IntersectorWrapper.cxx

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/*
   Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
 */

// wrapper to IIntersector tool to provide IPropagator functionality
//   default configuration wraps the RungeKutta intersector
// (c) ATLAS Detector software
 
#include "TrkExRungeKuttaIntersector/IntersectorWrapper.h"
#include "GaudiKernel/SystemOfUnits.h"
#include "TrkExUtils/TrackSurfaceIntersection.h"
#include "TrkGeometry/MagneticFieldProperties.h"
#include "TrkParameters/TrackParameters.h"
#include "TrkSurfaces/CylinderSurface.h"
#include "TrkSurfaces/DiscSurface.h"
#include "TrkSurfaces/PerigeeSurface.h"
#include "TrkSurfaces/PlaneSurface.h"
#include "TrkSurfaces/StraightLineSurface.h"
#include "TrkSurfaces/Surface.h"
#include <iomanip>
#include <memory>
#include <vector>
 
namespace Trk
{
 
//<<<<<< CLASS STRUCTURE INITIALIZATION                                 >>>>>>
 
IntersectorWrapper::IntersectorWrapper    (const std::string& type,
                                         const std::string& name,
                                         const IInterface* parent)
  :AthAlgTool     (type, name, parent)
  {
    declareInterface<Trk::IPropagator>(this);
  }
 
IntersectorWrapper::~IntersectorWrapper  (void)
= default;
 
//<<<<<< PUBLIC MEMBER FUNCTION DEFINITIONS                             >>>>>>
 
StatusCode
IntersectorWrapper::initialize(){
  // get the Tools
 
  ATH_CHECK(m_intersector.retrieve());
 
  ATH_MSG_VERBOSE( "Retrieved tool " << m_intersector );
 
  if (!m_linePropagator.empty()) {
    ATH_CHECK( m_linePropagator.retrieve());
  }
  return StatusCode::SUCCESS;
}
 
 
StatusCode IntersectorWrapper::finalize()
{
  return StatusCode::SUCCESS;
}
 
std::unique_ptr<NeutralParameters>
IntersectorWrapper::propagate (const NeutralParameters&       parameters,
                               const Surface&            surface,
                               PropDirection           dir,
                               const BoundaryCheck&            boundsCheck,
                               bool             curvilinear) const
{
  return m_linePropagator->propagate(parameters,surface,dir,boundsCheck,curvilinear);
}
 
std::unique_ptr<TrackParameters>
IntersectorWrapper::propagate (const EventContext&              /*ctx*/,
                               const TrackParameters&        parameters,
                               const Surface&            surface,
                               PropDirection           dir,
                               const BoundaryCheck&            boundsCheck,
                               const MagneticFieldProperties&    /*magProperties*/,
                               ParticleHypothesis     /*particle*/,
                               bool             curvilinear,
                               const TrackingVolume*) const
{
  Cache cache{};
  findIntersection(cache,parameters,surface, dir);
  createParameters(cache,surface,boundsCheck,curvilinear);
  return std::move(cache.m_parameters);
}
 
std::unique_ptr<TrackParameters>
IntersectorWrapper::propagate (const EventContext&              /*ctx*/,
                               const TrackParameters&        parameters,
                               const Surface&            surface,
                               PropDirection           dir,
                               const BoundaryCheck&            boundsCheck,
                               const MagneticFieldProperties&    /*magProperties*/,
                               std::optional<TransportJacobian>&        /*transportJac*/,
                               double&,
                               ParticleHypothesis     /*particle*/,
                               bool             curvilinear,
                               const TrackingVolume*) const
{
  Cache cache{};
  findIntersection(cache,parameters,surface,dir);
  createParameters(cache,surface,boundsCheck,curvilinear);
  return std::move(cache.m_parameters);
}
 
std::unique_ptr<TrackParameters>
IntersectorWrapper::propagateParameters (const EventContext&              /*ctx*/,
                                         const TrackParameters&      parameters,
                                         const Surface&          surface,
                                         PropDirection         dir,
                                         const BoundaryCheck&          boundsCheck,
                                         const MagneticFieldProperties&  /*magProperties*/,
                                         ParticleHypothesis       /*particle*/,
                                         bool               curvilinear,
                                         const TrackingVolume*) const
{
 
  Cache cache{};
  findIntersection(cache,parameters,surface,dir);
  createParameters(cache,surface,boundsCheck,curvilinear);
  return std::move(cache.m_parameters);
}
 
std::unique_ptr<TrackParameters>
IntersectorWrapper::propagateParameters (const EventContext&              /*ctx*/,
                                         const TrackParameters&      parameters,
                                         const Surface&          surface,
                                         PropDirection         dir,
                                         const BoundaryCheck&          boundsCheck,
                                         const MagneticFieldProperties& /*magProperties*/,
                                         std::optional<TransportJacobian>&      /*transportJac*/,
                                         ParticleHypothesis       /*particle*/,
                                         bool               curvilinear,
                                         const TrackingVolume*) const
{
  Cache cache{};
  findIntersection(cache,parameters,surface,dir);
  createParameters(cache,surface,boundsCheck,curvilinear);
  return std::move(cache.m_parameters);
}
 
std::optional<Trk::TrackSurfaceIntersection>
IntersectorWrapper::intersect (const EventContext&              /*ctx*/,
                               const TrackParameters&        parameters,
                               const Surface&            surface,
                               const MagneticFieldProperties&    /*magProperties*/,
                               ParticleHypothesis     /*particle*/,
                               const TrackingVolume*) const
{
  Cache cache{};
  findIntersection(cache,parameters,surface);
  auto solution = cache.m_intersection;
  return solution;
}
 
//<<<<<< PRIVATE MEMBER FUNCTION DEFINITIONS                            >>>>>>
 
void
IntersectorWrapper::createParameters (Cache& cache,
                                      const Surface& surface,
                                      const BoundaryCheck&     /*boundsCheck*/,
                                      bool      curvilinear) const
{
  cache.m_parameters    = nullptr;
  if (! cache.m_intersection) return;
 
  // curvilinear special (simple) case
  if (curvilinear)
  {
    cache.m_parameters=std::make_unique<CurvilinearParameters>(cache.m_intersection->position(),
                                                 cache.m_intersection->direction().phi(),
                                                 cache.m_intersection->direction().theta(),
                                                 cache.m_qOverP);
    return;
  }
 
  cache.m_parameters=surface.createUniqueTrackParameters(cache.m_intersection->position(),
                                                   cache.m_intersection->direction(),
                                                   cache.m_charge,std::nullopt);
  // unrecognized Surface
  if( !cache.m_parameters ) ATH_MSG_WARNING( " Failed to create parameters " );
}
 
void
IntersectorWrapper::findIntersection (Cache& cache,
                                      const TrackParameters& parameters,
                                      const Surface&     surface,
                                      PropDirection            dir) const
{
  cache.m_charge    =  parameters.charge();
  cache.m_momentum    =  parameters.momentum();
  cache.m_parameters= nullptr;
  cache.m_position    =  Amg::Vector3D(parameters.position());
  cache.m_qOverP    =  1./cache.m_momentum.mag();
  cache.m_intersection = std::make_optional<TrackSurfaceIntersection>(cache.m_position,cache.m_momentum*cache.m_qOverP,0.);
  cache.m_qOverP    *= cache.m_charge;
 
  const TrackSurfaceIntersection oldIntersection = (*cache.m_intersection);
  cache.m_intersection =
      m_intersector->intersectSurface(surface, oldIntersection, cache.m_qOverP);
  if (! cache.m_intersection)
  {
    ATH_MSG_DEBUG( " no intersection found " );
    return;
  }
 
  // check for correct propagation direction
  if ((dir == Trk::alongMomentum && cache.m_intersection->pathlength() < 0.)
      || (dir == Trk::oppositeMomentum && cache.m_intersection->pathlength() > 0.))
  {
    if (msgLvl(MSG::DEBUG))
    {
      if (dir == Trk::alongMomentum)
      {
        ATH_MSG_DEBUG( " requested alongMomentum, but pathlength "
                       << cache.m_intersection->pathlength() );
      }
      else if (dir == Trk::oppositeMomentum)
      {
        ATH_MSG_DEBUG( " requested oppositeMomentum, but pathlength "
                       << cache.m_intersection->pathlength() );
      }
    }
    cache.m_intersection=std::nullopt;
    return;
  }
 
  ATH_MSG_DEBUG( std::setiosflags(std::ios::fixed)
                 << " intersection at r,phi,z "
                 << std::setw(10) << std::setprecision(1) << cache.m_intersection->position().perp()
                 << std::setw(9)  << std::setprecision(4) << cache.m_intersection->position().phi()
                 << std::setw(10) << std::setprecision(1) << cache.m_intersection->position().z()
                 << " momentum "
                 << std::setw(9) << std::setprecision(3) << 1./std::abs(cache.m_qOverP*Gaudi::Units::GeV) );
}
 
} // end of namespace