int reduce_by_key_sink(
IKTuple &&ikeys, vector<V> const &ivals,
OKTuple &&okeys, vector<V> &ovals,
Comp, Oper
)
{
namespace fusion = boost::fusion;
typedef typename extract_value_types<IKTuple>::type K;
static_assert(
std::is_same<K, typename extract_value_types<OKTuple>::type>::value,
"Incompatible input and output key types");
precondition(
fusion::at_c<0>(ikeys).nparts() == 1 && ivals.nparts() == 1,
"reduce_by_key is only supported for single device contexts"
);
precondition(fusion::at_c<0>(ikeys).size() == ivals.size(),
"keys and values should have same size"
);
const auto &queue = fusion::at_c<0>(ikeys).queue_list();
backend::select_context(queue[0]);
const int NT_cpu = 1;
const int NT_gpu = 256;
const int NT = is_cpu(queue[0]) ? NT_cpu : NT_gpu;
size_t count = fusion::at_c<0>(ikeys).size();
size_t num_blocks = (count + NT - 1) / NT;
size_t scan_buf_size = alignup(num_blocks, NT);
backend::device_vector<int> key_sum (queue[0], scan_buf_size);
backend::device_vector<V> pre_sum (queue[0], scan_buf_size);
backend::device_vector<V> post_sum (queue[0], scan_buf_size);
backend::device_vector<V> offset_val(queue[0], count);
backend::device_vector<int> offset (queue[0], count);
/***** Kernel 0 *****/
auto krn0 = offset_calculation<K, Comp>(queue[0]);
krn0.push_arg(count);
boost::fusion::for_each(ikeys, do_push_arg(krn0));
krn0.push_arg(offset);
krn0(queue[0]);
VEX_FUNCTION(int, plus, (int, x)(int, y), return x + y;);
int reduce_by_key_sink(
IKTuple &&ikeys, vector<V> const &ivals,
OKTuple &&okeys, vector<V> &ovals,
Comp, Oper
)
{
namespace fusion = boost::fusion;
typedef typename extract_value_types<IKTuple>::type K;
static_assert(
std::is_same<K, typename extract_value_types<OKTuple>::type>::value,
"Incompatible input and output key types");
precondition(
fusion::at_c<0>(ikeys).nparts() == 1 && ivals.nparts() == 1,
"Sorting is only supported for single device contexts"
);
precondition(fusion::at_c<0>(ikeys).size() == ivals.size(),
"keys and values should have same size"
);
const auto &queue = fusion::at_c<0>(ikeys).queue_list();
backend::select_context(queue[0]);
const int NT_cpu = 1;
const int NT_gpu = 256;
const int NT = is_cpu(queue[0]) ? NT_cpu : NT_gpu;
size_t count = fusion::at_c<0>(ikeys).size();
size_t num_blocks = (count + NT - 1) / NT;
size_t scan_buf_size = alignup(num_blocks, NT);
backend::device_vector<int> key_sum (queue[0], scan_buf_size);
backend::device_vector<V> pre_sum (queue[0], scan_buf_size);
backend::device_vector<V> post_sum (queue[0], scan_buf_size);
backend::device_vector<V> offset_val(queue[0], count);
backend::device_vector<int> offset (queue[0], count);
/***** Kernel 0 *****/
auto krn0 = detail::offset_calculation<K, Comp>(queue[0]);
krn0.push_arg(count);
boost::fusion::for_each(ikeys, do_push_arg(krn0));
krn0.push_arg(offset);
krn0(queue[0]);
VEX_FUNCTION(plus, int(int, int), "return prm1 + prm2;");
detail::scan(queue[0], offset, offset, 0, false, plus);
/***** Kernel 1 *****/
auto krn1 = is_cpu(queue[0]) ?
detail::block_scan_by_key<NT_cpu, V, Oper>(queue[0]) :
detail::block_scan_by_key<NT_gpu, V, Oper>(queue[0]);
krn1.push_arg(count);
krn1.push_arg(offset);
krn1.push_arg(ivals(0));
krn1.push_arg(offset_val);
krn1.push_arg(key_sum);
krn1.push_arg(pre_sum);
krn1.config(num_blocks, NT);
krn1(queue[0]);
/***** Kernel 2 *****/
uint work_per_thread = std::max<uint>(1U, static_cast<uint>(scan_buf_size / NT));
auto krn2 = is_cpu(queue[0]) ?
detail::block_inclusive_scan_by_key<NT_cpu, V, Oper>(queue[0]) :
detail::block_inclusive_scan_by_key<NT_gpu, V, Oper>(queue[0]);
krn2.push_arg(num_blocks);
krn2.push_arg(key_sum);
krn2.push_arg(pre_sum);
krn2.push_arg(post_sum);
krn2.push_arg(work_per_thread);
krn2.config(1, NT);
krn2(queue[0]);
/***** Kernel 3 *****/
auto krn3 = detail::block_sum_by_key<V, Oper>(queue[0]);
krn3.push_arg(count);
krn3.push_arg(key_sum);
krn3.push_arg(post_sum);
krn3.push_arg(offset);
krn3.push_arg(offset_val);
krn3.config(num_blocks, NT);
krn3(queue[0]);
/***** resize okeys and ovals *****/
int out_elements;
offset.read(queue[0], count - 1, 1, &out_elements, true);
++out_elements;
boost::fusion::for_each(okeys, do_vex_resize(queue, out_elements));
ovals.resize(ivals.queue_list(), out_elements);
/***** Kernel 4 *****/
auto krn4 = detail::key_value_mapping<K, V>(queue[0]);
krn4.push_arg(count);
boost::fusion::for_each(ikeys, do_push_arg(krn4));
boost::fusion::for_each(okeys, do_push_arg(krn4));
krn4.push_arg(ovals(0));
krn4.push_arg(offset);
krn4.push_arg(offset_val);
krn4(queue[0]);
return out_elements;
}