Method Split

src/treelearner/voting_parallel_tree_learner.cpp:474–514

template <typename TREELEARNER_T>
void VotingParallelTreeLearner<TREELEARNER_T>::Split(Tree* tree, int best_Leaf, int* left_leaf, int* right_leaf) {
  TREELEARNER_T::Split(tree, best_Leaf, left_leaf, right_leaf);
  const SplitInfo& best_split_info = this->best_split_per_leaf_[best_Leaf];
  // set the global number of data for leaves
  global_data_count_in_leaf_[*left_leaf] = best_split_info.left_count;
  global_data_count_in_leaf_[*right_leaf] = best_split_info.right_count;
  auto p_left = smaller_leaf_splits_global_.get();
  auto p_right = larger_leaf_splits_global_.get();
  // init the global sumup info
  if (best_split_info.left_count < best_split_info.right_count) {
    smaller_leaf_splits_global_->Init(*left_leaf, this->data_partition_.get(),
      best_split_info.left_sum_gradient,
      best_split_info.left_sum_hessian);
    larger_leaf_splits_global_->Init(*right_leaf, this->data_partition_.get(),
      best_split_info.right_sum_gradient,
      best_split_info.right_sum_hessian);
  } else {
    smaller_leaf_splits_global_->Init(*right_leaf, this->data_partition_.get(),
      best_split_info.right_sum_gradient,
      best_split_info.right_sum_hessian);
    larger_leaf_splits_global_->Init(*left_leaf, this->data_partition_.get(),
      best_split_info.left_sum_gradient,
      best_split_info.left_sum_hessian);
    p_left = larger_leaf_splits_global_.get();
    p_right = smaller_leaf_splits_global_.get();
  }
  const int inner_feature_index = this->train_data_->InnerFeatureIndex(best_split_info.feature);
  bool is_numerical_split = this->train_data_->FeatureBinMapper(inner_feature_index)->bin_type() == BinType::NumericalBin;
  p_left->SetValueConstraint(best_split_info.min_constraint, best_split_info.max_constraint);
  p_right->SetValueConstraint(best_split_info.min_constraint, best_split_info.max_constraint);
  if (is_numerical_split) {
    double mid = (best_split_info.left_output + best_split_info.right_output) / 2.0f;
    if (best_split_info.monotone_type < 0) {
      p_left->SetValueConstraint(mid, best_split_info.max_constraint);
      p_right->SetValueConstraint(best_split_info.min_constraint, mid);
    } else if (best_split_info.monotone_type > 0) {
      p_left->SetValueConstraint(best_split_info.min_constraint, mid);
      p_right->SetValueConstraint(mid, best_split_info.max_constraint);
    }
  }
}

// instantiate template classes, otherwise linker cannot find the code
template class VotingParallelTreeLearner<GPUTreeLearner>;