Function TEST

tests/cpp/tree/test_approx.cc:32–86

}  // anonymous namespace

TEST(Approx, Partitioner) {
  size_t n_samples = 1024, n_features = 1, base_rowid = 0;
  Context ctx;
  ctx.InitAllowUnknown(Args{});
  CommonRowPartitioner partitioner{&ctx, n_samples, base_rowid, false};
  ASSERT_EQ(partitioner.base_rowid, base_rowid);
  ASSERT_EQ(partitioner.Size(), 1);
  ASSERT_EQ(partitioner.Partitions()[0].Size(), n_samples);

  auto const Xy = RandomDataGenerator{n_samples, n_features, 0}.GenerateDMatrix(true);
  auto hess = GenerateHess(n_samples);
  std::vector<CPUExpandEntry> candidates{{0, 0}};
  candidates.front().split.loss_chg = 0.4;

  for (auto const& page : Xy->GetBatches<GHistIndexMatrix>(&ctx, {64, hess, true})) {
    bst_feature_t const split_ind = 0;
    {
      auto min_value = -std::numeric_limits<float>::infinity();
      RegTree tree;
      CommonRowPartitioner partitioner{&ctx, n_samples, base_rowid, false};
      GetSplit(&tree, min_value, &candidates);
      partitioner.UpdatePosition(&ctx, page, candidates, tree.HostScView());
      ASSERT_EQ(partitioner.Size(), 3);
      ASSERT_EQ(partitioner[1].Size(), 0);
      ASSERT_EQ(partitioner[2].Size(), n_samples);
    }
    {
      CommonRowPartitioner partitioner{&ctx, n_samples, base_rowid, false};
      auto ptr = page.cut.Ptrs()[split_ind + 1];
      float split_value = page.cut.Values().at(ptr / 2);
      RegTree tree;
      GetSplit(&tree, split_value, &candidates);
      partitioner.UpdatePosition(&ctx, page, candidates, tree.HostScView());

      {
        auto left_nidx = tree[RegTree::kRoot].LeftChild();
        auto const& elem = partitioner[left_nidx];
        ASSERT_LT(elem.Size(), n_samples);
        ASSERT_GT(elem.Size(), 1);
        for (auto& it : elem) {
          auto value = page.cut.Values().at(page.index[it]);
          ASSERT_LE(value, split_value);
        }
      }
      {
        auto right_nidx = tree[RegTree::kRoot].RightChild();
        auto const& elem = partitioner[right_nidx];
        for (auto& it : elem) {
          auto value = page.cut.Values().at(page.index[it]);
          ASSERT_GT(value, split_value) << it;
        }
      }
    }
  }
}

TEST(Approx, InteractionConstraint) {
  auto constexpr kRows = 32;