PedestalCalculator.h

#ifndef TRACKING_RECO_PEDESTALCALCULATOR_H_
#define TRACKING_RECO_PEDESTALCALCULATOR_H_
 
#include <array>
#include <string>
#include <unordered_map>
 
#include "Framework/EventProcessor.h"
#include "Tracking/Reco/SiStripChannelMap.h"
 
namespace tracking::reco {
 
class PedestalCalculator : public framework::Analyzer {
 public:
  PedestalCalculator(const std::string& name, framework::Process& process)
      : framework::Analyzer(name, process) {}
 
  void configure(framework::config::Parameters& ps) override;
  void analyze(const framework::Event& event) override;
  void onProcessEnd() override;
 
 private:
  void writePedestalsJson();
 
  // Welford's online algorithm for numerically stable mean+variance.
  struct Accumulator {
    std::array<double, channelmap::K_SAMPLES_PER_APV_TRIGGER> mean_{};
    std::array<double, channelmap::K_SAMPLES_PER_APV_TRIGGER> m2_{};
    long n_{0};  // hit count for this channel
  };
 
  std::string input_collection_{"TrackerRawData"};
  std::string input_pass_name_{""};
  std::string output_file_{"pedestals.json"};
  std::string output_format_{"json"};
 
  std::unordered_map<std::string, Accumulator> accumulators_;
  long n_events_{0};
};
 
}  // namespace tracking::reco
 
#endif  // TRACKING_RECO_PEDESTALCALCULATOR_H_