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// $Id: G4FieldTrackUpdator.cc 90644 2015-06-05 13:19:36Z gcosmo $
//
//   M. Asai - first implementation Apr/28/2006
//
//---------------------------------------------------------------
//
// G4FieldTrackUpdator.cc
//
//---------------------------------------------------------------

#include "globals.hh"
#include "G4FieldTrackUpdator.hh"
#include "G4ThreeVector.hh"
#include "G4Track.hh"
#include "G4DynamicParticle.hh"
#include "G4TrackStatus.hh"
#include "G4FieldTrack.hh"

G4FieldTrack* G4FieldTrackUpdator::CreateFieldTrack(const G4Track* trk)
{
  G4FieldTrack* ftrk = new G4FieldTrack(
    trk->GetPosition(),
    trk->GetGlobalTime(),
    trk->GetMomentumDirection(),
    trk->GetKineticEnergy(),
    trk->GetDynamicParticle()->GetMass(),
    trk->GetDynamicParticle()->GetCharge(),
    trk->GetDynamicParticle()->GetPolarization(),
    0.0                   // magnetic dipole moment to be implemented
    );
  return ftrk;
}

void G4FieldTrackUpdator::Update(G4FieldTrack* ftrk,const G4Track* trk)
{
  const G4DynamicParticle* ptDynamicParticle= trk->GetDynamicParticle();

  // The following properties must be updated 1) for each new track, and 
  ftrk->SetRestMass(ptDynamicParticle->GetMass());   
  // 2) Since ion can lose/gain electrons, this must be done at every step
  
  ftrk->UpdateState(
    trk->GetPosition(),     
    trk->GetGlobalTime(),
    trk->GetMomentumDirection(),
    trk->GetKineticEnergy()
    );

#ifdef G4CHECK  
  if( ( trk->GetMomentum() - ftrk->GetMomentum()).mag2() > 1.e-16 * trk->GetMomentum().mag2() ){
     G4cerr << "ERROR> G4FieldTrackUpdator sees *Disagreement* in momentum " << G4endl;
     G4cout << "  FTupdator: Tracking Momentum= " << trk->GetMomentum() << G4endl;
     G4cout << "  FTupdator: FldTrack Momentum= " << ftrk->GetMomentum() << G4endl;
     G4cout << "  FTupdator: FldTrack-Tracking= " << ftrk->GetMomentum() - trk->GetMomentum() << G4endl;
  }
#endif

  ftrk->SetProperTimeOfFlight(trk->GetProperTime());

  ftrk->SetChargeAndMoments( ptDynamicParticle->GetCharge(),
                             ptDynamicParticle->GetMagneticMoment()); 
  ftrk->SetPDGSpin(          ptDynamicParticle->GetParticleDefinition()->GetPDGSpin() ); 
   // The charge can change during tracking
  ftrk->SetSpin( ptDynamicParticle->GetPolarization() );
}