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//---------------------------------------------------------------------------//
// 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_DETAIL_SERIAL_FIND_EXTREMA_HPP
#define BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_FIND_EXTREMA_HPP
#include <boost/compute/command_queue.hpp>
#include <boost/compute/types/fundamental.hpp>
#include <boost/compute/detail/meta_kernel.hpp>
#include <boost/compute/detail/iterator_range_size.hpp>
#include <boost/compute/container/detail/scalar.hpp>
namespace boost {
namespace compute {
namespace detail {
template<class InputIterator, class Compare>
inline InputIterator serial_find_extrema(InputIterator first,
InputIterator last,
Compare compare,
const bool find_minimum,
command_queue &queue)
{
typedef typename std::iterator_traits<InputIterator>::value_type value_type;
typedef typename std::iterator_traits<InputIterator>::difference_type difference_type;
const context &context = queue.get_context();
meta_kernel k("serial_find_extrema");
k <<
k.decl<value_type>("value") << " = " << first[k.expr<uint_>("0")] << ";\n" <<
k.decl<uint_>("value_index") << " = 0;\n" <<
"for(uint i = 1; i < size; i++){\n" <<
" " << k.decl<value_type>("candidate") << "="
<< first[k.expr<uint_>("i")] << ";\n" <<
"#ifndef BOOST_COMPUTE_FIND_MAXIMUM\n" <<
" if(" << compare(k.var<value_type>("candidate"),
k.var<value_type>("value")) << "){\n" <<
"#else\n" <<
" if(" << compare(k.var<value_type>("value"),
k.var<value_type>("candidate")) << "){\n" <<
"#endif\n" <<
" value = candidate;\n" <<
" value_index = i;\n" <<
" }\n" <<
"}\n" <<
"*index = value_index;\n";
size_t index_arg_index = k.add_arg<uint_ *>(memory_object::global_memory, "index");
size_t size_arg_index = k.add_arg<uint_>("size");
std::string options;
if(!find_minimum){
options = "-DBOOST_COMPUTE_FIND_MAXIMUM";
}
kernel kernel = k.compile(context, options);
// setup index buffer
scalar<uint_> index(context);
kernel.set_arg(index_arg_index, index.get_buffer());
// setup count
size_t count = iterator_range_size(first, last);
kernel.set_arg(size_arg_index, static_cast<uint_>(count));
// run kernel
queue.enqueue_task(kernel);
// read index and return iterator
return first + static_cast<difference_type>(index.read(queue));
}
} // end detail namespace
} // end compute namespace
} // end boost namespace
#endif // BOOST_COMPUTE_ALGORITHM_DETAIL_SERIAL_FIND_EXTREMA_HPP
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