aocsa commented on a change in pull request #11019:
URL: https://github.com/apache/arrow/pull/11019#discussion_r700775265
##########
File path: cpp/src/arrow/compute/kernels/vector_sort.cc
##########
@@ -1778,6 +1784,711 @@ class SortIndicesMetaFunction : public MetaFunction {
}
};
+// ----------------------------------------------------------------------
+// TopK/BottomK implementations
+
+using SelectKOptionsState = internal::OptionsWrapper<SelectKOptions>;
+const auto kDefaultTopKOptions = SelectKOptions::TopKDefault();
+const auto kDefaultBottomKOptions = SelectKOptions::BottomKDefault();
+
+const FunctionDoc top_k_doc(
+ "Return the indices that would partition an array array, record batch or
table\n"
+ "around a pivot",
+ ("@TODO"), {"input", "k"}, "PartitionNthOptions");
+
+const FunctionDoc bottom_k_doc(
+ "Return the indices that would partition an array array, record batch or
table\n"
+ "around a pivot",
+ ("@TODO"), {"input", "k"}, "PartitionNthOptions");
+
+Result<std::shared_ptr<ArrayData>> MakeMutableArrayForFixedSizedType(
+ std::shared_ptr<DataType> out_type, int64_t length, MemoryPool*
memory_pool) {
+ auto buffer_size = BitUtil::BytesForBits(
+ length * std::static_pointer_cast<UInt64Type>(out_type)->bit_width());
+ std::vector<std::shared_ptr<Buffer>> buffers(2);
+ ARROW_ASSIGN_OR_RAISE(buffers[1], AllocateResizableBuffer(buffer_size,
memory_pool));
+ auto out = std::make_shared<ArrayData>(out_type, length, buffers, 0);
+ return out;
+}
+
+class ArraySelecter : public TypeVisitor {
+ public:
+ ArraySelecter(ExecContext* ctx, const Array& array, int64_t k, const
SortOrder order,
+ Datum* output)
+ : TypeVisitor(),
+ ctx_(ctx),
+ array_(array),
+ k_(k),
+ physical_type_(GetPhysicalType(array.type())),
+ order_(order),
+ output_(output) {}
+
+ Status Run() { return physical_type_->Accept(this); }
+
+#define VISIT(TYPE) \
+ Status Visit(const TYPE& type) { return SelectKthInternal<TYPE>(); }
+
+ VISIT_PHYSICAL_TYPES(VISIT)
+
+#undef VISIT
+
+ template <typename InType>
+ Status SelectKthInternal() {
+ using GetView = GetViewType<InType>;
+ using ArrayType = typename TypeTraits<InType>::ArrayType;
+
+ ArrayType arr(array_.data());
+ std::vector<uint64_t> indices(arr.length());
+
+ uint64_t* indices_begin = indices.data();
+ uint64_t* indices_end = indices_begin + indices.size();
+ std::iota(indices_begin, indices_end, 0);
+ if (k_ > arr.length()) {
+ k_ = arr.length();
+ }
+ auto end_iter = PartitionNulls<ArrayType,
NonStablePartitioner>(indices_begin,
+
indices_end, arr, 0);
+ auto kth_begin = indices_begin + k_;
+ if (kth_begin > end_iter) {
+ kth_begin = end_iter;
+ }
+ std::function<bool(uint64_t, uint64_t)> cmp;
+ if (order_ == SortOrder::Ascending) {
+ cmp = [&arr](uint64_t left, uint64_t right) -> bool {
+ const auto lval = GetView::LogicalValue(arr.GetView(left));
+ const auto rval = GetView::LogicalValue(arr.GetView(right));
+ return lval < rval;
+ };
+ } else {
+ cmp = [&arr](uint64_t left, uint64_t right) -> bool {
+ const auto lval = GetView::LogicalValue(arr.GetView(left));
+ const auto rval = GetView::LogicalValue(arr.GetView(right));
+ return rval < lval;
+ };
+ }
+ arrow::internal::Heap<uint64_t, decltype(cmp)> heap(cmp);
+ uint64_t* iter = indices_begin;
+ for (; iter != kth_begin && heap.Size() < static_cast<size_t>(k_); ++iter)
{
+ heap.Push(*iter);
+ }
+ for (; iter != end_iter && heap.Size() > 0; ++iter) {
+ uint64_t x_index = *iter;
+ const auto lval = GetView::LogicalValue(arr.GetView(x_index));
+ const auto rval = GetView::LogicalValue(arr.GetView(heap.Top()));
+ if (order_ == SortOrder::Ascending) {
+ if (lval < rval) {
+ heap.ReplaceTop(x_index);
+ }
+ } else {
+ if (rval < lval) {
+ heap.ReplaceTop(x_index);
+ }
+ }
+ }
+
+ int64_t out_size = static_cast<int64_t>(heap.Size());
+ ARROW_ASSIGN_OR_RAISE(
+ auto take_indices,
+ MakeMutableArrayForFixedSizedType(uint64(), out_size,
ctx_->memory_pool()));
Review comment:
IMO it should return values to match pandas API.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscr...@arrow.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
