tree_learner.h

#ifndef LIGHTGBM_TREE_LEARNER_H_
#define LIGHTGBM_TREE_LEARNER_H_
 
 
#include <LightGBM/meta.h>
#include <LightGBM/config.h>
#include <LightGBM/json11.hpp>
 
#include <vector>
 
using namespace json11;
 
namespace LightGBM {
 
class Tree;
class Dataset;
class ObjectiveFunction;
 
class TreeLearner {
public:
  virtual ~TreeLearner() {}
 
  virtual void Init(const Dataset* train_data, bool is_constant_hessian) = 0;
 
  virtual void ResetTrainingData(const Dataset* train_data) = 0;
 
  virtual void ResetConfig(const Config* config) = 0;
 
  virtual Tree* Train(const score_t* gradients, const score_t* hessians, bool is_constant_hessian,
                      Json& forced_split_json) = 0;
 
  virtual Tree* FitByExistingTree(const Tree* old_tree, const score_t* gradients, const score_t* hessians) const = 0;
 
  virtual Tree* FitByExistingTree(const Tree* old_tree, const std::vector<int>& leaf_pred,
                                  const score_t* gradients, const score_t* hessians) = 0;
 
  virtual void SetBaggingData(const data_size_t* used_indices,
    data_size_t num_data) = 0;
 
  virtual void AddPredictionToScore(const Tree* tree, double* out_score) const = 0;
 
  virtual void RenewTreeOutput(Tree* tree, const ObjectiveFunction* obj, const double* prediction,
                               data_size_t total_num_data, const data_size_t* bag_indices, data_size_t bag_cnt) const = 0;
 
  virtual void RenewTreeOutput(Tree* tree, const ObjectiveFunction* obj, double prediction,
    data_size_t total_num_data, const data_size_t* bag_indices, data_size_t bag_cnt) const = 0;
 
  TreeLearner() = default;
  TreeLearner& operator=(const TreeLearner&) = delete;
  TreeLearner(const TreeLearner&) = delete;
 
  static TreeLearner* CreateTreeLearner(const std::string& learner_type,
    const std::string& device_type,
    const Config* config);
};
 
}  // namespace LightGBM
 
#endif   // LightGBM_TREE_LEARNER_H_