HcalAmplifier.cc

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#include "SimCalorimetry/HcalSimAlgos/interface/HcalAmplifier.h"
#include "SimCalorimetry/HcalSimAlgos/interface/HcalSimParameters.h"
#include "SimCalorimetry/HcalSimAlgos/interface/HPDIonFeedbackSim.h"
#include "SimCalorimetry/HcalSimAlgos/interface/HcalTimeSlewSim.h"
#include "SimCalorimetry/CaloSimAlgos/interface/CaloVSimParameterMap.h"
#include "SimCalorimetry/CaloSimAlgos/interface/CaloVNoiseSignalGenerator.h"
#include "CalibFormats/HcalObjects/interface/HcalDbService.h"
#include "CondFormats/HcalObjects/interface/HcalPedestal.h"
#include "CondFormats/HcalObjects/interface/HcalGain.h"
#include "CondFormats/HcalObjects/interface/HcalPedestalWidth.h"
#include "CondFormats/HcalObjects/interface/HcalGainWidth.h"
#include "CalibFormats/CaloObjects/interface/CaloSamples.h"
#include "DataFormats/HcalDetId/interface/HcalDetId.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

#include "CalibFormats/HcalObjects/interface/HcalCalibrations.h"

#include "CLHEP/Random/RandGaussQ.h"
#include "CLHEP/Random/RandFlat.h"

#include <cmath>
#include <cmath>

HcalAmplifier::HcalAmplifier(const CaloVSimParameterMap * parameters, bool addNoise, bool PreMix1, bool PreMix2) :
  theDbService(nullptr),
  theParameterMap(parameters),
  theNoiseSignalGenerator(nullptr),
  theIonFeedbackSim(nullptr),
  theTimeSlewSim(nullptr),
  theStartingCapId(0),
  addNoise_(addNoise),
  preMixDigi_(PreMix1),
  preMixAdd_(PreMix2)
{ }


void HcalAmplifier::setDbService(const HcalDbService * service) {
  theDbService = service;
  if(theIonFeedbackSim) theIonFeedbackSim->setDbService(service);
}


void HcalAmplifier::amplify(CaloSamples & frame, CLHEP::HepRandomEngine* engine) const {
  if(theIonFeedbackSim)
  {
    theIonFeedbackSim->addThermalNoise(frame, engine);
  }
  pe2fC(frame);
  // don't bother for blank signals
  if(theTimeSlewSim && frame.size()>4 && frame[4] > 1.e-6)
  {
    theTimeSlewSim->delay(frame, engine);
  }

  // if we are combining pre-mixed digis, we need noise and peds
  if(theNoiseSignalGenerator==nullptr || preMixAdd_ || !theNoiseSignalGenerator->contains(frame.id()) )
  {
    addPedestals(frame, engine);
  }
  LogDebug("HcalAmplifier") << frame;
}


void HcalAmplifier::pe2fC(CaloSamples & frame) const
{
  const CaloSimParameters & parameters = theParameterMap->simParameters(frame.id());
  frame *= parameters.photoelectronsToAnalog(frame.id());
}

void HcalAmplifier::addPedestals(CaloSamples & frame, CLHEP::HepRandomEngine* engine) const
{
  assert(theDbService != nullptr);
  HcalGenericDetId hcalGenDetId(frame.id());
  HcalGenericDetId::HcalGenericSubdetector hcalSubDet = hcalGenDetId.genericSubdet();

  if ( !( (frame.id().subdetId()==HcalGenericDetId::HcalGenBarrel) ||
      (frame.id().subdetId()==HcalGenericDetId::HcalGenEndcap) ||
      (frame.id().subdetId()==HcalGenericDetId::HcalGenForward) ||
      (frame.id().subdetId()==HcalGenericDetId::HcalGenOuter) ) ) return;

  if(hcalGenDetId.isHcalCastorDetId()) return;
  if(hcalGenDetId.isHcalZDCDetId()) return;

  const HcalCalibrationWidths & calibWidths = theDbService->getHcalCalibrationWidths(hcalGenDetId);
  const HcalCalibrations& calibs = theDbService->getHcalCalibrations(hcalGenDetId);

  double noise [32] = {0.}; //big enough
  if(addNoise_)
  {
    double gauss [32]; //big enough
    for (int i = 0; i < frame.size(); i++) gauss[i] = CLHEP::RandGaussQ::shoot(engine, 0., 1.);
    makeNoise(hcalSubDet, calibWidths, frame.size(), gauss, noise);
  }
   
  if(!preMixDigi_){  // if we are doing initial premix, no pedestals
    for (int tbin = 0; tbin < frame.size(); ++tbin) {
      int capId = (theStartingCapId + tbin)%4;
      double pedestal = calibs.pedestal(capId) + noise[tbin];
      frame[tbin] += pedestal;
    }
  }
}

void HcalAmplifier::makeNoise(HcalGenericDetId::HcalGenericSubdetector hcalSubDet, const HcalCalibrationWidths& width, int fFrames, double* fGauss, double* fNoise) const 
{
  // This is a simplified noise generation scheme using only the diagonal elements
  // (proposed by Salavat Abduline).
  // This is direct adaptation of the code in HcalPedestalWidth.cc
  
  // average over capId's
  double s_xx_mean =  0.25 * (width.pedestal(0)*width.pedestal(0) + 
                  width.pedestal(1)*width.pedestal(1) + 
                  width.pedestal(2)*width.pedestal(2) + 
                  width.pedestal(3)*width.pedestal(3));


  // Off-diagonal element approximation
  // In principle should come from averaging the values of elements (0.1), (1,2), (2,3), (3,0)
  // For now use the definition below (but keep structure of the code structure for development) 
  double s_xy_mean = -0.5 * s_xx_mean;
  // Use different parameter for HF to reproduce the noise rate after zero suppression.
  // Steven Won/Jim Hirschauer/Radek Ofierzynski 18.03.2010
  if (hcalSubDet == HcalGenericDetId::HcalGenForward) s_xy_mean = 0.08 * s_xx_mean;

  double term  = s_xx_mean*s_xx_mean - 2.*s_xy_mean*s_xy_mean;

  if (term < 0.) term = 1.e-50 ;
  double sigma = sqrt (0.5 * (s_xx_mean + sqrt(term)));
  double corr = sigma == 0. ? 0. : 0.5*s_xy_mean / sigma;

  for (int i = 0; i < fFrames; i++) {
    fNoise [i] = fGauss[i]*sigma;
    if (i > 0) fNoise [i] += fGauss[i-1]*corr;
    if (i < fFrames-1) fNoise [i] += fGauss[i+1]*corr;
  }
}