CaloCellGeometry Class Reference

#include <CaloCellGeometry.h>

Inheritance diagram for CaloCellGeometry:

Public Types
typedef float	CCGFloat
typedef EZMgrFL< GlobalPoint >	CornersMgr
enum	CornersSize { k_cornerSize = 8 }
typedef EZArrayFL< GlobalPoint >	CornersVec
typedef EZMgrFL< CCGFloat >	ParMgr
typedef EZArrayFL< CCGFloat >	ParVec
typedef std::vector< ParVec >	ParVecVec
typedef HepGeom::Point3D < CCGFloat >	Pt3D
typedef std::vector< Pt3D >	Pt3DVec
typedef HepGeom::Transform3D	Tr3D

Public Member Functions
bool	emptyCorners () const
float	etaPos () const
float	etaSpan () const
virtual const CornersVec &	getCorners () const =0
	Returns the corner points of this cell's volume. More...
const GlobalPoint &	getPosition () const
	Returns the position of reference for this cell. More...
virtual void	getTransform (Tr3D &tr, Pt3DVec *lptr) const
	--------— only needed by specific utility; overloaded when needed -— More...
bool	inside (const GlobalPoint &point) const
	Returns true if the specified point is inside this cell. More...
const CCGFloat *	param () const
float	phiPos () const
float	phiSpan () const
virtual void	vocalCorners (Pt3DVec &vec, const CCGFloat *pv, Pt3D &ref) const =0
virtual	~CaloCellGeometry ()

Static Public Member Functions
static const CCGFloat *	checkParmPtr (const std::vector< CCGFloat > &vd, ParVecVec &pvv)
static const CCGFloat *	getParmPtr (const std::vector< CCGFloat > &vd, ParMgr *mgr, ParVecVec &pvv)

Static Public Attributes
static const CCGFloat	k_ScaleFromDDDtoGeant

Protected Member Functions
	CaloCellGeometry (CornersVec::const_reference gp, const CornersMgr *mgr, const CCGFloat *par)
	CaloCellGeometry (const CornersVec &cv, const CCGFloat *par)
	CaloCellGeometry (void)
void	initSpan () const
CornersVec &	setCorners () const

Private Attributes
CornersVec	m_corners
float	m_dEta
float	m_dPhi
float	m_eta
const CCGFloat *	m_parms
float	m_phi
GlobalPoint	m_refPoint

Detailed Description

Abstract base class for an individual cell's geometry.

The base class declares a pure virtual function and also writes a definition (body) to force conscious acceptance of default behaviour.

If a derived class doesn't choose to override a normal virtual, it just inherits the base version's behaviour by default. If you want to provide a default behaviour but not let derived classes just inherit it "silently" like this, you can make it pure virtual but still provide a default that the derived class author has to call deliberately if he wants it:

class B {
  public:
      virtual bool f() = 0;
  };

  bool B::f() {
      return true;  // this is a good default, but
  }                 // shouldn't be used blindly

  class D : public B {
  public:
      bool f() {
          return B::f(); // if D wants the default
      }                  // behaviour, it has to say so
 };

Author

J. Mans, P. Meridiani

Definition at line 50 of file CaloCellGeometry.h.

Member Typedef Documentation

typedef float CaloCellGeometry::CCGFloat

Definition at line 54 of file CaloCellGeometry.h.

typedef EZMgrFL< GlobalPoint > CaloCellGeometry::CornersMgr

Definition at line 60 of file CaloCellGeometry.h.

typedef EZArrayFL< GlobalPoint > CaloCellGeometry::CornersVec

Definition at line 59 of file CaloCellGeometry.h.

typedef EZMgrFL< CCGFloat > CaloCellGeometry::ParMgr

Definition at line 64 of file CaloCellGeometry.h.

typedef EZArrayFL<CCGFloat> CaloCellGeometry::ParVec

Definition at line 62 of file CaloCellGeometry.h.

typedef std::vector<ParVec> CaloCellGeometry::ParVecVec

Definition at line 63 of file CaloCellGeometry.h.

typedef HepGeom::Point3D<CCGFloat> CaloCellGeometry::Pt3D

Definition at line 56 of file CaloCellGeometry.h.

typedef std::vector<Pt3D> CaloCellGeometry::Pt3DVec

Definition at line 57 of file CaloCellGeometry.h.

typedef HepGeom::Transform3D CaloCellGeometry::Tr3D

Definition at line 55 of file CaloCellGeometry.h.

Member Enumeration Documentation

enum CaloCellGeometry::CornersSize

Enumerator
k_cornerSize

Definition at line 66 of file CaloCellGeometry.h.

{ k_cornerSize = 8 };

Constructor & Destructor Documentation

CaloCellGeometry::~CaloCellGeometry ( )

virtual

Definition at line 26 of file CaloCellGeometry.cc.

{}

CaloCellGeometry::CaloCellGeometry ( CornersVec::const_reference  gp, const CornersMgr *  mgr, const CCGFloat *  par  )

protected

Definition at line 31 of file CaloCellGeometry.cc.

                                                      :
   m_refPoint ( gp  ),
   m_corners  ( mgr ),
   m_parms    ( par ),
   m_eta(gp.eta()), m_phi(gp.phi())
{}

CaloCellGeometry::CaloCellGeometry ( const CornersVec &  cv, const CCGFloat *  par  )

protected

Definition at line 40 of file CaloCellGeometry.cc.

                                            : 
   m_refPoint ( 0.25*( cv[0].x() + cv[1].x() + cv[2].x() + cv[3].x() ),
        0.25*( cv[0].y() + cv[1].y() + cv[2].y() + cv[3].y() ),
        0.25*( cv[0].z() + cv[1].z() + cv[2].z() + cv[3].z() )  ), 
   m_corners  ( cv ),
   m_parms    ( par ),
   m_eta( m_refPoint.eta()), m_phi(m_refPoint.phi())
{}

CaloCellGeometry::CaloCellGeometry ( void  )

protected

Definition at line 19 of file CaloCellGeometry.cc.

                                   :
   m_refPoint ( 0., 0., 0. ),
   m_corners  (  ) ,
   m_parms    ( (CCGFloat*) 0 ), m_eta(0), m_phi(0) 
{}

Member Function Documentation

const float * CaloCellGeometry::checkParmPtr ( const std::vector< CCGFloat > &  vd, CaloCellGeometry::ParVecVec &  pvv  )

static

Definition at line 131 of file CaloCellGeometry.cc.

References EZArrayFL< T >::begin(), cuy::ii, j, EZArrayFL< T >::size(), and findQualityFiles::v.

Referenced by getParmPtr().

{
   const float* pP ( 0 ) ;

   for( unsigned int ii ( 0 ) ; ii != pvv.size() ; ++ii )
   {
      const ParVec& v ( pvv[ii] ) ;
      assert( v.size() == vv.size() ) ;

      bool same ( true ) ;
      for( unsigned int j ( 0 ) ; j != vv.size() ; ++j )
      {
     same = same && ( fabs( vv[j] - v[j] )<1.e-6 ) ;
     if( !same ) break ;
      }
      if( same )
      {
     pP = &(*v.begin()) ;
     break ;
      }
   }
   return pP ;
}

bool CaloCellGeometry::emptyCorners ( ) const

inline

Definition at line 87 of file CaloCellGeometry.h.

References EZArrayFL< T >::empty(), and m_corners.

Referenced by operator<<().

{ return m_corners.empty() ;}

float CaloCellGeometry::etaPos ( ) const

inline

Definition at line 77 of file CaloCellGeometry.h.

References m_eta.

{ return m_eta;}

float CaloCellGeometry::etaSpan ( ) const

inline

Definition at line 80 of file CaloCellGeometry.h.

References m_dEta.

Referenced by reco::makeSpecific().

{ return m_dEta;}

const CaloCellGeometry::CornersVec & CaloCellGeometry::getCorners ( ) const

pure virtual

Returns the corner points of this cell's volume.

Implemented in IdealCastorTrapezoid, IdealObliquePrism, IdealZPrism, PreshowerStrip, GCC11_FINAL< T, TOPO >, and IdealZDCTrapezoid.

Definition at line 57 of file CaloCellGeometry.cc.

References m_corners.

Referenced by CaloGeometryHelper::buildCrystalArray(), HFClusterAlgo::clusterize(), PFRecHitProducerECAL::createEcalRecHit(), PFHCALDualTimeRecHitProducer::createHcalRecHit(), PFRecHitProducerHCAL::createHcalRecHit(), PFRecHitProducerHO::createHORecHit(), PFRecHitProducerPS::createRecHits(), CaloSubdetectorGeometry::deltaEta(), CaloSubdetectorGeometry::deltaPhi(), CaloTowersCreationAlgo::emCrystalShwrPos(), IdealZDCTrapezoid::getCorners(), PreshowerStrip::getCorners(), IdealZPrism::getCorners(), IdealObliquePrism::getCorners(), IdealCastorTrapezoid::getCorners(), HCaloDetIdAssociator::getDetIdPoints(), CaloDetIdAssociator::getDetIdPoints(), getTransform(), CaloTowersCreationAlgo::hadSegmentShwrPos(), CaloTowersCreationAlgo::hadShwPosFromCells(), initSpan(), inside(), JetMaker::makeSpecific(), operator<<(), EcalGeomPhiSymHelper::setup(), and ValidateGeometry::validateCaloGeometry().

{
   return m_corners ;
}

const float * CaloCellGeometry::getParmPtr ( const std::vector< CCGFloat > &  vd, CaloCellGeometry::ParMgr *  mgr, CaloCellGeometry::ParVecVec &  pvv  )

static

Definition at line 158 of file CaloCellGeometry.cc.

References prof2calltree::back, checkParmPtr(), and i.

Referenced by HcalFlexiHardcodeGeometryLoader::fillHBHO(), HcalFlexiHardcodeGeometryLoader::fillHE(), HcalFlexiHardcodeGeometryLoader::fillHF(), CaloTowerHardcodeGeometryLoader::makeCell(), CastorHardcodeGeometryLoader::makeCell(), ZdcHardcodeGeometryLoader::makeCell(), HcalHardcodeGeometryLoader::makeCell(), HcalDDDGeometryLoader::makeCell(), EcalTBHodoscopeGeometryLoaderFromDDD::makeGeometry(), and CaloGeometryDBEP< T, U >::produceAligned().

{
   const float* pP ( checkParmPtr( vv, pvv ) ) ;

   if( 0 == pP )
   {
      pvv.push_back( ParVec( mgr ) ) ;
      ParVec& back ( pvv.back() ) ;
      for( unsigned int i ( 0 ) ; i != vv.size() ; ++i )
      {
     back[i] = vv[i] ;
      }
      pP = &(*back.begin()) ;
   }
   return pP ;
}

const GlobalPoint& CaloCellGeometry::getPosition ( ) const

inline

Returns the position of reference for this cell.

Definition at line 76 of file CaloCellGeometry.h.

References m_refPoint.

Referenced by PreshowerHitMaker::addHit(), EcalTPGParamBuilder::analyze(), HcalRecHitsValidation::analyze(), CaloTowersCreationAlgo::assignHit(), EcalBoundaryInfoCalculator< EcalDetId >::boundaryRecHits(), CaloRecoTauAlgorithm::buildCaloTau(), CaloGeometryHelper::buildCrystalArray(), SuperClusterShapeAlgo::Calculate_Covariances(), ClusterShapeAlgo::Calculate_Covariances(), ClusterShapeAlgo::Calculate_EnergyDepTopology(), compEcalEnergySum(), compHcalEnergySum(), CaloTowersCreationAlgo::convert(), EcalClusterToolsT< noZS >::covariances(), PFRecHitProducerECAL::createEcalRecHit(), PFHCALDualTimeRecHitProducer::createHcalRecHit(), PFRecHitProducerHCAL::createHcalRecHit(), PFRecHitProducerHO::createHORecHit(), PFRecHitProducerPS::createRecHits(), DistanceToCell::DistanceToCell(), InvRingCalib::EERingDef(), CaloTowersCreationAlgo::emCrystalShwrPos(), GlobalHitsAnalyzer::fillECal(), GlobalHitsProdHist::fillECal(), GlobalHitsProducer::fillECal(), HCALRecHitAnalyzer::FillGeometry(), ECALRecHitAnalyzer::FillGeometry(), GlobalHitsAnalyzer::fillHCal(), GlobalHitsProdHist::fillHCal(), GlobalHitsProducer::fillHCal(), GlobalRecHitsAnalyzer::fillHCal(), GlobalRecHitsProducer::fillHCal(), EcalDeadCellBoundaryEnergyFilter::filter(), PFRecHitProducerECAL::findEcalRecHitGeometry(), PFRecHitProducerHO::findHORecHitGeometry(), EcalBoundaryInfoCalculator< EcalDetId >::gapRecHits(), TCTauAlgorithm::getCellMomentum(), HcalGeometry::getCells(), CaloSubdetectorGeometry::getCells(), EcalDeadCellTriggerPrimitiveFilter::getChannelStatusMaps(), EcalDeadCellDeltaRFilter::getChannelStatusMaps(), CaloGeometryHelper::getClosestCell(), HcalGeometry::getClosestCell(), CaloSubdetectorGeometry::getClosestCell(), EcalPreshowerGeometry::getClosestCellInPlane(), IdealZDCTrapezoid::getCorners(), IdealZPrism::getCorners(), PreshowerStrip::getCorners(), IdealObliquePrism::getCorners(), IdealCastorTrapezoid::getCorners(), L2TauModularIsolationProducer::getECALHits(), L2TauIsolationProducer::getECALHits(), L2TauNarrowConeIsolationProducer::getECALHits(), EcalClusterToolsT< noZS >::getEnergyDepTopology(), EcalHitMaker::getHits(), ParticleTowerProducer::getNearestTower(), CaloGeometry::getPosition(), HCaloDetIdAssociator::getPosition(), CaloDetIdAssociator::getPosition(), HcalGeometry::getSummary(), CaloSubdetectorGeometry::getSummary(), getTransform(), CaloTowersCreationAlgo::hadSegmentShwrPos(), CaloTowersCreationAlgo::hadShwPosFromCells(), CalorimetryManager::HDShowerSimulation(), PhotonFixCMS::initialise(), CaloGeometryHelper::initialize(), EcalRingCalibrationTools::initializeFromGeometry(), EcalPreshowerGeometry::initializeParms(), IslandClusterAlgo::makeClusters(), CosmicClusterAlgo::makeClusters(), Multi5x5ClusterAlgo::makeClusters(), HybridClusterAlgo::makeClusters(), PreshowerPhiClusterAlgo::makeOneCluster(), PreshowerClusterAlgo::makeOneCluster(), EcalClusterToolsT< noZS >::meanClusterPosition(), DistanceToCell::operator()(), operator<<(), HcalHitRelabeller::process(), EgammaHLTRechitInRegionsProducer::produce(), ParticleTowerProducer::produce(), JetCrystalsAssociator::produce(), CalorimetryManager::reconstructHCAL(), ParticleTowerProducer::resetTowers(), EcalRecHitWorkerRecover::run(), EcalGeomPhiSymHelper::setup(), CaloHitRespoNew::timeOfFlight(), EcalHitResponse::timeOfFlight(), and CaloHitResponse::timeOfFlight().

{return m_refPoint ; }

void CaloCellGeometry::getTransform ( Tr3D &  tr, Pt3DVec *  lptr  ) const

virtual

--------— only needed by specific utility; overloaded when needed -—

Reimplemented in GCC11_FINAL< T, TOPO >.

Definition at line 82 of file CaloCellGeometry.cc.

References angle(), getCorners(), getPosition(), i, mag(), AlCaHLTBitMon_ParallelJobs::p, param(), csvLumiCalc::unit, vocalCorners(), x, PV3DBase< T, PVType, FrameType >::x(), detailsBasic3DVector::y, PV3DBase< T, PVType, FrameType >::y(), detailsBasic3DVector::z, and PV3DBase< T, PVType, FrameType >::z().

Referenced by CaloSubdetectorGeometry::getSummary(), and HcalGeometry::getSummary().

{
   const GlobalPoint& p ( CaloCellGeometry::getPosition() ) ;
   const Pt3D gFront ( p.x(), p.y(), p.z() ) ;
   const DPt3D dgFront ( p.x(), p.y(), p.z() ) ;

   Pt3D lFront ;
   assert( 0 != param() ) ;
   Pt3DVec lc ( 8, Pt3D(0,0,0) ) ;
   vocalCorners( lc, param(), lFront ) ;

   DPt3D dlFront ( lFront.x(), lFront.y(), lFront.z() ) ;

   const Pt3D lBack ( 0.25*(lc[4]+lc[5]+lc[6]+lc[7]) ) ;
   const DPt3D dlBack ( lBack.x(), lBack.y(), lBack.z() ) ;

   const Pt3D dlOne ( lc[0].x(), lc[0].y(), lc[0].z() ) ;

   const CornersVec& cor ( getCorners() ) ;
   DPt3DVec dkor ( 8, DPt3D(0,0,0) ) ;
   for( unsigned int i ( 0 ) ; i != 8 ; ++i )
   {
      dkor[i] = DPt3D ( cor[i].x(), cor[i].y(), cor[i].z() ) ;
   }

   DPt3D  dgBack ( 0.25*( dkor[4]+dkor[5]+dkor[6]+dkor[7] ) ) ;

   const DVec3D dgAxis ( (dgBack-dgFront).unit() ) ;

   dgBack = ( dgFront + (dlBack-dlFront).mag()*dgAxis ) ;
   const DPt3D  dgOneT ( dgFront + ( dlOne - dlFront ).mag()*( dkor[0] - dgFront ).unit() ) ;

   const double dlangle ( ( dlBack - dlFront).angle( dlOne - dlFront ) ) ;
   const double dgangle ( ( dgBack - dgFront).angle( dgOneT- dgFront ) ) ;
   const double ddangle ( dlangle - dgangle ) ;

   const DPlane3D dgPl ( dgFront, dgOneT, dgBack ) ;
   const DPt3D    dp2  ( dgFront + dgPl.normal().unit() ) ;

   const DPt3D  dgOne ( dgFront + HepGeom::Rotate3D( -ddangle, dgFront, dp2 )*
              DVec3D ( dgOneT - dgFront ) ) ;

   tr = Tr3D( dlFront , dlBack , dlOne ,
          dgFront , dgBack , dgOne    ) ;

   if( 0 != lptr ) (*lptr) = lc ;
}

void CaloCellGeometry::initSpan ( ) const

inlineprotected

Definition at line 121 of file CaloCellGeometry.h.

References funct::abs(), eta(), getCorners(), m_dEta, m_dPhi, and phi.

Referenced by IdealCastorTrapezoid::IdealCastorTrapezoid(), IdealObliquePrism::IdealObliquePrism(), IdealZDCTrapezoid::IdealZDCTrapezoid(), IdealZPrism::IdealZPrism(), and PreshowerStrip::PreshowerStrip().

                        {
     m_dEta = std::abs(getCorners()[0].eta()-
                      getCorners()[2].eta());
     m_dPhi = std::abs(getCorners()[0].phi() -
                      getCorners()[2].phi());
  }

bool CaloCellGeometry::inside

(

const GlobalPoint &

point

)

const

Returns true if the specified point is inside this cell.

Definition at line 179 of file CaloCellGeometry.cc.

References getCorners(), i, AlCaHLTBitMon_ParallelJobs::p, funct::true, x, PV3DBase< T, PVType, FrameType >::x(), detailsBasic3DVector::y, PV3DBase< T, PVType, FrameType >::y(), detailsBasic3DVector::z, and PV3DBase< T, PVType, FrameType >::z().

Referenced by MuonCaloDistanceProducer::fillDistanceMap(), CastorGeometry::getClosestCell(), CaloDetIdAssociator::insideElement(), and HCaloDetIdAssociator::insideElement().

{
   bool ans ( false ) ;
   const Pt3D  p ( point.x(), point.y(), point.z() ) ;
   const CornersVec& cog ( getCorners() ) ;
   Pt3D  co[8] ;
   for( unsigned int i ( 0 ) ; i != 8 ; ++i )
   {
      co[i] = Pt3D ( cog[i].x(), cog[i].y(), cog[i].z() ) ;
   }

   const Plane3D  AA ( co[0], co[1], co[2] ) ; // z<0
   const Plane3D  BB ( co[6], co[5], co[4] ) ; // z>0

   if( AA.distance(p)*BB.distance(p) >= 0 )
   {
     const Plane3D  CC ( co[0], co[4], co[5] ) ; // x<0
     const Plane3D  DD ( co[2], co[6], co[7] ) ; // x>0
     if( CC.distance(p)*DD.distance(p) >= 0 )
     {
       const Plane3D  EE ( co[3], co[7], co[4] ) ; // y<0
       const Plane3D  FF ( co[1], co[5], co[6] ) ; // y>0
       if( EE.distance(p)*FF.distance(p) >= 0 )
       {
       ans = true ;
       }
      }
   }
   return ans ;
}

const CCGFloat* CaloCellGeometry::param ( ) const

inline

Definition at line 89 of file CaloCellGeometry.h.

References m_parms.

Referenced by IdealZDCTrapezoid::an(), IdealCastorTrapezoid::an(), HcalDDDGeometry::cellGeomPtr(), EcalTBHodoscopeGeometry::cellGeomPtr(), CaloTowerGeometry::cellGeomPtr(), ZdcGeometry::cellGeomPtr(), CastorGeometry::cellGeomPtr(), EcalPreshowerGeometry::cellGeomPtr(), HcalGeometry::cellGeomPtr(), IdealZPrism::dEta(), IdealObliquePrism::dEta(), IdealCastorTrapezoid::dh(), IdealZPrism::dPhi(), IdealObliquePrism::dPhi(), IdealCastorTrapezoid::dR(), IdealZDCTrapezoid::dx(), PreshowerStrip::dx(), IdealCastorTrapezoid::dxh(), IdealCastorTrapezoid::dxl(), IdealZDCTrapezoid::dy(), PreshowerStrip::dy(), IdealZDCTrapezoid::dz(), PreshowerStrip::dz(), IdealZPrism::dz(), IdealObliquePrism::dz(), IdealCastorTrapezoid::dz(), IdealZPrism::eta(), IdealObliquePrism::eta(), IdealZDCTrapezoid::getCorners(), IdealCastorTrapezoid::getCorners(), HcalGeometry::getSummary(), CaloSubdetectorGeometry::getSummary(), getTransform(), operator<<(), PreshowerStrip::tilt(), IdealZPrism::z(), and IdealObliquePrism::z().

{ return m_parms ;}

float CaloCellGeometry::phiPos ( ) const

inline

Definition at line 78 of file CaloCellGeometry.h.

References m_phi.

{ return m_phi;}

float CaloCellGeometry::phiSpan ( ) const

inline

Definition at line 81 of file CaloCellGeometry.h.

References m_dPhi.

Referenced by reco::makeSpecific().

{ return m_dPhi;}

CaloCellGeometry::CornersVec & CaloCellGeometry::setCorners ( ) const

protected

Definition at line 51 of file CaloCellGeometry.cc.

References m_corners.

Referenced by IdealZDCTrapezoid::getCorners(), IdealZPrism::getCorners(), PreshowerStrip::getCorners(), IdealObliquePrism::getCorners(), and IdealCastorTrapezoid::getCorners().

{
   return m_corners ; 
}

virtual void CaloCellGeometry::vocalCorners ( Pt3DVec &  vec, const CCGFloat *  pv, Pt3D &  ref  ) const

pure virtual

Implemented in IdealCastorTrapezoid, GCC11_FINAL< T, TOPO >, IdealObliquePrism, IdealZPrism, PreshowerStrip, and IdealZDCTrapezoid.

Referenced by getTransform().

Member Data Documentation

const float CaloCellGeometry::k_ScaleFromDDDtoGeant

static

Definition at line 68 of file CaloCellGeometry.h.

Referenced by EcalTBHodoscopeGeometryLoaderFromDDD::makeGeometry().

CornersVec CaloCellGeometry::m_corners

mutableprivate

Definition at line 130 of file CaloCellGeometry.h.

Referenced by emptyCorners(), getCorners(), and setCorners().

float CaloCellGeometry::m_dEta

mutableprivate

Definition at line 133 of file CaloCellGeometry.h.

Referenced by etaSpan(), and initSpan().

float CaloCellGeometry::m_dPhi

mutableprivate

Definition at line 134 of file CaloCellGeometry.h.

Referenced by initSpan(), and phiSpan().

float CaloCellGeometry::m_eta

private

Definition at line 132 of file CaloCellGeometry.h.

Referenced by etaPos().

const CCGFloat* CaloCellGeometry::m_parms

private

Definition at line 131 of file CaloCellGeometry.h.

Referenced by param().

float CaloCellGeometry::m_phi

private

Definition at line 132 of file CaloCellGeometry.h.

Referenced by phiPos().

GlobalPoint CaloCellGeometry::m_refPoint

private

Definition at line 129 of file CaloCellGeometry.h.

Referenced by getPosition().