TotPixelClusterSplitter.cxx

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/*
  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
*/
 
#include "SiClusterizationTool/TotPixelClusterSplitter.h"
 
#include "GaudiKernel/ServiceHandle.h"
#include "GeoPrimitives/GeoPrimitives.h"
#include "EventPrimitives/EventPrimitives.h"
 
#include "InDetPrepRawData/PixelCluster.h"
 
#include "InDetReadoutGeometry/SiDetectorElement.h"
#include <algorithm> //minmax_element
#include <tuple> //std::tuple
 
InDet::TotPixelClusterSplitter::TotPixelClusterSplitter(const std::string & type, const std::string & name, const IInterface * parent) :
  base_class(type, name, parent),
  m_minPixels(3),
  m_maxPixels(25)
{
}
 
StatusCode InDet::TotPixelClusterSplitter::initialize() {
 
  ATH_CHECK(m_pixelReadout.retrieve());
  ATH_CHECK(m_chargeDataKey.initialize());
 
  return StatusCode::SUCCESS;
}
 
StatusCode InDet::TotPixelClusterSplitter::finalize() {
  return StatusCode::SUCCESS;
}
 
std::vector<InDet::PixelClusterParts> 
InDet::TotPixelClusterSplitter::splitCluster( const InDet::PixelCluster & OrigCluster) const {
 
  std::vector<InDet::PixelClusterParts> Parts;
 
  const std::vector<Identifier> & Rdos = OrigCluster.rdoList();
  const unsigned int NumPixels = static_cast<unsigned int>(Rdos.size());
  const InDetDD::SiDetectorElement * Element = OrigCluster.detectorElement();
 
  // Check cluster-size bounds.
  if (NumPixels < m_minPixels || NumPixels > m_maxPixels) return Parts;
 
  std::vector<InDetDD::SiCellId> CellIds(NumPixels); //NumPixels entries of default constructed SiCellId
  
  auto getCellId=[Element](const Identifier & i){ return Element->cellIdFromIdentifier(i);};
  std::transform(Rdos.begin(),Rdos.end(), CellIds.begin(), getCellId);
 
  SG::ReadCondHandle<PixelChargeCalibCondData> calibDataHandle(m_chargeDataKey);
  const PixelChargeCalibCondData *calibData = *calibDataHandle;
 
  // Detect special pixels and exclude them if necessary.
  // Veto removed on 28-7-2011 by K. Barry - residual-level 
  // studies show RMS improvement when ganged-pixel containing 
  // clusters are split.
  
 
  // Determine maximum and minimum phi and eta indices.
  auto comparePhi=[](const InDetDD::SiCellId & a, const InDetDD::SiCellId & b){ return (a.phiIndex() < b.phiIndex());};
  auto compareEta=[](const InDetDD::SiCellId & a, const InDetDD::SiCellId & b){ return (a.etaIndex() < b.etaIndex());};
  const auto [pMinPhi,pMaxPhi] = std::minmax_element(CellIds.begin(), CellIds.end(), comparePhi);
  const auto [pMinEta,pMaxEta] = std::minmax_element(CellIds.begin(), CellIds.end(), compareEta);
  const auto & MinPhiIdx = pMinPhi->phiIndex();
  const auto & MaxPhiIdx = pMaxPhi->phiIndex();
  const auto & MinEtaIdx = pMinEta->etaIndex();
  const auto & MaxEtaIdx = pMaxEta->etaIndex();
  const int PhiWidth = MaxPhiIdx - MinPhiIdx + 1;
  const int EtaWidth = MaxEtaIdx - MinEtaIdx + 1;
  
  // In the future, might want to add a check here to see if the charge list is empty...
  const std::vector<float> & Charges = OrigCluster.chargeList();
 
  std::vector<float> PhiChargeHist(PhiWidth, 0.);
  unsigned int NumPhiMinima = 0;
  std::vector<unsigned int> PhiMinimaLoc(PhiWidth/2);
  std::vector<float> PhiMinimaQuality(PhiWidth/2);
  if (PhiWidth > 2)
  {
    // Fill up the phi-charge histogram. The values were initialized to zero by the vector constructor.
    for (unsigned int i = 0; i < NumPixels; i++)
      PhiChargeHist[CellIds[i].phiIndex() - MinPhiIdx] += Charges[i];
 
    // Minima search
    for (int i = 1; i < PhiWidth - 1; i++)
    {
      if (PhiChargeHist[i-1] <= PhiChargeHist[i] || PhiChargeHist[i] >= PhiChargeHist[i+1]) continue;
 
      PhiMinimaLoc[NumPhiMinima] = static_cast<unsigned int>(i);
      PhiMinimaQuality[NumPhiMinima++] = (PhiChargeHist[i+1] + PhiChargeHist[i-1] - 2.*PhiChargeHist[i]) /
                                      (PhiChargeHist[i+1] + PhiChargeHist[i-1]);
    }
  }
    
  std::vector<float> EtaChargeHist(EtaWidth, 0.);
  unsigned int NumEtaMinima = 0;
  std::vector<unsigned int> EtaMinimaLoc(EtaWidth/2);
  std::vector<float> EtaMinimaQuality(EtaWidth/2);
  const float LongPixScale = 2./3.;
  if (EtaWidth > 2)
  {
    float Scale;
    // Fill up the eta-charge histogram. The values were initialized to zero by the vector constructor.
    for (unsigned int i = 0; i < NumPixels; i++)
    {
      const int PixType = pixelType(CellIds[i].phiIndex(), CellIds[i].etaIndex());
      if ( (PixType % 2) == 1 )
        Scale = LongPixScale;
      else
        Scale = 1.;
      EtaChargeHist[CellIds[i].etaIndex() - MinEtaIdx] += Scale*Charges[i];
    }
 
    // Minima search
    for (int i = 1; i < EtaWidth - 1; i++)
    {
      if (EtaChargeHist[i-1] <= EtaChargeHist[i] || EtaChargeHist[i] >= EtaChargeHist[i+1]) continue;
 
      EtaMinimaLoc[NumEtaMinima] = static_cast<unsigned int>(i);
      EtaMinimaQuality[NumEtaMinima++] = (EtaChargeHist[i+1] + EtaChargeHist[i-1] - 2.*EtaChargeHist[i]) /
                                         (EtaChargeHist[i+1] + EtaChargeHist[i-1]);
    }
  }
 
  // Select the "best" minimum for splitting
  unsigned int bestMin = 0;
  float bestQual = -1.;
  SplitType Type = NoSplit;
  for (unsigned int i = 0; i < NumPhiMinima; i++)
  {
    if (PhiMinimaQuality[i] <= bestQual) continue;
    Type = PhiSplit;
    bestMin = PhiMinimaLoc[i];
    bestQual = PhiMinimaQuality[i];
  }
  for (unsigned int i = 0; i < NumEtaMinima; i++)
  {
    if (EtaMinimaQuality[i] <= bestQual) continue;
    Type = EtaSplit;
    bestMin = EtaMinimaLoc[i];
    bestQual = EtaMinimaQuality[i];
  }
  const int SplitIndex = static_cast<int>(bestMin);
 
  // Now it's time to do the split!
  if (Type == NoSplit)
  {
    return Parts;
  }
  if (Type != PhiSplit && Type != EtaSplit)
  {
    // Should never happen...major bug someplace if it does
    ATH_MSG_ERROR("<InDet::TotPixelClusterSplitter::splitCluster> : Unrecognized SplitType!");
    return Parts;
  }
 
  int Idx;
  int (InDetDD::SiCellId:: * const IndexFunc) () const = (Type == PhiSplit) ? &InDetDD::SiCellId::phiIndex
                                                                            : &InDetDD::SiCellId::etaIndex;
  const int LowIdx = (Type == PhiSplit) ? MinPhiIdx : MinEtaIdx;
 
  // Variables for PixelClusterParts
  std::vector<Identifier> SplitRdos[2];
  std::vector<int> Totgroups[2];
  std::vector<int> Lvl1groups[2];
 
  const std::vector<int>& OrigTots = OrigCluster.totList();
  const int Lvl1a = OrigCluster.LVL1A();
  
  const AtlasDetectorID* aid = Element->getIdHelper();
  if (aid==nullptr)
  {
    ATH_MSG_ERROR("Could not get ATLASDetectorID");
    return Parts;
  }
  
  if (aid->helper() != AtlasDetectorID::HelperType::Pixel){
    ATH_MSG_ERROR("Could not get PixelID pointer");
    return Parts;
  } 
  const PixelID* pixelIDp=static_cast<const PixelID*>(aid);
  const PixelID& pixelID = *pixelIDp;
 
  
  for (unsigned int i = 0; i < NumPixels; i++)
  {
    Idx = (CellIds[i].*IndexFunc)() - LowIdx;
    if (Idx < SplitIndex)
    {
      SplitRdos[0].push_back(Rdos[i]);
      Totgroups[0].push_back(OrigTots[i]);
      Lvl1groups[0].push_back(Lvl1a);
    }
    else if (Idx > SplitIndex)
    {
      SplitRdos[1].push_back(Rdos[i]);
      Totgroups[1].push_back(OrigTots[i]);
      Lvl1groups[1].push_back(Lvl1a);
    }
    else // only == remains
    {
      for (int j = 0; j < 2; j++)
      {
 
        Identifier pixid = Rdos[i];
        Identifier moduleID = pixelID.wafer_id(pixid);
        IdentifierHash moduleHash = pixelID.wafer_hash(moduleID); // wafer hash
        unsigned int FE = m_pixelReadout->getFE(pixid, moduleID);
        InDetDD::PixelDiodeType type = m_pixelReadout->getDiodeType(pixid);
 
        SplitRdos[j].push_back(Rdos[i]);
        Totgroups[j].push_back(calibData->getToT(type, moduleHash, FE, Charges[i] / 2.0));
        Lvl1groups[j].push_back(Lvl1a);
      }
    }
  }
 
  Parts.emplace_back(SplitRdos[0], Totgroups[0], Lvl1groups[0]);
  Parts.emplace_back(SplitRdos[1], Totgroups[1], Lvl1groups[1]);
    
  return Parts;
}
 
std::vector<InDet::PixelClusterParts> InDet::TotPixelClusterSplitter::splitCluster(
  const InDet::PixelCluster & OrigCluster, 
  const InDet::PixelClusterSplitProb &) const
{
  return splitCluster(OrigCluster);
}
 
int InDet::TotPixelClusterSplitter::pixelType(const int PhiIdx, const int EtaIdx) 
{
  if (EtaIdx%18 != 0 && EtaIdx%18 != 17)
  {
    if (PhiIdx==152 || PhiIdx==154 || PhiIdx==156 || PhiIdx==158 ||
        PhiIdx==169 || PhiIdx==171 || PhiIdx==173 || PhiIdx==175)
      return 4; // short inter-ganged pixel
    else if (PhiIdx==153 || PhiIdx==155 || PhiIdx==157 || PhiIdx==159 ||
             (PhiIdx > 159 && PhiIdx < 168) ||
             PhiIdx==168 || PhiIdx==170 || PhiIdx==172 || PhiIdx==174)
      return 2; // short ganged pixel
    else
      return 0; // short normal pixel
  }
  else
  {
    if (PhiIdx==152 || PhiIdx==154 || PhiIdx==156 || PhiIdx==158 ||
        PhiIdx==169 || PhiIdx==171 || PhiIdx==173 || PhiIdx==175)
      return 5; // long inter-ganged pixel
    else if (PhiIdx==153 || PhiIdx==155 || PhiIdx==157 || PhiIdx==159 ||
             (PhiIdx > 159 && PhiIdx < 168) ||
             PhiIdx==168 || PhiIdx==170 || PhiIdx==172 || PhiIdx==174)
      return 3; // long ganged pixel
    else
      return 1; // long normal pixel
  }
}