xgboost/src/tree/updater_quantile_hist.h
2023-01-19 23:28:18 +08:00

147 lines
4.5 KiB
C++

/*!
* Copyright 2017-2022 by XGBoost Contributors
* \file updater_quantile_hist.h
* \brief use quantized feature values to construct a tree
* \author Philip Cho, Tianqi Chen, Egor Smirnov
*/
#ifndef XGBOOST_TREE_UPDATER_QUANTILE_HIST_H_
#define XGBOOST_TREE_UPDATER_QUANTILE_HIST_H_
#include <xgboost/tree_updater.h>
#include <algorithm>
#include <limits>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include "xgboost/base.h"
#include "xgboost/data.h"
#include "xgboost/json.h"
#include "hist/evaluate_splits.h"
#include "hist/histogram.h"
#include "hist/expand_entry.h"
#include "common_row_partitioner.h"
#include "constraints.h"
#include "./param.h"
#include "./driver.h"
#include "../common/random.h"
#include "../common/timer.h"
#include "../common/hist_util.h"
#include "../common/row_set.h"
#include "../common/partition_builder.h"
#include "../common/column_matrix.h"
namespace xgboost {
namespace tree {
inline BatchParam HistBatch(TrainParam const& param) {
return {param.max_bin, param.sparse_threshold};
}
/*! \brief construct a tree using quantized feature values */
class QuantileHistMaker: public TreeUpdater {
public:
explicit QuantileHistMaker(Context const* ctx, ObjInfo task) : TreeUpdater(ctx), task_{task} {}
void Configure(const Args& args) override;
void Update(HostDeviceVector<GradientPair>* gpair, DMatrix* dmat,
common::Span<HostDeviceVector<bst_node_t>> out_position,
const std::vector<RegTree*>& trees) override;
bool UpdatePredictionCache(const DMatrix *data,
linalg::VectorView<float> out_preds) override;
void LoadConfig(Json const& in) override {
auto const& config = get<Object const>(in);
FromJson(config.at("train_param"), &this->param_);
}
void SaveConfig(Json* p_out) const override {
auto& out = *p_out;
out["train_param"] = ToJson(param_);
}
char const* Name() const override {
return "grow_quantile_histmaker";
}
bool HasNodePosition() const override { return true; }
protected:
// training parameter
TrainParam param_;
// actual builder that runs the algorithm
struct Builder {
public:
// constructor
explicit Builder(const size_t n_trees, const TrainParam& param, DMatrix const* fmat,
ObjInfo task, Context const* ctx)
: n_trees_(n_trees),
param_(param),
p_last_fmat_(fmat),
histogram_builder_{new HistogramBuilder<CPUExpandEntry>},
task_{task},
ctx_{ctx},
monitor_{std::make_unique<common::Monitor>()} {
monitor_->Init("Quantile::Builder");
}
// update one tree, growing
void UpdateTree(HostDeviceVector<GradientPair>* gpair, DMatrix* p_fmat, RegTree* p_tree,
HostDeviceVector<bst_node_t>* p_out_position);
bool UpdatePredictionCache(DMatrix const* data, linalg::VectorView<float> out_preds) const;
private:
// initialize temp data structure
void InitData(DMatrix* fmat, const RegTree& tree, std::vector<GradientPair>* gpair);
size_t GetNumberOfTrees();
CPUExpandEntry InitRoot(DMatrix* p_fmat, RegTree* p_tree,
const std::vector<GradientPair>& gpair_h);
void BuildHistogram(DMatrix* p_fmat, RegTree* p_tree,
std::vector<CPUExpandEntry> const& valid_candidates,
std::vector<GradientPair> const& gpair);
void LeafPartition(RegTree const& tree, common::Span<GradientPair const> gpair,
std::vector<bst_node_t>* p_out_position);
void ExpandTree(DMatrix* p_fmat, RegTree* p_tree, const std::vector<GradientPair>& gpair_h,
HostDeviceVector<bst_node_t>* p_out_position);
private:
const size_t n_trees_;
const TrainParam& param_;
std::shared_ptr<common::ColumnSampler> column_sampler_{
std::make_shared<common::ColumnSampler>()};
std::vector<GradientPair> gpair_local_;
std::unique_ptr<HistEvaluator<CPUExpandEntry>> evaluator_;
std::vector<CommonRowPartitioner> partitioner_;
// back pointers to tree and data matrix
const RegTree* p_last_tree_{nullptr};
DMatrix const* const p_last_fmat_;
std::unique_ptr<HistogramBuilder<CPUExpandEntry>> histogram_builder_;
ObjInfo task_;
// Context for number of threads
Context const* ctx_;
std::unique_ptr<common::Monitor> monitor_;
};
protected:
std::unique_ptr<Builder> pimpl_;
ObjInfo task_;
};
} // namespace tree
} // namespace xgboost
#endif // XGBOOST_TREE_UPDATER_QUANTILE_HIST_H_