CandidatePtrTransientTrack.cc

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#include "TrackingTools/TransientTrack/interface/CandidatePtrTransientTrack.h"
#include "TrackingTools/PatternTools/interface/TransverseImpactPointExtrapolator.h"
#include "Geometry/Records/interface/GlobalTrackingGeometryRecord.h"
#include "TrackingTools/TrajectoryState/interface/TrajectoryStateTransform.h"
#include "TrackingTools/PatternTools/interface/TSCBLBuilderNoMaterial.h"
#include <iostream>

/*
 * ThreadSafe statement:
 * This class is using mutable member data: initialTSOS, initialTSCP,
 * trajectoryStateClosestToBeamLine. To guarantee thread safeness we
 * rely on helper member data: m_TSOS, m_TSCP and m_SCTBL, respectively.
 * Each time we'll change mutable member data we rely on specific order of the
 * operator= and the store. It is important since C++11 will guarantee that
 * the value changed by the operator= will be seen by all threads as occuring
 * before the call to store and therefore the kSet == m_TSOS.load is always
 * guaranteed to be true if and only if the thread will see the most recent
 * value of initialTSOS
 */

using namespace reco;

CandidatePtrTransientTrack::CandidatePtrTransientTrack() : 
  Track(), ptr_(), theField(0), m_TSOS(kUnset), m_TSCP(kUnset), m_SCTBL(kUnset)
{
}


CandidatePtrTransientTrack::CandidatePtrTransientTrack( const CandidatePtr & ptr , const MagneticField* field) : 
  Track(* ptr->bestTrack()), ptr_(ptr), theField(field), m_TSOS(kUnset), m_TSCP(kUnset), m_SCTBL(kUnset)
{
  
  initialFTS = trajectoryStateTransform::initialFreeState(* ptr->bestTrack(), field);
}
CandidatePtrTransientTrack::CandidatePtrTransientTrack( const CandidatePtr & ptr , const MagneticField* field, const edm::ESHandle<GlobalTrackingGeometry>& tg) :
Track(* ptr->bestTrack()), ptr_(ptr), theField(field), m_TSOS(kUnset), m_TSCP(kUnset), m_SCTBL(kUnset), theTrackingGeometry(tg)
{
  
  initialFTS = trajectoryStateTransform::initialFreeState(* ptr->bestTrack(), field);
}


CandidatePtrTransientTrack::CandidatePtrTransientTrack( const CandidatePtrTransientTrack & tt ) :
  Track(tt), ptr_(tt.candidate()), theField(tt.field()), 
  initialFTS(tt.initialFreeState()), m_TSOS(kUnset), m_TSCP(kUnset)
{
  // see ThreadSafe statement above about the order of operator= and store
  if (kSet == tt.m_TSOS.load()) {
    initialTSOS= tt.impactPointState();
    m_TSOS.store(kSet);
  }
  // see ThreadSafe statement above about the order of operator= and store
  if (kSet == tt.m_TSCP.load()) {
    initialTSCP= tt.impactPointTSCP();
    m_TSCP.store(kSet);
  }
}

void CandidatePtrTransientTrack::setES(const edm::EventSetup& setup) {

  setup.get<GlobalTrackingGeometryRecord>().get(theTrackingGeometry); 

}

void CandidatePtrTransientTrack::setTrackingGeometry(const edm::ESHandle<GlobalTrackingGeometry>& tg) {

  theTrackingGeometry = tg;

}

void CandidatePtrTransientTrack::setBeamSpot(const BeamSpot& beamSpot)
{
  theBeamSpot = beamSpot;
  m_SCTBL = kUnset;
}

TrajectoryStateOnSurface CandidatePtrTransientTrack::impactPointState() const
{
  // see ThreadSafe statement above about the order of operator= and store
  if(kSet == m_TSOS.load()) return initialTSOS;
  TransverseImpactPointExtrapolator tipe(theField);
  auto tmp = tipe.extrapolate(initialFTS, initialFTS.position());
  char expected = kUnset;
  if(m_TSOS.compare_exchange_strong(expected, kSetting)) {
    initialTSOS = tmp;
    m_TSOS.store(kSet);
    return initialTSOS;
  }
  return tmp;
}

TrajectoryStateClosestToPoint CandidatePtrTransientTrack::impactPointTSCP() const
{
  // see ThreadSafe statement above about the order of operator= and store
  if(kSet == m_TSCP.load()) return initialTSCP;
  auto tmp = builder(initialFTS, initialFTS.position());
  char expected = kUnset;
  if(m_TSCP.compare_exchange_strong(expected, kSetting)) {
    initialTSCP = tmp;
    m_TSCP.store(kSet);
    return initialTSCP;
  }
  return tmp;
}

TrajectoryStateOnSurface CandidatePtrTransientTrack::outermostMeasurementState() const
{
    
    return trajectoryStateTransform::outerStateOnSurface((*this),*theTrackingGeometry,theField);
}

TrajectoryStateOnSurface CandidatePtrTransientTrack::innermostMeasurementState() const
{
    
    return trajectoryStateTransform::innerStateOnSurface((*this),*theTrackingGeometry,theField);
}

TrajectoryStateOnSurface 
CandidatePtrTransientTrack::stateOnSurface(const GlobalPoint & point) const
{
  TransverseImpactPointExtrapolator tipe(theField);
  return tipe.extrapolate(initialFTS, point);
}

TrajectoryStateClosestToBeamLine CandidatePtrTransientTrack::stateAtBeamLine() const
{
  // see ThreadSafe statement above about the order of operator= and store
  if(kSet == m_SCTBL.load()) return trajectoryStateClosestToBeamLine;
  TSCBLBuilderNoMaterial blsBuilder;
  const auto tmp = blsBuilder(initialFTS, theBeamSpot);
  char expected = kUnset;
  if(m_SCTBL.compare_exchange_strong(expected, kSetting)) {
      trajectoryStateClosestToBeamLine = tmp;
      m_SCTBL.store(kSet);
      return trajectoryStateClosestToBeamLine;
  }
  return tmp;
}