EcalRecAlgos/src/EcalUncalibRecHitTimingCCAlgo.cc

0001 #include "RecoLocalCalo/EcalRecAlgos/interface/EcalUncalibRecHitTimingCCAlgo.h"
0002
0003 EcalUncalibRecHitTimingCCAlgo::EcalUncalibRecHitTimingCCAlgo(const float startTime, const float stopTime)
0004     : startTime_(startTime), stopTime_(stopTime) {}
0005
0006 double EcalUncalibRecHitTimingCCAlgo::computeTimeCC(const EcalDataFrame& dataFrame,
0007                                                     const std::vector<double>& amplitudes,
0008                                                     const EcalPedestals::Item* aped,
0009                                                     const EcalMGPAGainRatio* aGain,
0010                                                     const FullSampleVector& fullpulse,
0011                                                     EcalUncalibratedRecHit& uncalibRecHit,
0012                                                     float& errOnTime,
0013                                                     const float targetTimePrecision,
0014                                                     const bool correctForOOT) const {
0015   constexpr unsigned int nsample = EcalDataFrame::MAXSAMPLES;
0016
0017   double maxamplitude = -std::numeric_limits<double>::max();
0018   float pulsenorm = 0.;
0019
0020   std::vector<float> pedSubSamples(nsample);
0021   for (unsigned int iSample = 0; iSample < nsample; iSample++) {
0022     const EcalMGPASample& sample = dataFrame.sample(iSample);
0023
0024     float amplitude = 0.;
0025     int gainId = sample.gainId();
0026
0027     double pedestal = 0.;
0028     double gainratio = 1.;
0029
0030     if (gainId == 0 || gainId == 3) {
0031       pedestal = aped->mean_x1;
0032       gainratio = aGain->gain6Over1() * aGain->gain12Over6();
0033     } else if (gainId == 1) {
0034       pedestal = aped->mean_x12;
0035       gainratio = 1.;
0036     } else if (gainId == 2) {
0037       pedestal = aped->mean_x6;
0038       gainratio = aGain->gain12Over6();
0039     }
0040
0041     amplitude = (static_cast<float>(sample.adc()) - pedestal) * gainratio;
0042
0043     if (gainId == 0) {
0044       //saturation
0045       amplitude = (4095. - pedestal) * gainratio;
0046     }
0047
0048     pedSubSamples[iSample] = amplitude;
0049
0050     if (amplitude > maxamplitude) {
0051       maxamplitude = amplitude;
0052     }
0053     pulsenorm += fullpulse(iSample);
0054   }
0055
0056   if (correctForOOT) {
0057     int ipulse = -1;
0058     for (auto const& amplit : amplitudes) {
0059       ipulse++;
0060       int bxp3 = ipulse - 2;
0061       int firstsamplet = std::max(0, bxp3);
0062       int offset = 7 - bxp3;
0063
0064       for (unsigned int isample = firstsamplet; isample < nsample; ++isample) {
0065         auto const pulse = fullpulse(isample + offset);
0066         pedSubSamples[isample] = std::max(0., pedSubSamples[isample] - amplit * pulse / pulsenorm);
0067       }
0068     }
0069   }
0070
0071   // Start of time computation
0072   float t0 = startTime_ + GLOBAL_TIME_SHIFT;
0073   float t3 = stopTime_ + GLOBAL_TIME_SHIFT;
0074   float t2 = (t3 + t0) / 2;
0075   float t1 = t2 - ONE_MINUS_GOLDEN_RATIO * (t3 - t0);
0076
0077   int counter = 0;
0078
0079   float cc1 = computeCC(pedSubSamples, fullpulse, t1);
0080   ++counter;
0081   float cc2 = computeCC(pedSubSamples, fullpulse, t2);
0082   ++counter;
0083
0084   while (std::abs(t3 - t0) > targetTimePrecision && counter < MAX_NUM_OF_ITERATIONS) {
0085     if (cc2 > cc1) {
0086       t0 = t1;
0087       t1 = t2;
0088       t2 = GOLDEN_RATIO * t2 + ONE_MINUS_GOLDEN_RATIO * t3;
0089       cc1 = cc2;
0090       cc2 = computeCC(pedSubSamples, fullpulse, t2);
0091       ++counter;
0092     } else {
0093       t3 = t2;
0094       t2 = t1;
0095       t1 = GOLDEN_RATIO * t1 + ONE_MINUS_GOLDEN_RATIO * t0;
0096       cc2 = cc1;
0097       cc1 = computeCC(pedSubSamples, fullpulse, t1);
0098       ++counter;
0099     }
0100   }
0101
0102   float tM = (t3 + t0) / 2 - GLOBAL_TIME_SHIFT;
0103   errOnTime = std::abs(t3 - t0) / ecalPh1::Samp_Period;
0104
0105   if (counter < MIN_NUM_OF_ITERATIONS || counter > MAX_NUM_OF_ITERATIONS - 1) {
0106     tM = TIME_WHEN_NOT_CONVERGING * ecalPh1::Samp_Period;
0107     //Negative error means that there was a problem with the CC
0108     errOnTime = -targetTimePrecision / ecalPh1::Samp_Period;
0109   }
0110   return -tM / ecalPh1::Samp_Period;
0111 }
0112
0113 FullSampleVector EcalUncalibRecHitTimingCCAlgo::interpolatePulse(const FullSampleVector& fullpulse,
0114                                                                  const float time) const {
0115   // t is in ns
0116   int shift = time / ecalPh1::Samp_Period;
0117   if (time < 0)
0118     shift -= 1;
0119   float tt = time / ecalPh1::Samp_Period - shift;
0120
0121   FullSampleVector interpPulse;
0122   // 2nd poly with avg
0123   unsigned int numberOfSamples = fullpulse.size();
0124   auto facM1orP2 = 0.25 * tt * (tt - 1);
0125   auto fac = (0.25 * (tt - 2) - 0.5 * (tt + 1)) * (tt - 1);
0126   auto facP1 = (0.25 * (tt + 1) - 0.5 * (tt - 2)) * tt;
0127   for (unsigned int i = 1; i < numberOfSamples - 2; ++i) {
0128     float a =
0129         facM1orP2 * fullpulse[i - 1] + fac * fullpulse[i] + facP1 * fullpulse[i + 1] + facM1orP2 * fullpulse[i + 2];
0130     if (a > 0)
0131       interpPulse[i] = a;
0132     else
0133       interpPulse[i] = 0;
0134   }
0135   interpPulse[0] = facM1orP2 * fullpulse[0] + facP1 * fullpulse[1] + facM1orP2 * fullpulse[2];
0136   interpPulse[numberOfSamples - 2] = facM1orP2 * fullpulse[numberOfSamples - 3] + fac * fullpulse[numberOfSamples - 2] +
0137                                      facP1 * fullpulse[numberOfSamples - 1];
0138   interpPulse[numberOfSamples - 1] = 2 * facM1orP2 * fullpulse[numberOfSamples - 2] -
0139                                      4 * facM1orP2 * fullpulse[numberOfSamples - 1] +
0140                                      facP1 * fullpulse[numberOfSamples - 1];
0141
0142   FullSampleVector interpPulseShifted;
0143   for (int i = 0; i < interpPulseShifted.size(); ++i) {
0144     if (i + shift >= 0 && i + shift < interpPulse.size())
0145       interpPulseShifted[i] = interpPulse[i + shift];
0146     else
0147       interpPulseShifted[i] = 0;
0148   }
0149   return interpPulseShifted;
0150 }
0151
0152 float EcalUncalibRecHitTimingCCAlgo::computeCC(const std::vector<float>& samples,
0153                                                const FullSampleVector& signalTemplate,
0154                                                const float time) const {
0155   constexpr int exclude = 1;
0156   float powerSamples = 0.;
0157   float powerTemplate = 0.;
0158   float cc = 0.;
0159   auto interpolated = interpolatePulse(signalTemplate, time);
0160   for (int i = exclude; i < int(samples.size() - exclude); ++i) {
0161     powerSamples += std::pow(samples[i], 2);
0162     powerTemplate += std::pow(interpolated[i], 2);
0163     cc += interpolated[i] * samples[i];
0164   }
0165
0166   float denominator = std::sqrt(powerTemplate * powerSamples);
0167   return cc / denominator;
0168 }