#include <EcalUncalibRecHitTimingCCAlgo.h>

Public Member Functions
double	computeTimeCC (const EcalDataFrame &dataFrame, const std::vector< double > &amplitudes, const EcalPedestals::Item aped, const EcalMGPAGainRatio aGain, const FullSampleVector &fullpulse, EcalUncalibratedRecHit &uncalibRecHit, float &errOnTime) const

	EcalUncalibRecHitTimingCCAlgo (const float startTime, const float stopTime, const float targetTimePrecision)

Private Member Functions
float	computeCC (const std::vector< float > &samples, const FullSampleVector &sigmalTemplate, const float t) const

FullSampleVector	interpolatePulse (const FullSampleVector &fullpulse, const float t=0) const

Private Attributes
const float	startTime_

const float	stopTime_

const float	targetTimePrecision_

Static Private Attributes
static constexpr float	GLOBAL_TIME_SHIFT = 100

static constexpr int	MAX_NUM_OF_ITERATIONS = 30

static constexpr int	MIN_NUM_OF_ITERATIONS = 2

static constexpr int	TIME_WHEN_NOT_CONVERGING = 100

Detailed Description

CrossCorrelation algorithm for timing reconstruction

Author: N. Minafra, J. King, C. Rogan

Definition at line 18 of file EcalUncalibRecHitTimingCCAlgo.h.

Constructor & Destructor Documentation

◆ EcalUncalibRecHitTimingCCAlgo()

EcalUncalibRecHitTimingCCAlgo::EcalUncalibRecHitTimingCCAlgo	(	const float	startTime,
		const float	stopTime,
		const float	targetTimePrecision
	)

Definition at line 3 of file EcalUncalibRecHitTimingCCAlgo.cc.

6 : startTime_(startTime), stopTime_(stopTime), targetTimePrecision_(targetTimePrecision) {}

Member Function Documentation

◆ computeCC()

float EcalUncalibRecHitTimingCCAlgo::computeCC	(	const std::vector< float > &	samples,
		const FullSampleVector &	sigmalTemplate,
		const float	t
	)		const

private

Definition at line 142 of file EcalUncalibRecHitTimingCCAlgo.cc.

                                                                        {
   constexpr int exclude = 1;
   float powerSamples = 0.;
   float powerTemplate = 0.;
   float cc = 0.;
   auto interpolated = interpolatePulse(signalTemplate, time);
   for (int i = exclude; i < int(samples.size() - exclude); ++i) {
     powerSamples += std::pow(samples[i], 2);
     powerTemplate += std::pow(interpolated[i], 2);
     cc += interpolated[i] * samples[i];
   }
  
   float denominator = std::sqrt(powerTemplate * powerSamples);
   return cc / denominator;
 }

References HLTTauDQMOffline_cfi::denominator, mps_fire::i, createfilelist::int, interpolatePulse(), funct::pow(), EgammaValidation_cff::samples, mathSSE::sqrt(), and protons_cff::time.

Referenced by computeTimeCC().

◆ computeTimeCC()

double EcalUncalibRecHitTimingCCAlgo::computeTimeCC	(	const EcalDataFrame &	dataFrame,
		const std::vector< double > &	amplitudes,
		const EcalPedestals::Item *	aped,
		const EcalMGPAGainRatio *	aGain,
		const FullSampleVector &	fullpulse,
		EcalUncalibratedRecHit &	uncalibRecHit,
		float &	errOnTime
	)		const

Definition at line 8 of file EcalUncalibRecHitTimingCCAlgo.cc.

                                                                             {
   constexpr unsigned int nsample = EcalDataFrame::MAXSAMPLES;
  
   double maxamplitude = -std::numeric_limits<double>::max();
   float pulsenorm = 0.;
  
   std::vector<float> pedSubSamples(nsample);
   for (unsigned int iSample = 0; iSample < nsample; iSample++) {
     const EcalMGPASample& sample = dataFrame.sample(iSample);
  
     float amplitude = 0.;
     int gainId = sample.gainId();
  
     double pedestal = 0.;
     double gainratio = 1.;
  
     if (gainId == 0 || gainId == 3) {
       pedestal = aped->mean_x1;
       gainratio = aGain->gain6Over1() * aGain->gain12Over6();
     } else if (gainId == 1) {
       pedestal = aped->mean_x12;
       gainratio = 1.;
     } else if (gainId == 2) {
       pedestal = aped->mean_x6;
       gainratio = aGain->gain12Over6();
     }
  
     amplitude = (static_cast<float>(sample.adc()) - pedestal) * gainratio;
  
     if (gainId == 0) {
       //saturation
       amplitude = (4095. - pedestal) * gainratio;
     }
  
     pedSubSamples[iSample] = amplitude;
  
     if (amplitude > maxamplitude) {
       maxamplitude = amplitude;
     }
     pulsenorm += fullpulse(iSample);
   }
  
   int ipulse = -1;
   for (auto const& amplit : amplitudes) {
     ipulse++;
     int bxp3 = ipulse - 2;
     int firstsamplet = std::max(0, bxp3);
     int offset = 7 - bxp3;
  
     for (unsigned int isample = firstsamplet; isample < nsample; ++isample) {
       auto const pulse = fullpulse(isample + offset);
       pedSubSamples[isample] = std::max(0., pedSubSamples[isample] - amplit * pulse / pulsenorm);
     }
   }
  
   // Start of time computation
   float tStart = startTime_ + GLOBAL_TIME_SHIFT;
   float tStop = stopTime_ + GLOBAL_TIME_SHIFT;
   float tM = (tStart + tStop) / 2;
  
   float distStart, distStop;
   int counter = 0;
  
   do {
     ++counter;
     distStart = computeCC(pedSubSamples, fullpulse, tStart);
     distStop = computeCC(pedSubSamples, fullpulse, tStop);
  
     if (distStart > distStop) {
       tStop = tM;
     } else {
       tStart = tM;
     }
     tM = (tStart + tStop) / 2;
  
   } while (tStop - tStart > targetTimePrecision_ && counter < MAX_NUM_OF_ITERATIONS);
  
   tM -= GLOBAL_TIME_SHIFT;
   errOnTime = targetTimePrecision_;
  
   if (counter < MIN_NUM_OF_ITERATIONS || counter > MAX_NUM_OF_ITERATIONS - 1) {
     tM = TIME_WHEN_NOT_CONVERGING * ecalPh1::Samp_Period;
     //Negative error means that there was a problem with the CC
     errOnTime = -targetTimePrecision_ / ecalPh1::Samp_Period;
   }
  
   return -tM / ecalPh1::Samp_Period;
 }

References CustomPhysics_cfi::amplitude, computeCC(), counter, EcalMGPAGainRatio::gain12Over6(), EcalMGPAGainRatio::gain6Over1(), ecalLiteDTU::gainId(), GLOBAL_TIME_SHIFT, SiStripPI::max, MAX_NUM_OF_ITERATIONS, EcalDataFrame::MAXSAMPLES, hltrates_dqm_sourceclient-live_cfg::offset, EcalCondDBWriter_cfi::pedestal, pulse(), ecalPh1::Samp_Period, simplePhotonAnalyzer_cfi::sample, EcalDataFrame::sample(), startTime_, stopTime_, targetTimePrecision_, and TIME_WHEN_NOT_CONVERGING.

◆ interpolatePulse()

FullSampleVector EcalUncalibRecHitTimingCCAlgo::interpolatePulse	(	const FullSampleVector &	fullpulse,
		const float	t = `0`
	)		const

private

Definition at line 103 of file EcalUncalibRecHitTimingCCAlgo.cc.

                                                                                          {
   // t is in ns
   int shift = time / ecalPh1::Samp_Period;
   if (time < 0)
     shift -= 1;
   float tt = time / ecalPh1::Samp_Period - shift;
  
   FullSampleVector interpPulse;
   // 2nd poly with avg
   unsigned int numberOfSamples = fullpulse.size();
   auto facM1orP2 = 0.25 * tt * (tt - 1);
   auto fac = (0.25 * (tt - 2) - 0.5 * (tt + 1)) * (tt - 1);
   auto facP1 = (0.25 * (tt + 1) - 0.5 * (tt - 2)) * tt;
   for (unsigned int i = 1; i < numberOfSamples - 2; ++i) {
     float a =
         facM1orP2 * fullpulse[i - 1] + fac * fullpulse[i] + facP1 * fullpulse[i + 1] + facM1orP2 * fullpulse[i + 2];
     if (a > 0)
       interpPulse[i] = a;
     else
       interpPulse[i] = 0;
   }
   interpPulse[0] = facM1orP2 * fullpulse[0] + facP1 * fullpulse[1] + facM1orP2 * fullpulse[2];
   interpPulse[numberOfSamples - 2] = facM1orP2 * fullpulse[numberOfSamples - 3] + fac * fullpulse[numberOfSamples - 2] +
                                      facP1 * fullpulse[numberOfSamples - 1];
   interpPulse[numberOfSamples - 1] = 2 * facM1orP2 * fullpulse[numberOfSamples - 2] -
                                      4 * facM1orP2 * fullpulse[numberOfSamples - 1] +
                                      facP1 * fullpulse[numberOfSamples - 1];
  
   FullSampleVector interpPulseShifted;
   for (int i = 0; i < interpPulseShifted.size(); ++i) {
     if (i + shift >= 0 && i + shift < interpPulse.size())
       interpPulseShifted[i] = interpPulse[i + shift];
     else
       interpPulseShifted[i] = 0;
   }
   return interpPulseShifted;
 }