inline void merge_sort_by_key_on_gpu(KeyIterator keys_first,
KeyIterator keys_last,
ValueIterator values_first,
Compare compare,
bool stable,
command_queue &queue)
{
typedef typename std::iterator_traits<KeyIterator>::value_type key_type;
typedef typename std::iterator_traits<ValueIterator>::value_type value_type;
size_t count = iterator_range_size(keys_first, keys_last);
if(count < 2){
return;
}
size_t block_size =
block_sort(
keys_first, values_first,
compare, count,
true /* sort_by_key */, stable /* stable */,
queue
);
// for small input size only block sort is performed
if(count <= block_size) {
return;
}
const context &context = queue.get_context();
bool result_in_temporary_buffer = false;
::boost::compute::vector<key_type> temp_keys(count, context);
::boost::compute::vector<value_type> temp_values(count, context);
for(; block_size < count; block_size *= 2) {
result_in_temporary_buffer = !result_in_temporary_buffer;
if(result_in_temporary_buffer) {
merge_blocks_on_gpu(keys_first, values_first,
temp_keys.begin(), temp_values.begin(),
compare, count, block_size,
true /* sort_by_key */, queue);
} else {
merge_blocks_on_gpu(temp_keys.begin(), temp_values.begin(),
keys_first, values_first,
compare, count, block_size,
true /* sort_by_key */, queue);
}
}
if(result_in_temporary_buffer) {
copy_async(temp_keys.begin(), temp_keys.end(), keys_first, queue);
copy_async(temp_values.begin(), temp_values.end(), values_first, queue);
}
}
void CurveTree::reorder_curve_keys(const vector<size_t>& ordering)
{
vector<CurveKey> temp_keys(m_curve_keys.size());
small_item_reorder(&m_curve_keys[0], &temp_keys[0], &ordering[0], ordering.size());
}
