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Handle duplicated values in sketching. (#6178)

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* Accumulate weights in duplicated values.
* Fix device id in iterative dmatrix.
This commit is contained in:
Jiaming Yuan
2020-10-10 19:32:44 +08:00
committed by GitHub
parent ab5b35134f
commit 2241563f23
9 changed files with 250 additions and 54 deletions
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19
src/common/device_helpers.cuh
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@@ -27,6 +27,7 @@
#include <sstream>
#include <string>
#include <vector>
#include <tuple>
#include "xgboost/logging.h"
#include "xgboost/host_device_vector.h"
@@ -1059,14 +1060,14 @@ struct SegmentedUniqueReduceOp {
*
* \return Number of unique values in total.
*/
template <typename KeyInIt, typename KeyOutIt, typename ValInIt,
template <typename DerivedPolicy, typename KeyInIt, typename KeyOutIt, typename ValInIt,
typename ValOutIt, typename Comp>
size_t
SegmentedUnique(KeyInIt key_segments_first, KeyInIt key_segments_last, ValInIt val_first,
SegmentedUnique(const thrust::detail::execution_policy_base<DerivedPolicy> &exec,
KeyInIt key_segments_first, KeyInIt key_segments_last, ValInIt val_first,
ValInIt val_last, KeyOutIt key_segments_out, ValOutIt val_out,
Comp comp) {
using Key = thrust::pair<size_t, typename thrust::iterator_traits<ValInIt>::value_type>;
dh::XGBCachingDeviceAllocator<char> alloc;
auto unique_key_it = dh::MakeTransformIterator<Key>(
thrust::make_counting_iterator(static_cast<size_t>(0)),
[=] __device__(size_t i) {
@@ -1083,7 +1084,7 @@ SegmentedUnique(KeyInIt key_segments_first, KeyInIt key_segments_last, ValInIt v
thrust::make_discard_iterator(),
detail::SegmentedUniqueReduceOp<Key, KeyOutIt>{key_segments_out});
auto uniques_ret = thrust::unique_by_key_copy(
thrust::cuda::par(alloc), unique_key_it, unique_key_it + n_inputs,
exec, unique_key_it, unique_key_it + n_inputs,
val_first, reduce_it, val_out,
[=] __device__(Key const &l, Key const &r) {
if (l.first == r.first) {
@@ -1094,8 +1095,16 @@ SegmentedUnique(KeyInIt key_segments_first, KeyInIt key_segments_last, ValInIt v
});
auto n_uniques = uniques_ret.second - val_out;
CHECK_LE(n_uniques, n_inputs);
thrust::exclusive_scan(thrust::cuda::par(alloc), key_segments_out,
thrust::exclusive_scan(exec, key_segments_out,
key_segments_out + segments_len, key_segments_out, 0);
return n_uniques;
}
template <typename... Inputs,
std::enable_if_t<std::tuple_size<std::tuple<Inputs...>>::value == 7>
* = nullptr>
size_t SegmentedUnique(Inputs &&...inputs) {
dh::XGBCachingDeviceAllocator<char> alloc;
return SegmentedUnique(thrust::cuda::par(alloc), std::forward<Inputs&&>(inputs)...);
}
} // namespace dh