Merge CPU sketching implementations.

* Merge sparse and dense.

amalgamation/xgboost-all0.cc

@@ -71,6 +71,7 @@
 #include "../src/common/common.cc"
 #include "../src/common/charconv.cc"
 #include "../src/common/timer.cc"
+#include "../src/common/quantile.cc"
 #include "../src/common/host_device_vector.cc"
 #include "../src/common/hist_util.cc"
 #include "../src/common/json.cc"

include/xgboost/data.h

@@ -239,6 +239,21 @@ struct BatchParam {
  }
 };
 
+struct HostSparsePageView {
+ using Inst = common::Span<Entry const>;
+
+ common::Span<bst_row_t const> offset;
+ common::Span<Entry const> data;
+
+ Inst operator[](size_t i) const {
+ auto size = *(offset.data() + i + 1) - *(offset.data() + i);
+ return {data.data() + *(offset.data() + i),
+ static_cast<Inst::index_type>(size)};
+ }
+
+ size_t Size() const { return offset.size() == 0 ? 0 : offset.size() - 1; }
+};
+
 /*!
  * \brief In-memory storage unit of sparse batch, stored in CSR format.
  */
@@ -270,6 +285,11 @@ class SparsePage {
  static_cast<Inst::index_type>(size)};
  }
 
+ HostSparsePageView GetView() const {
+ return {offset.ConstHostSpan(), data.ConstHostSpan()};
+ }
+
+
  /*! \brief constructor */
  SparsePage() {
  this->Clear();