TrackFindingBaseAlg.icc

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
namespace ActsTrk {
  template <class HandleArrayKeyType, class ContainerType>
  StatusCode TrackFindingBaseAlg::getContainersFromKeys(
      const EventContext &ctx,
      HandleArrayKeyType &handleKeyArray,
      std::vector<const ContainerType *> &outputContainers,
      std::size_t &sum) const {
    outputContainers.reserve(handleKeyArray.size());
    for (const auto &handleKey : handleKeyArray) {
      ATH_MSG_DEBUG("Reading input collection with key " << handleKey.key());
      auto handle = SG::makeHandle(handleKey, ctx);
      ATH_CHECK(handle.isValid());
      outputContainers.push_back(handle.cptr());
      ATH_MSG_DEBUG("Retrieved " << outputContainers.back()->size()
                                 << " input elements from key " << handle.key());
      sum += outputContainers.back()->size();
    }
 
    return StatusCode::SUCCESS;
  }
 
  template <class MeasurementSource>
  std::unique_ptr<Acts::BoundTrackParameters> TrackFindingBaseAlg::doRefit(
      const MeasurementSource &measurement,
      const Acts::BoundTrackParameters &initialParameters,
      const DetectorContextHolder &detContext,
      const bool paramsAtOutermostSurface) const {
    // Perform KF before CKF
    const Acts::Surface* targetSurface = nullptr;
    // get the proper surface
    if (not paramsAtOutermostSurface) {
      // inner-most surface
      targetSurface = m_unalibMeasSurfAcc.get(measurement.sp().front()->measurements().front());
    } else {
      // outer-most surface
      targetSurface = m_unalibMeasSurfAcc.get(measurement.sp().back()->measurements().back());
    }
    if (not targetSurface) {
      ATH_MSG_VERBOSE("Could not identify the target surface for fitting the provided seed");
      return nullptr;
    }
    const auto fittedSeedCollection = m_fitterTool->fit(measurement, initialParameters,
                                                        detContext.geometry, detContext.magField, detContext.calib,
                                                        *targetSurface);
    if (not fittedSeedCollection) {
      ATH_MSG_WARNING("KF Fitted Track is nullptr");
    }
    else if (fittedSeedCollection->size() != 1) {
      ATH_MSG_WARNING("KF produced " << fittedSeedCollection->size() << " tracks but should produce 1!");
    }
    else
    {
      const auto fittedSeed = fittedSeedCollection->getTrack(0);
      const auto trackState = paramsAtOutermostSurface ? fittedSeed.outermostTrackState()
                                                       : fittedSeed.innermostTrackState().value();
      const auto boundParameters = fittedSeed.createParametersFromState(trackState);
 
      // Check pTmin requirement
      const double etaSeed = -std::log(std::tan(0.5 * boundParameters.parameters()[Acts::eBoundTheta]));
      const auto &cutSet = getCuts(etaSeed);
      if (boundParameters.transverseMomentum() < cutSet.ptMin) {
        ATH_MSG_VERBOSE("min pt requirement not satisfied after param refinement: pt min is " << cutSet.ptMin << " but Refined params have pt of " << boundParameters.transverseMomentum());
        return nullptr;
      }
 
      // Return updated parameters
      return std::make_unique<Acts::BoundTrackParameters>(boundParameters);
    }
 
    // When skipping return unchanged parameters
    return std::make_unique<Acts::BoundTrackParameters>(initialParameters);
  };
}  // namespace ActsTrk