G4ErrorFreeTrajParam.cc

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// $Id: G4ErrorFreeTrajParam.cc 69014 2013-04-15 09:42:51Z gcosmo $
//
// ------------------------------------------------------------
//      GEANT 4 class implementation file 
// ------------------------------------------------------------
//

#include "G4ErrorFreeTrajParam.hh"
#include "G4ThreeVector.hh"
#include "G4SystemOfUnits.hh"

#include <iomanip>

//------------------------------------------------------------------------
G4ErrorFreeTrajParam::G4ErrorFreeTrajParam( const G4Point3D& pos,
                                            const G4Vector3D& mom )
{
  SetParameters( pos, mom );
}


//------------------------------------------------------------------------
void G4ErrorFreeTrajParam::SetParameters( const G4Point3D& pos,
                                          const G4Vector3D& mom )
{
  fInvP = 1./mom.mag();
  fDir = mom*fInvP;
  fLambda = 90.*deg - mom.theta();
  fPhi = mom.phi();
  G4Vector3D vxPerp(0.,0.,0.);
  if( mom.mag() > 0.) {
    vxPerp = mom/mom.mag();
  }
  G4Vector3D vyPerp = G4Vector3D( -vxPerp.y(), vxPerp.x(), 0.);
  vyPerp /= vyPerp.mag();
  G4Vector3D vzPerp = vxPerp.cross( vyPerp );
  vzPerp /= vzPerp.mag();
  // check if right handed
  //  fXPerp = pos.proj( mom );
  G4ThreeVector posv(pos);
  if( vyPerp.mag() != 0. ) {
    // now all 2 scalar memeber variables retain the signs
    //  fYPerp = posv.project( vyPerp ).mag();
    //  fZPerp = posv.project( vzPerp ).mag();
    fYPerp = posv.dot( vyPerp );
    fZPerp = posv.dot( vzPerp );
  } else {
    fYPerp = 0.;
    fZPerp = 0.;
  }
}

//------------------------------------------------------------------------
void G4ErrorFreeTrajParam::Update( const G4Track* aTrack )
{
  SetParameters( aTrack->GetPosition(), aTrack->GetMomentum() );

}


//------------------------------------------------------------------------
std::ostream& operator<<(std::ostream& out, const G4ErrorFreeTrajParam& tp)
{
  G4int oldprc = out.precision(8);
  out << " InvP= " << tp.fInvP << " Theta= "
      << tp.fLambda << " Phi= " << tp.fPhi << " YPerp= " << tp.fYPerp
      << " ZPerp= " << tp.fZPerp << G4endl;
  out << " momentum direction= " << tp.fDir << G4endl;
  out.precision(oldprc);
    
  return out;
}