::compute::unique_copy( first, last, result, ::boost::compute::equal_to<value_type>(), queue ); } } // end compute namespace } // end boost namespace #endif // BOOST_COMPUTE_ALGORITHM_UNIQUE_COPY_HPP