xgboost/tests/cpp/tree/test_prune.cc
Jiaming Yuan f0064c07ab
Refactor configuration [Part II]. (#4577)
* Refactor configuration [Part II].

* General changes:
** Remove `Init` methods to avoid ambiguity.
** Remove `Configure(std::map<>)` to avoid redundant copying and prepare for
   parameter validation. (`std::vector` is returned from `InitAllowUnknown`).
** Add name to tree updaters for easier debugging.

* Learner changes:
** Make `LearnerImpl` the only source of configuration.

    All configurations are stored and carried out by `LearnerImpl::Configure()`.

** Remove booster in C API.

    Originally kept for "compatibility reason", but did not state why.  So here
    we just remove it.

** Add a `metric_names_` field in `LearnerImpl`.
** Remove `LazyInit`.  Configuration will always be lazy.
** Run `Configure` before every iteration.

* Predictor changes:
** Allocate both cpu and gpu predictor.
** Remove cpu_predictor from gpu_predictor.

    `GBTree` is now used to dispatch the predictor.

** Remove some GPU Predictor tests.

* IO

No IO changes.  The binary model format stability is tested by comparing
hashing value of save models between two commits
2019-07-20 08:34:56 -04:00

65 lines
1.8 KiB
C++

/*!
* Copyright 2018-2019 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 kNCols = 16;
std::vector<std::pair<std::string, std::string>> cfg;
cfg.emplace_back(std::pair<std::string, std::string>(
"num_feature", std::to_string(kNCols)));
cfg.emplace_back(std::pair<std::string, std::string>(
"min_split_loss", "10"));
cfg.emplace_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);
auto lparam = CreateEmptyGenericParam(0, 0);
// prepare tree
RegTree tree = RegTree();
tree.param.InitAllowUnknown(cfg);
std::vector<RegTree*> trees {&tree};
// prepare pruner
std::unique_ptr<TreeUpdater> pruner(TreeUpdater::Create("prune", &lparam));
pruner->Configure(cfg);
// loss_chg < min_split_loss;
tree.ExpandNode(0, 0, 0, true, 0.0f, 0.3f, 0.4f, 0.0f, 0.0f);
pruner->Update(&gpair, dmat->get(), trees);
ASSERT_EQ(tree.NumExtraNodes(), 0);
// loss_chg > min_split_loss;
tree.ExpandNode(0, 0, 0, true, 0.0f, 0.3f, 0.4f, 11.0f, 0.0f);
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