SeedsToTrackParamsAlg.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/
 
#include "SeedsToTrackParamsAlg.h"
 
#include "TrkSurfaces/Surface.h"
#include "InDetReadoutGeometry/SiDetectorElement.h"
 
namespace ActsTrk {
 
  StatusCode SeedsToTrackParamsAlg::initialize() {
    ATH_MSG_INFO("Initializing " << name() << " ...");
 
    ATH_CHECK(m_ctxProvider.initialize());
    ATH_CHECK(m_geometryConvTool.retrieve());
    ATH_CHECK(m_paramEstimationTool.retrieve());
 
    ATH_CHECK(m_detEleCollKey.initialize());
    ATH_CHECK(m_inputSeedContainerKey.initialize());
    ATH_CHECK(m_outputTrackParamsCollectionKey.initialize());
 
    return StatusCode::SUCCESS;
  }
 
  StatusCode SeedsToTrackParamsAlg::execute(const EventContext& ctx) const {
    ATH_MSG_DEBUG("Executing " << name() << " ... ");
 
    const Acts::GeometryContext tgContext = m_ctxProvider.getGeometryContext(ctx);
    const Acts::MagneticFieldContext mfContext = m_ctxProvider.getMagneticFieldContext(ctx);
 
    SG::ReadHandle<ActsTrk::SeedContainer> seedContainerHandle = SG::makeHandle(m_inputSeedContainerKey, ctx);
    SG::ReadCondHandle<InDetDD::SiDetectorElementCollection> detEleHandle = SG::makeHandle(m_detEleCollKey, ctx);
 
    ATH_CHECK(seedContainerHandle.isValid());
    ATH_CHECK(detEleHandle.isValid());
 
    SG::WriteHandle<ActsTrk::BoundTrackParametersContainer> boundTrackParamsHandle = SG::makeHandle(m_outputTrackParamsCollectionKey, ctx);
    ATH_MSG_DEBUG("    \\__ Track Params Estimated `" << m_outputTrackParamsCollectionKey.key() << "` created ...");
    ATH_CHECK(boundTrackParamsHandle.record(std::make_unique<ActsTrk::BoundTrackParametersContainer>()));
    ActsTrk::BoundTrackParametersContainer *trackParams = boundTrackParamsHandle.ptr();
 
    const ActsTrk::SeedContainer &seeds = *seedContainerHandle;
    const InDetDD::SiDetectorElementCollection &detElements = *detEleHandle.cptr();
 
    for (std::size_t iseed = 0; iseed < seeds.size(); ++iseed) {
      ActsTrk::Seed seed = seeds[iseed];
 
      const bool useTopSp = m_autoReverseSearch && shouldReverseSearch(seed);
 
      auto retrieveSurfaceFunction = 
        [this, &detElements] (const ActsTrk::Seed& seed, bool useTopSp) -> const Acts::Surface& { 
          const xAOD::SpacePoint* sp = useTopSp ? seed.sp().back() : seed.sp().front();
          const InDetDD::SiDetectorElement* element = detElements.getDetectorElement(
                useTopSp ? sp->elementIdList().back() : sp->elementIdList().front());
          const Trk::Surface& atlas_surface = element->surface();
          return *m_geometryConvTool->convertSurfaceToActs(atlas_surface);
        };
 
      std::optional<Acts::BoundTrackParameters> optTrackParams =
        m_paramEstimationTool->estimateTrackParameters(
                               seed,
                               useTopSp,
                               tgContext,
                               mfContext,
                               retrieveSurfaceFunction);
 
      if (!optTrackParams.has_value()) {
        ATH_MSG_DEBUG("Failed to estimate track parameters for seed " << iseed);
        trackParams->push_back(std::unique_ptr<Acts::BoundTrackParameters>());
        continue;
      }
 
      trackParams->push_back(std::make_unique<Acts::BoundTrackParameters>(std::move(*optTrackParams)));
    }
 
    return StatusCode::SUCCESS;
  }
 
  bool SeedsToTrackParamsAlg::shouldReverseSearch(const ActsTrk::Seed& seed) const {
    const xAOD::SpacePoint* bottom_sp = seed.sp().front();
 
    const double r = bottom_sp->radius();
    const double z = std::abs(bottom_sp->z());
 
    const double rBoundary = m_useTopSpRZboundary.value()[0];
    const double zBoundary = m_useTopSpRZboundary.value()[1];
 
    return r > rBoundary || z > zBoundary;
  }
 
 
}