G4ErrorFreeTrajState.hh

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// $Id$
//
// Class Description:
//
// Represents a free G4ErrorTrajState
// It can be represented by the 5 variables
//     1/p, lambda, phi, y_perp, z_perp
// where lambda and phi are the dip and azimuthal angles related
// to the momentum components in the following way:
//            p_x = p cos(lambda) cos(phi)  ! lambda = 90 - theta
//            p_y = p cos(lambda) sin(phi)
//            p_z = p sin(lambda)
// y_perp and z_perp are the coordinates of the trajectory in a
// local orthonormal reference frame with the x_perp axis along the
// particle direction, the y_perp being parallel to the x-y plane.
//
// This class also takes care of propagating the error associated to 
// the trajectory 
 
// History:
// - Created:   P. Arce
// --------------------------------------------------------------------
 
#ifndef G4ErrorFreeTrajState_hh
#define G4ErrorFreeTrajState_hh
 
#include "globals.hh"
 
#include "G4ErrorMatrix.hh"
 
#include "G4ErrorTrajState.hh"
#include "G4ErrorFreeTrajParam.hh"
 
#include "G4Point3D.hh"
#include "G4Vector3D.hh"
 
class G4ErrorSurfaceTrajState;
 
class G4ErrorFreeTrajState : public G4ErrorTrajState
{
 public:  // with description
 
  G4ErrorFreeTrajState() : theFirstStep(true) {}
  G4ErrorFreeTrajState( const G4String& partName,
                        const G4Point3D& pos,
                        const G4Vector3D& mom,
                        const G4ErrorTrajErr& errmat = G4ErrorTrajErr(5,0) );
    // Constructor by providing particle, position and momentum
 
  G4ErrorFreeTrajState( const G4ErrorSurfaceTrajState& tpOS );
    // Constructor by providing G4ErrorSurfaceTrajState
 
  ~G4ErrorFreeTrajState(){}
 
  virtual G4int Update( const G4Track* aTrack );
    // update parameters from G4Track
 
  virtual G4int PropagateError( const G4Track* aTrack );
    // propagate the error along the step
 
  virtual void Dump( std::ostream& out = G4cout ) const;
    // dump TrajState parameters
 
  friend
    std::ostream& operator<<(std::ostream&, const G4ErrorFreeTrajState& ts);
 
  // Set and Get methods 
 
  virtual void SetPosition( const G4Point3D pos )
    { SetParameters( pos, fMomentum ); }
 
  virtual void SetMomentum( const G4Vector3D& mom )
    { SetParameters( fPosition, mom ); }
 
  void SetParameters( const G4Point3D& pos, const G4Vector3D& mom )
    {
      fPosition = pos;
      fMomentum = mom;
      fTrajParam.SetParameters( pos, mom );
    }
 
  G4ErrorFreeTrajParam GetParameters() const
    { return fTrajParam; }
 
  G4ErrorMatrix GetTransfMat() const
    { return theTransfMat; }
 
 private:  
 
  void Init();
    // define TrajState type and build charge
 
  G4int PropagateErrorMSC( const G4Track* aTrack );
    // add the error associated to multiple scattering
 
  void CalculateEffectiveZandA( const G4Material* mate, double& effZ, double& effA );
    // calculate effective Z and A (needed by PropagateErrorMSC)
  
  G4int PropagateErrorIoni( const G4Track* aTrack );
    // add the error associated to ionization energy loss
 
 
 private:
 
  G4ErrorFreeTrajParam fTrajParam;
 
  G4ErrorMatrix theTransfMat;
 
  G4bool theFirstStep; // to count if transf mat is updated or initialized
};
 
#endif