TrackBasedCalib.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 "GPUO2InterfaceConfiguration.h"
#include "TRDCalibration/TrackBasedCalib.h"
#include "TRDCalibration/CalibrationParams.h"
#include "DataFormatsTRD/Constants.h"
#include "DataFormatsGlobalTracking/RecoContainer.h"
#include "DetectorsBase/GeometryManager.h"
#include "TRDBase/Geometry.h"
#include "TRDBase/PadPlane.h"
#include "CommonUtils/NameConf.h"
#include "CommonConstants/GeomConstants.h"
#include "DataFormatsTPC/TrackTPC.h"
#include "ReconstructionDataFormats/TrackTPCITS.h"
#include <cmath>
#include <fairlogger/Logger.h>
 
using namespace o2::trd;
using namespace o2::trd::constants;
 
void TrackBasedCalib::reset()
{
  mAngResHistos.reset();
  mGainCalibHistos.clear();
}
 
void TrackBasedCalib::init()
{
  bz = o2::base::Propagator::Instance()->getNominalBz();
  mRecoParam.init(bz);
}
 
void TrackBasedCalib::setInput(const o2::globaltracking::RecoContainer& input)
{
  mTracksInITSTPCTRD = input.getITSTPCTRDTracks<TrackTRD>();
  mTracksInTPCTRD = input.getTPCTRDTracks<TrackTRD>();
  mTrackletsRaw = input.getTRDTracklets();
  mTrackletsCalib = input.getTRDCalibratedTracklets();
  mTracksTPC = input.getTPCTracks();
  mTracksITSTPC = input.getTPCITSTracks();
}
 
void TrackBasedCalib::calculateGainCalibObjs()
{
  if (!mLocalGain) {
    LOG(alarm) << "No Local gain map available. Please upload valid object to CCDB.";
  }
 
  int nTracksSuccessTPCTRD = filldEdx(mTracksInTPCTRD, true);
  int nTracksSuccessITSTPCTRD = filldEdx(mTracksInITSTPCTRD, false);
 
  LOGP(info, "Gain Calibration: Successfully processed {} tracks ({} from ITS-TPC-TRD and {} from TPC-TRD) and collected {} data points",
       nTracksSuccessITSTPCTRD + nTracksSuccessTPCTRD, nTracksSuccessITSTPCTRD, nTracksSuccessTPCTRD, mGainCalibHistos.size());
}
 
void TrackBasedCalib::calculateAngResHistos()
{
  if (mTrackletsRaw.size() != mTrackletsCalib.size()) {
    LOG(error) << "TRD raw tracklet container size differs from calibrated tracklet container size";
    return;
  }
 
  if (!mNoiseCalib) {
    LOG(alarm) << "No MCM noise map available. Please upload valid object to CCDB.";
  }
 
  LOGF(info, "As input tracks are available: %lu ITS-TPC-TRD tracks and %lu TPC-TRD tracks", mTracksInITSTPCTRD.size(), mTracksInTPCTRD.size());
 
  auto& params = TRDCalibParams::Instance();
  int nTracksSuccessITSTPCTRD = doTrdOnlyTrackFits(mTracksInITSTPCTRD);
  int nTracksSuccessTPCTRD = params.rejectTPCTRD ? 0 : doTrdOnlyTrackFits(mTracksInTPCTRD);
 
  LOGF(info, "Successfully processed %i tracks (%i from ITS-TPC-TRD and %i from TPC-TRD) and collected %lu angular residuals",
       nTracksSuccessITSTPCTRD + nTracksSuccessTPCTRD, nTracksSuccessITSTPCTRD, nTracksSuccessTPCTRD, mAngResHistos.getNEntries());
  // mAngResHistos.print();
}
 
int TrackBasedCalib::filldEdx(gsl::span<const TrackTRD>& tracks, bool isTPCTRD)
{
  auto& params = TRDCalibParams::Instance();
  int nTracksSuccess = 0;
  for (const auto& trkIn : tracks) {
 
    if (trkIn.getNtracklets() < params.nTrackletsMinGainCalib) {
      continue;
    }
 
    if (trkIn.getP() < params.pMin || trkIn.getP() > params.pMax) {
      continue;
    }
 
    auto id = trkIn.getRefGlobalTrackId();
    float dEdxTPC;
    if (isTPCTRD) {
      dEdxTPC = mTracksTPC[id].getdEdx().dEdxTotTPC;
    } else {
      dEdxTPC = mTracksTPC[mTracksITSTPC[id].getRefTPC()].getdEdx().dEdxTotTPC;
    }
    if (dEdxTPC < params.dEdxTPCMin || dEdxTPC > params.dEdxTPCMax) {
      continue;
    }
 
    if (std::isnan(trkIn.getSnp())) {
      LOG(alarm) << "Track with invalid parameters found: " << trkIn.getRefGlobalTrackId();
      continue;
    }
 
    for (int iLayer = NLAYER - 1; iLayer >= 0; --iLayer) {
      if (trkIn.getTrackletIndex(iLayer) == -1) {
        continue;
      }
      if (mNoiseCalib && mNoiseCalib->isTrackletFromNoisyMCM(mTrackletsRaw[trkIn.getTrackletIndex(iLayer)])) {
        // ignore tracklets which originate from noisy MCMs
        continue;
      }
 
      // Remove split tracklets
      if (trkIn.getIsCrossingNeighbor(iLayer)) {
        continue;
      }
 
      int trkltId = trkIn.getTrackletIndex(iLayer);
      int trkltDet = mTrackletsRaw[trkltId].getDetector();
      int trkltSec = trkltDet / (NLAYER * NSTACK);
 
      const auto& tracklet = mTrackletsRaw[trkltId];
 
      auto q0 = tracklet.getQ0();
      auto q1 = tracklet.getQ1();
      auto q2 = tracklet.getQ2();
      if (q0 == 0 || q1 == 0 || q2 == 0 || q0 >= 127 || q1 >= 127 || q2 >= 62) {
        continue;
      }
 
      // Correction for tracklet angle
      const auto& trackletCalib = mTrackletsCalib[trkltId];
      float tgl = trkIn.getTgl();
      float snp = trkIn.getSnpAt(o2::math_utils::sector2Angle(trkltSec), trackletCalib.getX(), bz);
 
      if (std::abs(snp) > 1.) {
        continue;
      }
 
      // This is the track length normalised to the track length at zero angle
      // l/l0 = sqrt(dx^2 + dy^2 + dz^2)/dx = sqrt(1 + (dy/dx)^2 + (dz/dx)^2)
      // (dz/dx)^2 = tan^2(lambda), (dy/dx)^2 = tan^2(phi) = sin^2(phi)/(1-sin^2(phi))
      float trkLength = sqrt(1 + snp * snp / (1 - snp * snp) + tgl * tgl);
      if (TMath::Abs(trkLength) < 1) {
        LOGP(warn, "Invalid track length {} for angles snp {} and tgl {}", trkLength, snp, tgl);
        continue;
      }
 
      float localGainCorr = 1.;
      if (mLocalGain) {
        localGainCorr = mLocalGain->getValue(trkltDet, tracklet.getPadCol(mApplyShift), tracklet.getPadRow());
      }
      if (TMath::Abs(localGainCorr) < 0.0001f) {
        LOGP(warn, "Invalid localGainCorr {} for det {}, pad col {}, pad row {}", localGainCorr, trkltDet, tracklet.getPadCol(mApplyShift), tracklet.getPadRow());
        continue;
      }
 
      unsigned int dEdx = (q0 + q1 + q2) / trkLength / localGainCorr;
      if (dEdx >= NBINSGAINCALIB) {
        continue;
      }
      int chamberOffset = trkltDet * NBINSGAINCALIB;
      mGainCalibHistos.push_back(chamberOffset + dEdx);
    }
 
    // here we can count the number of successfully processed tracks
    ++nTracksSuccess;
  } // end of track loop
  return nTracksSuccess;
}
 
int TrackBasedCalib::doTrdOnlyTrackFits(gsl::span<const TrackTRD>& tracks)
{
  auto& params = TRDCalibParams::Instance();
  int nTracksSuccess = 0;
  for (const auto& trkIn : tracks) {
    if (trkIn.getNtracklets() < params.nTrackletsMin) {
      // with less than 3 tracklets the TRD-only refit not meaningful
      if (trkIn.getNtracklets() < params.nTrackletsMinLoose || !((trkIn.getTrackletIndex(0) >= 0 && (trkIn.getTrackletIndex(NLAYER - 1) >= 0 || trkIn.getTrackletIndex(NLAYER - 2) >= 0))) || (trkIn.getTrackletIndex(1) >= 0 && trkIn.getTrackletIndex(NLAYER - 1) >= 0)) {
        // we check if we have enough lever arm, i.e. (first and last) or (second and last) or (first and before last) are present
        continue;
      }
    }
    if (trkIn.getPt() < params.minPtCalib) {
      // we reject low pt tracks which might suffer from multiple scattering (giving lower quality of the TRD-only fit)
      continue;
    }
 
    auto trkWork = trkIn; // input is const, so we need to create a copy
    bool trackFailed = false;
 
    trkWork.setChi2(0.f);
    trkWork.resetCovariance(20);
 
    if (std::isnan(trkWork.getSnp())) {
      LOG(alarm) << "Track with invalid parameters found: " << trkWork.getRefGlobalTrackId();
      continue;
    }
 
    // reject tracks which cross sectors within TRD (if the extrapolation from the outer TRD to the outer TPC leads to a change in sector or close to the sector edges with 5 cm  margin), which have larger uncertainties and probably more fakes
    float yOuterTPC = trkIn.getOuterParam().getYAt(o2::constants::geom::XTPCOuterRef, bz);
    if (std::fabs(yOuterTPC) > o2::constants::geom::XTPCOuterRef * tan(M_PI / 18.) - 5.) {
      continue;
    }
 
    // first inward propagation (TRD track fit)
    int currLayer = NLAYER;
    for (int iLayer = NLAYER - 1; iLayer >= 0; --iLayer) {
      if (trkWork.getTrackletIndex(iLayer) == -1) {
        continue;
      }
      if (mNoiseCalib && mNoiseCalib->isTrackletFromNoisyMCM(mTrackletsRaw[trkWork.getTrackletIndex(iLayer)])) {
        // ignore tracklets which originate from noisy MCMs
        continue;
      }
      if (propagateAndUpdate(trkWork, iLayer, true)) {
        trackFailed = true;
        break;
      }
      currLayer = iLayer;
    }
    if (trackFailed) {
      continue;
    }
 
    // outward propagation (smoothing)
    for (int iLayer = currLayer + 1; iLayer < NLAYER; ++iLayer) {
      if (trkWork.getTrackletIndex(iLayer) == -1) {
        continue;
      }
      if (mNoiseCalib && mNoiseCalib->isTrackletFromNoisyMCM(mTrackletsRaw[trkWork.getTrackletIndex(iLayer)])) {
        // ignore tracklets which originate from noisy MCMs
        continue;
      }
      if (propagateAndUpdate(trkWork, iLayer, true)) {
        trackFailed = true;
        break;
      }
      currLayer = iLayer;
    }
    if (trackFailed) {
      continue;
    }
 
    // second inward propagation (collect angular differences between tracklets + TRD track)
    for (int iLayer = currLayer; iLayer >= 0; --iLayer) {
      if (trkWork.getTrackletIndex(iLayer) == -1) {
        continue;
      }
      if (mNoiseCalib && mNoiseCalib->isTrackletFromNoisyMCM(mTrackletsRaw[trkWork.getTrackletIndex(iLayer)])) {
        // ignore tracklets which originate from noisy MCMs
        continue;
      }
      if (propagateAndUpdate(trkWork, iLayer, false)) {
        trackFailed = true;
        break;
      }
 
      if (trkWork.getReducedChi2() > params.chi2RedMax) {
        // set an upper bound on acceptable tracks we use for qc
        continue;
      }
 
      float trkAngle = o2::math_utils::asin(trkWork.getSnp()) * TMath::RadToDeg();
      int trkltId = trkWork.getTrackletIndex(iLayer);
      // tracklet angle, corrected for pad tilt
      const PadPlane* pad = Geometry::instance()->getPadPlane(mTrackletsRaw[trkltId].getDetector());
      float tilt = tan(TMath::DegToRad() * pad->getTiltingAngle()); // tilt is signed! and returned in degrees
      float tiltCorrUp = tilt * trkWork.getTgl() * Geometry::cdrHght();
      float padLength = pad->getRowSize(mTrackletsRaw[trkltId].getPadRow());
      if (!((trkWork.getSigmaZ2() < (padLength * padLength / 12.f)) && (std::fabs(mTrackletsCalib[trkltId].getZ() - trkWork.getZ()) < padLength))) {
        tiltCorrUp = 0.f;
      }
 
      // use uncalibrated dy because online calibration does not work otherwise
      float trkltDy = mTrackletsRaw[trkltId].getUncalibratedDy(30.f / o2::trd::constants::VDRIFTDEFAULT) + tiltCorrUp;
      float trkltAngle = o2::math_utils::atan(trkltDy / Geometry::cdrHght()) * TMath::RadToDeg();
      float angleDeviation = trkltAngle - trkAngle;
      if (mAngResHistos.addEntry(angleDeviation, trkAngle, mTrackletsRaw[trkltId].getDetector())) {
        // track impact angle out of histogram range
        continue;
      }
    }
 
    // here we can count the number of successfully processed tracks
    ++nTracksSuccess;
  } // end of track loop
  return nTracksSuccess;
}
 
bool TrackBasedCalib::propagateAndUpdate(TrackTRD& trk, int iLayer, bool doUpdate) const
{
  // Propagates the track to TRD layer iLayer and updates the track
  // parameters (if requested)
  // returns 0 in case of success
 
  auto propagator = o2::base::Propagator::Instance();
 
  int trkltId = trk.getTrackletIndex(iLayer);
  int trkltDet = mTrackletsRaw[trkltId].getDetector();
  int trkltSec = trkltDet / (NLAYER * NSTACK);
 
  if (trkltSec != o2::math_utils::angle2Sector(trk.getAlpha())) {
    if (!trk.rotate(o2::math_utils::sector2Angle(trkltSec))) {
      LOGF(debug, "Track could not be rotated in tracklet coordinate system");
      return 1;
    }
  }
 
  if (!propagator->PropagateToXBxByBz(trk, mTrackletsCalib[trkltId].getX(), mMaxSnp, mMaxStep, mMatCorr)) {
    LOGF(debug, "Track propagation failed in layer %i (pt=%f, xTrk=%f, xToGo=%f)", iLayer, trk.getPt(), trk.getX(), mTrackletsCalib[trkltId].getX());
    return 1;
  }
 
  if (!doUpdate) {
    // nothing more to be done
    return 0;
  }
 
  const PadPlane* pad = Geometry::instance()->getPadPlane(trkltDet);
  float tilt = tan(TMath::DegToRad() * pad->getTiltingAngle()); // tilt is signed! and returned in degrees
  float tiltCorrUp = tilt * (mTrackletsCalib[trkltId].getZ() - trk.getZ());
  float zPosCorrUp = mTrackletsCalib[trkltId].getZ() + mRecoParam.getZCorrCoeffNRC() * trk.getTgl();
  float padLength = pad->getRowSize(mTrackletsRaw[trkltId].getPadRow());
  if (!((trk.getSigmaZ2() < (padLength * padLength / 12.f)) && (std::fabs(mTrackletsCalib[trkltId].getZ() - trk.getZ()) < padLength))) {
    tiltCorrUp = 0.f;
  }
 
  std::array<float, 2> trkltPosUp{mTrackletsCalib[trkltId].getY() - tiltCorrUp, zPosCorrUp};
  std::array<float, 3> trkltCovUp;
  mRecoParam.recalcTrkltCov(tilt, trk.getSnp(), pad->getRowSize(mTrackletsRaw[trkltId].getPadRow()), trkltCovUp);
 
  if (!trk.update(trkltPosUp, trkltCovUp)) {
    LOGF(info, "Failed to update track with space point in layer %i", iLayer);
    return 1;
  }
  return 0;
}