Advanced features Advanced features Makoto Asai (SLAC Computing - PowerPoint PPT Presentation

Advanced features Advanced features Makoto Asai (SLAC Computing Services) Makoto Asai (SLAC Computing Services) Geant4 Tutorial Course @ Fermi Lab Geant4 Tutorial Course @ Fermi Lab th , 2003 October 29 th October 29 , 2003

Contents Contents � More on user action classes More on user action classes � more difficult User- -defined trajectory defined trajectory User � � most difficult Suspend, postpone or kill a track Suspend, postpone or kill a track � � Stack management expert only Stack management � � Cuts per region Cuts per region � � Event biasing Event biasing � � Defining a new shape Defining a new shape � � Parameterization (fast simulation) and ghost volume Parameterization (fast simulation) and ghost volume � � Making a new physics process Making a new physics process � � � Some remarks on external functionalities Some remarks on external functionalities � � Persistency Persistency � � Parallelization and integration in a distributed computing Parallelization and integration in a distributed computing � environment environment Advanced features - - M.Asai (SLAC) M.Asai (SLAC) - - Oct. 29, 2003 @ Fermi Lab Oct. 29, 2003 @ Fermi Lab 2 Advanced features 2

More on user action classes - - 1 1 More on user action classes User- -defined trajectory defined trajectory User and and Attaching user information to Attaching user information to some kernel classes some kernel classes

Attaching user information Attaching user information � Abstract classes Abstract classes � � User can use his/her own class derived from the provided base cl User can use his/her own class derived from the provided base class ass � � G4Run, G4VHit, G4VDigit, G4VTrajectory, G4VTrajectoryPoint G4Run, G4VHit, G4VDigit, G4VTrajectory, G4VTrajectoryPoint � � Concrete classes Concrete classes � � User can attach a user information class object User can attach a user information class object � � G4Event G4Event - - G4VUserEventInformation G4VUserEventInformation � � G4Track G4Track - - G4VUserTrackInformation G4VUserTrackInformation � � G4PrimaryVertex G4PrimaryVertex - - G4VUserPrimaryVertexInformation G4VUserPrimaryVertexInformation � � G4PrimaryParticle G4PrimaryParticle - - G4VUserPrimaryParticleInformation G4VUserPrimaryParticleInformation � � G4Region G4Region - - G4VUserRegionInformation G4VUserRegionInformation � � Classes in Classes in green green are coming with Geant4 version 6.0. are coming with Geant4 version 6.0. � � User information class object is deleted when associated Geant4 User information class object is deleted when associated Geant4 � class object is deleted. class object is deleted. Advanced features - - M.Asai (SLAC) M.Asai (SLAC) - - Oct. 29, 2003 @ Fermi Lab Oct. 29, 2003 @ Fermi Lab 4 Advanced features 4

Trajectory and trajectory point Trajectory and trajectory point � Trajectory and trajectory point class objects persist until the Trajectory and trajectory point class objects persist until the end of an end of an � event. event. � And most likely stored to disk as "simulation truth" And most likely stored to disk as "simulation truth" � � G4VTrajectory G4VTrajectory is the abstract base class to represent a trajectory, and is the abstract base class to represent a trajectory, and � G4VTrajectoryPoint is the abstract base class to represent a point which G4VTrajectoryPoint is the abstract base class to represent a point which makes up the trajectory. makes up the trajectory. � In general, trajectory class is expected to have a vector of tra In general, trajectory class is expected to have a vector of trajectory jectory � points. points. � Geant4 provides Geant4 provides G4Trajectoy G4Trajectoy and and G4TrajectoryPoint G4TrajectoryPoint concrete classes concrete classes � as defaults. as defaults. � If the user wants to keep some additional information and/or wan If the user wants to keep some additional information and/or wants to ts to � change the drawing style of a trajectory, he/she is encouraged to o change the drawing style of a trajectory, he/she is encouraged t implement his/her own concrete classes. implement his/her own concrete classes. � Such user Such user- -defined trajectory object should be instantiated in defined trajectory object should be instantiated in � () in user tracking action and set to in user tracking action and set to PreUserTrackingAction() PreUserTrackingAction G4TrackingManager G4TrackingManager Advanced features - - M.Asai (SLAC) M.Asai (SLAC) - - Oct. 29, 2003 @ Fermi Lab Oct. 29, 2003 @ Fermi Lab 5 Advanced features 5

More on user action classes - - 2 2 More on user action classes Suspend, postpone or kill a track Suspend, postpone or kill a track

G4TrackStatus G4TrackStatus � enum enum G4TrackStatus G4TrackStatus � � fAlive fAlive � � Continue tracking Continue tracking � � fStopButAlive fStopButAlive � � Invoke active rest physics processes and kill the current track Invoke active rest physics processes and kill the current track � afterward afterward � fStopAndKill fStopAndKill � � Kill the current track Kill the current track � � Secondaries Secondaries are still alive are still alive � � fKillTrackAndSecondaries fKillTrackAndSecondaries � � Kill the current track and also associated Kill the current track and also associated secondaries secondaries. . � � fSuspend fSuspend � � Suspend the current track and send it back to the stack. Suspend the current track and send it back to the stack. � � Associated Associated secondaries secondaries are also sent to the stack. Given a stack are also sent to the stack. Given a stack � is "last- is "last -in in- -first first- -out", out", secondaries secondaries are tracked preceded to the are tracked preceded to the suspended track. suspended track. � fPostponeToNextEvent fPostponeToNextEvent � � Postpone the tracking of the current track to the next event. Postpone the tracking of the current track to the next event. � � Associated Associated secondaries secondaries are sent to the stack are sent to the stack � Advanced features - - M.Asai (SLAC) M.Asai (SLAC) - - Oct. 29, 2003 @ Fermi Lab Oct. 29, 2003 @ Fermi Lab 7 Advanced features 7

Set the track status Set the track status � In In UserSteppingAction UserSteppingAction, user can change the status of a track. , user can change the status of a track. � void MySteppingAction::UserSteppingAction MySteppingAction::UserSteppingAction void (const G4Step * theStep theStep) ) (const G4Step * { { G4Track* theTrack theTrack = = theStep theStep- -> >GetTrack GetTrack(); (); G4Track* if(…) theTrack theTrack- -> >SetTrackStatus SetTrackStatus(fSuspend (fSuspend); ); if(…) } } � If a track is killed, physics quantities of the track (energy, c If a track is killed, physics quantities of the track (energy, charge, etc.) harge, etc.) � are not conserved but completely lost. are not conserved but completely lost. Advanced features - - M.Asai (SLAC) M.Asai (SLAC) - - Oct. 29, 2003 @ Fermi Lab Oct. 29, 2003 @ Fermi Lab 8 Advanced features 8

More on user action classes - - 3 3 More on user action classes Stack management Stack management