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lightgbm-org--lightgbm/src/boosting/gbdt_prediction.cpp
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2026-07-13 13:27:18 +08:00

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/*!
* Copyright (c) 2017-2026 Microsoft Corporation. All rights reserved.
* Copyright (c) 2017-2026 The LightGBM developers. All rights reserved.
* Licensed under the MIT License. See LICENSE file in the project root for license information.
*/
#include <LightGBM/objective_function.h>
#include <LightGBM/prediction_early_stop.h>
#include <LightGBM/utils/openmp_wrapper.h>
#include <unordered_map>
#include "gbdt.h"
namespace LightGBM {
void GBDT::PredictRaw(const double* features, double* output, const PredictionEarlyStopInstance* early_stop) const {
int early_stop_round_counter = 0;
// set zero
std::memset(output, 0, sizeof(double) * num_tree_per_iteration_);
const int end_iteration_for_pred = start_iteration_for_pred_ + num_iteration_for_pred_;
for (int i = start_iteration_for_pred_; i < end_iteration_for_pred; ++i) {
// predict all the trees for one iteration
for (int k = 0; k < num_tree_per_iteration_; ++k) {
output[k] += models_[i * num_tree_per_iteration_ + k]->Predict(features);
}
// check early stopping
++early_stop_round_counter;
if (early_stop->round_period == early_stop_round_counter) {
if (early_stop->callback_function(output, num_tree_per_iteration_)) {
return;
}
early_stop_round_counter = 0;
}
}
}
void GBDT::PredictRawByMap(const std::unordered_map<int, double>& features, double* output, const PredictionEarlyStopInstance* early_stop) const {
int early_stop_round_counter = 0;
// set zero
std::memset(output, 0, sizeof(double) * num_tree_per_iteration_);
const int end_iteration_for_pred = start_iteration_for_pred_ + num_iteration_for_pred_;
for (int i = start_iteration_for_pred_; i < end_iteration_for_pred; ++i) {
// predict all the trees for one iteration
for (int k = 0; k < num_tree_per_iteration_; ++k) {
output[k] += models_[i * num_tree_per_iteration_ + k]->PredictByMap(features);
}
// check early stopping
++early_stop_round_counter;
if (early_stop->round_period == early_stop_round_counter) {
if (early_stop->callback_function(output, num_tree_per_iteration_)) {
return;
}
early_stop_round_counter = 0;
}
}
}
void GBDT::Predict(const double* features, double* output, const PredictionEarlyStopInstance* early_stop) const {
PredictRaw(features, output, early_stop);
if (average_output_) {
for (int k = 0; k < num_tree_per_iteration_; ++k) {
output[k] /= num_iteration_for_pred_;
}
}
if (objective_function_ != nullptr) {
objective_function_->ConvertOutput(output, output);
}
}
void GBDT::PredictByMap(const std::unordered_map<int, double>& features, double* output, const PredictionEarlyStopInstance* early_stop) const {
PredictRawByMap(features, output, early_stop);
if (average_output_) {
for (int k = 0; k < num_tree_per_iteration_; ++k) {
output[k] /= num_iteration_for_pred_;
}
}
if (objective_function_ != nullptr) {
objective_function_->ConvertOutput(output, output);
}
}
void GBDT::PredictLeafIndex(const double* features, double* output) const {
int start_tree = start_iteration_for_pred_ * num_tree_per_iteration_;
int num_trees = num_iteration_for_pred_ * num_tree_per_iteration_;
const auto* models_ptr = models_.data() + start_tree;
for (int i = 0; i < num_trees; ++i) {
output[i] = models_ptr[i]->PredictLeafIndex(features);
}
}
void GBDT::PredictLeafIndexByMap(const std::unordered_map<int, double>& features, double* output) const {
int start_tree = start_iteration_for_pred_ * num_tree_per_iteration_;
int num_trees = num_iteration_for_pred_ * num_tree_per_iteration_;
const auto* models_ptr = models_.data() + start_tree;
for (int i = 0; i < num_trees; ++i) {
output[i] = models_ptr[i]->PredictLeafIndexByMap(features);
}
}
} // namespace LightGBM