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// $Id: G4ImportanceProcess.hh,v 1.4 2008/04/21 09:10:28 ahoward Exp $
// GEANT4 tag $Name: geant4-09-04-beta-01 $
//
// ----------------------------------------------------------------------
// Class G4ImportanceProcess
//
// Class description:
//
// Used internally by importance sampling in the "mass" geometry.
// This process is a forced post step process. I will apply
// importance sampling if the particle crosses a boundary in the 
// "mass" geometry.

// Author: Michael Dressel (Michael.Dressel@cern.ch)
// ----------------------------------------------------------------------
#ifndef G4ImportanceProcess_hh
#define G4ImportanceProcess_hh G4ImportanceProcess_hh

#include "G4VProcess.hh"
#include "G4VTrackTerminator.hh"

class G4SamplingPostStepAction;
class G4VImportanceAlgorithm;
class G4VIStore;

class G4Step;
class G4Navigator;
class G4TransportationManager;
class G4PathFinder;
class G4VTouchable;

#include "G4FieldTrack.hh"
#include "G4TouchableHandle.hh"


class G4ImportanceProcess : public G4VProcess, public G4VTrackTerminator
{

public:  // with description

  G4ImportanceProcess(const G4VImportanceAlgorithm &aImportanceAlgorithm,
                          const G4VIStore &aIstore,
                          const G4VTrackTerminator *TrackTerminator,
                          const G4String &aName = "ImportanceProcess", G4bool para = false);
    // creates a G4ParticleChange

  virtual ~G4ImportanceProcess();
    // delete the G4ParticleChange


  //--------------------------------------------------------------
  // Set Paralle World
  //--------------------------------------------------------------

  void SetParallelWorld(G4String parallelWorldName);
  void SetParallelWorld(G4VPhysicalVolume* parallelWorld);

  //--------------------------------------------------------------
  //     Process interface
  //--------------------------------------------------------------

  void StartTracking(G4Track*);
  

  virtual G4double 
  PostStepGetPhysicalInteractionLength(const G4Track& aTrack,
                                       G4double   previousStepSize,
                                       G4ForceCondition* condition);
    // make process beeing forced
  virtual G4VParticleChange *PostStepDoIt(const G4Track&, const G4Step&);
    // manage the importance sampling in the "mass" geometry

  virtual void KillTrack() const;
    // used in case no scoring process follows that does the killing

  virtual const G4String &GetName() const;


public:  // without description

  //  no operation in  AtRestDoIt and  AlongStepDoIt

  virtual G4double 
  AlongStepGetPhysicalInteractionLength(const G4Track&,
                                        G4double  ,
                                        G4double  ,
                                        G4double& ,
                                        G4GPILSelection*);
  virtual G4double 
  AtRestGetPhysicalInteractionLength(const G4Track& ,
                                     G4ForceCondition*);
  
  virtual G4VParticleChange* 
  AtRestDoIt(const G4Track&, const G4Step&);


  virtual G4VParticleChange* 
  AlongStepDoIt(const G4Track&, const G4Step&);
  
private:
  
  G4ImportanceProcess(const G4ImportanceProcess &);
  G4ImportanceProcess &operator=(const G4ImportanceProcess &);
  
private:

  void CopyStep(const G4Step & step);

  G4Step * fGhostStep;
  G4StepPoint * fGhostPreStepPoint;
  G4StepPoint * fGhostPostStepPoint;

  G4ParticleChange *fParticleChange;
  const G4VImportanceAlgorithm &fImportanceAlgorithm;
  const G4VIStore &fIStore;
  G4SamplingPostStepAction *fPostStepAction;

  G4TransportationManager* fTransportationManager;
  G4PathFinder*        fPathFinder;

  // -------------------------------
  // Navigation in the Ghost World:
  // -------------------------------
  G4String             fGhostWorldName;
  G4VPhysicalVolume*   fGhostWorld;
  G4Navigator*         fGhostNavigator;
  G4int                fNavigatorID;
  G4TouchableHandle    fOldGhostTouchable;
  G4TouchableHandle    fNewGhostTouchable;
  G4FieldTrack         fFieldTrack;
  G4double             fGhostSafety;
  G4bool               fOnBoundary;

  G4bool               paraflag;

};

#endif