/usr/include/boost/compute/algorithm
Edit: /usr/include/boost/compute/algorithm/merge.hpp (5037B)
//---------------------------------------------------------------------------//
// Copyright (c) 2013 Kyle Lutz
//
// 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_MERGE_HPP
#define BOOST_COMPUTE_ALGORITHM_MERGE_HPP
#include
#include
#include
#include
#include
#include
#include
#include
#include
namespace boost {
namespace compute {
/// Merges the sorted values in the range [\p first1, \p last1) with the sorted
/// values in the range [\p first2, last2) and stores the result in the range
/// beginning at \p result. Values are compared using the \p comp function. If
/// no comparision function is given, \c less is used.
///
/// \param first1 first element in the first range to merge
/// \param last1 last element in the first range to merge
/// \param first2 first element in the second range to merge
/// \param last2 last element in the second range to merge
/// \param result first element in the result range
/// \param comp comparison function (by default \c less)
/// \param queue command queue to perform the operation
///
/// \return \c OutputIterator to the end of the result range
///
/// Space complexity: \Omega(distance(\p first1, \p last1) + distance(\p first2, \p last2))
///
/// \see inplace_merge()
template
inline OutputIterator merge(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
InputIterator2 last2,
OutputIterator result,
Compare comp,
command_queue &queue = system::default_queue())
{
BOOST_STATIC_ASSERT(is_device_iterator::value);
BOOST_STATIC_ASSERT(is_device_iterator::value);
BOOST_STATIC_ASSERT(is_device_iterator::value);
typedef typename std::iterator_traits::value_type input1_type;
typedef typename std::iterator_traits::value_type input2_type;
typedef typename std::iterator_traits::value_type output_type;
const device &device = queue.get_device();
std::string cache_key =
std::string("__boost_merge_") + type_name() + "_"
+ type_name() + "_" + type_name();
boost::shared_ptr parameters =
detail::parameter_cache::get_global_cache(device);
// default serial merge threshold depends on device type
size_t default_serial_merge_threshold = 32768;
if(device.type() & device::gpu) {
default_serial_merge_threshold = 2048;
}
// loading serial merge threshold parameter
const size_t serial_merge_threshold =
parameters->get(cache_key, "serial_merge_threshold",
static_cast(default_serial_merge_threshold));
// choosing merge algorithm
const size_t total_count =
detail::iterator_range_size(first1, last1)
+ detail::iterator_range_size(first2, last2);
// for small inputs serial merge turns out to outperform
// merge with merge path algorithm
if(total_count <= serial_merge_threshold){
return detail::serial_merge(first1, last1, first2, last2, result, comp, queue);
}
return detail::merge_with_merge_path(first1, last1, first2, last2, result, comp, queue);
}
/// \overload
template
inline OutputIterator merge(InputIterator1 first1,
InputIterator1 last1,
InputIterator2 first2,
InputIterator2 last2,
OutputIterator result,
command_queue &queue = system::default_queue())
{
BOOST_STATIC_ASSERT(is_device_iterator::value);
BOOST_STATIC_ASSERT(is_device_iterator::value);
BOOST_STATIC_ASSERT(is_device_iterator::value);
typedef typename std::iterator_traits::value_type value_type;
less less_than;
return merge(first1, last1, first2, last2, result, less_than, queue);
}
} // end compute namespace
} // end boost namespace
#endif // BOOST_COMPUTE_ALGORITHM_MERGE_HPP