inline void radix_sort_impl(const buffer_iterator<T> first,
const buffer_iterator<T> last,
const buffer_iterator<T2> values_first,
const bool ascending,
command_queue &queue)
{
typedef T value_type;
typedef typename radix_sort_value_type<sizeof(T)>::type sort_type;
const device &device = queue.get_device();
const context &context = queue.get_context();
// if we have a valid values iterator then we are doing a
// sort by key and have to set up the values buffer
bool sort_by_key = (values_first.get_buffer().get() != 0);
// load (or create) radix sort program
std::string cache_key =
std::string("__boost_radix_sort_") + type_name<value_type>();
if(sort_by_key){
cache_key += std::string("_with_") + type_name<T2>();
}
boost::shared_ptr<program_cache> cache =
program_cache::get_global_cache(context);
boost::shared_ptr<parameter_cache> parameters =
detail::parameter_cache::get_global_cache(device);
// sort parameters
const uint_ k = parameters->get(cache_key, "k", 4);
const uint_ k2 = 1 << k;
const uint_ block_size = parameters->get(cache_key, "tpb", 128);
// sort program compiler options
std::stringstream options;
options << "-DK_BITS=" << k;
options << " -DT=" << type_name<sort_type>();
options << " -DBLOCK_SIZE=" << block_size;
if(boost::is_floating_point<value_type>::value){
options << " -DIS_FLOATING_POINT";
}
if(boost::is_signed<value_type>::value){
options << " -DIS_SIGNED";
}
if(sort_by_key){
options << " -DSORT_BY_KEY";
options << " -DT2=" << type_name<T2>();
options << enable_double<T2>();
}
if(ascending){
options << " -DASC";
}
// load radix sort program
program radix_sort_program = cache->get_or_build(
cache_key, options.str(), radix_sort_source, context
);
kernel count_kernel(radix_sort_program, "count");
kernel scan_kernel(radix_sort_program, "scan");
kernel scatter_kernel(radix_sort_program, "scatter");
size_t count = detail::iterator_range_size(first, last);
uint_ block_count = static_cast<uint_>(count / block_size);
if(block_count * block_size != count){
block_count++;
}
// setup temporary buffers
vector<value_type> output(count, context);
vector<T2> values_output(sort_by_key ? count : 0, context);
vector<uint_> offsets(k2, context);
vector<uint_> counts(block_count * k2, context);
const buffer *input_buffer = &first.get_buffer();
uint_ input_offset = static_cast<uint_>(first.get_index());
const buffer *output_buffer = &output.get_buffer();
uint_ output_offset = 0;
const buffer *values_input_buffer = &values_first.get_buffer();
uint_ values_input_offset = static_cast<uint_>(values_first.get_index());
const buffer *values_output_buffer = &values_output.get_buffer();
uint_ values_output_offset = 0;
for(uint_ i = 0; i < sizeof(sort_type) * CHAR_BIT / k; i++){
// write counts
count_kernel.set_arg(0, *input_buffer);
count_kernel.set_arg(1, input_offset);
count_kernel.set_arg(2, static_cast<uint_>(count));
count_kernel.set_arg(3, counts);
count_kernel.set_arg(4, offsets);
count_kernel.set_arg(5, block_size * sizeof(uint_), 0);
count_kernel.set_arg(6, i * k);
queue.enqueue_1d_range_kernel(count_kernel,
0,
block_count * block_size,
block_size);
// scan counts
if(k == 1){
typedef uint2_ counter_type;
::boost::compute::exclusive_scan(
make_buffer_iterator<counter_type>(counts.get_buffer(), 0),
make_buffer_iterator<counter_type>(counts.get_buffer(), counts.size() / 2),
make_buffer_iterator<counter_type>(counts.get_buffer()),
queue
);
}
else if(k == 2){
typedef uint4_ counter_type;
::boost::compute::exclusive_scan(
make_buffer_iterator<counter_type>(counts.get_buffer(), 0),
make_buffer_iterator<counter_type>(counts.get_buffer(), counts.size() / 4),
make_buffer_iterator<counter_type>(counts.get_buffer()),
queue
);
}
else if(k == 4){
typedef uint16_ counter_type;
::boost::compute::exclusive_scan(
make_buffer_iterator<counter_type>(counts.get_buffer(), 0),
make_buffer_iterator<counter_type>(counts.get_buffer(), counts.size() / 16),
make_buffer_iterator<counter_type>(counts.get_buffer()),
queue
);
}
else {
BOOST_ASSERT(false && "unknown k");
break;
}
// scan global offsets
scan_kernel.set_arg(0, counts);
scan_kernel.set_arg(1, offsets);
scan_kernel.set_arg(2, block_count);
queue.enqueue_task(scan_kernel);
// scatter values
scatter_kernel.set_arg(0, *input_buffer);
scatter_kernel.set_arg(1, input_offset);
scatter_kernel.set_arg(2, static_cast<uint_>(count));
scatter_kernel.set_arg(3, i * k);
scatter_kernel.set_arg(4, counts);
scatter_kernel.set_arg(5, offsets);
scatter_kernel.set_arg(6, *output_buffer);
scatter_kernel.set_arg(7, output_offset);
if(sort_by_key){
scatter_kernel.set_arg(8, *values_input_buffer);
scatter_kernel.set_arg(9, values_input_offset);
scatter_kernel.set_arg(10, *values_output_buffer);
scatter_kernel.set_arg(11, values_output_offset);
}
queue.enqueue_1d_range_kernel(scatter_kernel,
0,
block_count * block_size,
block_size);
// swap buffers
std::swap(input_buffer, output_buffer);
std::swap(values_input_buffer, values_output_buffer);
std::swap(input_offset, output_offset);
std::swap(values_input_offset, values_output_offset);
}
}
inline void radix_sort(Iterator first,
Iterator last,
command_queue &queue)
{
typedef typename
std::iterator_traits<Iterator>::value_type
value_type;
typedef typename
radix_sort_value_type<sizeof(value_type)>::type
sort_type;
const context &context = queue.get_context();
size_t count = detail::iterator_range_size(first, last);
// sort parameters
const uint_ k = 4;
const uint_ k2 = 1 << k;
const uint_ block_size = 128;
uint_ block_count = count / block_size;
if(block_count * block_size != count){
block_count++;
}
// setup kernels
program radix_sort_program =
program::create_with_source(radix_sort_source, context);
std::stringstream options;
options << "-DK=" << k;
options << " -DT=" << type_name<sort_type>();
options << " -DBLOCK_SIZE=" << block_size;
if(boost::is_floating_point<value_type>::value){
options << " -DIS_FLOATING_POINT";
}
if(boost::is_signed<value_type>::value){
options << " -DIS_SIGNED";
}
radix_sort_program.build(options.str());
kernel count_kernel(radix_sort_program, "count");
kernel scan_kernel(radix_sort_program, "scan");
kernel scatter_kernel(radix_sort_program, "scatter");
// setup temporary buffers
vector<value_type> output(count, context);
vector<uint_> offsets(k2, context);
vector<uint_> counts(block_count * k2, context);
const buffer *input_buffer = &first.get_buffer();
const buffer *output_buffer = &output.get_buffer();
for(uint_ i = 0; i < sizeof(sort_type) * CHAR_BIT / k; i++){
// write counts
count_kernel.set_arg(0, *input_buffer);
count_kernel.set_arg(1, static_cast<uint_>(count));
count_kernel.set_arg(2, counts.get_buffer());
count_kernel.set_arg(3, offsets.get_buffer());
count_kernel.set_arg(4, block_size * sizeof(uint_), 0);
count_kernel.set_arg(5, i * k);
queue.enqueue_1d_range_kernel(count_kernel,
0,
block_count * block_size,
block_size);
// scan counts
if(k == 1){
typedef uint2_ counter_type;
::boost::compute::exclusive_scan(
make_buffer_iterator<counter_type>(counts.get_buffer(), 0),
make_buffer_iterator<counter_type>(counts.get_buffer(), counts.size() / 2),
make_buffer_iterator<counter_type>(counts.get_buffer()),
queue
);
}
else if(k == 2){
typedef uint4_ counter_type;
::boost::compute::exclusive_scan(
make_buffer_iterator<counter_type>(counts.get_buffer(), 0),
make_buffer_iterator<counter_type>(counts.get_buffer(), counts.size() / 4),
make_buffer_iterator<counter_type>(counts.get_buffer()),
queue
);
}
else if(k == 4){
typedef uint16_ counter_type;
::boost::compute::exclusive_scan(
make_buffer_iterator<counter_type>(counts.get_buffer(), 0),
make_buffer_iterator<counter_type>(counts.get_buffer(), counts.size() / 16),
make_buffer_iterator<counter_type>(counts.get_buffer()),
queue
);
}
else {
BOOST_ASSERT(false && "unknown k");
break;
}
// scan global offsets
scan_kernel.set_arg(0, counts.get_buffer());
scan_kernel.set_arg(1, offsets.get_buffer());
scan_kernel.set_arg(2, block_count);
queue.enqueue_task(scan_kernel);
// scatter values
scatter_kernel.set_arg(0, *input_buffer);
scatter_kernel.set_arg(1, static_cast<uint_>(count));
scatter_kernel.set_arg(2, i * k);
scatter_kernel.set_arg(3, counts.get_buffer());
scatter_kernel.set_arg(4, offsets.get_buffer());
scatter_kernel.set_arg(5, *output_buffer);
queue.enqueue_1d_range_kernel(scatter_kernel,
0,
block_count * block_size,
block_size);
// swap buffers
std::swap(input_buffer, output_buffer);
}
}