Geant4 StackingAction

Documentation

• http://geant4.web.cern.ch/geant4/G4UsersDocuments/UsersGuides/ForApplicationDeveloper/html/UserActions/OptionalActions.html

G4UserStackingAction

source/event/include/G4UserStackingAction.hh:

44 class G4UserStackingAction
45 {
46   public:
47       G4UserStackingAction();
48       virtual ~G4UserStackingAction();
49   protected:
50       G4StackManager * stackManager;
51   public:
52       inline void SetStackManager(G4StackManager * value)
53       { stackManager = value; }
54
55   public: // with description
56 //---------------------------------------------------------------
57 // vitual methods to be implemented by user
58 //---------------------------------------------------------------
59 //
60       virtual G4ClassificationOfNewTrack
61         ClassifyNewTrack(const G4Track* aTrack);

Documentation Extracts

• http://geant4.web.cern.ch/geant4/G4UsersDocuments/UsersGuides/ForApplicationDeveloper/html/UserActions/OptionalActions.html

ClassifyNewTrack

ClassifyNewTrack() is invoked by G4StackManager whenever a new G4Track object is “pushed” onto a stack by G4EventManager. ClassifyNewTrack() returns an enumerator, G4ClassificationOfNewTrack, whose value indicates to which stack, if any, the track will be sent. This value should be determined by the user. G4ClassificationOfNewTrack has four possible values:

1. fUrgent - track is placed in the urgent stack
2. fWaiting - track is placed in the waiting stack, and will not be simulated until the urgent stack is empty
3. fPostpone - track is postponed to the next event
4. fKill - the track is deleted immediately and not stored in any stack.

These assignments may be made based on the origin of the track which is obtained as follows: G4int parent_ID = aTrack->get_parentID(); where

1. parent_ID = 0 indicates a primary particle
2. parent_ID > 0 indicates a secondary particle
3. parent_ID < 0 indicates postponed particle from previous event.

• always returning fUrgent would result in stepping proceeding for tracks as they arise, ie with OP mixed up with everything else

NewStage : deal with the wait stack

NewStage() is invoked when the urgent stack is empty and the waiting stack contains at least one G4Track object. Here the user may kill or re-assign to different stacks all the tracks in the waiting stack by calling the stackManager->ReClassify() method which, in turn, calls the ClassifyNewTrack() method.

If no user action is taken, all tracks in the waiting stack are transferred to the urgent stack.

• HMM: so can see how long the Optical Photons are taking could first collect them into the wait stack and then “do nothing” at NewStage

The user may also decide to abort the current event even though some tracks may remain in the waiting stack by calling stackManager->clear(). This method is valid and safe only if it is called from the G4UserStackingAction class.

A global method of event abortion is:

G4UImanager * UImanager = G4UImanager::GetUIpointer();
UImanager->ApplyCommand("/event/abort");

PrepareNewEvent

PrepareNewEvent() is invoked at the beginning of each event. At this point no primary particles have been converted to tracks, so the urgent and waiting stacks are empty. However, there may be tracks in the postponed-to-next-event stack; for each of these the ClassifyNewTrack() method is called and the track is assigned to the appropriate stack.

StackingAction Source

delta:geant4.10.00.p01 blyth$ find source -name '*.cc' -exec grep -l StackingAction {} \;

source/run/src/G4RunManager.cc                         #  just holds userStackingAction property
source/event/src/G4EventManager.cc                     #  just holds userStackingAction property also
source/event/src/G4StackManager.cc                     #  invokes the action and acts on classification in G4StackManager::PushOneTrack

source/event/src/G4AdjointStackingAction.cc
source/event/src/G4UserStackingAction.cc               # default empty-ish implementation

source/run/src/G4AdjointSimManager.cc
source/run/src/G4MaterialScanner.cc
source/run/src/G4MTRunManager.cc
source/run/src/G4VUserActionInitialization.cc
source/run/src/G4WorkerRunManager.cc

source/visualization/RayTracer/src/G4RTWorkerInitialization.cc
source/visualization/RayTracer/src/G4TheRayTracer.cc

813 void G4RunManager::SetUserAction(G4UserStackingAction* userAction)
814 {
815   eventManager->SetUserAction(userAction);
816   userStackingAction = userAction;
817 }

315 void G4EventManager::SetUserAction(G4UserStackingAction* userAction)
316 {
317   userStackingAction = userAction;
318   trackContainer->SetUserStackingAction(userAction);        ## trackContainer is G4StackManager
319 }

57 G4ClassificationOfNewTrack G4UserStackingAction::ClassifyNewTrack
58 (const G4Track*)
59 {
60   return fUrgent;
61 }
62
63 void G4UserStackingAction::NewStage()
64 {;}
65
66 void G4UserStackingAction::PrepareNewEvent()
67 {;}
68

StackingAction examples

delta:geant4.10.00.p01 blyth$ find examples -name '*.cc' -exec grep -l ClassifyNewTrack {} \;
examples/advanced/composite_calorimeter/src/CCalStackingAction.cc
examples/advanced/underground_physics/src/DMXStackingAction.cc
examples/basic/B3/src/B3StackingAction.cc
examples/extended/electromagnetic/TestEm1/src/StackingAction.cc
examples/extended/electromagnetic/TestEm17/src/StackingAction.cc
examples/extended/electromagnetic/TestEm18/src/StackingAction.cc
examples/extended/electromagnetic/TestEm5/src/StackingAction.cc
examples/extended/electromagnetic/TestEm6/src/StackingAction.cc
examples/extended/electromagnetic/TestEm8/src/StackingAction.cc
examples/extended/eventgenerator/HepMC/HepMCEx01/src/ExN04StackingAction.cc
examples/extended/exoticphysics/phonon/src/XPhononStackingAction.cc
examples/extended/exoticphysics/phonon/src/XPrimaryGeneratorAction.cc
examples/extended/field/field04/src/F04StackingAction.cc
examples/extended/hadronic/Hadr01/src/StackingAction.cc
examples/extended/hadronic/Hadr02/src/StackingAction.cc
examples/extended/hadronic/Hadr04/src/StackingAction.cc
examples/extended/medical/fanoCavity/src/StackingAction.cc
examples/extended/optical/LXe/src/LXeStackingAction.cc
examples/extended/optical/OpNovice/src/OpNoviceStackingAction.cc
examples/extended/optical/wls/src/WLSStackingAction.cc
examples/extended/parallel/TopC/ParN04/src/ExN04StackingAction.cc
examples/extended/runAndEvent/RE01/src/RE01StackingAction.cc
examples/extended/runAndEvent/RE05/src/RE05StackingAction.cc
delta:geant4.10.00.p01 blyth$