metric.h

#ifndef LIGHTGBM_METRIC_H_
#define LIGHTGBM_METRIC_H_
 
#include <LightGBM/utils/log.h>
#include <LightGBM/utils/common.h>
 
#include <LightGBM/meta.h>
#include <LightGBM/config.h>
#include <LightGBM/dataset.h>
#include <LightGBM/objective_function.h>
 
#include <vector>
 
namespace LightGBM {
 
class Metric {
public:
  virtual ~Metric() {}
 
  virtual void Init(const Metadata& metadata, data_size_t num_data) = 0;
 
  virtual const std::vector<std::string>& GetName() const = 0;
 
  virtual double factor_to_bigger_better() const = 0;
  virtual std::vector<double> Eval(const double* score, const ObjectiveFunction* objective) const = 0;
 
  Metric() = default;
  Metric& operator=(const Metric&) = delete;
  Metric(const Metric&) = delete;
 
  LIGHTGBM_EXPORT static Metric* CreateMetric(const std::string& type, const Config& config);
};
 
class DCGCalculator {
public:
  static void DefaultEvalAt(std::vector<int>* eval_at);
  static void DefaultLabelGain(std::vector<double>* label_gain);
  static void Init(const std::vector<double>& label_gain);
 
  static double CalDCGAtK(data_size_t k, const label_t* label,
    const double* score, data_size_t num_data);
 
  static void CalDCG(const std::vector<data_size_t>& ks,
    const label_t* label, const double* score,
    data_size_t num_data, std::vector<double>* out);
 
  static double CalMaxDCGAtK(data_size_t k,
    const label_t* label, data_size_t num_data);
 
  static void CheckLabel(const label_t* label, data_size_t num_data);
 
  static void CalMaxDCG(const std::vector<data_size_t>& ks,
    const label_t* label, data_size_t num_data, std::vector<double>* out);
 
  inline static double GetDiscount(data_size_t k) { return discount_[k]; }
 
private:
  static std::vector<double> label_gain_;
  static std::vector<double> discount_;
  static const data_size_t kMaxPosition;
};
 
 
}  // namespace LightGBM
 
 
#endif   // LightGBM_METRIC_H_