GlobalCellTowerAlgTool.cxx

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
#include "GlobalCellTowerAlgTool.h"
#include "GlobalLArCell.h"
 
 
namespace GlobalSim {
  
  // Main constructor
  GlobalCellTowerAlgTool::GlobalCellTowerAlgTool(const std::string& type, const std::string& name, const IInterface* parent) :
    base_class(type, name, parent) {
  }
 
 
  // Initialize function running before first event
  StatusCode GlobalCellTowerAlgTool::initialize() {
       
    CHECK(m_gblLArCellContainerKey.initialize());
    CHECK(m_gblCellTowers.initialize());
 
    return StatusCode::SUCCESS;
  }
 
 
  // Main functional block running for each event
  StatusCode GlobalCellTowerAlgTool::run(const EventContext& ctx) const {
 
    ATH_MSG_DEBUG("Building cell towers");
 
    // Read in GlobalLArCellContainer
    auto h_gblLArCells = SG::makeHandle(m_gblLArCellContainerKey, ctx);
    CHECK(h_gblLArCells.isValid());
    const auto & gblLArCells = *h_gblLArCells;
 
    // Define tower array (98 eta bins x 64 phi bins)
    static constexpr int nEta{98};
    static constexpr int nPhi{64};
 
    auto pTowerEnergies = std::make_unique<std::array<std::array<float, nPhi>, nEta>>();
    auto & towerEnergies = *pTowerEnergies;
    for (const auto& cell : gblLArCells) {
 
        // Compute eta and phi indices (binning in steps of 0.1)
        int eta_index = static_cast<int>(std::floor(cell->eta() * 10)) + 49;
        int phi_index = static_cast<int>(std::floor(cell->phi() * 10)) + 32;
 
        // Ensure indices are within bounds
        if (eta_index < 0 || eta_index >= nEta || phi_index < 0 || phi_index >= nPhi) continue;
 
        // Add cell energy to the corresponding tower
        towerEnergies[eta_index][phi_index] += cell->getEnergy();
    }
 
    auto h_towerTOBs = SG::makeHandle(m_gblCellTowers, ctx);
    auto towers = std::make_unique<GenericTobContainer>();
    towers->reserve(nEta * nPhi);
 
    for (int etaBin = 0; etaBin < nEta; ++etaBin) {
        for (int phiBin = 0; phiBin < nPhi; ++phiBin) {
 
           if (towerEnergies[etaBin][phiBin] == 0) continue;
           int energyBits = std::clamp(static_cast<int>(towerEnergies[etaBin][phiBin]), 0, (1 << 13) - 1);
 
           std::string bit_string = makeTowerBits(energyBits, etaBin, phiBin);
 
           towers->emplace_back(std::make_shared<GenericTob>(bit_string));
        }
    }
 
    ATH_MSG_DEBUG("Built " << towers->size() << " cell towers and stored them as GenericTobs");
 
    CHECK(h_towerTOBs.record(std::move(towers))); 
 
    return StatusCode::SUCCESS;
  }
 
 
  // Function which assembles the TOB bitstream for a tower
  std::string GlobalCellTowerAlgTool::makeTowerBits(int energy, int etaBin, int phiBin) {
      return GlobalCellTowerAlgTool::toBinary(energy, 13) +
          GlobalCellTowerAlgTool::toBinary(etaBin, 9) +
          GlobalCellTowerAlgTool::toBinary(phiBin, 7) +
          std::string(3, '0');
  }
 
 
  // Overrides toString() function from base class, unused here
  std::string GlobalCellTowerAlgTool::toString() const {
      return {};
  }
 
} //namespace GlobalSim