dc/d33/G4Navigator_8hh_source.html

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//

// class G4Navigator

//

// Class description:

//

// A class for use by the tracking management, able to obtain/calculate

// dynamic tracking time information such as the distance to the next volume,

// or to find the physical volume containing a given point in the world

// reference system. The navigator maintains a transformation history and

// other information to optimise the tracking time performance.


// - Created.                                  Paul Kent,     Jul 95/96

// - Made Navigator Abstract                   G. Cosmo,      Nov  2003

// - Added check mode                          G. Cosmo,      Mar  2004

// - Zero step protections                     J.A. / G.C.,   Nov  2004

// *********************************************************************


#ifndef G4NAVIGATOR_HH

#define G4NAVIGATOR_HH


#include "geomdefs.hh"


#include "G4ThreeVector.hh"

#include "G4AffineTransform.hh"

#include "G4RotationMatrix.hh"


#include "G4LogicalVolume.hh"             // Used in inline methods

#include "G4GRSVolume.hh"                 //    "         "

#include "G4GRSSolid.hh"                  //    "         "

#include "G4TouchableHandle.hh"           //    "         "

#include "G4TouchableHistoryHandle.hh"


#include "G4NavigationHistory.hh"

#include "G4NormalNavigation.hh"

#include "G4VoxelNavigation.hh"

#include "G4ParameterisedNavigation.hh"

#include "G4ReplicaNavigation.hh"

#include "G4RegularNavigation.hh"

#include "G4VExternalNavigation.hh"


#include <iostream>


class G4VPhysicalVolume;


class G4Navigator

{

  public:  // with description


  friend std::ostream& operator << (std::ostream &os, const G4Navigator &n);


  G4Navigator();

    // Constructor - initialisers and setup.


  G4Navigator(const G4Navigator&) = delete;

  G4Navigator& operator=(const G4Navigator&) = delete;

    // Copy constructor & assignment operator not allowed.


  virtual ~G4Navigator();

    // Destructor. No actions.


  virtual G4double ComputeStep(const G4ThreeVector& pGlobalPoint,

                               const G4ThreeVector& pDirection,

                               const G4double pCurrentProposedStepLength,

                                     G4double& pNewSafety);

    // Calculate the distance to the next boundary intersected

    // along the specified NORMALISED vector direction and

    // from the specified point in the global coordinate

    // system. LocateGlobalPointAndSetup or LocateGlobalPointWithinVolume

    // must have been called with the same global point prior to this call.

    // The isotropic distance to the nearest boundary is also

    // calculated (usually an underestimate). The current

    // proposed Step length is used to avoid intersection

    // calculations: if it can be determined that the nearest

    // boundary is >pCurrentProposedStepLength away, kInfinity

    // is returned together with the computed isotropic safety

    // distance. Geometry must be closed.


  G4double CheckNextStep(const G4ThreeVector& pGlobalPoint,

                         const G4ThreeVector& pDirection,

                         const G4double pCurrentProposedStepLength,

                               G4double& pNewSafety);

    // Same as above, but do not disturb the state of the Navigator.


  virtual

  G4VPhysicalVolume* ResetHierarchyAndLocate(const G4ThreeVector& point,

                                             const G4ThreeVector& direction,

                                             const G4TouchableHistory& h);


    // Resets the geometrical hierarchy and search for the volumes deepest

    // in the hierarchy containing the point in the global coordinate space.

    // The direction is used to check if a volume is entered.

    // The search begin is the geometrical hierarchy at the location of the

    // last located point, or the endpoint of the previous Step if

    // SetGeometricallyLimitedStep() has been called immediately before.

    //

    // Important Note: In order to call this the geometry MUST be closed.


  virtual

  G4VPhysicalVolume* LocateGlobalPointAndSetup(const G4ThreeVector& point,

                                      const G4ThreeVector* direction = nullptr,

                                      const G4bool pRelativeSearch = true,

                                      const G4bool ignoreDirection = true);

    // Search the geometrical hierarchy for the volumes deepest in the hierarchy

    // containing the point in the global coordinate space. Two main cases are:

    //  i) If pRelativeSearch=false it makes use of no previous/state

    //     information. Returns the physical volume containing the point,

    //     with all previous mothers correctly set up.

    // ii) If pRelativeSearch is set to true, the search begin is the

    //     geometrical hierarchy at the location of the last located point,

    //     or the endpoint of the previous Step if SetGeometricallyLimitedStep()

    //     has been called immediately before.

    // The direction is used (to check if a volume is entered) if either

    //   - the argument ignoreDirection is false, or

    //   - the Navigator has determined that it is on an edge shared by two or

    //     more volumes.  (This is state information.)

    //

    // Important Note: In order to call this the geometry MUST be closed.


  virtual

  void LocateGlobalPointWithinVolume(const G4ThreeVector& position);

    // Notify the Navigator that a track has moved to the new Global point

    // 'position', that is known to be within the current safety.

    // No check is performed to ensure that it is within  the volume.

    // This method can be called instead of LocateGlobalPointAndSetup ONLY if

    // the caller is certain that the new global point (position) is inside the

    // same volume as the previous position.  Usually this can be guaranteed

    // only if the point is within safety.


  inline void LocateGlobalPointAndUpdateTouchableHandle(

                const G4ThreeVector&       position,

                const G4ThreeVector&       direction,

                      G4TouchableHandle&   oldTouchableToUpdate,

                const G4bool               RelativeSearch = true);

    // First, search the geometrical hierarchy like the above method

    // LocateGlobalPointAndSetup(). Then use the volume found and its

    // navigation history to update the touchable.


  inline void LocateGlobalPointAndUpdateTouchable(

                const G4ThreeVector&       position,

                const G4ThreeVector&       direction,

                      G4VTouchable*        touchableToUpdate,

                const G4bool               RelativeSearch = true);

    // First, search the geometrical hierarchy like the above method

    // LocateGlobalPointAndSetup(). Then use the volume found and its

    // navigation history to update the touchable.


  inline void LocateGlobalPointAndUpdateTouchable(

                const G4ThreeVector&       position,

                      G4VTouchable*        touchableToUpdate,

                const G4bool               RelativeSearch = true);

    // Same as the method above but missing direction.


  inline void SetGeometricallyLimitedStep();

    // Inform the navigator that the previous Step calculated

    // by the geometry was taken in its entirety.


  virtual G4double ComputeSafety(const G4ThreeVector& globalpoint,

                                 const G4double pProposedMaxLength = DBL_MAX,

                                 const G4bool keepState = true);

    // Calculate the isotropic distance to the nearest boundary from the

    // specified point in the global coordinate system.

    // The globalpoint utilised must be within the current volume.

    // The value returned is usually an underestimate.

    // The proposed maximum length is used to avoid volume safety

    //  calculations.  The geometry must be closed.

    // To ensure minimum side effects from the call, keepState

    //  must be true.


   virtual G4bool RecheckDistanceToCurrentBoundary(

                               const G4ThreeVector& pGlobalPoint,

                               const G4ThreeVector& pDirection,

                               const G4double CurrentProposedStepLength,

                                     G4double* prDistance,

                                     G4double* prNewSafety = nullptr) const;

    // Trial method for checking potential displacement for MS

    // Check new Globalpoint, to see whether it is in current volume

    // (mother) and not in potential entering daughter.

    // If in mother, check distance to boundary along pDirection.

    // If in entering daughter, check distance back to boundary.

    // NOTE:

    // Can be called only after ComputeStep is called - before ReLocation

    // Deals only with current volume (and potentially entered)


  inline G4VPhysicalVolume* GetWorldVolume() const;

    // Return the current  world (`topmost') volume.


  inline void SetWorldVolume(G4VPhysicalVolume* pWorld);

    // Set the world (`topmost') volume. This must be positioned at

    // origin (0,0,0) and unrotated.


  inline G4GRSVolume* CreateGRSVolume() const;

  inline G4GRSSolid* CreateGRSSolid() const;

  inline G4TouchableHistory* CreateTouchableHistory() const;

  inline G4TouchableHistory* CreateTouchableHistory(const G4NavigationHistory*) const;

    // `Touchable' creation methods: caller has deletion responsibility.


  virtual G4TouchableHistoryHandle CreateTouchableHistoryHandle() const;

    // Returns a reference counted handle to a touchable history.


  virtual G4ThreeVector GetLocalExitNormal(G4bool* valid);

  virtual G4ThreeVector GetLocalExitNormalAndCheck(const G4ThreeVector& point,

                                                         G4bool* valid);

  virtual G4ThreeVector GetGlobalExitNormal(const G4ThreeVector& point,

                                                  G4bool* valid);

    // Return Exit Surface Normal and validity too.

    // Can only be called if the Navigator's last Step has crossed a

    // volume geometrical boundary.

    // It returns the Normal to the surface pointing out of the volume that

    // was left behind and/or into the volume that was entered.

    // Convention:

    //   The *local* normal is in the coordinate system of the *final* volume.

    // Restriction:

    //   Normals are not available for replica volumes (returns valid= false)

    // These methods takes full care about how to calculate this normal,

    // but if the surfaces are not convex it will return valid=false.


  inline G4int GetVerboseLevel() const;

  inline void  SetVerboseLevel(G4int level);

    // Get/Set Verbose(ness) level.

    // [if level>0 && G4VERBOSE, printout can occur]


  inline G4bool IsActive() const;

    // Verify if the navigator is active.

  inline void  Activate(G4bool flag);

    // Activate/inactivate the navigator.


  inline G4bool EnteredDaughterVolume() const;

    // The purpose of this function is to inform the caller if the track is

    // entering a daughter volume while exiting from the current volume.

    // This method returns

    // - True only in case 1) above, that is when the Step has caused

    //   the track to arrive at a boundary of a daughter.

    // - False in cases 2), 3) and 4), i.e. in all other cases.

    // This function is not guaranteed to work if SetGeometricallyLimitedStep()

    // was not called when it should have been called.

  inline G4bool ExitedMotherVolume() const;

    // Verify if the step has exited the mother volume.


  inline void CheckMode(G4bool mode);

    // Run navigation in "check-mode", therefore using additional

    // verifications and more strict correctness conditions.

    // Is effective only with G4VERBOSE set.

  inline G4bool IsCheckModeActive() const;

  inline void SetPushVerbosity(G4bool mode);

    // Set/unset verbosity for pushed tracks (default is true).


  void PrintState() const;

    // Print the internal state of the Navigator (for debugging).

    // The level of detail is according to the verbosity.


  inline const G4AffineTransform& GetGlobalToLocalTransform() const;

  inline const G4AffineTransform  GetLocalToGlobalTransform() const;

    // Obtain the transformations Global/Local (and inverse).

    // Clients of these methods must copy the data if they need to keep it.


  G4AffineTransform GetMotherToDaughterTransform(G4VPhysicalVolume* dVolume,

                                                 G4int dReplicaNo,

                                                 EVolume dVolumeType );

    // Obtain mother to daughter transformation


  inline void ResetStackAndState();

    // Reset stack and minimum or navigator state machine necessary for reset

    // as needed by LocalGlobalPointAndSetup.

    // [Does not perform clears, resizes, or reset fLastLocatedPointLocal]


  inline G4int SeverityOfZeroStepping( G4int* noZeroSteps ) const;

    // Report on severity of error and number of zero steps,

    // in case Navigator is stuck and is returning zero steps.

    // Values: 1 (small problem),  5 (correcting),

    //         9 (ready to abandon), 10 (abandoned)


  inline G4ThreeVector GetCurrentLocalCoordinate() const;

    // Return the local coordinate of the point in the reference system

    // of its containing volume that was found by LocalGlobalPointAndSetup.

    // The local coordinate of the last located track.


  inline G4ThreeVector NetTranslation() const;

  inline G4RotationMatrix NetRotation() const;

    // Compute+return the local->global translation/rotation of current volume.


  inline void EnableBestSafety( G4bool value = false );

    // Enable best-possible evaluation of isotropic safety.


  inline G4VExternalNavigation* GetExternalNavigation() const;

  inline void SetExternalNavigation(G4VExternalNavigation* externalNav);

    // Accessor & modifier for custom external navigation.


  inline G4Navigator* Clone() const;

    // Cloning feature for use in MT applications to clone

    // navigator, including external sub-navigator.

    // Client has responsibility for ownership of returned allocated pointer.


 protected:  // with description


  void SetSavedState();

    // ( fValidExitNormal, fExitNormal, fExiting, fEntering,

    //   fBlockedPhysicalVolume, fBlockedReplicaNo, fLastStepWasZero);

    // Extended to include:

    // ( fLastLocatedPointLocal, fLocatedOutsideWorld;

    //   fEnteredDaughter, fExitedMother

    //   fPreviousSftOrigin, sPreviousSafety)  Safety Sphere.


  void RestoreSavedState();

    // Copy aspects of the state, to enable a non-state changing

    // call to ComputeStep().


  virtual void ResetState();

    // Utility method to reset the navigator state machine.


  inline G4ThreeVector ComputeLocalPoint(const G4ThreeVector& rGlobPoint) const;

    // Return position vector in local coordinate system, given a position

    // vector in world coordinate system.


  inline G4ThreeVector ComputeLocalAxis(const G4ThreeVector& pVec) const;

    // Return the local direction of the specified vector in the reference

    // system of the volume that was found by LocalGlobalPointAndSetup.

    // The Local Coordinates of point in world coordinate system.


  inline EVolume VolumeType(const G4VPhysicalVolume *pVol) const;

    // Characterise `type' of volume - normal/replicated/parameterised.


  inline EVolume CharacteriseDaughters(const G4LogicalVolume *pLog) const;

    // Characterise daughter of logical volume.


  inline G4int GetDaughtersRegularStructureId(const G4LogicalVolume *pLv) const;

    // Get regular structure ID of first daughter


  virtual void SetupHierarchy();

    // Renavigate & reset hierarchy described by current history

    // o Reset volumes

    // o Recompute transforms and/or solids of replicated/parameterised

    //   volumes.


  G4bool CheckOverlapsIterative(G4VPhysicalVolume* vol);

    // Utility method to trigger overlaps check on a volume with reported

    // overlaps ordered by relevance. Used in ComputeStep() when loopings

    // with zero step are detected.


 private:


  void ComputeStepLog(const G4ThreeVector& pGlobalpoint,

                             G4double moveLenSq) const;

    // Log and checks for steps larger than the tolerance


 protected:  // without description


  G4double kCarTolerance, fMinStep, fSqTol;

    // Cached tolerances.


  //

  // BEGIN State information

  //


  G4NavigationHistory fHistory;

    // Transformation and history of the current path

    // through the geometrical hierarchy.


  G4bool fEnteredDaughter;

    // A memory of whether in this Step a daughter volume is entered

    // (set in Compute & Locate).

    //  After Compute: it expects to enter a daughter

    //  After Locate:  it has entered a daughter


  G4bool fExitedMother;

    // A similar memory whether the Step exited current "mother" volume

    // completely, not entering daughter.


  G4bool fWasLimitedByGeometry = false;

    // Set true if last Step was limited by geometry.


  G4ThreeVector fStepEndPoint;

    // Endpoint of last ComputeStep

    // can be used for optimisation (e.g. when computing safety).

  G4ThreeVector fLastStepEndPointLocal;

    // Position of the end-point of the last call to ComputeStep

    // in last Local coordinates.


  G4int fVerbose = 0;

    // Verbose(ness) level  [if > 0, printout can occur].


 private:


  G4bool fActive = false;

    // States if the navigator is activated or not.


  G4bool fLastTriedStepComputation = false;

    // Whether ComputeStep was called since the last call to a Locate method

    // Uses: - distinguish parts of state which differ before/after calls

    //         to ComputeStep or one of the Locate methods;

    //       - avoid two consecutive calls to compute-step (illegal).


  G4bool fEntering,fExiting;

    // Entering/Exiting volumes blocking/setup

    // o If exiting

    //      volume ptr & replica number (set & used by Locate..())

    //      used for blocking on redescent of geometry

    // o If entering

    //      volume ptr & replica number (set by ComputeStep(),used by

    //      Locate..()) of volume for `automatic' entry


  G4VPhysicalVolume* fBlockedPhysicalVolume;

  G4int fBlockedReplicaNo;


  G4ThreeVector fLastLocatedPointLocal;

    // Position of the last located point relative to its containing volume.

  G4bool fLocatedOutsideWorld;

    // Whether the last call to Locate methods left the world


  G4bool fValidExitNormal;    // Set true if have leaving volume normal

  G4ThreeVector fExitNormal;  // Leaving volume normal, in the

                              // volume containing the exited

                              // volume's coordinate system

  G4ThreeVector fGrandMotherExitNormal;  // Leaving volume normal, in its

                                         // own coordinate system

  G4bool  fChangedGrandMotherRefFrame;   // Whether frame is changed


  G4ThreeVector fExitNormalGlobalFrame;  // Leaving volume normal, in the

                                         // global coordinate system

  G4bool  fCalculatedExitNormal;  // Has it been computed since

                                  // the last call to ComputeStep

                                  // Covers both Global and GrandMother


  // Count zero steps - as one or two can occur due to changing momentum at

  //                    a boundary or at an edge common between volumes

  //                  - several are likely a problem in the geometry

  //                    description or in the navigation

  //

  G4bool fLastStepWasZero;

    // Whether the last ComputeStep moved Zero. Used to check for edges.


  G4bool fLocatedOnEdge;

    // Whether the Navigator has detected an edge

  G4int fNumberZeroSteps;

    // Number of preceding moves that were Zero. Reset to 0 after finite step

  G4int fActionThreshold_NoZeroSteps = 10;

    // After this many failed/zero steps, act (push etc)

  G4int fAbandonThreshold_NoZeroSteps = 25;

    // After this many failed/zero steps, abandon track


  G4ThreeVector  fPreviousSftOrigin;

  G4double       fPreviousSafety;

    // Memory of last safety origin & value. Used in ComputeStep to ensure

    // that origin of current Step is in the same volume as the point of the

    // last relocation


  G4VPhysicalVolume* fLastMotherPhys = nullptr;

    // Memory of the mother volume during previous step.

    //  Intended use: inform user in case of stuck track.


  //

  // END State information

  //


  // Save key state information (NOT the navigation history stack)

  //

  struct G4SaveNavigatorState

  {

     G4ThreeVector sExitNormal;

     G4bool sValidExitNormal;

     G4bool sEntering, sExiting;

     G4VPhysicalVolume* spBlockedPhysicalVolume;

     G4int sBlockedReplicaNo;

     G4int sLastStepWasZero;

     G4bool sWasLimitedByGeometry;


     //  Potentially relevant

     //

     G4bool sLocatedOutsideWorld;

     G4ThreeVector sLastLocatedPointLocal;

     G4bool sEnteredDaughter, sExitedMother;

     G4ThreeVector sPreviousSftOrigin;

     G4double sPreviousSafety;

  } fSaveState;


  // Tracking Invariants

  //

  G4VPhysicalVolume* fTopPhysical = nullptr;

    // A link to the topmost physical volume in the detector.

    // Must be positioned at the origin and unrotated.


  // Utility information

  //

  G4bool fCheck = false;

    // Check-mode flag  [if true, more strict checks are performed].

  G4bool fPushed = false, fWarnPush = true;

    // Push flags  [if true, means a stuck particle has been pushed].


  // Helpers/Utility classes

  //

  G4NormalNavigation fnormalNav;

  G4VoxelNavigation fvoxelNav;

  G4ParameterisedNavigation fparamNav;

  G4ReplicaNavigation freplicaNav;

  G4RegularNavigation fregularNav;

  G4VExternalNavigation* fpExternalNav = nullptr;

  G4VoxelSafety* fpVoxelSafety;

};


#include "G4Navigator.icc"


#endif


// NOTES:

//

// The following methods provide detailed information when a Step has

// arrived at a geometrical boundary.  They distinguish between the different

// causes that can result in the track leaving its current volume.

//

// Four cases are possible:

//

// 1) The particle has reached a boundary of a daughter of the current volume:

//     (this could cause the relocation to enter the daughter itself

//     or a potential granddaughter or further descendant)

//

// 2) The particle has reached a boundary of the current

//     volume, exiting into a mother (regardless the level

//     at which it is located in the tree):

//

// 3) The particle has reached a boundary of the current

//     volume, exiting into a volume which is not in its

//     parental hierarchy:

//

// 4) The particle is not on a boundary between volumes:

//     the function returns an exception, and the caller is

//     reccomended to compare the G4touchables associated

//     to the preStepPoint and postStepPoint to handle this case.

//

//   G4bool        EnteredDaughterVolume()

//   G4bool        IsExitNormalValid()

//   G4ThreeVector GetLocalExitNormal()

//

// The expected usefulness of these methods is to allow the caller to

// determine how to compute the surface normal at the volume boundary. The two

// possibilities are to obtain the normal from:

//

//   i) the solid associated with the volume of the initial point of the Step.

//      This is valid for cases 2 and 3.

//      (Note that the initial point is generally the PreStepPoint of a Step).

//   or

//

//  ii) the solid of the final point, ie of the volume after the relocation.

//      This is valid for case 1.

//      (Note that the final point is generally the PreStepPoint of a Step).

//

// This way the caller can always get a valid normal, pointing outside

// the solid for which it is computed, that can be used at his own

// discretion.