PixelClusteringTool.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
#include "PixelClusteringTool.h"
 
#include <Acts/Clusterization/Clusterization.hpp>
 
#include <xAODInDetMeasurement/PixelCluster.h>
#include <xAODInDetMeasurement/PixelClusterContainer.h>
#include <xAODInDetMeasurement/PixelClusterAuxContainer.h>
#include <InDetPrepRawData/SiWidth.h>
#include <TrkSurfaces/Surface.h>
 
#include <unordered_set>
#include <stdexcept>
 
using CLHEP::micrometer;
 
// Helper functions for use with ACTS clusterization
// Put these in the InDet namespace so that ACTS can find them
// via ADL.
//
namespace ActsTrk {
  static inline int getCellRow(const typename PixelClusteringTool::Cell& cell) { return cell.ROW; }
  static inline int getCellColumn(const typename PixelClusteringTool::Cell& cell) { return cell.COL; }
  static inline void clusterReserve(PixelClusteringTool::Cluster& cl,
                    std::size_t n)
  {
    cl.ids.reserve(n);
    cl.tots.reserve(n);
  }  
  static inline void clusterAddCell(PixelClusteringTool::Cluster& cl,
                    const PixelClusteringTool::Cell& cell)
  {
    cl.ids.push_back(cell.ID);
    cl.tots.push_back(cell.TOT);
    if (cell.LVL1 < cl.lvl1min)
      cl.lvl1min = cell.LVL1;
  }
 
StatusCode PixelClusteringTool::initialize()
{
  ATH_MSG_DEBUG("Initializing " << name() << " ...");
 
  ATH_MSG_DEBUG("   " << m_addCorners );
  ATH_MSG_DEBUG("   " << m_useWeightedPos );
  ATH_MSG_DEBUG("   " << m_broadErrors );
  ATH_MSG_DEBUG("   " << m_checkGanged );
    
  ATH_CHECK(m_pixelLorentzAngleTool.retrieve());
 
  ATH_CHECK(m_chargeDataKey.initialize(not m_chargeDataKey.empty()));
 
  ATH_MSG_INFO("   Charge Data Key:" << m_chargeDataKey);
 
  ATH_CHECK( detStore()->retrieve(m_pixelID, "PixelID") );
  
  ATH_MSG_DEBUG(name() << " successfully initialized");
  return StatusCode::SUCCESS;
}
 
PixelClusteringTool::PixelClusteringTool(
    const std::string& type, const std::string& name, const IInterface* parent)
    : base_class(type,name,parent)
{}
 
StatusCode
PixelClusteringTool::makeCluster(PixelClusteringTool::Cluster &cluster,
                 const InDetDD::SiDetectorElement* element,
                 const InDetDD::PixelModuleDesign& design,
                 const PixelChargeCalibCondData *calibData,
                 const PixelChargeCalibCondData::CalibrationStrategy calibStrategy,
                 const double lorentz_shift,
                                 size_t icluster,
                                 xAOD::PixelCluster::ClusterVars& clusterVars) const
{ 
 
  Amg::Vector2D pos_acc(0,0);
  int tot_acc = 0;
 
  std::vector<float> chargeList;
  if (calibData) chargeList.reserve(cluster.ids.size());
  
  InDetDD::PixelDiodeTree::CellIndexType rowmax = std::numeric_limits<InDetDD::PixelDiodeTree::CellIndexType>::min();
  InDetDD::PixelDiodeTree::CellIndexType colmax = std::numeric_limits<InDetDD::PixelDiodeTree::CellIndexType>::min();
  InDetDD::PixelDiodeTree::CellIndexType rowmin = std::numeric_limits<InDetDD::PixelDiodeTree::CellIndexType>::max();
  InDetDD::PixelDiodeTree::CellIndexType colmin = std::numeric_limits<InDetDD::PixelDiodeTree::CellIndexType>::max();
  InDetDD::PixelDiodeTree::DiodeProxyWithPosition colmin_diode{};
  InDetDD::PixelDiodeTree::DiodeProxyWithPosition colmax_diode{};
  InDetDD::PixelDiodeTree::DiodeProxyWithPosition rowmin_diode{};
  InDetDD::PixelDiodeTree::DiodeProxyWithPosition rowmax_diode{};
 
  // We temporary comment this since it is not used
  // bool hasGanged = false;
 
  IdentifierHash moduleHash = element->identifyHash();
 
  for (size_t i = 0; i < cluster.ids.size(); i++) {
 
    //Construct the identifier class
    Identifier id = Identifier(cluster.ids[i]);
 
    // We temporary comment this since it is not used
    // TODO: Check how the ganged info is used in legacy
    // if (multiChip)  {
    //   hasGanged = hasGanged ||
    //  m_pixelRDOTool->isGanged(id, element).has_value();
    // }
 
    int tot = cluster.tots.at(i);
    float charge = tot;
 
    std::array<InDetDD::PixelDiodeTree::CellIndexType,2> diode_idx
       = InDetDD::PixelDiodeTree::makeCellIndex(m_pixelID->phi_index(id),
                                                m_pixelID->eta_index(id));
    InDetDD::PixelDiodeTree::DiodeProxyWithPosition si_param ( design.diodeProxyFromIdxCachePosition(diode_idx));
 
    if (calibData) {
      // Retrieving the calibration only depends on FE and not per cell (can be further optimized)
      // Single FE modules could have an optimized getCharge function where the calib constants are cached
      std::uint32_t feValue = design.getFE(si_param);
      auto diode_type = design.getDiodeType(si_param);
      if (m_isITk){
        if (design.getReadoutTechnology() != InDetDD::PixelReadoutTechnology::RD53) {
    ATH_MSG_ERROR("Chip type is not recognized!");
    return StatusCode::FAILURE;
        }
 
        charge = calibData->getCharge(diode_type,
              calibStrategy,
              moduleHash,
              feValue,
              tot);
        chargeList.push_back(charge);
      } else {
        charge = calibData->getCharge(diode_type,
                                      moduleHash,
                                      feValue,
                                      tot);
 
        // These numbers are taken from the Cluster Maker Tool
        if (design.getReadoutTechnology() != InDetDD::PixelReadoutTechnology::RD53 && (moduleHash < 12 or moduleHash > 2035)) {
          charge = tot/8.0*(8000.0-1200.0)+1200.0;
        }
        chargeList.push_back(charge);
      }
    }
    
    const InDetDD::PixelDiodeTree::CellIndexType &row = diode_idx[0];
    const InDetDD::PixelDiodeTree::CellIndexType &col = diode_idx[1];
    if (row>rowmax) {
       rowmax=row;
       rowmax_diode = si_param;
    }
    if (row<rowmin) {
       rowmin=row;
       rowmin_diode = si_param;
    }
    if (col>colmax) {
       colmax=col;
       colmax_diode = si_param;
    }
    if (col<colmin) {
       colmin=col;
       colmin_diode = si_param;
    }
 
    // We compute the digital position as a sum of all RDO positions
    // all with the same weight of 1
    // We do not compute a charge-weighted center of gravity here (by default) since
    // we observe it to be worse than the digital position
    // ToT-weighted center of gravity must not be used
    if (m_useWeightedPos) {
      pos_acc += charge * si_param.position();
      tot_acc += charge;
    } else {
      pos_acc += si_param.position();
      tot_acc += 1;
    }
    
  }
  
  if (tot_acc > 0)
    pos_acc /= tot_acc;
 
  
  const int colWidth = colmax - colmin + 1;
  const int rowWidth = rowmax - rowmin + 1;
 
  double etaWidth = colmax_diode.xEtaMax() - colmin_diode.xEtaMin(); // design.widthFromColumnRange(colmin, colmax);
  double phiWidth = rowmax_diode.xPhiMax() - rowmin_diode.xPhiMin(); // design.widthFromColumnRange(colmin, colmax);
 
  // ask for Lorentz correction, get global position
  const Amg::Vector2D localPos = pos_acc;
  Amg::Vector2D locpos(localPos[Trk::locX]+lorentz_shift, localPos[Trk::locY]);
  // find global position of element
  const Amg::Transform3D& T = element->surface().transform();
  double Ax[3] = {T(0,0),T(1,0),T(2,0)};
  double Ay[3] = {T(0,1),T(1,1),T(2,1)};
  double R [3] = {T(0,3),T(1,3),T(2,3)};
  
  const Amg::Vector2D&    M = locpos;
  Amg::Vector3D globalPos(M[0]*Ax[0]+M[1]*Ay[0]+R[0],M[0]*Ax[1]+M[1]*Ay[1]+R[1],M[0]*Ax[2]+M[1]*Ay[2]+R[2]);
 
  // Compute error matrix
  float width0, width1;
  if (m_broadErrors) {
      // Use cluster width
      width0 = phiWidth;
      width1 = etaWidth;
  } else {
      // Use average pixel width
      width0 = phiWidth / rowWidth;
      width1 = etaWidth / colWidth;
  }
 
  // Actually create the cluster (i.e. fill the values)
  
  Eigen::Matrix<float,2,1> localPosition(locpos.x(), locpos.y());
  Eigen::Matrix<float,2,2> localCovariance = Eigen::Matrix<float,2,2>::Zero();
  localCovariance(0, 0) = width0 * width0 / 12.0f; 
  localCovariance(1, 1) = width1 * width1 / 12.0f;
  
  clusterVars.identifierHash[icluster] = moduleHash;
  xAOD::VectorMap<2>(clusterVars.localPositionDim2[icluster].data()) = localPosition;
  xAOD::MatrixMap<2>(clusterVars.localCovarianceDim2[icluster].data()) = localCovariance;
  clusterVars.identifier[icluster] = cluster.ids.front();
  clusterVars.rdoList[icluster] = std::move(cluster.ids);
  xAOD::VectorMap<3>(clusterVars.globalPosition[icluster].data()) = globalPos.cast<float>();
  clusterVars.totList[icluster] = std::move(cluster.tots);
  clusterVars.lvl1a[icluster] = cluster.lvl1min;
  clusterVars.channelsInPhi[icluster] = rowWidth;
  clusterVars.channelsInEta[icluster] = colWidth;
  clusterVars.widthInEta[icluster] = etaWidth;
    
  return StatusCode::SUCCESS;
}
 
StatusCode
PixelClusteringTool::clusterize(const EventContext& /*ctx*/,
                const RawDataCollection& RDOs,
                const InDet::SiDetectorElementStatus& pixelDetElStatus,
                const InDetDD::SiDetectorElement& element,
        Acts::Ccl::ClusteringData& data,
                std::vector<ClusterCollection>& collection) const
{
  IdentifierHash idHash = RDOs.identifyHash();
  collection.emplace_back();
  if ( not pixelDetElStatus.isGood(idHash) ) {
    // the module being flagged as bad is not a failure
    // An empty cluster collection needs to be added because the assumption
    // is that there is one element per element RawDataCollection.
    return StatusCode::SUCCESS;
  }
 
  // Retrieve the cells from the detector element
  CellCollection cells = unpackRDOs(RDOs, pixelDetElStatus, element);
 
  Acts::Ccl::createClusters<CellCollection, ClusterCollection, 2>
    (data, cells, collection.back(), Acts::Ccl::DefaultConnect<Cell, 2>(m_addCorners));
  
  return StatusCode::SUCCESS;
}
 
 
std::any PixelClusteringTool::makeVars (SG::AuxVectorData& cont) const
{
  return std::any (xAOD::PixelCluster::ClusterVars (cont));
}
 
 
StatusCode
PixelClusteringTool::makeClusters(const EventContext& ctx,
                  typename IPixelClusteringTool::ClusterCollection& clusters,
                  const InDetDD::SiDetectorElement& element,
                                  size_t icluster,
                                  std::any& vars,
                  typename ClusterContainer::iterator /*itrContainer*/) const
{
  // Retrieve the calibration data
  const PixelChargeCalibCondData *calibData = nullptr;
  if (not m_chargeDataKey.empty()) {
    SG::ReadCondHandle<PixelChargeCalibCondData> calibDataHandle = SG::makeHandle( m_chargeDataKey, ctx );
    calibData = calibDataHandle.cptr();
    
    if (!calibData) {
      ATH_MSG_ERROR("PixelChargeCalibCondData requested but couldn't be retrieved from " << m_chargeDataKey.key());
      return StatusCode::FAILURE;
    }
  }
  
  // Get the element design
  const InDetDD::PixelModuleDesign& design = 
    static_cast<const InDetDD::PixelModuleDesign&>(element.design());
  
  // Get the calibration strategy for this module. 
  // Default to RD53 if the calibData is not available. That is fine because it won't be used anyway
  auto calibrationStrategy = calibData ? calibData->getCalibrationStrategy(element.identifyHash()) : PixelChargeCalibCondData::CalibrationStrategy::RD53;
 
  double lorentz_shift = m_pixelLorentzAngleTool->getLorentzShift(element.identifyHash(), ctx);
 
  auto* clusterVars = std::any_cast<xAOD::PixelCluster::ClusterVars> (&vars);
  if (!clusterVars) throw std::bad_any_cast();
 
  for (typename IPixelClusteringTool::Cluster& cl : clusters) {
    ATH_CHECK(makeCluster(cl,
                          &element,
                          design,
                          calibData,
                          calibrationStrategy,
                          lorentz_shift,
                          icluster++,
                          *clusterVars));
  }
  
  return StatusCode::SUCCESS;
}
 
typename IPixelClusteringTool::CellCollection
PixelClusteringTool::unpackRDOs(const RawDataCollection& RDOs,
                const InDet::SiDetectorElementStatus& pixelDetElStatus,
                const InDetDD::SiDetectorElement& element) const
{
  // Get the element design
  const InDetDD::PixelModuleDesign& design =
    static_cast<const InDetDD::PixelModuleDesign&>(element.design());
  CellCollection cells;
  cells.reserve(300);
  
  const IdentifierHash& idHash = RDOs.identifyHash();
  for (const auto *const rdo : RDOs) {
    const Identifier& rdoID = rdo->identify();
    std::array<InDetDD::PixelDiodeTree::CellIndexType,2> diode_idx
      = InDetDD::PixelDiodeTree::makeCellIndex(m_pixelID->phi_index(rdoID),
                                               m_pixelID->eta_index(rdoID));
    InDetDD::PixelDiodeTree::DiodeProxy si_param ( design.diodeProxyFromIdx(diode_idx));
    std::uint32_t fe = design.getFE(si_param);
    
    // check if good RDO
    // the pixel RDO tool here says always good if m_useModuleMap is false
    if (not pixelDetElStatus.isChipGood(idHash, fe)) {
      continue;
    }
    
    const int lvl1 = rdo->getLVL1A();
    const int tot = rdo->getToT();
    
    cells.emplace_back(m_pixelID->phi_index(rdoID),
                       m_pixelID->eta_index(rdoID),
                       tot,
                       lvl1,
                       rdoID.get_compact());
    
    if ( m_checkGanged ) {
      std::optional<Identifier> gangedID = isGanged(rdoID, element);
      if (gangedID.has_value()) {
        cells.emplace_back(m_pixelID->phi_index(*gangedID),
                           m_pixelID->eta_index(*gangedID),
                           tot,
                           lvl1,
                           gangedID->get_compact());
      }
    }
    
  }
 
  return cells;
}
 
inline std::optional<Identifier>
PixelClusteringTool::isGanged(const Identifier& rdoID,
                  const InDetDD::SiDetectorElement& element)
{
  // If the pixel is ganged, returns a new identifier for it
  InDetDD::SiCellId cellID = element.cellIdFromIdentifier( rdoID );
  if ( element.numberOfConnectedCells( cellID ) > 1 ) {
    InDetDD::SiCellId gangedCellID = element.connectedCell( cellID, 1 );
    return element.identifierFromCellId( gangedCellID );
  } 
  return std::nullopt;
}
  
} // namespace ActsTrk