L1EGammaEECalibrator.cc

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#include "L1Trigger/L1CaloTrigger/interface/L1EGammaEECalibrator.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/ParameterSet/interface/FileInPath.h"
#include "boost/property_tree/ptree.hpp"
#include "boost/property_tree/json_parser.hpp"
#include <iterator>

namespace l1tp2 {
  std::vector<float> as_vector(boost::property_tree::ptree const& pt,
                               boost::property_tree::ptree::key_type const& key) {
    std::vector<float> ret;
    for (const auto& item : pt.get_child(key))
      ret.push_back(item.second.get_value<float>());
    return ret;
  }
};  // namespace l1tp2

L1EGammaEECalibrator::L1EGammaEECalibrator(const edm::ParameterSet& pset) {
  //read the JSON file and populate the eta - pt bins and the value container
  boost::property_tree::ptree calibration_map;
  read_json(pset.getParameter<edm::FileInPath>("calibrationFile").fullPath(), calibration_map);

  auto eta_l = l1tp2::as_vector(calibration_map, "eta_l");
  std::copy(eta_l.begin(), eta_l.end(), std::inserter(eta_bins, eta_bins.end()));
  auto eta_h = l1tp2::as_vector(calibration_map, "eta_h");
  eta_bins.insert(eta_h.back());

  auto pt_l = l1tp2::as_vector(calibration_map, "pt_l");
  std::copy(pt_l.begin(), pt_l.end(), std::inserter(pt_bins, pt_bins.end()));
  auto pt_h = l1tp2::as_vector(calibration_map, "pt_h");
  pt_bins.insert(pt_h.back());

  auto calib_data = l1tp2::as_vector(calibration_map, "calib");
  auto n_bins_eta = eta_bins.size();
  auto n_bins_pt = pt_bins.size();
  calib_factors.reserve(n_bins_eta * n_bins_pt);
  for (auto calib_f = calib_data.begin(); calib_f != calib_data.end(); ++calib_f) {
    auto index = calib_f - calib_data.begin();
    int eta_bin = etaBin(eta_l[index]);
    int pt_bin = ptBin(pt_l[index]);
    calib_factors[(eta_bin * n_bins_pt) + pt_bin] = *calib_f;
  }
}

int L1EGammaEECalibrator::bin(const std::set<float>& container, float value) const {
  auto bin_l = container.upper_bound(value);
  if (bin_l == container.end()) {
    // value not mapped to any bin
    return -1;
  }
  return std::distance(container.begin(), bin_l) - 1;
}

float L1EGammaEECalibrator::calibrationFactor(const float& pt, const float& eta) const {
  int bin_eta = etaBin(eta);
  int bin_pt = ptBin(pt);
  if (bin_eta == -1 || bin_pt == -1)
    return 1.;
  auto n_bins_pt = pt_bins.size();
  return calib_factors[(bin_eta * n_bins_pt) + bin_pt];
}