PreMixingSiStripWorker.cc

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#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/ConsumesCollector.h"
#include "FWCore/Framework/interface/ProducerBase.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FWCore/ServiceRegistry/interface/Service.h"
#include "DataFormats/Common/interface/Handle.h"
#include "SimGeneral/MixingModule/interface/PileUpEventPrincipal.h"
#include "SimDataFormats/PileupSummaryInfo/interface/PileupSummaryInfo.h"
#include "CondFormats/SiStripObjects/interface/SiStripBadStrip.h"
#include "CalibTracker/Records/interface/SiStripDependentRecords.h"

#include "DataFormats/Common/interface/Handle.h"
#include "FWCore/Utilities/interface/RandomNumberGenerator.h"

//Data Formats
#include "DataFormats/Common/interface/DetSetVector.h"
#include "DataFormats/Common/interface/DetSet.h"
#include "DataFormats/SiStripDigi/interface/SiStripDigi.h"

#include "CondFormats/SiStripObjects/interface/SiStripNoises.h"
#include "CondFormats/SiStripObjects/interface/SiStripPedestals.h"
#include "CondFormats/SiStripObjects/interface/SiStripThreshold.h"
#include "CondFormats/SiStripObjects/interface/SiStripApvSimulationParameters.h"
#include "CalibFormats/SiStripObjects/interface/SiStripGain.h"
#include "SimTracker/SiStripDigitizer/interface/SiTrivialDigitalConverter.h"
#include "SimTracker/SiStripDigitizer/interface/SiGaussianTailNoiseAdder.h"
#include "RecoLocalTracker/SiStripZeroSuppression/interface/SiStripFedZeroSuppression.h"

#include "Geometry/TrackerGeometryBuilder/interface/TrackerGeometry.h"
#include "Geometry/CommonDetUnit/interface/GeomDet.h"
#include "Geometry/TrackerGeometryBuilder/interface/StripGeomDetUnit.h"
#include "Geometry/CommonTopologies/interface/StripTopology.h"
#include "Geometry/CommonDetUnit/interface/GeomDetType.h"

#include "CLHEP/Random/RandFlat.h"

#include "SimGeneral/PreMixingModule/interface/PreMixingWorker.h"
#include "SimGeneral/PreMixingModule/interface/PreMixingWorkerFactory.h"

#include <map>
#include <memory>

class PreMixingSiStripWorker : public PreMixingWorker {
public:
  PreMixingSiStripWorker(const edm::ParameterSet& ps, edm::ProducerBase& producer, edm::ConsumesCollector&& iC);
  ~PreMixingSiStripWorker() override = default;

  void initializeEvent(edm::Event const& e, edm::EventSetup const& c) override;
  void addSignals(edm::Event const& e, edm::EventSetup const& es) override;
  void addPileups(PileUpEventPrincipal const& pep, edm::EventSetup const& es) override;
  void put(edm::Event& e, edm::EventSetup const& iSetup, std::vector<PileupSummaryInfo> const& ps, int bs) override;

private:
  void DMinitializeDetUnit(StripGeomDetUnit const* det, const edm::EventSetup& iSetup);

  // data specifiers

  edm::InputTag SistripLabelSig_;        // name given to collection of SiStrip digis
  edm::InputTag SiStripPileInputTag_;    // InputTag for pileup strips
  std::string SiStripDigiCollectionDM_;  // secondary name to be given to new SiStrip digis

  edm::InputTag SistripAPVLabelSig_;  // where to find vector of dead APVs
  edm::InputTag SiStripAPVPileInputTag_;
  std::string SistripAPVListDM_;  // output tag

  //

  typedef float Amplitude;
  typedef std::pair<uint16_t, Amplitude> RawDigi;  // Replacement for SiStripDigi with pulse height instead of integer ADC
  typedef std::vector<SiStripDigi> OneDetectorMap;  // maps by strip ID for later combination - can have duplicate strips
  typedef std::vector<RawDigi> OneDetectorRawMap;  // maps by strip ID for later combination - can have duplicate strips
  typedef std::map<uint32_t, OneDetectorMap> SiGlobalIndex;        // map to all data for each detector ID
  typedef std::map<uint32_t, OneDetectorRawMap> SiGlobalRawIndex;  // map to all data for each detector ID

  typedef SiDigitalConverter::DigitalVecType DigitalVecType;

  SiGlobalIndex SiHitStorage_;
  SiGlobalRawIndex SiRawDigis_;

  // variables for temporary storage of mixed hits:
  typedef std::map<int, Amplitude> SignalMapType;
  typedef std::map<uint32_t, SignalMapType> signalMaps;

  const SignalMapType* getSignal(uint32_t detID) const {
    auto where = signals_.find(detID);
    if (where == signals_.end()) {
      return nullptr;
    }
    return &where->second;
  }

  signalMaps signals_;

  // to keep track of dead APVs from HIP interactions
  typedef std::multimap<uint32_t, std::bitset<6>> APVMap;

  APVMap theAffectedAPVmap_;

  // for noise adding:

  std::string gainLabel;
  bool SingleStripNoise;
  bool peakMode;
  double theThreshold;
  double theElectronPerADC;
  bool APVSaturationFromHIP_;
  int theFedAlgo;
  std::string geometryType;

  std::unique_ptr<SiGaussianTailNoiseAdder> theSiNoiseAdder;
  std::unique_ptr<SiStripFedZeroSuppression> theSiZeroSuppress;
  std::unique_ptr<SiTrivialDigitalConverter> theSiDigitalConverter;

  edm::ESHandle<TrackerGeometry> pDD;

  // bad channels for each detector ID
  std::map<unsigned int, std::vector<bool>> allBadChannels;
  // channels killed by HIP interactions for each detector ID
  std::map<unsigned int, std::vector<bool>> allHIPChannels;
  // first and last channel wit signal for each detector ID
  std::map<unsigned int, size_t> firstChannelsWithSignal;
  std::map<unsigned int, size_t> lastChannelsWithSignal;

  bool includeAPVSimulation_;
  const double fracOfEventsToSimAPV_;
  const double apv_maxResponse_;
  const double apv_rate_;
  const double apv_mVPerQ_;
  const double apv_fCPerElectron_;

  //----------------------------

  class StrictWeakOrdering {
  public:
    bool operator()(SiStripDigi i, SiStripDigi j) const { return i.strip() < j.strip(); }
  };

  class StrictWeakRawOrdering {
  public:
    bool operator()(RawDigi i, RawDigi j) const { return i.first < j.first; }
  };
};

PreMixingSiStripWorker::PreMixingSiStripWorker(const edm::ParameterSet& ps,
                                               edm::ProducerBase& producer,
                                               edm::ConsumesCollector&& iC)
    : gainLabel(ps.getParameter<std::string>("Gain")),
      SingleStripNoise(ps.getParameter<bool>("SingleStripNoise")),
      peakMode(ps.getParameter<bool>("APVpeakmode")),
      theThreshold(ps.getParameter<double>("NoiseSigmaThreshold")),
      theElectronPerADC(ps.getParameter<double>(peakMode ? "electronPerAdcPeak" : "electronPerAdcDec")),
      APVSaturationFromHIP_(ps.getParameter<bool>("APVSaturationFromHIP")),
      theFedAlgo(ps.getParameter<int>("FedAlgorithm_PM")),
      geometryType(ps.getParameter<std::string>("GeometryType")),
      theSiZeroSuppress(new SiStripFedZeroSuppression(theFedAlgo)),
      theSiDigitalConverter(new SiTrivialDigitalConverter(theElectronPerADC, false)),  // no premixing
      includeAPVSimulation_(ps.getParameter<bool>("includeAPVSimulation")),
      fracOfEventsToSimAPV_(ps.getParameter<double>("fracOfEventsToSimAPV")),
      apv_maxResponse_(ps.getParameter<double>("apv_maxResponse")),
      apv_rate_(ps.getParameter<double>("apv_rate")),
      apv_mVPerQ_(ps.getParameter<double>("apv_mVPerQ")),
      apv_fCPerElectron_(ps.getParameter<double>("apvfCPerElectron"))

{
  // declare the products to produce

  SistripLabelSig_ = ps.getParameter<edm::InputTag>("SistripLabelSig");
  SiStripPileInputTag_ = ps.getParameter<edm::InputTag>("SiStripPileInputTag");

  SiStripDigiCollectionDM_ = ps.getParameter<std::string>("SiStripDigiCollectionDM");
  SistripAPVListDM_ = ps.getParameter<std::string>("SiStripAPVListDM");

  producer.produces<edm::DetSetVector<SiStripDigi>>(SiStripDigiCollectionDM_);
  producer.produces<bool>(SiStripDigiCollectionDM_ + "SimulatedAPVDynamicGain");

  if (APVSaturationFromHIP_) {
    SistripAPVLabelSig_ = ps.getParameter<edm::InputTag>("SistripAPVLabelSig");
    SiStripAPVPileInputTag_ = ps.getParameter<edm::InputTag>("SistripAPVPileInputTag");
    iC.consumes<std::vector<std::pair<int, std::bitset<6>>>>(SistripAPVLabelSig_);
  }
  iC.consumes<edm::DetSetVector<SiStripDigi>>(SistripLabelSig_);
  // clear local storage for this event
  SiHitStorage_.clear();

  edm::Service<edm::RandomNumberGenerator> rng;
  if (!rng.isAvailable()) {
    throw cms::Exception("Psiguration") << "SiStripDigitizer requires the RandomNumberGeneratorService\n"
                                           "which is not present in the psiguration file.  You must add the service\n"
                                           "in the configuration file or remove the modules that require it.";
  }

  theSiNoiseAdder.reset(new SiGaussianTailNoiseAdder(theThreshold));
}

void PreMixingSiStripWorker::initializeEvent(const edm::Event& e, edm::EventSetup const& iSetup) {
  // initialize individual detectors so we can copy real digitization code:

  iSetup.get<TrackerDigiGeometryRecord>().get(geometryType, pDD);

  for (auto iu = pDD->detUnits().begin(); iu != pDD->detUnits().end(); ++iu) {
    unsigned int detId = (*iu)->geographicalId().rawId();
    DetId idet = DetId(detId);
    unsigned int isub = idet.subdetId();
    if ((isub == StripSubdetector::TIB) || (isub == StripSubdetector::TID) || (isub == StripSubdetector::TOB) ||
        (isub == StripSubdetector::TEC)) {
      auto stripdet = dynamic_cast<StripGeomDetUnit const*>((*iu));
      assert(stripdet != nullptr);
      DMinitializeDetUnit(stripdet, iSetup);
    }
  }
}

void PreMixingSiStripWorker::DMinitializeDetUnit(StripGeomDetUnit const* det, const edm::EventSetup& iSetup) {
  edm::ESHandle<SiStripBadStrip> deadChannelHandle;
  iSetup.get<SiStripBadChannelRcd>().get(deadChannelHandle);

  unsigned int detId = det->geographicalId().rawId();
  int numStrips = (det->specificTopology()).nstrips();

  SiStripBadStrip::Range detBadStripRange = deadChannelHandle->getRange(detId);
  //storing the bad strip of the the module. the module is not removed but just signal put to 0
  std::vector<bool>& badChannels = allBadChannels[detId];
  std::vector<bool>& hipChannels = allHIPChannels[detId];
  badChannels.clear();
  badChannels.insert(badChannels.begin(), numStrips, false);
  hipChannels.clear();
  hipChannels.insert(hipChannels.begin(), numStrips, false);

  for (SiStripBadStrip::ContainerIterator it = detBadStripRange.first; it != detBadStripRange.second; ++it) {
    SiStripBadStrip::data fs = deadChannelHandle->decode(*it);
    for (int strip = fs.firstStrip; strip < fs.firstStrip + fs.range; ++strip)
      badChannels[strip] = true;
  }
  firstChannelsWithSignal[detId] = numStrips;
  lastChannelsWithSignal[detId] = 0;
}

void PreMixingSiStripWorker::addSignals(const edm::Event& e, edm::EventSetup const& es) {
  // fill in maps of hits

  edm::Handle<edm::DetSetVector<SiStripDigi>> input;

  if (e.getByLabel(SistripLabelSig_, input)) {
    OneDetectorMap LocalMap;

    //loop on all detsets (detectorIDs) inside the input collection
    edm::DetSetVector<SiStripDigi>::const_iterator DSViter = input->begin();
    for (; DSViter != input->end(); DSViter++) {
#ifdef DEBUG
      LogDebug("PreMixingSiStripWorker") << "Processing DetID " << DSViter->id;
#endif

      LocalMap.clear();
      LocalMap.reserve((DSViter->data).size());
      LocalMap.insert(LocalMap.end(), (DSViter->data).begin(), (DSViter->data).end());

      SiHitStorage_.insert(SiGlobalIndex::value_type(DSViter->id, LocalMap));
    }
  }

  // keep here for future reference.  In current implementation, HIP killing is done once in PU file
  /*  if(APVSaturationFromHIP_) {
      edm::Handle<std::vector<std::pair<int,std::bitset<6>> > >  APVinput;

      if( e.getByLabel(SistripAPVLabelSig_,APVinput) ) {

      std::vector<std::pair<int,std::bitset<6>> >::const_iterator entry = APVinput->begin();
      for( ; entry != APVinput->end(); entry++) {
      theAffectedAPVmap_.insert(APVMap::value_type(entry->first, entry->second));
      }
      }
      } */

}  // end of addSiStripSignals

void PreMixingSiStripWorker::addPileups(PileUpEventPrincipal const& pep, edm::EventSetup const& es) {
  LogDebug("PreMixingSiStripWorker") << "\n===============> adding pileups from event  " << pep.principal().id()
                                     << " for bunchcrossing " << pep.bunchCrossing();

  // fill in maps of hits; same code as addSignals, except now applied to the pileup events

  edm::Handle<edm::DetSetVector<SiStripDigi>> inputHandle;
  pep.getByLabel(SiStripPileInputTag_, inputHandle);

  if (inputHandle.isValid()) {
    const auto& input = *inputHandle;

    OneDetectorMap LocalMap;

    //loop on all detsets (detectorIDs) inside the input collection
    edm::DetSetVector<SiStripDigi>::const_iterator DSViter = input.begin();
    for (; DSViter != input.end(); DSViter++) {
#ifdef DEBUG
      LogDebug("PreMixingSiStripWorker") << "Pileups: Processing DetID " << DSViter->id;
#endif

      // find correct local map (or new one) for this detector ID

      SiGlobalIndex::const_iterator itest;

      itest = SiHitStorage_.find(DSViter->id);

      if (itest != SiHitStorage_.end()) {  // this detID already has hits, add to existing map

        LocalMap = itest->second;

        // fill in local map with extra channels
        LocalMap.insert(LocalMap.end(), (DSViter->data).begin(), (DSViter->data).end());
        std::stable_sort(LocalMap.begin(), LocalMap.end(), PreMixingSiStripWorker::StrictWeakOrdering());
        SiHitStorage_[DSViter->id] = LocalMap;

      } else {  // fill local storage with this information, put in global collection

        LocalMap.clear();
        LocalMap.reserve((DSViter->data).size());
        LocalMap.insert(LocalMap.end(), (DSViter->data).begin(), (DSViter->data).end());

        SiHitStorage_.insert(SiGlobalIndex::value_type(DSViter->id, LocalMap));
      }
    }

    if (APVSaturationFromHIP_) {
      edm::Handle<std::vector<std::pair<int, std::bitset<6>>>> inputAPVHandle;
      pep.getByLabel(SiStripAPVPileInputTag_, inputAPVHandle);

      if (inputAPVHandle.isValid()) {
        const auto& APVinput = inputAPVHandle;

        std::vector<std::pair<int, std::bitset<6>>>::const_iterator entry = APVinput->begin();
        for (; entry != APVinput->end(); entry++) {
          theAffectedAPVmap_.insert(APVMap::value_type(entry->first, entry->second));
        }
      }
    }
  }
}

void PreMixingSiStripWorker::put(edm::Event& e,
                                 edm::EventSetup const& iSetup,
                                 std::vector<PileupSummaryInfo> const& ps,
                                 int bs) {
  // set up machinery to do proper noise adding:
  edm::ESHandle<SiStripGain> gainHandle;
  edm::ESHandle<SiStripNoises> noiseHandle;
  edm::ESHandle<SiStripThreshold> thresholdHandle;
  edm::ESHandle<SiStripPedestals> pedestalHandle;
  edm::ESHandle<SiStripBadStrip> deadChannelHandle;
  edm::ESHandle<SiStripApvSimulationParameters> apvSimulationParametersHandle;
  edm::ESHandle<TrackerTopology> tTopo;
  iSetup.get<SiStripGainSimRcd>().get(gainLabel, gainHandle);
  iSetup.get<SiStripNoisesRcd>().get(noiseHandle);
  iSetup.get<SiStripThresholdRcd>().get(thresholdHandle);
  iSetup.get<SiStripPedestalsRcd>().get(pedestalHandle);

  edm::Service<edm::RandomNumberGenerator> rng;
  CLHEP::HepRandomEngine* engine = &rng->getEngine(e.streamID());

  const bool simulateAPVInThisEvent = includeAPVSimulation_ && (CLHEP::RandFlat::shoot(engine) < fracOfEventsToSimAPV_);
  float nTruePU = 0.;  // = ps.getTrueNumInteractions();
  if (simulateAPVInThisEvent) {
    iSetup.get<TrackerTopologyRcd>().get(tTopo);
    iSetup.get<SiStripApvSimulationParametersRcd>().get(apvSimulationParametersHandle);
    const auto it = std::find_if(
        std::begin(ps), std::end(ps), [](const PileupSummaryInfo& bxps) { return bxps.getBunchCrossing() == 0; });
    if (it != std::begin(ps)) {
      nTruePU = it->getTrueNumInteractions();
    } else {
      edm::LogWarning("PreMixingSiStripWorker") << "Could not find PileupSummaryInfo for current bunch crossing";
      nTruePU = std::begin(ps)->getTrueNumInteractions();
    }
  }

  std::map<int, std::bitset<6>> DeadAPVList;
  DeadAPVList.clear();

  // First, have to convert all ADC counts to raw pulse heights so that values can be added properly
  // In PreMixing, pulse heights are saved with ADC = sqrt(9.0*PulseHeight) - have to undo.

  // This is done here because it's the only place we have access to EventSetup
  // Simultaneously, merge lists of hit channels in each DetId.
  // Signal Digis are in the list first, have to merge lists of hit strips on the fly,
  // add signals on duplicates later

  OneDetectorRawMap LocalRawMap;

  // Now, loop over hits and add them to the map in the proper sorted order
  // Note: We are assuming that the hits from the Signal events have been created in
  // "PreMix" mode, rather than in the standard ADC conversion routines.  If not, this
  // doesn't work at all.

  // At the moment, both Signal and Reconstituted PU hits have the same compression algorithm.
  // If this were different, and one needed gains, the conversion back to pulse height can only
  // be done in this routine.  So, yes, there is an extra loop over hits here in the current code,
  // because, in principle, one could convert to pulse height during the read/store phase.

  for (SiGlobalIndex::const_iterator IDet = SiHitStorage_.begin(); IDet != SiHitStorage_.end(); IDet++) {
    uint32_t detID = IDet->first;

    OneDetectorMap LocalMap = IDet->second;

    //loop over hit strips for this DetId, do conversion to pulse height, store.

    LocalRawMap.clear();

    OneDetectorMap::const_iterator iLocal = LocalMap.begin();
    for (; iLocal != LocalMap.end(); ++iLocal) {
      uint16_t currentStrip = iLocal->strip();
      float signal = float(iLocal->adc());
      if (iLocal->adc() == 1022)
        signal = 1500.;  // average values for overflows
      if (iLocal->adc() == 1023)
        signal = 3000.;

      //convert signals back to raw counts

      float ReSignal = signal * signal / 9.0;  // The PreMixing conversion is adc = sqrt(9.0*pulseHeight)

      RawDigi NewRawDigi = std::make_pair(currentStrip, ReSignal);

      LocalRawMap.push_back(NewRawDigi);
    }

    // save information for this detiD into global map
    SiRawDigis_.insert(SiGlobalRawIndex::value_type(detID, LocalRawMap));
  }

  // If we are killing APVs, merge list of dead ones before we digitize

  int NumberOfBxBetweenHIPandEvent = 1e3;

  if (APVSaturationFromHIP_) {
    // calculate affected BX parameter

    bool HasAtleastOneAffectedAPV = false;
    while (!HasAtleastOneAffectedAPV) {
      for (int bx = floor(300.0 / 25.0); bx > 0; bx--) {  //Reminder: make these numbers not hard coded!!
        float temp = CLHEP::RandFlat::shoot(engine) < 0.5 ? 1 : 0;
        if (temp == 1 && bx < NumberOfBxBetweenHIPandEvent) {
          NumberOfBxBetweenHIPandEvent = bx;
          HasAtleastOneAffectedAPV = true;
        }
      }
    }

    APVMap::const_iterator iAPVchk;
    uint32_t formerID = 0;
    uint32_t currentID;
    std::bitset<6> NewAPVBits;

    for (APVMap::const_iterator iAPV = theAffectedAPVmap_.begin(); iAPV != theAffectedAPVmap_.end(); ++iAPV) {
      currentID = iAPV->first;

      if (currentID == formerID) {  // we have to OR these
        for (int ibit = 0; ibit < 6; ++ibit) {
          NewAPVBits[ibit] = NewAPVBits[ibit] || (iAPV->second)[ibit];
        }
      } else {
        DeadAPVList[currentID] = NewAPVBits;
        //save pointers for next iteration
        formerID = currentID;
        NewAPVBits = iAPV->second;
      }

      iAPVchk = iAPV;
      if ((++iAPVchk) == theAffectedAPVmap_.end()) {  //make sure not to lose the last one
        DeadAPVList[currentID] = NewAPVBits;
      }
    }
  }
  //

  //  Ok, done with merging raw signals and APVs - now add signals on duplicate strips

  // collection of Digis to put in the event
  std::vector<edm::DetSet<SiStripDigi>> vSiStripDigi;

  // loop through our collection of detectors, merging hits and making a new list of "signal" digis

  // clear some temporary storage for later digitization:

  signals_.clear();

  // big loop over Detector IDs:
  for (SiGlobalRawIndex::const_iterator IDet = SiRawDigis_.begin(); IDet != SiRawDigis_.end(); IDet++) {
    uint32_t detID = IDet->first;

    SignalMapType Signals;
    Signals.clear();

    OneDetectorRawMap LocalMap = IDet->second;

    //counter variables
    int formerStrip = -1;
    int currentStrip;
    float ADCSum = 0;

    //loop over hit strips for this DetId, add duplicates

    OneDetectorRawMap::const_iterator iLocalchk;
    OneDetectorRawMap::const_iterator iLocal = LocalMap.begin();
    for (; iLocal != LocalMap.end(); ++iLocal) {
      currentStrip = iLocal->first;  // strip is first element

      if (currentStrip == formerStrip) {  // we have to add these digis together

        ADCSum += iLocal->second;  // raw pulse height is second element.
      } else {
        if (formerStrip != -1) {
          Signals.insert(std::make_pair(formerStrip, ADCSum));
        }
        // save pointers for next iteration
        formerStrip = currentStrip;
        ADCSum = iLocal->second;  // lone ADC
      }

      iLocalchk = iLocal;
      if ((++iLocalchk) == LocalMap.end()) {  //make sure not to lose the last one
        Signals.insert(std::make_pair(formerStrip, ADCSum));
      }
    }
    // save merged map:
    signals_.insert(std::make_pair(detID, Signals));
  }

  //Now, do noise, zero suppression, take into account bad channels, etc.
  // This section stolen from SiStripDigitizerAlgorithm
  // must loop over all detIds in the tracker to get all of the noise added properly.
  for (const auto& iu : pDD->detUnits()) {
    const StripGeomDetUnit* sgd = dynamic_cast<const StripGeomDetUnit*>(iu);
    if (sgd != nullptr) {
      uint32_t detID = sgd->geographicalId().rawId();

      edm::DetSet<SiStripDigi> SSD(detID);  // Make empty collection with this detector ID

      int numStrips = (sgd->specificTopology()).nstrips();

      // see if there is some signal on this detector

      const SignalMapType* theSignal(getSignal(detID));

      std::vector<float> detAmpl(numStrips, 0.);
      if (theSignal) {
        for (const auto& amp : *theSignal) {
          detAmpl[amp.first] = amp.second;
        }
      }

      //removing signal from the dead (and HIP effected) strips
      std::vector<bool>& badChannels = allBadChannels[detID];

      for (int strip = 0; strip < numStrips; ++strip) {
        if (badChannels[strip])
          detAmpl[strip] = 0.;
      }

      if (simulateAPVInThisEvent) {
        // Get index in apv baseline distributions corresponding to z of detSet and PU
        const StripTopology* topol = dynamic_cast<const StripTopology*>(&(sgd->specificTopology()));
        LocalPoint localPos = topol->localPosition(0);
        GlobalPoint globalPos = sgd->surface().toGlobal(Local3DPoint(localPos.x(), localPos.y(), localPos.z()));
        float detSet_z = fabs(globalPos.z());
        float detSet_r = globalPos.perp();

        const uint32_t SubDet = DetId(detID).subdetId();
        // Simulate APV response for each strip
        for (int strip = 0; strip < numStrips; ++strip) {
          if (detAmpl[strip] > 0) {
            // Convert charge from electrons to fC
            double stripCharge = detAmpl[strip] * apv_fCPerElectron_;

            // Get APV baseline
            double baselineV = 0;
            if (SubDet == StripSubdetector::TIB) {
              baselineV = apvSimulationParametersHandle->sampleTIB(tTopo->tibLayer(detID), detSet_z, nTruePU, engine);
            } else if (SubDet == StripSubdetector::TOB) {
              baselineV = apvSimulationParametersHandle->sampleTOB(tTopo->tobLayer(detID), detSet_z, nTruePU, engine);
            } else if (SubDet == StripSubdetector::TID) {
              baselineV = apvSimulationParametersHandle->sampleTID(tTopo->tidWheel(detID), detSet_r, nTruePU, engine);
            } else if (SubDet == StripSubdetector::TEC) {
              baselineV = apvSimulationParametersHandle->sampleTEC(tTopo->tecWheel(detID), detSet_r, nTruePU, engine);
            }
            // Fitted parameters from G Hall/M Raymond
            double maxResponse = apv_maxResponse_;
            double rate = apv_rate_;

            double outputChargeInADC = 0;
            if (baselineV < apv_maxResponse_) {
              // Convert V0 into baseline charge
              double baselineQ = -1.0 * rate * log(2 * maxResponse / (baselineV + maxResponse) - 1);

              // Add charge deposited in this BX
              double newStripCharge = baselineQ + stripCharge;

              // Apply APV response
              double signalV = 2 * maxResponse / (1 + exp(-1.0 * newStripCharge / rate)) - maxResponse;
              double gain = signalV - baselineV;

              // Convert gain (mV) to charge (assuming linear region of APV) and then to electrons
              double outputCharge = gain / apv_mVPerQ_;
              outputChargeInADC = outputCharge / apv_fCPerElectron_;
            }

            // Output charge back to original container
            detAmpl[strip] = outputChargeInADC;
          }
        }
      }

      if (APVSaturationFromHIP_) {
        std::bitset<6>& bs = DeadAPVList[detID];

        if (bs.any()) {
          // Here below is the scaling function which describes the evolution of the baseline (i.e. how the charge is suppressed).
          // This must be replaced as soon as we have a proper modeling of the baseline evolution from VR runs
          float Shift =
              1 - NumberOfBxBetweenHIPandEvent / floor(300.0 / 25.0);  //Reminder: make these numbers not hardcoded!!
          float randomX = CLHEP::RandFlat::shoot(engine);
          float scalingValue = (randomX - Shift) * 10.0 / 7.0 - 3.0 / 7.0;

          for (int strip = 0; strip < numStrips; ++strip) {
            if (!badChannels[strip] && bs[strip / 128] == 1) {
              detAmpl[strip] *= scalingValue > 0 ? scalingValue : 0.0;
            }
          }
        }
      }

      SiStripNoises::Range detNoiseRange = noiseHandle->getRange(detID);
      SiStripApvGain::Range detGainRange = gainHandle->getRange(detID);

      // Gain conversion is already done during signal adding
      //convert our signals back to raw counts so that we can add noise properly:

      /*
        if(theSignal) {
        for(unsigned int iv = 0; iv!=detAmpl.size(); iv++) {
        float signal = detAmpl[iv];
        if(signal > 0) {
        float gainValue = gainHandle->getStripGain(iv, detGainRange);
        signal *= theElectronPerADC/gainValue;
        detAmpl[iv] = signal;
        }
        }
        }
      */

      //SiStripPedestals::Range detPedestalRange = pedestalHandle->getRange(detID);

      // -----------------------------------------------------------

      size_t firstChannelWithSignal = 0;
      size_t lastChannelWithSignal = numStrips;

      if (SingleStripNoise) {
        std::vector<float> noiseRMSv;
        noiseRMSv.clear();
        noiseRMSv.insert(noiseRMSv.begin(), numStrips, 0.);
        for (int strip = 0; strip < numStrips; ++strip) {
          if (!badChannels[strip]) {
            float gainValue = gainHandle->getStripGain(strip, detGainRange);
            noiseRMSv[strip] = (noiseHandle->getNoise(strip, detNoiseRange)) * theElectronPerADC / gainValue;
          }
        }
        theSiNoiseAdder->addNoiseVR(detAmpl, noiseRMSv, engine);
      } else {
        int RefStrip = int(numStrips / 2.);
        while (RefStrip < numStrips &&
               badChannels[RefStrip]) {  //if the refstrip is bad, I move up to when I don't find it
          RefStrip++;
        }
        if (RefStrip < numStrips) {
          float RefgainValue = gainHandle->getStripGain(RefStrip, detGainRange);
          float RefnoiseRMS = noiseHandle->getNoise(RefStrip, detNoiseRange) * theElectronPerADC / RefgainValue;

          theSiNoiseAdder->addNoise(
              detAmpl, firstChannelWithSignal, lastChannelWithSignal, numStrips, RefnoiseRMS, engine);
        }
      }

      DigitalVecType digis;
      theSiZeroSuppress->suppress(
          theSiDigitalConverter->convert(detAmpl, gainHandle, detID), digis, detID, noiseHandle, thresholdHandle);

      SSD.data = digis;

      // stick this into the global vector of detector info
      vSiStripDigi.push_back(SSD);

    }  // end of loop over one detector

  }  // end of big loop over all detector IDs

  // put the collection of digis in the event
  edm::LogInfo("PreMixingSiStripWorker") << "total # Merged strips: " << vSiStripDigi.size();

  // make new digi collection

  std::unique_ptr<edm::DetSetVector<SiStripDigi>> MySiStripDigis(new edm::DetSetVector<SiStripDigi>(vSiStripDigi));

  // put collection

  e.put(std::move(MySiStripDigis), SiStripDigiCollectionDM_);
  e.put(std::make_unique<bool>(simulateAPVInThisEvent), SiStripDigiCollectionDM_ + "SimulatedAPVDynamicGain");

  // clear local storage for this event
  SiHitStorage_.clear();
  SiRawDigis_.clear();
  signals_.clear();
}

DEFINE_PREMIXING_WORKER(PreMixingSiStripWorker);