139 lines
5.3 KiB
Plaintext
139 lines
5.3 KiB
Plaintext
//---------------------------------------------------------------------------//
|
|
// Copyright (c) 2016 Jakub Szuppe <j.szuppe@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_FIND_EXTREMA_ON_CPU_HPP
|
|
#define BOOST_COMPUTE_ALGORITHM_DETAIL_FIND_EXTREMA_ON_CPU_HPP
|
|
|
|
#include <algorithm>
|
|
|
|
#include <boost/compute/algorithm/detail/find_extrema_with_reduce.hpp>
|
|
#include <boost/compute/algorithm/detail/find_extrema_with_atomics.hpp>
|
|
#include <boost/compute/algorithm/detail/serial_find_extrema.hpp>
|
|
#include <boost/compute/detail/iterator_range_size.hpp>
|
|
#include <boost/compute/iterator/buffer_iterator.hpp>
|
|
|
|
namespace boost {
|
|
namespace compute {
|
|
namespace detail {
|
|
|
|
template<class InputIterator, class Compare>
|
|
inline InputIterator find_extrema_on_cpu(InputIterator first,
|
|
InputIterator last,
|
|
Compare compare,
|
|
const bool find_minimum,
|
|
command_queue &queue)
|
|
{
|
|
typedef typename std::iterator_traits<InputIterator>::value_type input_type;
|
|
typedef typename std::iterator_traits<InputIterator>::difference_type difference_type;
|
|
size_t count = iterator_range_size(first, last);
|
|
|
|
const device &device = queue.get_device();
|
|
const uint_ compute_units = queue.get_device().compute_units();
|
|
|
|
boost::shared_ptr<parameter_cache> parameters =
|
|
detail::parameter_cache::get_global_cache(device);
|
|
std::string cache_key =
|
|
"__boost_find_extrema_cpu_"
|
|
+ boost::lexical_cast<std::string>(sizeof(input_type));
|
|
|
|
// for inputs smaller than serial_find_extrema_threshold
|
|
// serial_find_extrema algorithm is used
|
|
uint_ serial_find_extrema_threshold = parameters->get(
|
|
cache_key,
|
|
"serial_find_extrema_threshold",
|
|
16384 * sizeof(input_type)
|
|
);
|
|
serial_find_extrema_threshold =
|
|
(std::max)(serial_find_extrema_threshold, uint_(2 * compute_units));
|
|
|
|
const context &context = queue.get_context();
|
|
if(count < serial_find_extrema_threshold) {
|
|
return serial_find_extrema(first, last, compare, find_minimum, queue);
|
|
}
|
|
|
|
meta_kernel k("find_extrema_on_cpu");
|
|
buffer output(context, sizeof(input_type) * compute_units);
|
|
buffer output_idx(
|
|
context, sizeof(uint_) * compute_units,
|
|
buffer::read_write | buffer::alloc_host_ptr
|
|
);
|
|
|
|
size_t count_arg = k.add_arg<uint_>("count");
|
|
size_t output_arg =
|
|
k.add_arg<input_type *>(memory_object::global_memory, "output");
|
|
size_t output_idx_arg =
|
|
k.add_arg<uint_ *>(memory_object::global_memory, "output_idx");
|
|
|
|
k <<
|
|
"uint block = " <<
|
|
"(uint)ceil(((float)count)/get_global_size(0));\n" <<
|
|
"uint index = get_global_id(0) * block;\n" <<
|
|
"uint end = min(count, index + block);\n" <<
|
|
|
|
"uint value_index = index;\n" <<
|
|
k.decl<input_type>("value") << " = " << first[k.var<uint_>("index")] << ";\n" <<
|
|
|
|
"index++;\n" <<
|
|
"while(index < end){\n" <<
|
|
k.decl<input_type>("candidate") <<
|
|
" = " << first[k.var<uint_>("index")] << ";\n" <<
|
|
"#ifndef BOOST_COMPUTE_FIND_MAXIMUM\n" <<
|
|
"bool compare = " << compare(k.var<input_type>("candidate"),
|
|
k.var<input_type>("value")) << ";\n" <<
|
|
"#else\n" <<
|
|
"bool compare = " << compare(k.var<input_type>("value"),
|
|
k.var<input_type>("candidate")) << ";\n" <<
|
|
"#endif\n" <<
|
|
"value = compare ? candidate : value;\n" <<
|
|
"value_index = compare ? index : value_index;\n" <<
|
|
"index++;\n" <<
|
|
"}\n" <<
|
|
"output[get_global_id(0)] = value;\n" <<
|
|
"output_idx[get_global_id(0)] = value_index;\n";
|
|
|
|
size_t global_work_size = compute_units;
|
|
std::string options;
|
|
if(!find_minimum){
|
|
options = "-DBOOST_COMPUTE_FIND_MAXIMUM";
|
|
}
|
|
kernel kernel = k.compile(context, options);
|
|
|
|
kernel.set_arg(count_arg, static_cast<uint_>(count));
|
|
kernel.set_arg(output_arg, output);
|
|
kernel.set_arg(output_idx_arg, output_idx);
|
|
queue.enqueue_1d_range_kernel(kernel, 0, global_work_size, 0);
|
|
|
|
buffer_iterator<input_type> result = serial_find_extrema(
|
|
make_buffer_iterator<input_type>(output),
|
|
make_buffer_iterator<input_type>(output, global_work_size),
|
|
compare,
|
|
find_minimum,
|
|
queue
|
|
);
|
|
|
|
uint_* output_idx_host_ptr =
|
|
static_cast<uint_*>(
|
|
queue.enqueue_map_buffer(
|
|
output_idx, command_queue::map_read,
|
|
0, global_work_size * sizeof(uint_)
|
|
)
|
|
);
|
|
|
|
difference_type extremum_idx =
|
|
static_cast<difference_type>(*(output_idx_host_ptr + result.get_index()));
|
|
return first + extremum_idx;
|
|
}
|
|
|
|
} // end detail namespace
|
|
} // end compute namespace
|
|
} // end boost namespace
|
|
|
|
#endif // BOOST_COMPUTE_ALGORITHM_DETAIL_FIND_EXTREMA_ON_CPU_HPP
|