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geant4/source/processes/transportation/src/G4Transportation.cc
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//
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//
// $Id: G4Transportation.cc,v 1.55.2.1 2006/06/29 21:12:28 gunter Exp $
// GEANT4 tag $Name: geant4-08-01 $
//
// ------------------------------------------------------------
// GEANT 4 include file implementation
//
// ------------------------------------------------------------
//
// This class is a process responsible for the transportation of
// a particle, ie the geometrical propagation that encounters the
// geometrical sub-volumes of the detectors.
//
// It is also tasked with part of updating the "safety".
//
// =======================================================================
// Modified:
// 19 Jan 2006, P.MoraDeFreitas: Fix for suspended tracks (StartTracking)
// 11 Aug 2004, M.Asai: Add G4VSensitiveDetector* for updating stepPoint.
// 21 June 2003, J.Apostolakis: Calling field manager with
// track, to enable it to configure its accuracy
// 13 May 2003, J.Apostolakis: Zero field areas now taken into
// account correclty in all cases (thanks to W Pokorski).
// 29 June 2001, J.Apostolakis, D.Cote-Ahern, P.Gumplinger:
// correction for spin tracking
// 20 Febr 2001, J.Apostolakis: update for new FieldTrack
// 22 Sept 2000, V.Grichine: update of Kinetic Energy
// 9 June 1999, J.Apostolakis & S.Giani: protect full relocation
// in DEBUG for track starting on surface that
// goes step < tolerance.
// Created: 19 March 1997, J. Apostolakis
// =======================================================================
#include "G4Transportation.hh"
#include "G4ProductionCutsTable.hh"
#include "G4ParticleTable.hh"
#include "G4ChordFinder.hh"
class G4VSensitiveDetector;
//////////////////////////////////////////////////////////////////////////
//
// Constructor
G4Transportation::G4Transportation( G4int verboseLevel )
: G4VProcess( G4String("Transportation"), fTransportation ),
fParticleIsLooping( false ),
fPreviousSftOrigin (0.,0.,0.),
fPreviousSafety ( 0.0 ),
fThreshold_Warning_Energy( 100 * MeV ),
fThreshold_Important_Energy( 250 * MeV ),
fThresholdTrials( 10 ),
fUnimportant_Energy( 1 * MeV ),
fNoLooperTrials(0),
fSumEnergyKilled( 0.0 ), fMaxEnergyKilled( 0.0 ),
fVerboseLevel( verboseLevel )
{
G4TransportationManager* transportMgr ;
transportMgr = G4TransportationManager::GetTransportationManager() ;
fLinearNavigator = transportMgr->GetNavigatorForTracking() ;
// fGlobalFieldMgr = transportMgr->GetFieldManager() ;
fFieldPropagator = transportMgr->GetPropagatorInField() ;
// Cannot determine whether a field exists here,
// because it would only work if the field manager has informed
// about the detector's field before this transportation process
// is constructed.
// Instead later the method DoesGlobalFieldExist() is called
fCurrentTouchableHandle = new G4TouchableHistory();
fEndGlobalTimeComputed = false;
fCandidateEndGlobalTime = 0;
}
//////////////////////////////////////////////////////////////////////////
G4Transportation::~G4Transportation()
{
if( (fVerboseLevel > 0) && (fSumEnergyKilled > 0.0 ) ){
G4cout << " G4Transportation: Statistics for looping particles " << G4endl;
G4cout << " Sum of energy of loopers killed: " << fSumEnergyKilled << G4endl;
G4cout << " Max energy of loopers killed: " << fMaxEnergyKilled << G4endl;
}
}
//////////////////////////////////////////////////////////////////////////
//
// Responsibilities:
// Find whether the geometry limits the Step, and to what length
// Calculate the new value of the safety and return it.
// Store the final time, position and momentum.
G4double G4Transportation::
AlongStepGetPhysicalInteractionLength( const G4Track& track,
G4double, // previousStepSize
G4double currentMinimumStep,
G4double& currentSafety,
G4GPILSelection* selection )
{
G4double geometryStepLength, newSafety ;
fParticleIsLooping = false ;
// Initial actions moved to StartTrack()
// --------------------------------------
// Note: in case another process changes touchable handle
// it will be necessary to add here (for all steps)
// fCurrentTouchableHandle = aTrack->GetTouchableHandle();
// GPILSelection is set to defaule value of CandidateForSelection
// It is a return value
//
*selection = CandidateForSelection ;
// Get initial Energy/Momentum of the track
//
const G4DynamicParticle* pParticle = track.GetDynamicParticle() ;
const G4ParticleDefinition* pParticleDef = pParticle->GetDefinition() ;
G4ThreeVector startMomentumDir = pParticle->GetMomentumDirection() ;
G4ThreeVector startPosition = track.GetPosition() ;
// G4double theTime = track.GetGlobalTime() ;
// The Step Point safety can be limited by other geometries and/or the
// assumptions of any process - it's not always the geometrical safety.
// We calculate the starting point's isotropic safety here.
//
G4ThreeVector OriginShift = startPosition - fPreviousSftOrigin ;
G4double MagSqShift = OriginShift.mag2() ;
if( MagSqShift >= sqr(fPreviousSafety) )
{
currentSafety = 0.0 ;
}
else
{
currentSafety = fPreviousSafety - std::sqrt(MagSqShift) ;
}
// Is the particle charged ?
//
G4double particleCharge = pParticle->GetCharge() ;
fGeometryLimitedStep = false ;
// fEndGlobalTimeComputed = false ;
// There is no need to locate the current volume. It is Done elsewhere:
// On track construction
// By the tracking, after all AlongStepDoIts, in "Relocation"
// Check whether the particle have an (EM) field force exerting upon it
//
G4FieldManager* fieldMgr=0;
G4bool fieldExertsForce = false ;
if( (particleCharge != 0.0) )
{
fieldMgr= fFieldPropagator->FindAndSetFieldManager( track.GetVolume() );
if (fieldMgr != 0) {
// If the field manager has no field, there is no field !
fieldExertsForce = (fieldMgr->GetDetectorField() != 0);
}
}
// Choose the calculation of the transportation: Field or not
//
if( !fieldExertsForce )
{
G4double linearStepLength ;
if( currentMinimumStep <= currentSafety )
{
// The Step is guaranteed to be taken
//
geometryStepLength = currentMinimumStep ;
fGeometryLimitedStep = false ;
}
else
{
// Find whether the straight path intersects a volume
//
linearStepLength = fLinearNavigator->ComputeStep( startPosition,
startMomentumDir,
currentMinimumStep,
newSafety) ;
// Remember last safety origin & value.
//
fPreviousSftOrigin = startPosition ;
fPreviousSafety = newSafety ;
// The safety at the initial point has been re-calculated:
//
currentSafety = newSafety ;
if( linearStepLength <= currentMinimumStep)
{
// The geometry limits the Step size (an intersection was found.)
//
geometryStepLength = linearStepLength ;
fGeometryLimitedStep = true ;
}
else
{
// The full Step is taken.
//
geometryStepLength = currentMinimumStep ;
fGeometryLimitedStep = false ;
}
}
endpointDistance = geometryStepLength ;
// Calculate final position
//
fTransportEndPosition = startPosition+geometryStepLength*startMomentumDir ;
// Momentum direction, energy and polarisation are unchanged by transport
//
fTransportEndMomentumDir = startMomentumDir ;
fTransportEndKineticEnergy = track.GetKineticEnergy() ;
fTransportEndSpin = track.GetPolarization();
fParticleIsLooping = false ;
fMomentumChanged = false ;
fEndGlobalTimeComputed = false ;
}
else // A field exerts force
{
G4double momentumMagnitude = pParticle->GetTotalMomentum() ;
G4ThreeVector EndUnitMomentum ;
G4double lengthAlongCurve ;
G4double restMass = pParticleDef->GetPDGMass() ;
fFieldPropagator->SetChargeMomentumMass( particleCharge, // in e+ units
momentumMagnitude, // in Mev/c
restMass ) ;
// Message the field Manager, to configure it for this track
fieldMgr->ConfigureForTrack( &track );
G4ThreeVector spin = track.GetPolarization() ;
G4FieldTrack aFieldTrack = G4FieldTrack( startPosition,
track.GetMomentumDirection(),
0.0,
track.GetKineticEnergy(),
restMass,
track.GetVelocity(),
track.GetGlobalTime(), // Lab.
track.GetProperTime(), // Part.
&spin ) ;
if( currentMinimumStep > 0 )
{
// Do the Transport in the field (non recti-linear)
//
lengthAlongCurve = fFieldPropagator->ComputeStep( aFieldTrack,
currentMinimumStep,
currentSafety,
track.GetVolume() ) ;
if( lengthAlongCurve < currentMinimumStep)
{
geometryStepLength = lengthAlongCurve ;
fGeometryLimitedStep = true ;
}
else
{
geometryStepLength = currentMinimumStep ;
fGeometryLimitedStep = false ;
}
}
else
{
geometryStepLength = lengthAlongCurve= 0.0 ;
fGeometryLimitedStep = false ;
}
// Remember last safety origin & value.
//
fPreviousSftOrigin = startPosition ;
fPreviousSafety = currentSafety ;
// Get the End-Position and End-Momentum (Dir-ection)
//
fTransportEndPosition = aFieldTrack.GetPosition() ;
// Momentum: Magnitude and direction can be changed too now ...
//
fMomentumChanged = true ;
fTransportEndMomentumDir = aFieldTrack.GetMomentumDir() ;
fTransportEndKineticEnergy = aFieldTrack.GetKineticEnergy() ;
if( fFieldPropagator->GetCurrentFieldManager()->DoesFieldChangeEnergy() )
{
// If the field can change energy, then the time must be integrated
// - so this should have been updated
//
fCandidateEndGlobalTime = aFieldTrack.GetLabTimeOfFlight();
fEndGlobalTimeComputed = true;
// was ( fCandidateEndGlobalTime != track.GetGlobalTime() );
// a cleaner way is to have FieldTrack knowing whether time is updated.
}
else
{
// The energy should be unchanged by field transport,
// - so the time changed will be calculated elsewhere
//
fEndGlobalTimeComputed = false;
// Check that the integration preserved the energy
// - and if not correct this!
G4double startEnergy= track.GetKineticEnergy();
G4double endEnergy= fTransportEndKineticEnergy;
static G4int no_inexact_steps=0, no_large_ediff;
G4double absEdiff = std::fabs(startEnergy- endEnergy);
if( absEdiff > perMillion * endEnergy )
{
no_inexact_steps++;
// Possible statistics keeping here ...
}
if( fVerboseLevel > 1 )
{
if( std::fabs(startEnergy- endEnergy) > perThousand * endEnergy )
{
static G4int no_warnings= 0, warnModulo=1, moduloFactor= 10;
no_large_ediff ++;
if( (no_large_ediff% warnModulo) == 0 )
{
no_warnings++;
G4cout << "WARNING - G4Transportation::AlongStepGetPIL()" << G4endl
<< " Energy changed in Step, more than 1/1000: " << G4endl
<< " Start= " << startEnergy << G4endl
<< " End= " << endEnergy << G4endl
<< " Relative change= "
<< (startEnergy-endEnergy)/startEnergy << G4endl;
G4cout << " Energy has been corrected -- however, review"
<< " field propagation parameters for accuracy." << G4endl;
G4cerr << "ERROR - G4Transportation::AlongStepGetPIL()" << G4endl
<< " Bad 'endpoint'. Energy change detected"
<< " and corrected," << G4endl
<< " occurred already "
<< no_large_ediff << " times." << G4endl;
if( no_large_ediff == warnModulo * moduloFactor )
{
warnModulo *= moduloFactor;
}
}
}
} // end of if (fVerboseLevel)
// Correct the energy for fields that conserve it
// This - hides the integration error
// - but gives a better physical answer
fTransportEndKineticEnergy= track.GetKineticEnergy();
}
fTransportEndSpin = aFieldTrack.GetSpin();
fParticleIsLooping = fFieldPropagator->IsParticleLooping() ;
endpointDistance = (fTransportEndPosition - startPosition).mag() ;
}
// If we are asked to go a step length of 0, and we are on a boundary
// then a boundary will also limit the step -> we must flag this.
//
if( currentMinimumStep == 0.0 )
{
if( currentSafety == 0.0 ) fGeometryLimitedStep = true ;
}
// Update the safety starting from the end-point,
// if it will become negative at the end-point.
//
if( currentSafety < endpointDistance )
{
G4double endSafety =
fLinearNavigator->ComputeSafety( fTransportEndPosition) ;
currentSafety = endSafety ;
fPreviousSftOrigin = fTransportEndPosition ;
fPreviousSafety = currentSafety ;
// Because the Stepping Manager assumes it is from the start point,
// add the StepLength
//
currentSafety += endpointDistance ;
#ifdef G4DEBUG_TRANSPORT
G4cout.precision(16) ;
G4cout << "***Transportation::AlongStepGPIL ** " << G4endl ;
G4cout << " Called Navigator->ComputeSafety at "
<< fTransportEndPosition
<< " and it returned safety= " << endSafety << G4endl ;
G4cout << " Adding endpoint distance " << endpointDistance
<< " we obtain pseudo-safety= " << currentSafety << G4endl ;
#endif
}
fParticleChange.ProposeTrueStepLength(geometryStepLength) ;
return geometryStepLength ;
}
//////////////////////////////////////////////////////////////////////////
//
// Initialize ParticleChange (by setting all its members equal
// to corresponding members in G4Track)
G4VParticleChange* G4Transportation::AlongStepDoIt( const G4Track& track,
const G4Step& stepData )
{
fParticleChange.Initialize(track) ;
// Code for specific process
//
fParticleChange.ProposePosition(fTransportEndPosition) ;
fParticleChange.ProposeMomentumDirection(fTransportEndMomentumDir) ;
fParticleChange.ProposeEnergy(fTransportEndKineticEnergy) ;
fParticleChange.SetMomentumChanged(fMomentumChanged) ;
fParticleChange.ProposePolarization(fTransportEndSpin);
G4double deltaTime = 0.0 ;
// Calculate Lab Time of Flight (ONLY if field Equations used it!)
// G4double endTime = fCandidateEndGlobalTime;
// G4double delta_time = endTime - startTime;
G4double startTime = track.GetGlobalTime() ;
if (!fEndGlobalTimeComputed)
{
// The time was not integrated .. make the best estimate possible
//
G4double finalVelocity = track.GetVelocity() ;
G4double initialVelocity = stepData.GetPreStepPoint()->GetVelocity() ;
G4double stepLength = track.GetStepLength() ;
static const G4ParticleDefinition* fOpticalPhoton =
G4ParticleTable::GetParticleTable()->FindParticle("opticalphoton");
const G4DynamicParticle* fpDynamicParticle = track.GetDynamicParticle();
if (fpDynamicParticle->GetDefinition()== fOpticalPhoton)
{
// A photon is in the medium of the final point
// during the step, so it has the final velocity.
deltaTime = stepLength/finalVelocity ;
}
else if (finalVelocity > 0.0)
{
G4double meanInverseVelocity ;
// deltaTime = stepLength/finalVelocity ;
meanInverseVelocity = 0.5
* ( 1.0 / initialVelocity + 1.0 / finalVelocity ) ;
deltaTime = stepLength * meanInverseVelocity ;
}
else
{
deltaTime = stepLength/initialVelocity ;
}
fCandidateEndGlobalTime = startTime + deltaTime ;
}
else
{
deltaTime = fCandidateEndGlobalTime - startTime ;
}
fParticleChange.ProposeGlobalTime( fCandidateEndGlobalTime ) ;
// Now Correct by Lorentz factor to get "proper" deltaTime
G4double restMass = track.GetDynamicParticle()->GetMass() ;
G4double deltaProperTime = deltaTime*( restMass/track.GetTotalEnergy() ) ;
fParticleChange.ProposeProperTime(track.GetProperTime() + deltaProperTime) ;
//fParticleChange. ProposeTrueStepLength( track.GetStepLength() ) ;
// If the particle is caught looping or is stuck (in very difficult
// boundaries) in a magnetic field (doing many steps)
// THEN this kills it ...
//
if ( fParticleIsLooping )
{
G4double endEnergy= fTransportEndKineticEnergy;
if( (endEnergy < fThreshold_Important_Energy)
|| (fNoLooperTrials >= fThresholdTrials ) ){
// Kill the looping particle
//
fParticleChange.ProposeTrackStatus( fStopAndKill ) ;
// 'Bare' statistics
fSumEnergyKilled += endEnergy;
if( endEnergy > fMaxEnergyKilled) { fMaxEnergyKilled= endEnergy; }
#ifdef G4VERBOSE
if( (fVerboseLevel > 1) ||
( endEnergy > fThreshold_Warning_Energy ) ) {
G4cout << " G4Transportation is killing track that is looping or stuck "
<< G4endl
<< " This track has " << track.GetKineticEnergy() / MeV
<< " MeV energy." << G4endl;
}
#endif
fNoLooperTrials=0;
}
else{
fNoLooperTrials ++;
}
}else{
fNoLooperTrials=0;
}
// Another (sometimes better way) is to use a user-limit maximum Step size
// to alleviate this problem ..
// Introduce smooth curved trajectories to particle-change
//
fParticleChange.SetPointerToVectorOfAuxiliaryPoints
(fFieldPropagator->GimmeTrajectoryVectorAndForgetIt() );
return &fParticleChange ;
}
//////////////////////////////////////////////////////////////////////////
//
// This ensures that the PostStep action is always called,
// so that it can do the relocation if it is needed.
//
G4double G4Transportation::
PostStepGetPhysicalInteractionLength( const G4Track&,
G4double, // previousStepSize
G4ForceCondition* pForceCond )
{
*pForceCond = Forced ;
return DBL_MAX ; // was kInfinity ; but convention now is DBL_MAX
}
/////////////////////////////////////////////////////////////////////////////
//
G4VParticleChange* G4Transportation::PostStepDoIt( const G4Track& track,
const G4Step& )
{
G4TouchableHandle retCurrentTouchable ; // The one to return
// Initialize ParticleChange (by setting all its members equal
// to corresponding members in G4Track)
// fParticleChange.Initialize(track) ; // To initialise TouchableChange
fParticleChange.ProposeTrackStatus(track.GetTrackStatus()) ;
// If the Step was determined by the volume boundary,
// logically relocate the particle
if(fGeometryLimitedStep)
{
// fCurrentTouchable will now become the previous touchable,
// and what was the previous will be freed.
// (Needed because the preStepPoint can point to the previous touchable)
fLinearNavigator->SetGeometricallyLimitedStep() ;
fLinearNavigator->
LocateGlobalPointAndUpdateTouchableHandle( track.GetPosition(),
track.GetMomentumDirection(),
fCurrentTouchableHandle,
true ) ;
// Check whether the particle is out of the world volume
// If so it has exited and must be killed.
//
if( fCurrentTouchableHandle->GetVolume() == 0 )
{
fParticleChange.ProposeTrackStatus( fStopAndKill ) ;
}
retCurrentTouchable = fCurrentTouchableHandle ;
fParticleChange.SetTouchableHandle( fCurrentTouchableHandle ) ;
}
else // fGeometryLimitedStep is false
{
#ifdef G4DEBUG_POSTSTEP_TRANSPORT
// Although the location is changed, we know that the physical
// volume remains constant.
// In order to help in checking the user geometry
// we perform a full-relocation and check its result
// *except* if we have made a very small step from a boundary
// (i.e. remaining inside the tolerance)
G4bool startAtSurface_And_MoveEpsilon ;
startAtSurface_And_MoveEpsilon =
(stepData.GetPreStepPoint()->GetSafety() == 0.0) &&
(stepData.GetStepLength() < kCarTolerance ) ;
if( startAtSurface_And_MoveEpsilon )
{
fLinearNavigator->
LocateGlobalPointAndUpdateTouchableHandle( track.GetPosition(),
track.GetMomentumDirection(),
fCurrentTouchableHandle,
true );
if( fCurrentTouchableHandle->GetVolume() != track.GetVolume() )
{
G4cerr << " ERROR: A relocation within safety has"
<< " caused a volume change! " << G4endl ;
G4cerr << " The old volume is called "
<< track.GetVolume()->GetName() << G4endl ;
G4cerr << " The new volume is called " ;
if ( fCurrentTouchableHandle->GetVolume() != 0 )
{
G4cerr << fCurrentTouchableHandle->GetVolume()->GetName()
<< G4endl ;
}
else
{
G4cerr << "Out of World" << G4endl ;
}
G4cerr.precision(7) ;
G4cerr << " The position is " << track.GetPosition() << G4endl ;
// Let us relocate again, for debuging
//
fLinearNavigator->
LocateGlobalPointAndUpdateTouchableHandle(track.GetPosition(),
track.GetMomentumDirection(),
fCurrentTouchableHandle,
true ) ;
G4cerr << " The newer volume is called " ;
if ( fCurrentTouchableHandle->GetVolume() != 0 )
{
G4cerr << fCurrentTouchableHandle->GetVolume()->GetName()
<< G4endl ;
}
else
{
G4cerr << "Out of World" << G4endl ;
}
}
assert( fCurrentTouchableHandle->GetVolume()->GetName() ==
track.GetVolume()->GetName() ) ;
retCurrentTouchable = fCurrentTouchableHandle ;
fParticleChange.SetTouchableHandle( fCurrentTouchableHandle ) ;
}
else
{
retCurrentTouchable = track.GetTouchableHandle() ;
fParticleChange.SetTouchableHandle( track.GetTouchableHandle() ) ;
}
// This must be done in the above if ( AtSur ) fails
// We also do it for if (true) in order to get debug/opt to
// behave as exactly the same way as possible.
//
fLinearNavigator->LocateGlobalPointWithinVolume( track.GetPosition() ) ;
#else // ie #ifndef G4DEBUG_POSTSTEP_TRANSPORT does a quick relocation
// This serves only to move the Navigator's location
//
fLinearNavigator->LocateGlobalPointWithinVolume( track.GetPosition() ) ;
// The value of the track's current Touchable is retained.
// (and it must be correct because we must use it below to
// overwrite the (unset) one in particle change)
// Although in general this is fCurrentTouchable, at the start of
// a step it could be different ... ??
//
fParticleChange.SetTouchableHandle( track.GetTouchableHandle() ) ;
retCurrentTouchable = track.GetTouchableHandle() ;
#endif
} // endif ( fGeometryLimitedStep )
const G4VPhysicalVolume* pNewVol = retCurrentTouchable->GetVolume() ;
const G4Material* pNewMaterial = 0 ;
const G4VSensitiveDetector* pNewSensitiveDetector = 0 ;
if( pNewVol != 0 )
{
pNewMaterial= pNewVol->GetLogicalVolume()->GetMaterial();
pNewSensitiveDetector= pNewVol->GetLogicalVolume()->GetSensitiveDetector();
}
// ( <const_cast> pNewMaterial ) ;
// ( <const_cast> pNewSensitiveDetector) ;
fParticleChange.SetMaterialInTouchable( (G4Material *) pNewMaterial ) ;
fParticleChange.SetSensitiveDetectorInTouchable( (G4VSensitiveDetector *) pNewSensitiveDetector ) ;
const G4MaterialCutsCouple* pNewMaterialCutsCouple = 0;
if( pNewVol != 0 )
{
pNewMaterialCutsCouple=pNewVol->GetLogicalVolume()->GetMaterialCutsCouple();
}
if( pNewVol!=0 && pNewMaterialCutsCouple!=0 && pNewMaterialCutsCouple->GetMaterial()!=pNewMaterial )
{
// for parametrized volume
//
pNewMaterialCutsCouple =
G4ProductionCutsTable::GetProductionCutsTable()
->GetMaterialCutsCouple(pNewMaterial,
pNewMaterialCutsCouple->GetProductionCuts());
}
fParticleChange.SetMaterialCutsCoupleInTouchable( pNewMaterialCutsCouple );
// temporarily until Get/Set Material of ParticleChange,
// and StepPoint can be made const.
// Set the touchable in ParticleChange
// this must always be done because the particle change always
// uses this value to overwrite the current touchable pointer.
//
fParticleChange.SetTouchableHandle(retCurrentTouchable) ;
return &fParticleChange ;
}
// New method takes over the responsibility to reset the state of G4Transportation
// object at the start of a new track or the resumption of a suspended track.
void
G4Transportation::StartTracking(G4Track* aTrack)
{
G4VProcess::StartTracking(aTrack);
// The actions here are those that were taken in AlongStepGPIL
// when track.GetCurrentStepNumber()==1
// reset safety value and center
//
fPreviousSafety = 0.0 ;
fPreviousSftOrigin = G4ThreeVector(0.,0.,0.) ;
// reset looping counter -- for motion in field
if( aTrack->GetCurrentStepNumber()==1 ) {
fNoLooperTrials= 0;
}
// ChordFinder reset internal state
//
if( DoesGlobalFieldExist() ) {
G4ChordFinder* chordF= fFieldPropagator->GetChordFinder();
if( chordF ) chordF->ResetStepEstimate();
}
// Update the current touchable handle (from the track's)
//
fCurrentTouchableHandle = aTrack->GetTouchableHandle();
}