eflowCellSubtractionFacilitator.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
// Athena Headers
#include "eflowCellSubtractionFacilitator.h"
//#include "eflowCellPosition.h"
 
#include "AthenaKernel/getMessageSvc.h"
#include "CaloEvent/CaloCell.h"
#include "GaudiKernel/Bootstrap.h"
#include "GaudiKernel/IMessageSvc.h"
#include "GaudiKernel/ISvcLocator.h"
#include "xAODCaloEvent/CaloClusterKineHelper.h"
 
// C++ Headers
#include <map>
 
eflowCellSubtractionFacilitator::eflowCellSubtractionFacilitator()
  : AsgMessaging("eflowCellSubtractionFacilitator")
{}
 
double
eflowCellSubtractionFacilitator::subtractCells(
  eflowRingSubtractionManager& cellSubtractionManager,
  eflowRecTrack& theTrack,
  xAOD::CaloCluster* tracksCluster,
  eflowCellList& orderedCells,
  bool& annFlag, bool addCPData) const
{
  std::vector<std::pair<xAOD::CaloCluster*, bool>> localClusterBoolPairVec(
    1, std::pair(tracksCluster, false));
  return subtractCells(
    cellSubtractionManager, theTrack, localClusterBoolPairVec, orderedCells, annFlag, addCPData);
}
 
void
eflowCellSubtractionFacilitator::updateClusterKinematics(
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters)
{
  for (auto& thisPair : tracksClusters)
    updateClusterKinematics(thisPair.first);
}
 
void
eflowCellSubtractionFacilitator::updateClusterKinematics(
  xAOD::CaloCluster* theCluster)
{
  float oldEnergy = theCluster->e();
  CaloClusterKineHelper::calculateKine(theCluster, true, true);
  if (0.0 != oldEnergy) {
    float energyAdjustment = theCluster->e() / oldEnergy;
    theCluster->setRawE(theCluster->rawE() * energyAdjustment);
    theCluster->setRawEta(theCluster->eta());
    theCluster->setRawPhi(theCluster->phi());
  }
}
 
double
eflowCellSubtractionFacilitator::getTotalEnergy(
  const std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters)
{
  double eClustersOld = 0;
  /* Summed energy of all clusters before subtraction */
  for (auto& thisPair : tracksClusters)
    eClustersOld += (thisPair.first)->e();
  return eClustersOld;
}
 
double
eflowCellSubtractionFacilitator::getRingsEnergy(
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters,
  CellIt beginRing,
  CellIt endRing)
{
  /* Get total energy of ringes from beginRing to endRing */
 
  double eRing(0.0);
  for (CellIt it = beginRing; it != endRing; ++it) {
    /* Loop over Rings */
    for (const std::pair<const CaloCell*, int>& thisPair : it->second) {
      /* Loop over Cells */
      xAOD::CaloCluster* clus = tracksClusters[thisPair.second].first;
      CaloClusterCellLink::iterator theIterator =
        eflowCellSubtractionFacilitator::getCellIterator(clus, thisPair.first);
      double cellWeight = theIterator.weight();
      eRing += thisPair.first->energy() * cellWeight;
    }
  }
 
  return eRing;
}
 
void
eflowCellSubtractionFacilitator::annihilateClusters(
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters, bool& annFlag,
  eflowRecTrack& theTrack, bool addCPData)
{
  for (auto& thisPair : tracksClusters) {
    xAOD::CaloCluster* thisCluster = thisPair.first;
    CaloClusterCellLink* theCellLink = thisCluster->getOwnCellLinks();
    CaloClusterCellLink::iterator theFirstCell = theCellLink->begin();
    CaloClusterCellLink::iterator theLastCell = theCellLink->end();
 
    //We don't advance the iterator, theCell, because we call removeCell. This avoids issues with
    //invalid iterators that would otherwise occur and cause only a subset of cells to be processed.
    //We also have to reset the lastCell iterator after each call to ensure the loop exits at the end, 
    //instead of being stuck in an infinite loop.
    for (; theFirstCell != theLastCell;){
      if (addCPData) theTrack.addSubtractedCaloCell(ElementLink<CaloCellContainer>("AllCalo",theFirstCell.index()),theFirstCell.weight());
      thisCluster->removeCell(*theFirstCell);
      theLastCell = theCellLink->end();
    }
    thisCluster->setCalE(0.0);
    thisCluster->setRawE(0.0);
    // set the subtracted status to true
    thisPair.second = true;
  }
  annFlag = true;
}
 
void
eflowCellSubtractionFacilitator::subtractPartialRings(
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters,
  CellIt beginRing,
  CellIt endRing,
  double targetRingEnergy,
  double eRings, eflowRecTrack& theTrack,
  bool addCPData) const
{ 
  if (eRings == 0.)[[unlikely]]{
    ATH_MSG_ERROR("eflowCellSubtractionFacilitator::subtractPartialRings: eRings is zero.");
    return;
  }
  for (CellIt itRing = beginRing; itRing != endRing; ++itRing) {
    /* Loop over Rings */
    for (const std::pair<const CaloCell*, int>& thisPair : itRing->second) {
      /* Loop over Cells */
      xAOD::CaloCluster* cluster = tracksClusters[thisPair.second].first;
      // flag this cluster as having had subtraction applied to it
      tracksClusters[thisPair.second].second = true;
      const CaloCell* cell = thisPair.first;
      CaloClusterCellLink::iterator theIterator =
        eflowCellSubtractionFacilitator::getCellIterator(cluster, cell);
      double oldCellWeight = theIterator.weight();
      double ringWeight = targetRingEnergy / eRings;
      const double newCellWeight = oldCellWeight * ringWeight;
      ATH_MSG_DEBUG("eflowCellSubtractionFacilitator: Cluster with e "
                    << cluster->e()
                    << " is changing weight of cell with energy " << cell->e()
                    << " from " << oldCellWeight << " to " << newCellWeight);
      theIterator.reweight(newCellWeight);
      if (addCPData) theTrack.addSubtractedCaloCell(ElementLink<CaloCellContainer>("AllCalo",theIterator.index()),newCellWeight);
    }
  }
}
 
void
eflowCellSubtractionFacilitator::subtractFullRings(
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters,
  CellIt beginRing,
  CellIt endRing, eflowRecTrack& theTrack,
  bool addCPData) const
{
  /* Subtract full ring */
 
  for (CellIt itRing = beginRing; itRing != endRing; ++itRing) {
    /* Loop over Rings */
    for (const std::pair<const CaloCell*, int>& thisPair : itRing->second) {
      /* Loop over Cells */
      xAOD::CaloCluster* cluster = tracksClusters[thisPair.second].first;
      // flag this cluster as having had subtraction applied to it
      tracksClusters[thisPair.second].second = true;
      ATH_MSG_DEBUG("eflowCellSubtractionFacilitator: Cluster with e "
                    << cluster->e() << " is removing cell with e "
                    << thisPair.first->e());
      CaloClusterCellLink::iterator theIterator = this->getCellIterator(cluster, thisPair.first);
      if (addCPData) theTrack.addSubtractedCaloCell(ElementLink<CaloCellContainer>("AllCalo",theIterator.index()),theIterator.weight());
      cluster->removeCell(thisPair.first);
    }
  }
}
 
bool
eflowCellSubtractionFacilitator::subtractRings(
  eflowRingSubtractionManager& cellSubtractionManager,
  const std::pair<eflowCaloENUM, short>& ring,
  double& eSubtracted,
  const double eExpect,
  eflowCellList& orderedCells,
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters,
  bool& annFlag, eflowRecTrack& theTrack,
  bool addCPData ) const
{
  /* Subtract energy from ring, return TRUE if the whole expected energy is
   * subtracted */
 
  const eflowCaloENUM subtLayer = ring.first;
  const short ringNo = ring.second;
 
  const double r1 = ringNo * cellSubtractionManager.ringThickness(subtLayer);
  const double r2 =
    (ringNo + 1) * cellSubtractionManager.ringThickness(subtLayer);
 
  CellIt beginRing = orderedCells.getLowerBound(subtLayer, r1);
  CellIt endRing = orderedCells.getLowerBound(subtLayer, r2);
 
  /* Get total energy of Rings from beginRing to endRing */
  double eRings = getRingsEnergy(tracksClusters, beginRing, endRing);
 
  if (eSubtracted + eRings > eExpect) {
    /* Subtract partial ring */
 
    ATH_MSG_DEBUG("eflowCellSubtractionFacilitator: Subtracting partial ring, "
                  "eSubtracted, eRings and eExpect are "
                  << eSubtracted << ", " << eRings << ", " << eExpect);
 
    /* Target ring energy is ring energy minus the energy that still needs to be
     * subtracted */
    double targetRingEnergy = eRings - (eExpect - eSubtracted);
    ATH_MSG_DEBUG("eflowCellSubtractionFacilitator: targetRingEnergy is "
                  << targetRingEnergy);
    subtractPartialRings(
      tracksClusters, beginRing, endRing, targetRingEnergy, eRings, theTrack, addCPData);
    eSubtracted = eExpect;
 
    /* Update the cluster four-momenta having done the subtraction */
    updateClusterKinematics(tracksClusters);
 
    return true;
 
  } else {
    /* Subtract full ring */
 
    ATH_MSG_DEBUG("eflowCellSubtractionFacilitator: Subtracting full ring ");
 
    subtractFullRings(tracksClusters, beginRing, endRing, theTrack, addCPData);
    orderedCells.deleteFromList(beginRing, endRing);
    eSubtracted += eRings;
 
    /* If no energy left */
    double eClustersOld = getTotalEnergy(tracksClusters);
    if (std::fabs(eClustersOld - eSubtracted) < 1.0e-6 * eClustersOld) {
      /* Annihilate clusters, clear orderedCells, and update subtracted cluster
       * kinematics */
      annihilateClusters(tracksClusters,annFlag, theTrack, addCPData);
      orderedCells.eraseList();
      updateClusterKinematics(tracksClusters);
 
      return true;
    }
 
    return false;
  }
}
 
bool
eflowCellSubtractionFacilitator::subtractCaloCell(double& eSubtracted,
                                                  const double eExpect,
                                                  xAOD::CaloCluster* cluster,
                                                  const CaloCell* cell, 
                                                  eflowRecTrack& theTrack,
                                                  bool addCPData)
{
 
  CaloClusterCellLink::iterator theIterator =
    eflowCellSubtractionFacilitator::getCellIterator(cluster, cell);
  double oldCellWeight = theIterator.weight();
  double oldCellEnergy = cell->energy() * oldCellWeight;
 
  if (oldCellEnergy != 0. && eSubtracted + oldCellEnergy > eExpect) {
    /* Target cell energy is cell energy minus the energy that still needs to be
     * subtracted */
    double targetCellEnergy = oldCellEnergy - (eExpect - eSubtracted);
 
    double energyWeight = targetCellEnergy / oldCellEnergy;
    double newCellWeight = oldCellWeight * energyWeight;
    theIterator.reweight(newCellWeight);
    if (addCPData) theTrack.addSubtractedCaloCell(ElementLink<CaloCellContainer>("AllCalo",theIterator.index()), energyWeight*theIterator.weight());
 
    eSubtracted = eExpect;
 
    /* Update the cluster four-momenta having done the subtraction */
    updateClusterKinematics(cluster);
 
    return true;
 
  } else {
    if (addCPData) theTrack.addSubtractedCaloCell(ElementLink<CaloCellContainer>("AllCalo",theIterator.index()),theIterator.weight());
    cluster->removeCell(cell);
    eSubtracted += oldCellEnergy;
 
    /* Update the clusters having done the subtraction */
    updateClusterKinematics(cluster);
    return false;
  }
}
 
bool
eflowCellSubtractionFacilitator::subtractReorderedCells(
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters,
  double eSubtracted,
  const double eExpect,
  eflowCellList& reorderedCells, 
  eflowRecTrack& theTrack,
  bool addCPData)
{
  CellIt itCellPosition = reorderedCells.begin();
  CellIt endCellPosition = reorderedCells.end();
  while (itCellPosition != endCellPosition) {
    /* Loop cells */
    std::vector<std::pair<const CaloCell*, int>>::iterator itEntry =
      itCellPosition->second.begin();
    std::vector<std::pair<const CaloCell*, int>>::iterator endEntry =
      itCellPosition->second.end();
    for (; itEntry != endEntry; ++itEntry) {
      const std::pair<const CaloCell*, int> thisPair = *itEntry;
      xAOD::CaloCluster* cluster = tracksClusters[thisPair.second].first;
      // flag this cluster as having had subtraction applied to it
      tracksClusters[thisPair.second].second = true;
      const CaloCell* cell = thisPair.first;
      bool isFinished = subtractCaloCell(eSubtracted, eExpect, cluster, cell, theTrack, addCPData);
      if (isFinished)
        return true;
    }
    /* Erase the CellPosition from the cell list */
    CellIt tmp = itCellPosition;
    ++itCellPosition;
    reorderedCells.deleteFromList(tmp);
  }
  return false;
}
 
double
eflowCellSubtractionFacilitator::subtractCells(
  eflowRingSubtractionManager& cellSubtractionManager,
  eflowRecTrack& theTrack,
  std::vector<std::pair<xAOD::CaloCluster*, bool>>& tracksClusters,
  eflowCellList& orderedCells,
  bool& annFlag, bool addCPData) const
{
 
  const double trackEnergy = theTrack.getTrack()->e();
  const double eExpect = cellSubtractionManager.fudgeMean() * trackEnergy;
  const double sigmaEExpect =
    cellSubtractionManager.fudgeStdDev() * trackEnergy;
  ATH_MSG_DEBUG("eflowCellSubtractionFacilitator: For track with trackEnergy "
                << trackEnergy << " expect to subtract " << eExpect
                << " with width of " << sigmaEExpect);
 
  double eSubtracted = 0.0;
 
  /*
   * Ring subtraction
   */
  std::map<double, RingId>::const_iterator ringIt =
    cellSubtractionManager.rankBegin();
  std::map<double, RingId>::const_iterator ringEnd =
    cellSubtractionManager.rankEnd();
  for (; ringIt != ringEnd; ++ringIt) {
    bool isFinished = subtractRings(cellSubtractionManager,
                                    ringIt->second,
                                    eSubtracted,
                                    eExpect,
                                    orderedCells,
                                    tracksClusters,
                                    annFlag,
                                    theTrack,
                                    addCPData);
    if (isFinished) {
      return sigmaEExpect;
    }
  }
 
  /* Update the cluster four-momenta */
  updateClusterKinematics(tracksClusters);
 
  if (orderedCells.mapSize() <= 0 || eSubtracted >= eExpect) {
    return sigmaEExpect;
  }
 
  /*
   * Cell subtraction
   */
  /* Increasing dR (not by layer) for cell subtraction */
  orderedCells.reorderWithoutLayers();
 
  bool isFinished =
    subtractReorderedCells(tracksClusters, eSubtracted, eExpect, orderedCells, theTrack, addCPData);
  if (isFinished) {
    return sigmaEExpect;
  }
 
  /* Update the cluster four-momenta */
  updateClusterKinematics(tracksClusters);
 
  return sigmaEExpect;
}
 
CaloClusterCellLink::iterator
eflowCellSubtractionFacilitator::getCellIterator(
  xAOD::CaloCluster* thisCluster,
  const CaloCell* thisCell)
{
 
  // SLOW! Can we move to directly work with iterators in future?
 
  // We have to use non-const iterators so that we are allowed to modify the
  // cell weights
  CaloClusterCellLink* theCells = thisCluster->getOwnCellLinks();
 
  CaloClusterCellLink::iterator itCell = theCells->begin();
  CaloClusterCellLink::iterator endCell = theCells->end();
  for (; itCell != endCell; ++itCell) {
    const CaloCell* pCell = (*itCell);
    if (pCell == thisCell) { // Pointer comparison!
      return itCell;
    }
  }
 
  // if no match is found then return end of container
  return endCell;
}