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Support learning rate for zero-hessian objectives. (#8866)

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This commit is contained in:
Jiaming Yuan
2023-03-06 20:33:28 +08:00
committed by GitHub
parent 173096a6a7
commit 228a46e8ad
34 changed files with 464 additions and 434 deletions
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28
tests/cpp/objective/test_regression_obj.cc
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@@ -6,8 +6,9 @@
#include <xgboost/json.h>
#include <xgboost/objective.h>
#include "../../../src/common/linalg_op.h" // begin,end
#include "../../../src/common/linalg_op.h" // for begin, end
#include "../../../src/objective/adaptive.h"
#include "../../../src/tree/param.h" // for TrainParam
#include "../helpers.h"
#include "xgboost/base.h"
#include "xgboost/data.h"
@@ -408,9 +409,13 @@ TEST(Objective, DeclareUnifiedTest(AbsoluteError)) {
h_predt[i] = labels[i] + i;
}
obj->UpdateTreeLeaf(position, info, predt, 0, &tree);
ASSERT_EQ(tree[1].LeafValue(), -1);
ASSERT_EQ(tree[2].LeafValue(), -4);
tree::TrainParam param;
param.Init(Args{});
auto lr = param.learning_rate;
obj->UpdateTreeLeaf(position, info, param.learning_rate, predt, 0, &tree);
ASSERT_EQ(tree[1].LeafValue(), -1.0f * lr);
ASSERT_EQ(tree[2].LeafValue(), -4.0f * lr);
}
TEST(Objective, DeclareUnifiedTest(AbsoluteErrorLeaf)) {
@@ -457,11 +462,16 @@ TEST(Objective, DeclareUnifiedTest(AbsoluteErrorLeaf)) {
ASSERT_EQ(tree.GetNumLeaves(), 4);
auto empty_leaf = tree[4].LeafValue();
obj->UpdateTreeLeaf(position, info, predt, t, &tree);
ASSERT_EQ(tree[3].LeafValue(), -5);
ASSERT_EQ(tree[4].LeafValue(), empty_leaf);
ASSERT_EQ(tree[5].LeafValue(), -10);
ASSERT_EQ(tree[6].LeafValue(), -14);
tree::TrainParam param;
param.Init(Args{});
auto lr = param.learning_rate;
obj->UpdateTreeLeaf(position, info, lr, predt, t, &tree);
ASSERT_EQ(tree[3].LeafValue(), -5.0f * lr);
ASSERT_EQ(tree[4].LeafValue(), empty_leaf * lr);
ASSERT_EQ(tree[5].LeafValue(), -10.0f * lr);
ASSERT_EQ(tree[6].LeafValue(), -14.0f * lr);
}
}

10
tests/cpp/tree/hist/test_evaluate_splits.cc
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@@ -24,7 +24,7 @@ void TestEvaluateSplits(bool force_read_by_column) {
auto dmat = RandomDataGenerator(kRows, kCols, 0).Seed(3).GenerateDMatrix();
auto evaluator = HistEvaluator<CPUExpandEntry>{&ctx, param, dmat->Info(), sampler};
auto evaluator = HistEvaluator<CPUExpandEntry>{&ctx, &param, dmat->Info(), sampler};
common::HistCollection hist;
std::vector<GradientPair> row_gpairs = {
{1.23f, 0.24f}, {0.24f, 0.25f}, {0.26f, 0.27f}, {2.27f, 0.28f},
@@ -96,7 +96,7 @@ TEST(HistEvaluator, Apply) {
param.UpdateAllowUnknown(Args{{"min_child_weight", "0"}, {"reg_lambda", "0.0"}});
auto dmat = RandomDataGenerator(kNRows, kNCols, 0).Seed(3).GenerateDMatrix();
auto sampler = std::make_shared<common::ColumnSampler>();
auto evaluator_ = HistEvaluator<CPUExpandEntry>{&ctx, param, dmat->Info(), sampler};
auto evaluator_ = HistEvaluator<CPUExpandEntry>{&ctx, &param, dmat->Info(), sampler};
CPUExpandEntry entry{0, 0, 10.0f};
entry.split.left_sum = GradStats{0.4, 0.6f};
@@ -123,7 +123,7 @@ TEST_F(TestPartitionBasedSplit, CPUHist) {
// check the evaluator is returning the optimal split
std::vector<FeatureType> ft{FeatureType::kCategorical};
auto sampler = std::make_shared<common::ColumnSampler>();
HistEvaluator<CPUExpandEntry> evaluator{&ctx, param_, info_, sampler};
HistEvaluator<CPUExpandEntry> evaluator{&ctx, &param_, info_, sampler};
evaluator.InitRoot(GradStats{total_gpair_});
RegTree tree;
std::vector<CPUExpandEntry> entries(1);
@@ -153,7 +153,7 @@ auto CompareOneHotAndPartition(bool onehot) {
RandomDataGenerator(kRows, kCols, 0).Seed(3).Type(ft).MaxCategory(n_cats).GenerateDMatrix();
auto sampler = std::make_shared<common::ColumnSampler>();
auto evaluator = HistEvaluator<CPUExpandEntry>{&ctx, param, dmat->Info(), sampler};
auto evaluator = HistEvaluator<CPUExpandEntry>{&ctx, &param, dmat->Info(), sampler};
std::vector<CPUExpandEntry> entries(1);
for (auto const &gmat : dmat->GetBatches<GHistIndexMatrix>({32, param.sparse_threshold})) {
@@ -204,7 +204,7 @@ TEST_F(TestCategoricalSplitWithMissing, HistEvaluator) {
info.num_col_ = 1;
info.feature_types = {FeatureType::kCategorical};
Context ctx;
auto evaluator = HistEvaluator<CPUExpandEntry>{&ctx, param_, info, sampler};
auto evaluator = HistEvaluator<CPUExpandEntry>{&ctx, &param_, info, sampler};
evaluator.InitRoot(GradStats{parent_sum_});
std::vector<CPUExpandEntry> entries(1);

10
tests/cpp/tree/test_evaluate_splits.h
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@@ -1,5 +1,5 @@
/*!
* Copyright 2022 by XGBoost Contributors
/**
* Copyright 2022-2023 by XGBoost Contributors
*/
#include <gtest/gtest.h>
#include <xgboost/data.h>
@@ -12,8 +12,7 @@
#include "../../../src/tree/split_evaluator.h"
#include "../helpers.h"
namespace xgboost {
namespace tree {
namespace xgboost::tree {
/**
* \brief Enumerate all possible partitions for categorical split.
*/
@@ -151,5 +150,4 @@ class TestCategoricalSplitWithMissing : public testing::Test {
ASSERT_EQ(right_sum.GetHess(), parent_sum_.GetHess() - left_sum.GetHess());
}
};
} // namespace tree
} // namespace xgboost
} // namespace xgboost::tree

38
tests/cpp/tree/test_gpu_hist.cu
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@@ -1,5 +1,5 @@
/*!
* Copyright 2017-2022 XGBoost contributors
/**
* Copyright 2017-2023 by XGBoost contributors
*/
#include <gtest/gtest.h>
#include <thrust/device_vector.h>
@@ -13,6 +13,7 @@
#include "../../../src/common/common.h"
#include "../../../src/data/sparse_page_source.h"
#include "../../../src/tree/constraints.cuh"
#include "../../../src/tree/param.h" // for TrainParam
#include "../../../src/tree/updater_gpu_common.cuh"
#include "../../../src/tree/updater_gpu_hist.cu"
#include "../filesystem.h" // dmlc::TemporaryDirectory
@@ -21,8 +22,7 @@
#include "xgboost/context.h"
#include "xgboost/json.h"
namespace xgboost {
namespace tree {
namespace xgboost::tree {
TEST(GpuHist, DeviceHistogram) {
// Ensures that node allocates correctly after reaching `kStopGrowingSize`.
dh::safe_cuda(cudaSetDevice(0));
@@ -83,11 +83,12 @@ void TestBuildHist(bool use_shared_memory_histograms) {
int const kNRows = 16, kNCols = 8;
TrainParam param;
std::vector<std::pair<std::string, std::string>> args {
{"max_depth", "6"},
{"max_leaves", "0"},
Args args{
{"max_depth", "6"},
{"max_leaves", "0"},
};
param.Init(args);
auto page = BuildEllpackPage(kNRows, kNCols);
BatchParam batch_param{};
Context ctx{CreateEmptyGenericParam(0)};
@@ -168,7 +169,6 @@ void TestHistogramIndexImpl() {
int constexpr kNRows = 1000, kNCols = 10;
// Build 2 matrices and build a histogram maker with that
Context ctx(CreateEmptyGenericParam(0));
tree::GPUHistMaker hist_maker{&ctx, ObjInfo{ObjInfo::kRegression}},
hist_maker_ext{&ctx, ObjInfo{ObjInfo::kRegression}};
@@ -179,15 +179,14 @@ void TestHistogramIndexImpl() {
std::unique_ptr<DMatrix> hist_maker_ext_dmat(
CreateSparsePageDMatrixWithRC(kNRows, kNCols, 128UL, true, tempdir));
std::vector<std::pair<std::string, std::string>> training_params = {
{"max_depth", "10"},
{"max_leaves", "0"}
};
Args training_params = {{"max_depth", "10"}, {"max_leaves", "0"}};
TrainParam param;
param.UpdateAllowUnknown(training_params);
hist_maker.Configure(training_params);
hist_maker.InitDataOnce(hist_maker_dmat.get());
hist_maker.InitDataOnce(&param, hist_maker_dmat.get());
hist_maker_ext.Configure(training_params);
hist_maker_ext.InitDataOnce(hist_maker_ext_dmat.get());
hist_maker_ext.InitDataOnce(&param, hist_maker_ext_dmat.get());
// Extract the device maker from the histogram makers and from that its compressed
// histogram index
@@ -237,13 +236,15 @@ void UpdateTree(HostDeviceVector<GradientPair>* gpair, DMatrix* dmat,
{"subsample", std::to_string(subsample)},
{"sampling_method", sampling_method},
};
TrainParam param;
param.UpdateAllowUnknown(args);
Context ctx(CreateEmptyGenericParam(0));
tree::GPUHistMaker hist_maker{&ctx,ObjInfo{ObjInfo::kRegression}};
hist_maker.Configure(args);
std::vector<HostDeviceVector<bst_node_t>> position(1);
hist_maker.Update(gpair, dmat, common::Span<HostDeviceVector<bst_node_t>>{position}, {tree});
hist_maker.Update(&param, gpair, dmat, common::Span<HostDeviceVector<bst_node_t>>{position},
{tree});
auto cache = linalg::VectorView<float>{preds->DeviceSpan(), {preds->Size()}, 0};
hist_maker.UpdatePredictionCache(dmat, cache);
}
@@ -391,13 +392,11 @@ TEST(GpuHist, ConfigIO) {
Json j_updater { Object() };
updater->SaveConfig(&j_updater);
ASSERT_TRUE(IsA<Object>(j_updater["gpu_hist_train_param"]));
ASSERT_TRUE(IsA<Object>(j_updater["train_param"]));
updater->LoadConfig(j_updater);
Json j_updater_roundtrip { Object() };
updater->SaveConfig(&j_updater_roundtrip);
ASSERT_TRUE(IsA<Object>(j_updater_roundtrip["gpu_hist_train_param"]));
ASSERT_TRUE(IsA<Object>(j_updater_roundtrip["train_param"]));
ASSERT_EQ(j_updater, j_updater_roundtrip);
}
@@ -414,5 +413,4 @@ TEST(GpuHist, MaxDepth) {
ASSERT_THROW({learner->UpdateOneIter(0, p_mat);}, dmlc::Error);
}
} // namespace tree
} // namespace xgboost
} // namespace xgboost::tree

32
tests/cpp/tree/test_histmaker.cc
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@@ -5,11 +5,10 @@
#include <xgboost/tree_model.h>
#include <xgboost/tree_updater.h>
#include "../../../src/tree/param.h" // for TrainParam
#include "../helpers.h"
namespace xgboost {
namespace tree {
namespace xgboost::tree {
std::shared_ptr<DMatrix> GenerateDMatrix(std::size_t rows, std::size_t cols){
return RandomDataGenerator{rows, cols, 0.6f}.Seed(3).GenerateDMatrix();
}
@@ -45,11 +44,11 @@ TEST(GrowHistMaker, InteractionConstraint)
std::unique_ptr<TreeUpdater> updater{
TreeUpdater::Create("grow_histmaker", &ctx, ObjInfo{ObjInfo::kRegression})};
updater->Configure(Args{
{"interaction_constraints", "[[0, 1]]"},
{"num_feature", std::to_string(kCols)}});
TrainParam param;
param.UpdateAllowUnknown(
Args{{"interaction_constraints", "[[0, 1]]"}, {"num_feature", std::to_string(kCols)}});
std::vector<HostDeviceVector<bst_node_t>> position(1);
updater->Update(p_gradients.get(), p_dmat.get(), position, {&tree});
updater->Update(&param, p_gradients.get(), p_dmat.get(), position, {&tree});
ASSERT_EQ(tree.NumExtraNodes(), 4);
ASSERT_EQ(tree[0].SplitIndex(), 1);
@@ -64,9 +63,10 @@ TEST(GrowHistMaker, InteractionConstraint)
std::unique_ptr<TreeUpdater> updater{
TreeUpdater::Create("grow_histmaker", &ctx, ObjInfo{ObjInfo::kRegression})};
updater->Configure(Args{{"num_feature", std::to_string(kCols)}});
std::vector<HostDeviceVector<bst_node_t>> position(1);
updater->Update(p_gradients.get(), p_dmat.get(), position, {&tree});
TrainParam param;
param.Init(Args{});
updater->Update(&param, p_gradients.get(), p_dmat.get(), position, {&tree});
ASSERT_EQ(tree.NumExtraNodes(), 10);
ASSERT_EQ(tree[0].SplitIndex(), 1);
@@ -83,7 +83,6 @@ void TestColumnSplit(int32_t rows, int32_t cols, RegTree const& expected_tree) {
Context ctx;
std::unique_ptr<TreeUpdater> updater{
TreeUpdater::Create("grow_histmaker", &ctx, ObjInfo{ObjInfo::kRegression})};
updater->Configure(Args{{"num_feature", std::to_string(cols)}});
std::vector<HostDeviceVector<bst_node_t>> position(1);
std::unique_ptr<DMatrix> sliced{
@@ -91,7 +90,9 @@ void TestColumnSplit(int32_t rows, int32_t cols, RegTree const& expected_tree) {
RegTree tree;
tree.param.num_feature = cols;
updater->Update(p_gradients.get(), sliced.get(), position, {&tree});
TrainParam param;
param.Init(Args{});
updater->Update(&param, p_gradients.get(), sliced.get(), position, {&tree});
EXPECT_EQ(tree.NumExtraNodes(), 10);
EXPECT_EQ(tree[0].SplitIndex(), 1);
@@ -115,14 +116,13 @@ TEST(GrowHistMaker, ColumnSplit) {
Context ctx;
std::unique_ptr<TreeUpdater> updater{
TreeUpdater::Create("grow_histmaker", &ctx, ObjInfo{ObjInfo::kRegression})};
updater->Configure(Args{{"num_feature", std::to_string(kCols)}});
std::vector<HostDeviceVector<bst_node_t>> position(1);
updater->Update(p_gradients.get(), p_dmat.get(), position, {&expected_tree});
TrainParam param;
param.Init(Args{});
updater->Update(&param, p_gradients.get(), p_dmat.get(), position, {&expected_tree});
}
auto constexpr kWorldSize = 2;
RunWithInMemoryCommunicator(kWorldSize, TestColumnSplit, kRows, kCols, std::cref(expected_tree));
}
} // namespace tree
} // namespace xgboost
} // namespace xgboost::tree

7
tests/cpp/tree/test_prediction_cache.cc
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@@ -7,6 +7,7 @@
#include <memory>
#include "../../../src/tree/param.h" // for TrainParam
#include "../helpers.h"
namespace xgboost {
@@ -75,9 +76,11 @@ class TestPredictionCache : public ::testing::Test {
RegTree tree;
std::vector<RegTree *> trees{&tree};
auto gpair = GenerateRandomGradients(n_samples_);
updater->Configure(Args{{"max_bin", "64"}});
tree::TrainParam param;
param.UpdateAllowUnknown(Args{{"max_bin", "64"}});
std::vector<HostDeviceVector<bst_node_t>> position(1);
updater->Update(&gpair, Xy_.get(), position, trees);
updater->Update(&param, &gpair, Xy_.get(), position, trees);
HostDeviceVector<float> out_prediction_cached;
out_prediction_cached.SetDevice(ctx.gpu_id);
out_prediction_cached.Resize(n_samples_);

44
tests/cpp/tree/test_prune.cc
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@@ -1,20 +1,20 @@
/*!
* Copyright 2018-2019 by Contributors
/**
* Copyright 2018-2023 by XGBoost Contributors
*/
#include <gtest/gtest.h>
#include <xgboost/data.h>
#include <xgboost/host_device_vector.h>
#include <xgboost/tree_updater.h>
#include <xgboost/learner.h>
#include <gtest/gtest.h>
#include <vector>
#include <string>
#include <memory>
#include <xgboost/tree_updater.h>
#include <memory>
#include <string>
#include <vector>
#include "../../../src/tree/param.h" // for TrainParam
#include "../helpers.h"
namespace xgboost {
namespace tree {
namespace xgboost::tree {
TEST(Updater, Prune) {
int constexpr kCols = 16;
@@ -36,28 +36,30 @@ TEST(Updater, Prune) {
tree.param.UpdateAllowUnknown(cfg);
std::vector<RegTree*> trees {&tree};
// prepare pruner
TrainParam param;
param.UpdateAllowUnknown(cfg);
std::unique_ptr<TreeUpdater> pruner(
TreeUpdater::Create("prune", &ctx, ObjInfo{ObjInfo::kRegression}));
pruner->Configure(cfg);
// loss_chg < min_split_loss;
std::vector<HostDeviceVector<bst_node_t>> position(trees.size());
tree.ExpandNode(0, 0, 0, true, 0.0f, 0.3f, 0.4f, 0.0f, 0.0f,
/*left_sum=*/0.0f, /*right_sum=*/0.0f);
pruner->Update(&gpair, p_dmat.get(), position, trees);
pruner->Update(&param, &gpair, p_dmat.get(), position, 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,
/*left_sum=*/0.0f, /*right_sum=*/0.0f);
pruner->Update(&gpair, p_dmat.get(), position, trees);
pruner->Update(&param, &gpair, p_dmat.get(), position, trees);
ASSERT_EQ(tree.NumExtraNodes(), 2);
// loss_chg == min_split_loss;
tree.Stat(0).loss_chg = 10;
pruner->Update(&gpair, p_dmat.get(), position, trees);
pruner->Update(&param, &gpair, p_dmat.get(), position, trees);
ASSERT_EQ(tree.NumExtraNodes(), 2);
@@ -71,10 +73,10 @@ TEST(Updater, Prune) {
0, 0.5f, true, 0.3, 0.4, 0.5,
/*loss_chg=*/19.0f, 0.0f,
/*left_sum=*/0.0f, /*right_sum=*/0.0f);
cfg.emplace_back("max_depth", "1");
pruner->Configure(cfg);
pruner->Update(&gpair, p_dmat.get(), position, trees);
cfg.emplace_back("max_depth", "1");
param.UpdateAllowUnknown(cfg);
pruner->Update(&param, &gpair, p_dmat.get(), position, trees);
ASSERT_EQ(tree.NumExtraNodes(), 2);
tree.ExpandNode(tree[0].LeftChild(),
@@ -82,9 +84,9 @@ TEST(Updater, Prune) {
/*loss_chg=*/18.0f, 0.0f,
/*left_sum=*/0.0f, /*right_sum=*/0.0f);
cfg.emplace_back("min_split_loss", "0");
pruner->Configure(cfg);
pruner->Update(&gpair, p_dmat.get(), position, trees);
param.UpdateAllowUnknown(cfg);
pruner->Update(&param, &gpair, p_dmat.get(), position, trees);
ASSERT_EQ(tree.NumExtraNodes(), 2);
}
} // namespace tree
} // namespace xgboost
} // namespace xgboost::tree

17
tests/cpp/tree/test_refresh.cc
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@@ -1,14 +1,15 @@
/*!
* Copyright 2018-2019 by Contributors
/**
* Copyright 2018-2013 by XGBoost Contributors
*/
#include <gtest/gtest.h>
#include <xgboost/host_device_vector.h>
#include <xgboost/tree_updater.h>
#include <gtest/gtest.h>
#include <vector>
#include <string>
#include <memory>
#include <string>
#include <vector>
#include "../../../src/tree/param.h" // for TrainParam
#include "../helpers.h"
namespace xgboost {
@@ -43,9 +44,11 @@ TEST(Updater, Refresh) {
tree.Stat(cleft).base_weight = 1.2;
tree.Stat(cright).base_weight = 1.3;
refresher->Configure(cfg);
std::vector<HostDeviceVector<bst_node_t>> position;
refresher->Update(&gpair, p_dmat.get(), position, trees);
tree::TrainParam param;
param.UpdateAllowUnknown(cfg);
refresher->Update(&param, &gpair, p_dmat.get(), position, trees);
bst_float constexpr kEps = 1e-6;
ASSERT_NEAR(-0.183392, tree[cright].LeafValue(), kEps);

27
tests/cpp/tree/test_tree_stat.cc
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@@ -1,7 +1,11 @@
/**
* Copyright 2020-2023 by XGBoost Contributors
*/
#include <gtest/gtest.h>
#include <xgboost/tree_model.h>
#include <xgboost/tree_updater.h>
#include "../../../src/tree/param.h" // for TrainParam
#include "../helpers.h"
namespace xgboost {
@@ -21,6 +25,9 @@ class UpdaterTreeStatTest : public ::testing::Test {
}
void RunTest(std::string updater) {
tree::TrainParam param;
param.Init(Args{});
Context ctx(updater == "grow_gpu_hist" ? CreateEmptyGenericParam(0)
: CreateEmptyGenericParam(Context::kCpuId));
auto up = std::unique_ptr<TreeUpdater>{
@@ -29,7 +36,7 @@ class UpdaterTreeStatTest : public ::testing::Test {
RegTree tree;
tree.param.num_feature = kCols;
std::vector<HostDeviceVector<bst_node_t>> position(1);
up->Update(&gpairs_, p_dmat_.get(), position, {&tree});
up->Update(&param, &gpairs_, p_dmat_.get(), position, {&tree});
tree.WalkTree([&tree](bst_node_t nidx) {
if (tree[nidx].IsLeaf()) {
@@ -69,28 +76,33 @@ class UpdaterEtaTest : public ::testing::Test {
void RunTest(std::string updater) {
Context ctx(updater == "grow_gpu_hist" ? CreateEmptyGenericParam(0)
: CreateEmptyGenericParam(Context::kCpuId));
float eta = 0.4;
auto up_0 = std::unique_ptr<TreeUpdater>{
TreeUpdater::Create(updater, &ctx, ObjInfo{ObjInfo::kClassification})};
up_0->Configure(Args{{"eta", std::to_string(eta)}});
up_0->Configure(Args{});
tree::TrainParam param0;
param0.Init(Args{{"eta", std::to_string(eta)}});
auto up_1 = std::unique_ptr<TreeUpdater>{
TreeUpdater::Create(updater, &ctx, ObjInfo{ObjInfo::kClassification})};
up_1->Configure(Args{{"eta", "1.0"}});
tree::TrainParam param1;
param1.Init(Args{{"eta", "1.0"}});
for (size_t iter = 0; iter < 4; ++iter) {
RegTree tree_0;
{
tree_0.param.num_feature = kCols;
std::vector<HostDeviceVector<bst_node_t>> position(1);
up_0->Update(&gpairs_, p_dmat_.get(), position, {&tree_0});
up_0->Update(&param0, &gpairs_, p_dmat_.get(), position, {&tree_0});
}
RegTree tree_1;
{
tree_1.param.num_feature = kCols;
std::vector<HostDeviceVector<bst_node_t>> position(1);
up_1->Update(&gpairs_, p_dmat_.get(), position, {&tree_1});
up_1->Update(&param1, &gpairs_, p_dmat_.get(), position, {&tree_1});
}
tree_0.WalkTree([&](bst_node_t nidx) {
if (tree_0[nidx].IsLeaf()) {
@@ -139,17 +151,18 @@ class TestMinSplitLoss : public ::testing::Test {
// test gamma
{"gamma", std::to_string(gamma)}};
tree::TrainParam param;
param.UpdateAllowUnknown(args);
Context ctx(updater == "grow_gpu_hist" ? CreateEmptyGenericParam(0)
: CreateEmptyGenericParam(Context::kCpuId));
std::cout << ctx.gpu_id << std::endl;
auto up = std::unique_ptr<TreeUpdater>{
TreeUpdater::Create(updater, &ctx, ObjInfo{ObjInfo::kRegression})};
up->Configure(args);
up->Configure({});
RegTree tree;
std::vector<HostDeviceVector<bst_node_t>> position(1);
up->Update(&gpair_, dmat_.get(), position, {&tree});
up->Update(&param, &gpair_, dmat_.get(), position, {&tree});
auto n_nodes = tree.NumExtraNodes();
return n_nodes;