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CaloHitResponse.cc

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#include "SimCalorimetry/CaloSimAlgos/interface/CaloHitResponse.h" 
#include "SimDataFormats/CaloHit/interface/PCaloHit.h" 
#include "SimCalorimetry/CaloSimAlgos/interface/CaloVSimParameterMap.h"
#include "SimCalorimetry/CaloSimAlgos/interface/CaloSimParameters.h"
#include "SimCalorimetry/CaloSimAlgos/interface/CaloVShape.h"
#include "SimCalorimetry/CaloSimAlgos/interface/CaloVHitCorrection.h"
#include "SimCalorimetry/CaloSimAlgos/interface/CaloVHitFilter.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "Geometry/CaloGeometry/interface/CaloSubdetectorGeometry.h"
#include "Geometry/CaloGeometry/interface/CaloCellGeometry.h"
#include "FWCore/ServiceRegistry/interface/Service.h"
#include "FWCore/Utilities/interface/RandomNumberGenerator.h"
#include "CLHEP/Random/RandPoissonQ.h"
#include "CLHEP/Random/RandFlat.h"
#include "FWCore/Utilities/interface/Exception.h"

#include "CLHEP/Units/PhysicalConstants.h"
#include<iostream>


CaloHitResponse::CaloHitResponse(const CaloVSimParameterMap * parametersMap, 
                                 const CaloVShape * shape)
: theAnalogSignalMap(),
  theParameterMap(parametersMap), 
  theShape(shape),  
  theHitCorrection(0),
  theHitFilter(0),
  theGeometry(0),
  theRandPoisson(0),
  theMinBunch(-10), 
  theMaxBunch(10),
  thePhaseShift_(1.)
{
}


CaloHitResponse::~CaloHitResponse()
{
  delete theRandPoisson;
}


void CaloHitResponse::setBunchRange(int minBunch, int maxBunch) {
  theMinBunch = minBunch;
  theMaxBunch = maxBunch;
}


void CaloHitResponse::setRandomEngine(CLHEP::HepRandomEngine & engine)
{
  theRandPoisson = new CLHEP::RandPoissonQ(engine);
}


void CaloHitResponse::run(MixCollection<PCaloHit> & hits) {

  for(MixCollection<PCaloHit>::MixItr hitItr = hits.begin();
      hitItr != hits.end(); ++hitItr)
  {
    // check the bunch crossing range
    if ( hitItr.bunch() < theMinBunch || hitItr.bunch() > theMaxBunch ) 
      { continue; }
  
    add(*hitItr);
  } // loop over hits
}


void CaloHitResponse::add(const PCaloHit & hit)
{
  // check the hit time makes sense
  if ( isnan(hit.time()) ) { return; }

  // maybe it's not from this subdetector
  if(theHitFilter == 0 || theHitFilter->accepts(hit)) {
    LogDebug("CaloHitResponse") << hit;
    CaloSamples signal(makeAnalogSignal(hit));
    LogDebug("CaloHitResponse") << signal;
    add(signal);
  }
}


void CaloHitResponse::add(const CaloSamples & signal)
{
  DetId id(signal.id());
  CaloSamples * oldSignal = findSignal(id);
  if (oldSignal == 0) {
    theAnalogSignalMap[id] = signal;
  } else  {
    // need a "+=" to CaloSamples
    int sampleSize =  oldSignal->size();
    assert(sampleSize == signal.size());
    assert(signal.presamples() == oldSignal->presamples());

    for(int i = 0; i < sampleSize; ++i) {
      (*oldSignal)[i] += signal[i];
    }
  }
}


CaloSamples CaloHitResponse::makeAnalogSignal(const PCaloHit & inputHit) const {

  // see if we need to correct the hit 
  PCaloHit hit = inputHit;

  if(theHitCorrection != 0) {
    theHitCorrection->correct(hit);
  }

  DetId detId(hit.id());
  const CaloSimParameters & parameters = theParameterMap->simParameters(detId);

  double signal = analogSignalAmplitude(hit, parameters);

  double jitter = hit.time() - timeOfFlight(detId);

  // assume bins count from zero, go for center of bin
  const double tzero = parameters.timePhase() -jitter -
     BUNCHSPACE*(parameters.binOfMaximum()-thePhaseShift_);
  double binTime = tzero;

  CaloSamples result(makeBlankSignal(detId));

  for(int bin = 0; bin < result.size(); bin++) {
    result[bin] += (*theShape)(binTime)* signal;
    binTime += BUNCHSPACE;
  }

  return result;
} 


double CaloHitResponse::analogSignalAmplitude(const PCaloHit & hit, const CaloSimParameters & parameters) const {

  if(!theRandPoisson)
  {
    edm::Service<edm::RandomNumberGenerator> rng;
    if ( ! rng.isAvailable()) {
      throw cms::Exception("Configuration")
        << "CaloHitResponse requires the RandomNumberGeneratorService\n"
        "which is not present in the configuration file.  You must add the service\n"
        "in the configuration file or remove the modules that require it.";
    }
    theRandPoisson = new CLHEP::RandPoissonQ(rng->getEngine());
  }

  // OK, the "energy" in the hit could be a real energy, deposited energy,
  // or pe count.  This factor converts to photoelectrons
  double npe = hit.energy() * parameters.simHitToPhotoelectrons( DetId(hit.id()) );
  // do we need to doPoisson statistics for the photoelectrons?
  if(parameters.doPhotostatistics()) {
    npe = theRandPoisson->fire(npe);
  }
  return npe;
}


CaloSamples * CaloHitResponse::findSignal(const DetId & detId) {
  CaloSamples * result = 0;
  AnalogSignalMap::iterator signalItr = theAnalogSignalMap.find(detId);
  if(signalItr == theAnalogSignalMap.end()) {
     result = 0;
  } 
  else {
     result = &(signalItr->second);
  }
  return result;
}


CaloSamples CaloHitResponse::makeBlankSignal(const DetId & detId) const {
  const CaloSimParameters & parameters = theParameterMap->simParameters(detId);
  CaloSamples result(detId, parameters.readoutFrameSize());
  result.setPresamples(parameters.binOfMaximum()-1);
  return result;
}


double CaloHitResponse::timeOfFlight(const DetId & detId) const {
  // not going to assume there's one of these per subdetector.
  // Take the whole CaloGeometry and find the right subdet
  double result = 0.;
  if(theGeometry == 0) {
    edm::LogWarning("CaloHitResponse") << "No Calo Geometry set, so no time of flight correction";
  } 
  else {
    const CaloCellGeometry* cellGeometry = theGeometry->getSubdetectorGeometry(detId)->getGeometry(detId);
    if(cellGeometry == 0) {
       edm::LogWarning("CaloHitResponse") << "No Calo cell found for ID"
         << detId.rawId() << " so no time-of-flight subtraction will be done";
    }
    else {
      double distance = cellGeometry->getPosition().mag();
      result =  distance * cm / c_light; // Units of c_light: mm/ns
    }
  }
  return result;
}

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