LtrCalibData.h

// 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.

/// \file LtrCalibData.h
/// \brief calibration data from laser track calibration
///
/// This class holds the calibration output data of CalibLaserTracks
///
/// \author Jens Wiechula, Jens.Wiechula@ikf.uni-frankfurt.de

#ifndef AliceO2_TPC_LtrCalibData_H_
#define AliceO2_TPC_LtrCalibData_H_

#include <fairlogger/Logger.h>
#include <Rtypes.h>

namespace o2::tpc
{

struct LtrCalibData {
  size_t processedTFs{};               ///< number of processed TFs with laser track candidates
  uint64_t firstTime{};                ///< first time stamp of processed TFs
  uint64_t lastTime{};                 ///< last time stamp of processed TFs
  long creationTime{};                 ///< time of creation
  float dvCorrectionA{1.f};            ///< drift velocity correction factor A-Side (inverse multiplicative)
  float dvCorrectionC{1.f};            ///< drift velocity correction factor C-Side (inverse multiplicative)
  float dvOffsetA{};                   ///< drift velocity trigger offset A-Side
  float dvOffsetC{};                   ///< drift velocity trigger offset C-Side
  float refVDrift{};                   ///< reference vdrift for which factor was extracted
  float refTimeOffset{0.};             ///< additive time offset reference (\mus)
  float timeOffsetCorr{0.};            ///< additive time offset correction (\mus)
  uint16_t nTracksA{};                 ///< number of tracks used for A-Side fit
  uint16_t nTracksC{};                 ///< number of tracks used for C-Side fit
  std::vector<uint16_t> matchedLtrIDs; ///< matched laser track IDs
  std::vector<uint16_t> nTrackTF;      ///< number of laser tracks per TF
  std::vector<float> dEdx;             ///< dE/dx of each track
  float tp{0.f};                       ///< temperature over pressure ratio

  bool isValid() const
  {
    return (std::abs(dvCorrectionA - 1.f) < 0.2) || (std::abs(dvCorrectionC - 1.f) < 0.2);
  }

  float getDriftVCorrection() const
  {
    float correction = 0;
    int nCorr = 0;
    // only allow +- 20% around reference correction
    if (std::abs(dvCorrectionA - 1.f) < 0.2) {
      correction += dvCorrectionA;
      ++nCorr;
    } else {
      LOGP(warning, "abs(dvCorrectionA ({}) - 1) >= 0.2, not using for combined estimate", dvCorrectionA);
    }

    if (std::abs(dvCorrectionC - 1.f) < 0.2) {
      correction += dvCorrectionC;
      ++nCorr;
    } else {
      LOGP(warning, "abs(dvCorrectionC ({}) - 1) >= 0.2, not using for combined estimate", dvCorrectionC);
    }

    if (nCorr == 0) {
      LOGP(error, "no valid drift velocity correction");
      return 1.f;
    }

    return correction / nCorr;
  }

  float getVDrift() const { return refVDrift / getDriftVCorrection(); }

  float getTimeOffset() const { return refTimeOffset + timeOffsetCorr; }

  // renormalize reference and correction either to provided new reference (if >0) or to correction 1 wrt current reference
  void normalize(float newVRef = 0.f)
  {
    if (refVDrift == 0.) {
      LOG(error) << "LtrCalibData data has no reference";
      return;
    }
    if (getDriftVCorrection() == 0) {
      LOGP(error, "Drift correction is 0: dvCorrectionA={}, dvCorrectionC={}, nTracksA={}, nTracksC={}", dvCorrectionA, dvCorrectionC, nTracksA, nTracksC);
      return;
    }
    if (newVRef == 0.) {
      newVRef = refVDrift / getDriftVCorrection();
    }
    float fact = newVRef / refVDrift;
    refVDrift = newVRef;
    dvCorrectionA *= fact;
    dvCorrectionC *= fact;
  }

  // similarly, the time offset reference is set to provided newRefTimeOffset (if > -998) or modified to have timeOffsetCorr to
  // be 0 otherwise

  void normalizeOffset(float newRefTimeOffset = -999.)
  {
    if (newRefTimeOffset > -999.) {
      timeOffsetCorr = getTimeOffset() - newRefTimeOffset;
      refTimeOffset = newRefTimeOffset;
    } else {
      refTimeOffset = getTimeOffset();
      timeOffsetCorr = 0.;
    }
  }

  float getT0A() const { return (250.f * (1.f - dvCorrectionA) - dvOffsetA) / refVDrift; }
  float getT0C() const { return (250.f * (1.f - dvCorrectionC) + dvOffsetC) / refVDrift; }
  float getZOffsetA() const { return (250.f * (1.f - dvCorrectionA) - dvOffsetA) / dvCorrectionA; }
  float getZOffsetC() const { return (250.f * (1.f - dvCorrectionC) + dvOffsetC) / dvCorrectionC; }

  void reset()
  {
    processedTFs = 0;
    firstTime = 0;
    lastTime = 0;
    creationTime = 0;
    dvCorrectionA = 0;
    dvCorrectionC = 0;
    dvOffsetA = 0;
    dvOffsetC = 0;
    nTracksA = 0;
    nTracksC = 0;
    refVDrift = 0;
    refTimeOffset = 0;
    timeOffsetCorr = 0;
    matchedLtrIDs.clear();
    nTrackTF.clear();
    dEdx.clear();
  }

  ClassDefNV(LtrCalibData, 5);
};

} // namespace o2::tpc
#endif