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//---------------------------------------------------------------------------//
// Copyright (c) 2015 Jakub Pola <jakub.pola@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_SCATTER_IF_HPP
#define BOOST_COMPUTE_ALGORITHM_SCATTER_IF_HPP
#include <boost/algorithm/string/replace.hpp>
#include <boost/compute/system.hpp>
#include <boost/compute/exception.hpp>
#include <boost/compute/command_queue.hpp>
#include <boost/compute/iterator/buffer_iterator.hpp>
#include <boost/compute/type_traits/type_name.hpp>
#include <boost/compute/detail/iterator_range_size.hpp>
#include <boost/compute/detail/meta_kernel.hpp>
namespace boost {
namespace compute {
namespace detail {
template<class InputIterator, class MapIterator, class StencilIterator, class OutputIterator, class Predicate>
class scatter_if_kernel : meta_kernel
{
public:
scatter_if_kernel() : meta_kernel("scatter_if")
{}
void set_range(InputIterator first,
InputIterator last,
MapIterator map,
StencilIterator stencil,
OutputIterator result,
Predicate predicate)
{
m_count = iterator_range_size(first, last);
m_input_offset = first.get_index();
m_output_offset = result.get_index();
m_input_offset_arg = add_arg<uint_>("input_offset");
m_output_offset_arg = add_arg<uint_>("output_offset");
*this <<
"const uint i = get_global_id(0);\n" <<
"uint i1 = " << map[expr<uint_>("i")] <<
" + output_offset;\n" <<
"uint i2 = i + input_offset;\n" <<
if_(predicate(stencil[expr<uint_>("i")])) << "\n" <<
result[expr<uint_>("i1")] << "=" <<
first[expr<uint_>("i2")] << ";\n";
}
event exec(command_queue &queue)
{
if(m_count == 0) {
return event();
}
set_arg(m_input_offset_arg, uint_(m_input_offset));
set_arg(m_output_offset_arg, uint_(m_output_offset));
return exec_1d(queue, 0, m_count);
}
private:
size_t m_count;
size_t m_input_offset;
size_t m_input_offset_arg;
size_t m_output_offset;
size_t m_output_offset_arg;
};
} // end detail namespace
/// Copies the elements from the range [\p first, \p last) to the range
/// beginning at \p result using the output indices from the range beginning
/// at \p map if stencil is resolved to true. By default the predicate is
/// an identity
///
/// Space complexity: \Omega(1)
template<class InputIterator, class MapIterator, class StencilIterator, class OutputIterator,
class Predicate>
inline void scatter_if(InputIterator first,
InputIterator last,
MapIterator map,
StencilIterator stencil,
OutputIterator result,
Predicate predicate,
command_queue &queue = system::default_queue())
{
detail::scatter_if_kernel<InputIterator, MapIterator, StencilIterator, OutputIterator, Predicate> kernel;
kernel.set_range(first, last, map, stencil, result, predicate);
kernel.exec(queue);
}
template<class InputIterator, class MapIterator, class StencilIterator, class OutputIterator>
inline void scatter_if(InputIterator first,
InputIterator last,
MapIterator map,
StencilIterator stencil,
OutputIterator result,
command_queue &queue = system::default_queue())
{
typedef typename std::iterator_traits<StencilIterator>::value_type T;
scatter_if(first, last, map, stencil, result, identity<T>(), queue);
}
} // end compute namespace
} // end boost namespace
#endif // BOOST_COMPUTE_ALGORITHM_SCATTER_IF_HPP
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