InDetPhysHitDecoratorAlg.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#include "InDetPhysHitDecoratorAlg.h"
#include "safeDecorator.h"
#include "TrkParameters/TrackParameters.h" // Contains typedef to Trk::CurvilinearParameters
#include "TrkToolInterfaces/ITrackHoleSearchTool.h"
#include "TrkToolInterfaces/IUpdator.h"
#include "InDetRIO_OnTrack/SiClusterOnTrack.h"
#include "TrkEventPrimitives/ResidualPull.h"
#include "TrkToolInterfaces/IResidualPullCalculator.h"
#include "TrkTrack/TrackCollection.h"
// for the identifiers
#include "AtlasDetDescr/AtlasDetectorID.h"
#include "InDetIdentifier/PixelID.h"
#include "InDetIdentifier/SCT_ID.h"
#include "InDetIdentifier/TRT_ID.h"
#include "InDetPrepRawData/SiCluster.h"
//
#include <tuple>
#include <limits>
 
 
InDetPhysHitDecoratorAlg::InDetPhysHitDecoratorAlg(const std::string& name, ISvcLocator* pSvcLocator) :
    AthReentrantAlgorithm(name,pSvcLocator),
    m_holeSearchTool("InDet::InDetTrackHoleSearchTool"),
    m_updatorHandle("Trk::KalmanUpdator/TrkKalmanUpdator"),
    m_residualPullCalculator("Trk::ResidualPullCalculator/ResidualPullCalculator"),
    m_idHelper(nullptr),
    m_pixelID(nullptr),
    m_sctID(nullptr),
    m_trtID(nullptr) {
    declareProperty("InDetTrackHoleSearchTool", m_holeSearchTool);
    declareProperty("Updator", m_updatorHandle);
    declareProperty("ResidualPullCalculator", m_residualPullCalculator);
}
 
InDetPhysHitDecoratorAlg::~InDetPhysHitDecoratorAlg () {
}
 
StatusCode
InDetPhysHitDecoratorAlg::initialize() {
    ATH_CHECK(m_holeSearchTool.retrieve());
    if (not (m_updatorHandle.empty())) {
        ATH_CHECK(m_updatorHandle.retrieve());
    }
    ATH_CHECK(m_lorentzAngleTool.retrieve());
 
    std::vector<std::string> float_decor_names(kNFloatDecorators);
    std::vector<std::string> int_decor_names(kNIntDecorators);
    std::vector<std::string> uint64_decor_names(kNUInt64Decorators);
 
    int_decor_names[kDecorRegion]="measurement_region";
    int_decor_names[kDecorDet]="measurement_det";
    int_decor_names[kDecorILayer]="measurement_iLayer";
    int_decor_names[kDecorType]="measurement_type";
    int_decor_names[kDecorPhiWidth]="hitResiduals_phiWidth";
    int_decor_names[kDecorEtaWidth]="hitResiduals_etaWidth";
 
    float_decor_names[kDecorResidualLocX]="hitResiduals_residualLocX";
    float_decor_names[kDecorPullLocX]="hitResiduals_pullLocX";
    float_decor_names[kDecorMeasLocX]="measurementLocX";
    float_decor_names[kDecorTrkParamLocX]="trackParamLocX";
    float_decor_names[kDecorMeasLocCovX]="measurementLocCovX";
 
    float_decor_names[kDecorResidualLocY]="hitResiduals_residualLocY";
    float_decor_names[kDecorPullLocY]="hitResiduals_pullLocY";
    float_decor_names[kDecorMeasLocY]="measurementLocY";
    float_decor_names[kDecorTrkParamLocY]="trackParamLocY";
    float_decor_names[kDecorMeasLocCovY]="measurementLocCovY";
 
    float_decor_names[kDecorAngle]="angle";
    float_decor_names[kDecorEtaLoc]="etaloc";
 
    uint64_decor_names[kDecorID]="surfaceID";
 
    ATH_CHECK( m_trkParticleName.initialize() );
    IDPVM::createDecoratorKeys(*this,m_trkParticleName,m_prefix,float_decor_names,m_floatDecor);
    IDPVM::createDecoratorKeys(*this,m_trkParticleName,m_prefix, int_decor_names, m_intDecor);
    IDPVM::createDecoratorKeys(*this,m_trkParticleName,m_prefix, uint64_decor_names, m_uint64Decor);
    assert( m_intDecor.size() == kNIntDecorators);
    assert( m_uint64Decor.size() == kNUInt64Decorators);
    assert( m_floatDecor.size() == kNFloatDecorators);
 
    // ID Helper
    m_idHelper = new AtlasDetectorID;
 
    // Get the dictionary manager from the detector store
    ATH_CHECK(detStore()->retrieve(m_idHelper, "AtlasID"));
    ATH_CHECK(detStore()->retrieve(m_pixelID, "PixelID"));
    ATH_CHECK(detStore()->retrieve(m_sctID, "SCT_ID"));
    ATH_CHECK(detStore()->retrieve(m_trtID, "TRT_ID"));
 
    if (m_residualPullCalculator.empty()) {
        ATH_MSG_INFO("No residual/pull calculator for general hit residuals configured.");
        ATH_MSG_INFO("It is recommended to give R/P calculators to the det-specific tool handle lists then.");
    } else if (m_residualPullCalculator.retrieve().isFailure()) {
        ATH_MSG_FATAL( "Could not retrieve " << m_residualPullCalculator << " (to calculate residuals and pulls) " );
    } else {
        ATH_MSG_INFO("Generic hit residuals & pulls will be calculated in one or both available local coordinates");
    }
    return StatusCode::SUCCESS;
}
 
StatusCode
InDetPhysHitDecoratorAlg::finalize() {
    return StatusCode::SUCCESS;
}
 
// to migrate to AthReentrantAlgorithm later
StatusCode
InDetPhysHitDecoratorAlg::execute(const EventContext &ctx) const {
    SG::ReadHandle<xAOD::TrackParticleContainer> ptracks(m_trkParticleName, ctx);
    if ((not ptracks.isValid())) {
      ATH_MSG_ERROR("Cannot get ReadHandle " << m_trkParticleName);
      return StatusCode::FAILURE;
    }
 
    std::vector< SG::WriteDecorHandle<xAOD::TrackParticleContainer,std::vector<float> > >
      float_decor( IDPVM::createDecorators<xAOD::TrackParticleContainer, std::vector<float> >(m_floatDecor, ctx) );
    std::vector< SG::WriteDecorHandle<xAOD::TrackParticleContainer,std::vector<int> > >
      int_decor( IDPVM::createDecorators<xAOD::TrackParticleContainer,std::vector<int> >(m_intDecor, ctx) );
    std::vector< SG::WriteDecorHandle<xAOD::TrackParticleContainer,std::vector<uint64_t> > >
      uint64_decor( IDPVM::createDecorators<xAOD::TrackParticleContainer,std::vector<uint64_t> >(m_uint64Decor, ctx) );
 
    for (const xAOD::TrackParticle *trk_particle : *ptracks) {
      if (not decorateTrack(*trk_particle, float_decor, int_decor, uint64_decor) ) {
        ATH_MSG_ERROR("Could not decorate track");
        return StatusCode::FAILURE;
      }
    }
    return StatusCode::SUCCESS;
}
 
bool
InDetPhysHitDecoratorAlg::decorateTrack(const xAOD::TrackParticle &particle,
                                        std::vector< SG::WriteDecorHandle<xAOD::TrackParticleContainer,std::vector<float> > > &float_decor,
                                        std::vector< SG::WriteDecorHandle<xAOD::TrackParticleContainer,std::vector<int> > > &int_decor,
                                        std::vector< SG::WriteDecorHandle<xAOD::TrackParticleContainer,std::vector<uint64_t> > > &uint64_decor) const
{
    int trackNumber(0);
 
    using SingleResult_t = std::tuple<int, int, int, // detector, region, layer index,
                                      float, float, // residual local position X, pull local position X
                                      float, float, // residual local position Y, pull local position Y
                                      int, int, int, // cluster dimensions in phi and eta directions, measurement type
                                      float, float, // measurement local position X, measurement local position Y
                                      float, float,// track parameter local X, track parameter local Y
                                      float, float, // track angle in local module frame and associated eta
                                      float, float, uint64_t>; // measurement covariance local X, measurement covariance local Y, surface identifier
    using TrackResult_t = std::vector<SingleResult_t>;
    const float invalidFloat(-1.);
    const int invalidInteger(-1);
    const uint64_t invalidID(0);
    const SingleResult_t invalidResult = std::make_tuple(invalidInteger, invalidInteger, invalidInteger,
                                                         invalidFloat, invalidFloat, invalidFloat, invalidFloat,
                                                         invalidInteger, invalidInteger, invalidInteger,
                                                         invalidFloat, invalidFloat, invalidFloat, invalidFloat,
                                                         invalidFloat, invalidFloat, invalidFloat, invalidFloat,
                                                         invalidID);
    bool isUnbiased(true);
    // get element link to the original track
    const ElementLink< TrackCollection >& trackLink = particle.trackLink();
    if (trackLink.isValid()) {
        ATH_MSG_VERBOSE("Track link found ");
        std::unique_ptr<const Trk::Track> trackWithHoles(m_holeSearchTool->getTrackWithHoles(**trackLink));
        const auto& allTrackStates = *(trackWithHoles->trackStateOnSurfaces());
        const int numberOfHits(allTrackStates.size());
        unsigned int trackParametersCounter(numberOfHits);
        TrackResult_t result;
        result.reserve(numberOfHits);
        if (!m_updatorHandle.empty()) {
            isUnbiased = true;
        } else {
            ATH_MSG_WARNING("The updater handle is empty, now using biased estimators");
            isUnbiased = false;
        }
        ATH_MSG_DEBUG("Num. track states in track " << ++trackNumber << ": " << allTrackStates.size());
 
        for (const auto *const thisTrackState: allTrackStates) {
            // Copy logic from InDetRttPerformance to get hits/outliers/holes
            // Variable specifying measurement type filled
            SingleResult_t thisResult(invalidResult);
            if (not thisTrackState) { // is this check needed?
                msg(MSG::ERROR) << "TSOS is NULL" << (thisTrackState) << endmsg;
                continue;
            }
            Identifier surfaceID;
            const Trk::MeasurementBase* mesb = (thisTrackState)->measurementOnTrack();
            const Trk::RIO_OnTrack* hit = mesb ? dynamic_cast<const Trk::RIO_OnTrack*>(mesb) : nullptr;
            if (mesb && !hit) {
                continue; // skip pseudomeasurements
            }
            // Get surfaceID, different for measuremnt hits & outliers, and holes
            if (mesb && mesb->associatedSurface().associatedDetectorElement()) {
                surfaceID = mesb->associatedSurface().associatedDetectorElement()->identify();
            } // Holes
            else {
                if (not (thisTrackState)->trackParameters()) {
                    msg(MSG::INFO) << "TSOS surface is NULL" << endmsg;
                    continue;
                }
                surfaceID = (thisTrackState)->trackParameters()->associatedSurface().associatedDetectorElementIdentifier();
            }
            bool isMesb = (thisTrackState)->type(Trk::TrackStateOnSurface::Measurement);
            bool isOutl = (thisTrackState)->type(Trk::TrackStateOnSurface::Outlier);
            bool isHole = (thisTrackState)->type(Trk::TrackStateOnSurface::Hole);
 
            int measureType = -1;
            if (isMesb) {
                measureType = 0;
            }
            if (isOutl) {
                measureType = 1;
            }
            if (isHole) {
                measureType = 2;
            }
 
            bool anyHit = isMesb || isOutl || isHole;
            if (!anyHit) {
                continue;
            }
            Subdetector det(INVALID_DETECTOR);
            Region r(INVALID_REGION);
            int iLayer(invalidInteger);
            const bool successfulIdentification = decideDetectorRegion(surfaceID, det, r, iLayer);
            if (not successfulIdentification) {
                ATH_MSG_DEBUG("Could not identify surface");
                continue;
            }
            uint64_t Surface_ID = surfaceID.get_compact();
            // defining invalid values, they will be filled when and where needed
            float residualLocX(invalidFloat), pullLocX(invalidFloat);
            float residualLocY(invalidFloat), pullLocY(invalidFloat);
            float measurementLocX(invalidFloat), trackParamLocX(invalidFloat), measurementLocCovX(invalidFloat);
            float measurementLocY(invalidFloat), trackParamLocY(invalidFloat), measurementLocCovY(invalidFloat);
            float angle(0.), etaloc(0.);
            int phiWidth(invalidInteger), etaWidth(invalidInteger);
            std::optional<Trk::ResidualPull> residualPull(std::nullopt);
            const Trk::TrackParameters* biasedTrackParameters = thisTrackState->trackParameters();
            if (biasedTrackParameters) {
                ATH_MSG_VERBOSE("biased track parameters ok");
            }
            ATH_MSG_VERBOSE("checking mesb and track parameters");
            if (mesb && biasedTrackParameters) {
                ATH_MSG_DEBUG("mesb and biased track parameters are ok");
                // for outliers, the measurement is not part of the fit, so track parameters are already unbiased
                std::unique_ptr<const Trk::TrackParameters> cleanup_trackparam;
                const Trk::TrackParameters* trackParameters =
                    (!thisTrackState->type(Trk::TrackStateOnSurface::Outlier)) ? getUnbiasedTrackParameters(
                        biasedTrackParameters, mesb, isUnbiased) : biasedTrackParameters;
 
                if (trackParameters != biasedTrackParameters) {
                    cleanup_trackparam.reset(trackParameters);
                }
                if (not trackParameters) {
                    ATH_MSG_DEBUG("unbiased track parameters pointer is NULL");
                }
 
                Trk::ResidualPull::ResidualType resType =
                    (isUnbiased) ? (Trk::ResidualPull::Unbiased) : (Trk::ResidualPull::Biased);
 
                residualPull= m_residualPullCalculator->residualPull(hit, trackParameters, resType);
                ATH_MSG_VERBOSE("checking residual pull");
                if (not residualPull) {
                    ATH_MSG_DEBUG("residualPull is NULL");
                    continue;
                }
 
                ATH_MSG_DEBUG("residualPull is OK");
 
                residualLocX = 1000. * residualPull->residual()[Trk::loc1]; // residuals in microns
                pullLocX = residualPull->pull()[Trk::loc1];
                measurementLocX = hit->localParameters()[Trk::loc1];
                trackParamLocX = trackParameters->parameters()[Trk::loc1];
                measurementLocCovX = hit->localCovariance()(Trk::loc1,Trk::loc1);
 
                if (residualPull->dimension() > 1) {
                    residualLocY = 1000. * residualPull->residual()[Trk::loc2];
                    pullLocY = residualPull->pull()[Trk::loc2];
                    measurementLocY = hit->localParameters()[Trk::loc2];
                    trackParamLocY = trackParameters->parameters()[Trk::loc2];
                    measurementLocCovY = hit->localCovariance()(Trk::loc2,Trk::loc2);
                }
 
                // Unbiased residuals
                measureType = 4;
 
                if (hit && isUnbiased) {
                    // Cluster width determination
                    if ((det == L0PIXBARR)or(det == PIXEL) or(det == SCT)) {
                        const InDet::SiCluster* pCluster = dynamic_cast <const InDet::SiCluster*>(hit->prepRawData());
                        if (pCluster) {
                            InDet::SiWidth width = pCluster->width();
                            phiWidth = int(width.colRow().x());
                            etaWidth = int(width.colRow().y());
 
                            // get candidate track angle in module local frame
                            Amg::Vector3D my_track = trackParameters->momentum();
                            const InDetDD::SiDetectorElement* element = pCluster->detectorElement();
                            Amg::Vector3D my_normal = element->normal();
                            Amg::Vector3D my_phiax = element->phiAxis();
                            Amg::Vector3D my_etaax = element->etaAxis();
                            float trkphicomp = my_track.dot(my_phiax);
                            float trketacomp = my_track.dot(my_etaax);
                            float trknormcomp = my_track.dot(my_normal);
                            double bowphi = atan2(trkphicomp,trknormcomp);
                            double boweta = atan2(trketacomp,trknormcomp);
 
                            float tanl = m_lorentzAngleTool->getTanLorentzAngle(element->identifyHash(), Gaudi::Hive::currentContext());
                            int readoutside = element->design().readoutSide();
 
                            // map the angles of inward-going tracks onto [-PI/2, PI/2]
                            if(bowphi > M_PI/2) bowphi -= M_PI;
                            if(bowphi < -M_PI/2) bowphi += M_PI;
 
                            // finally, subtract the Lorentz angle effect
                            // the readoutside term is needed because of a bug in old
                            // geometry versions (CSC-01-* and CSC-02-*)
                            angle = atan(tan(bowphi)-readoutside*tanl);
 
                            double thetaloc=-999.;
                            if(boweta > -0.5*M_PI && boweta < M_PI/2.) {
                                thetaloc = M_PI/2.-boweta;
                            } else if(boweta > M_PI/2. && boweta < M_PI) {
                                thetaloc = 1.5*M_PI-boweta;
                            } else { // 3rd quadrant
                                thetaloc = -0.5*M_PI-boweta;
                            }
                            etaloc = -1*log(tan(thetaloc/2.));
                        }
                    }
                    ATH_MSG_VERBOSE("hit and isUnbiased ok");
                }
            } else {
                if (not mesb) {
                    ATH_MSG_VERBOSE("mesb not ok");
                }
                if (not biasedTrackParameters) {
                    ATH_MSG_VERBOSE("biasedTrackParameters were not found");
                }
                --trackParametersCounter;
            }
            thisResult = std::make_tuple(det, r, iLayer,
                                         residualLocX, pullLocX, residualLocY, pullLocY,
                                         phiWidth, etaWidth, measureType,
                                         measurementLocX, measurementLocY,
                                         trackParamLocX, trackParamLocY,
                                         angle, etaloc,
                                         measurementLocCovX, measurementLocCovY,
                                         Surface_ID);
          result.push_back(thisResult);
        } // end of for loop*/
        ATH_MSG_DEBUG( "Out of " << numberOfHits << " hits, " << trackParametersCounter
                        << " had track params, and " << result.size() << " had residuals.");
        if (not result.empty()) {
            const unsigned int arraySize = result.size();
            std::vector<int> result_det;
            result_det.reserve(arraySize);
            std::vector<int> result_r;
            result_r.reserve(arraySize);
            std::vector<int> result_iLayer;
            result_iLayer.reserve(arraySize);
            std::vector<float> result_residualLocX;
            result_residualLocX.reserve(arraySize);
            std::vector<float> result_pullLocX;
            result_pullLocX.reserve(arraySize);
            std::vector<float> result_residualLocY;
            result_residualLocY.reserve(arraySize);
            std::vector<float> result_pullLocY;
            result_pullLocY.reserve(arraySize);
            std::vector<int> result_phiWidth;
            result_phiWidth.reserve(arraySize);
            std::vector<int> result_etaWidth;
            result_etaWidth.reserve(arraySize);
            std::vector<int> result_measureType;
            result_measureType.reserve(arraySize);
            std::vector<float> result_measurementLocX;
            result_measurementLocX.reserve(arraySize);
            std::vector<float> result_measurementLocY;
            result_measurementLocY.reserve(arraySize);
            std::vector<float> result_trackParamLocX;
            result_trackParamLocX.reserve(arraySize);
            std::vector<float> result_trackParamLocY;
            result_trackParamLocY.reserve(arraySize);
            std::vector<float> result_angle;
            result_angle.reserve(arraySize);
            std::vector<float> result_etaloc;
            result_etaloc.reserve(arraySize);
            std::vector<float> result_measurementLocCovX;
            result_measurementLocCovX.reserve(arraySize);
            std::vector<float> result_measurementLocCovY;
            result_measurementLocCovY.reserve(arraySize);
            std::vector<uint64_t> result_surfaceID;
            result_surfaceID.reserve(arraySize);
 
            for (const SingleResult_t& single_result : result) {
                result_det.push_back(std::get<0>(single_result));
                result_r.push_back(std::get<1>(single_result));
                result_iLayer.push_back(std::get<2>(single_result));
                result_residualLocX.push_back(std::get<3>(single_result));
                result_pullLocX.push_back(std::get<4>(single_result));
                result_residualLocY.push_back(std::get<5>(single_result));
                result_pullLocY.push_back(std::get<6>(single_result));
                result_phiWidth.push_back(std::get<7>(single_result));
                result_etaWidth.push_back(std::get<8>(single_result));
                result_measureType.push_back(std::get<9>(single_result));
                result_measurementLocX.push_back(std::get<10>(single_result));
                result_measurementLocY.push_back(std::get<11>(single_result));
                result_trackParamLocX.push_back(std::get<12>(single_result));
                result_trackParamLocY.push_back(std::get<13>(single_result));
                result_angle.push_back(std::get<14>(single_result));
                result_etaloc.push_back(std::get<15>(single_result));
                result_measurementLocCovX.push_back(std::get<16>(single_result));
                result_measurementLocCovY.push_back(std::get<17>(single_result));
                result_surfaceID.push_back(std::get<18>(single_result));
            }
 
            int_decor[kDecorRegion](particle) = result_r;
            int_decor[kDecorDet](particle) = result_det;
            int_decor[kDecorILayer](particle) = result_iLayer;
            int_decor[kDecorPhiWidth](particle) = result_phiWidth;
            int_decor[kDecorEtaWidth](particle) = result_etaWidth;
            int_decor[kDecorType](particle) = result_measureType;
 
            float_decor[kDecorResidualLocX](particle) = result_residualLocX;
            float_decor[kDecorPullLocX](particle) = result_pullLocX;
            float_decor[kDecorMeasLocX](particle) = result_measurementLocX;
            float_decor[kDecorTrkParamLocX](particle) = result_trackParamLocX;
            float_decor[kDecorMeasLocCovX](particle) = result_measurementLocCovX;
 
            float_decor[kDecorResidualLocY](particle) = result_residualLocY;
            float_decor[kDecorPullLocY](particle) = result_pullLocY;
            float_decor[kDecorMeasLocY](particle) = result_measurementLocY;
            float_decor[kDecorTrkParamLocY](particle) = result_trackParamLocY;
            float_decor[kDecorMeasLocCovY](particle) = result_measurementLocCovY;
 
            float_decor[kDecorAngle](particle) = result_angle;
            float_decor[kDecorEtaLoc](particle) = result_etaloc;
 
            uint64_decor[kDecorID](particle) = result_surfaceID;
 
            return true;
      } else {
          // particle below pt threshold for decoration. Since this is not an error now "true" is returned.
          // If "false" is returned the job would be aborted.
          return true;
      }
    } else {
      ATH_MSG_ERROR("No valid track link found ");
    }
    return false;
}
 
bool InDetPhysHitDecoratorAlg::decideDetectorRegion(const Identifier& id, Subdetector& detector,
                                                    Region& region, int& layer) const {
    bool success(false);
    const int pixelSctBarrelIndex(0);
    const int trtBarrelIndex(1);
 
    detector = INVALID_DETECTOR;
    region = INVALID_REGION;
 
    if (m_idHelper->is_pixel(id)) {
        detector = PIXEL;
        region = (m_pixelID->barrel_ec(id) == pixelSctBarrelIndex) ? (BARREL) : (ENDCAP);
        layer = m_pixelID->layer_disk(id);
        if (BARREL == region and layer == 0) {
            detector = L0PIXBARR;
        }
    }
    else if (m_idHelper->is_sct(id)) {
        detector = SCT;
        region = (m_sctID->barrel_ec(id) == pixelSctBarrelIndex) ? (BARREL) : (ENDCAP);
        layer = m_sctID->layer_disk(id);
    }
    else if (m_idHelper->is_trt(id)) {
        detector = TRT;
        region = (std::abs(m_trtID->barrel_ec(id)) == trtBarrelIndex) ? (BARREL) : (ENDCAP);
        layer = m_trtID->layer_or_wheel(id);
    }
    success = (detector != INVALID_DETECTOR) and (region != INVALID_REGION);
 
    return success;
}
 
const Trk::TrackParameters*
InDetPhysHitDecoratorAlg::getUnbiasedTrackParameters(const Trk::TrackParameters* trkParameters,
                                                      const Trk::MeasurementBase* measurement,
                                                      bool &isUnbiased) const {
    const Trk::TrackParameters* unbiasedTrkParameters(trkParameters);
 
    if (!m_updatorHandle.empty() && (isUnbiased)) {
        if (trkParameters->covariance()) {
            // Get unbiased state
            unbiasedTrkParameters = m_updatorHandle->removeFromState(*trkParameters,
                                                                     measurement->localParameters(),
                                                                     measurement->localCovariance()).release();
            if (!unbiasedTrkParameters) {
                ATH_MSG_INFO(  "Could not get unbiased track parameters, use normal parameters" );
                isUnbiased = false;
            }
        } else if (not m_alreadyWarned) {
            // warn only once!
            ATH_MSG_WARNING("TrackParameters contain no covariance, unbiased track states can not be calculated "
                            "(ie. pulls and residuals will be too small)" );
            m_alreadyWarned = true;
            isUnbiased = false;
        } else {
            isUnbiased = false;
        } // end if no measured track parameter
    }
    return unbiasedTrkParameters;
}