Digitizer.cxx

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
 
#include "EMCALSimulation/Digitizer.h"
#include "EMCALSimulation/SimParam.h"
#include "EMCALSimulation/DigitsWriteoutBuffer.h"
#include "DataFormatsEMCAL/Digit.h"
#include "EMCALBase/Hit.h"
#include "MathUtils/Cartesian.h"
#include "SimulationDataFormat/MCCompLabel.h"
#include "EMCALSimulation/DigitsWriteoutBuffer.h"
#include <climits>
#include <forward_list>
#include <chrono>
#include <TRandom.h>
#include <TF1.h>
#include <fairlogger/Logger.h> // for LOG
#include "CommonDataFormat/InteractionRecord.h"
#include "CommonUtils/TreeStreamRedirector.h"
#include "SimConfig/DigiParams.h"
#include "DetectorsRaw/HBFUtilsInitializer.h"
#include "DetectorsRaw/HBFUtils.h"
 
ClassImp(o2::emcal::Digitizer);
 
using o2::emcal::Digit;
using o2::emcal::Hit;
 
using namespace o2::emcal;
 
//_______________________________________________________________________
void Digitizer::init()
{
  mSimParam = &(o2::emcal::SimParam::Instance());
  auto randomSeed = std::chrono::high_resolution_clock::now().time_since_epoch().count();
  if (o2::conf::DigiParams::Instance().seed != 0) {
    randomSeed = o2::conf::DigiParams::Instance().seed;
  }
  mRandomGenerator = new TRandom3(randomSeed);
 
  float tau = mSimParam->getTimeResponseTau();
  float N = mSimParam->getTimeResponsePower();
 
  mSmearEnergy = mSimParam->doSmearEnergy();
  mSimulateTimeResponse = mSimParam->doSimulateTimeResponse();
 
  mDigits.init();
  mDigits.reserve();
  /*
  if ((mDelay - mTimeWindowStart) != 0)
  {
    mDigits.setBufferSize(mDigits.getBufferSize() + (mDelay - mTimeWindowStart));
    mDigits.reserve();
  }
  */
 
  if (mSimulateTimeResponse) {
    // for each phase create a template distribution
    TF1 RawResponse("RawResponse", rawResponseFunction, 0, 256, 5);
    RawResponse.SetParameters(1., 0., tau, N, 0.);
 
    for (int phase = 0; phase < 4; phase++) {
      // parameter 1: Handling phase + delay
      // phase: 25 ns * phase index (-4)
      // delay: Average signal delay
      for (int itofbin = 0; itofbin < EMC_TOF_BINS; itofbin++) {
        double tofbincenter = itofbin * EMC_TOF_BINWITH + 0.5 * EMC_TOF_BINWITH;
        RawResponse.SetParameter(1, 0.25 * phase + (tofbincenter + mSimParam->getSignalDelay()) / constants::EMCAL_TIMESAMPLE);
        for (int sample = 0; sample < constants::EMCAL_MAXTIMEBINS; sample++) {
          mAmplitudeInTimeBins[phase][itofbin][sample] = RawResponse.Eval(sample);
        }
      }
    }
  } else {
  }
 
  mIRFirstSampledTF = o2::raw::HBFUtils::Instance().getFirstSampledTFIR();
 
  if (mEnableDebugStreaming) {
    mDebugStream = std::make_unique<o2::utils::TreeStreamRedirector>("emcaldigitsDebug.root", "RECREATE");
  }
}
 
//_______________________________________________________________________
double Digitizer::rawResponseFunction(double* x, double* par)
{
  double signal = 0.;
  double tau = par[2];
  double n = par[3];
  double ped = par[4];
  double xx = (x[0] - par[1] + tau) / tau;
 
  // par[0] amp, par[1] peak time
 
  if (xx <= 0) {
    signal = ped;
  } else {
    signal = ped + par[0] * std::pow(xx, n) * std::exp(n * (1 - xx));
  }
 
  return signal;
}
 
//_______________________________________________________________________
void Digitizer::clear()
{
  mDigits.clear();
}
 
//_______________________________________________________________________
void Digitizer::process(const std::vector<LabeledDigit>& labeledSDigits)
{
 
  for (auto labeleddigit : labeledSDigits) {
 
    int tower = labeleddigit.getTower();
 
    sampleSDigit(labeleddigit.getDigit());
 
    if (mTempDigitVector.size() == 0) {
      continue;
    }
 
    std::vector<LabeledDigit> listofLabeledDigit;
 
    for (auto& digit : mTempDigitVector) {
      Int_t id = digit.getTower();
 
      auto labels = labeleddigit.getLabels();
      LabeledDigit d(digit, labels[0]);
      int iLabel(0);
      for (auto& label : labels) {
        if (digit.getAmplitude() < __DBL_EPSILON__) {
          label.setAmplitudeFraction(0);
        }
        if (iLabel == 0) {
          continue;
        }
        d.addLabel(label);
        iLabel++;
      }
      listofLabeledDigit.push_back(d);
    }
    mDigits.addDigits(tower, listofLabeledDigit);
  }
}
 
//_______________________________________________________________________
void Digitizer::sampleSDigit(const Digit& sDigit)
{
  mTempDigitVector.clear();
  Int_t tower = sDigit.getTower();
  Double_t energy = sDigit.getAmplitude();
 
  if (mSmearEnergy) {
    energy = smearEnergy(energy);
  }
 
  if (energy < __DBL_EPSILON__) {
    return;
  }
 
  // check if this hit because it comes from an event before readout starts and it does not effect this RO
  LOG(debug) << "mIsBeforeFirstRO " << mIsBeforeFirstRO << "     sDigit.getTimeStamp() " << sDigit.getTimeStamp() << "    mSimParam->getSignalDelay() " << mSimParam->getSignalDelay() << "   mPhase " << mPhase << "   total: " << sDigit.getTimeStamp() + mSimParam->getSignalDelay() + mPhase * 25 << "   EMC_TOF_MAX " << EMC_TOF_MAX << "  mTimeBCns " << mTimeBCns;
  if (mIsBeforeFirstRO && sDigit.getTimeStamp() + mTimeBCns < 0) {
    LOG(debug) << "disregard this hit because it comes from an event before readout starts and it does not effect this RO";
    return;
  }
 
  Double_t energies[15];
  if (mSimulateTimeResponse) {
    if (sDigit.getTimeStamp() + mSimParam->getSignalDelay() + mPhase * 25 > EMC_TOF_MAX) {
      // Digit time larger than sampling window, will not be sampled
      // For time response simulation take also signal delay and phase into account
      return;
    }
    int tofbin = static_cast<int>(sDigit.getTimeStamp() / EMC_TOF_BINWITH);
    if (tofbin >= EMC_TOF_BINS) {
      tofbin = EMC_TOF_BINS - 1;
    }
    for (int sample = 0; sample < mAmplitudeInTimeBins[mPhase][tofbin].size(); sample++) {
 
      double val = energy * (mAmplitudeInTimeBins[mPhase][tofbin][sample]);
      energies[sample] = val;
      double digitTime = mEventTimeOffset * constants::EMCAL_TIMESAMPLE;
      Digit digit(tower, val, digitTime);
      mTempDigitVector.push_back(digit);
    }
  } else {
    if (sDigit.getTimeStamp() > EMC_TOF_MAX) {
      // Digit time larger than sampling window, will not be sampled
      // In non-sampled mode only apply the max. time window
      return;
    }
    Digit digit(tower, energy, smearTime(sDigit.getTimeStamp(), energy));
    mTempDigitVector.push_back(digit);
  }
 
  if (mEnableDebugStreaming) {
    double timeStamp = sDigit.getTimeStamp();
    (*mDebugStream).GetFile()->cd();
    (*mDebugStream) << "DigitsTimeSamples"
                    << "Tower=" << tower
                    << "Time=" << timeStamp
                    << "DigitEnergy=" << energy
                    << "Sample0=" << energies[0]
                    << "Sample1=" << energies[1]
                    << "Sample2=" << energies[2]
                    << "Sample3=" << energies[3]
                    << "Sample4=" << energies[4]
                    << "Sample5=" << energies[5]
                    << "Sample6=" << energies[6]
                    << "Sample7=" << energies[7]
                    << "Sample8=" << energies[8]
                    << "Sample9=" << energies[9]
                    << "Sample10=" << energies[10]
                    << "Sample11=" << energies[11]
                    << "Sample12=" << energies[12]
                    << "Sample13=" << energies[13]
                    << "Sample14=" << energies[14]
                    << "\n";
  }
}
 
//_______________________________________________________________________
double Digitizer::smearEnergy(double energy)
{
  Double_t fluct = (energy * mSimParam->getMeanPhotonElectron()) / mSimParam->getGainFluctuations();
  energy *= mRandomGenerator->Poisson(fluct) / fluct;
  return energy;
}
 
double Digitizer::smearTime(double time, double energy)
{
  return mRandomGenerator->Gaus(time + mSimParam->getSignalDelay(), mSimParam->getTimeResolution(energy));
}
 
//_______________________________________________________________________
void Digitizer::setEventTime(o2::InteractionTimeRecord record, bool trigger)
{
 
  mDigits.forwardMarker(record, trigger);
 
  mPhase = mSimParam->doSimulateL1Phase() ? mDigits.getPhase() : 0;
 
  mEventTimeOffset = 0;
 
  if (mPhase == 4) {
    mPhase = 0;
    mEventTimeOffset++;
  }
 
  // get time difference between current bc and start of RO in ns
  auto nbc = record.differenceInBC(mIRFirstSampledTF);
  mTimeBCns = record.getTimeOffsetWrtBC();
  mTimeBCns += nbc * o2::constants::lhc::LHCBunchSpacingNS;
 
  if (nbc < 0) {
    // this event is before the first RO
    mIsBeforeFirstRO = true;
  } else {
    mIsBeforeFirstRO = false;
  }
}