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Diffstat (limited to 'boost/compute/algorithm/gather.hpp')
-rw-r--r-- | boost/compute/algorithm/gather.hpp | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/boost/compute/algorithm/gather.hpp b/boost/compute/algorithm/gather.hpp new file mode 100644 index 0000000000..b2f725d54e --- /dev/null +++ b/boost/compute/algorithm/gather.hpp @@ -0,0 +1,84 @@ +//---------------------------------------------------------------------------// +// 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_GATHER_HPP +#define BOOST_COMPUTE_ALGORITHM_GATHER_HPP + +#include <boost/compute/command_queue.hpp> +#include <boost/compute/detail/iterator_range_size.hpp> +#include <boost/compute/detail/meta_kernel.hpp> +#include <boost/compute/exception.hpp> +#include <boost/compute/iterator/buffer_iterator.hpp> +#include <boost/compute/system.hpp> +#include <boost/compute/type_traits/type_name.hpp> + +namespace boost { +namespace compute { +namespace detail { + +template<class InputIterator, class MapIterator, class OutputIterator> +class gather_kernel : public meta_kernel +{ +public: + gather_kernel() : meta_kernel("gather") + {} + + void set_range(MapIterator first, + MapIterator last, + InputIterator input, + OutputIterator result) + { + m_count = iterator_range_size(first, last); + m_offset = first.get_index(); + + *this << + "const uint i = get_global_id(0);\n" << + result[expr<uint_>("i")] << "=" << + input[first[expr<uint_>("i")]] << ";\n"; + } + + event exec(command_queue &queue) + { + if(m_count == 0) { + return event(); + } + + return exec_1d(queue, m_offset, m_count); + } + +private: + size_t m_count; + size_t m_offset; +}; + +} // end detail namespace + +/// Copies the elements using the indices from the range [\p first, \p last) +/// to the range beginning at \p result using the input values from the range +/// beginning at \p input. +/// +/// \see scatter() +template<class InputIterator, class MapIterator, class OutputIterator> +inline void gather(MapIterator first, + MapIterator last, + InputIterator input, + OutputIterator result, + command_queue &queue = system::default_queue()) +{ + detail::gather_kernel<InputIterator, MapIterator, OutputIterator> kernel; + + kernel.set_range(first, last, input, result); + kernel.exec(queue); +} + +} // end compute namespace +} // end boost namespace + +#endif // BOOST_COMPUTE_ALGORITHM_GATHER_HPP |