xgboost/tests/cpp/tree/test_prune.cc
Jiaming Yuan 19ee0a3579
Refactor fast-hist, add tests for some updaters. (#3836)
Add unittest for prune.

Add unittest for refresh.

Refactor fast_hist.

* Remove fast_hist_param.
* Rename to quantile_hist.

Add unittests for QuantileHist.

* Refactor QuantileHist into .h and .cc file.
* Remove sync.h.
* Remove MGPU_mock test.

Rename fast hist method to quantile hist.
2018-11-07 21:15:07 +13:00

73 lines
1.9 KiB
C++

/*!
* Copyright 2018 by Contributors
*/
#include "../helpers.h"
#include "../../../src/common/host_device_vector.h"
#include <xgboost/tree_updater.h>
#include <gtest/gtest.h>
#include <vector>
#include <string>
#include <memory>
namespace xgboost {
namespace tree {
TEST(Updater, Prune) {
int constexpr n_rows = 32, n_cols = 16;
std::vector<std::pair<std::string, std::string>> cfg;
cfg.push_back(std::pair<std::string, std::string>(
"num_feature", std::to_string(n_cols)));
cfg.push_back(std::pair<std::string, std::string>(
"min_split_loss", "10"));
cfg.push_back(std::pair<std::string, std::string>(
"silent", "1"));
// These data are just place holders.
HostDeviceVector<GradientPair> gpair =
{ {0.50f, 0.25f}, {0.50f, 0.25f}, {0.50f, 0.25f}, {0.50f, 0.25f},
{0.25f, 0.24f}, {0.25f, 0.24f}, {0.25f, 0.24f}, {0.25f, 0.24f} };
auto dmat = CreateDMatrix(32, 16, 0.4, 3);
// prepare tree
RegTree tree = RegTree();
tree.InitModel();
tree.param.InitAllowUnknown(cfg);
std::vector<RegTree*> trees {&tree};
// prepare pruner
std::unique_ptr<TreeUpdater> pruner(TreeUpdater::Create("prune"));
pruner->Init(cfg);
// loss_chg < min_split_loss;
tree.AddChilds(0);
int cleft = tree[0].LeftChild();
int cright = tree[0].RightChild();
tree[cleft].SetLeaf(0.3f, 0);
tree[cright].SetLeaf(0.4f, 0);
pruner->Update(&gpair, dmat->get(), trees);
ASSERT_EQ(tree.NumExtraNodes(), 0);
// loss_chg > min_split_loss;
tree.AddChilds(0);
cleft = tree[0].LeftChild();
cright = tree[0].RightChild();
tree[cleft].SetLeaf(0.3f, 0);
tree[cright].SetLeaf(0.4f, 0);
tree.Stat(0).loss_chg = 11;
pruner->Update(&gpair, dmat->get(), trees);
ASSERT_EQ(tree.NumExtraNodes(), 2);
// loss_chg == min_split_loss;
tree.Stat(0).loss_chg = 10;
pruner->Update(&gpair, dmat->get(), trees);
ASSERT_EQ(tree.NumExtraNodes(), 2);
delete dmat;
}
} // namespace tree
} // namespace xgboost