add early tracking exit in G4HepEmTrackingManager

CMakeLists.txt

@@ -4,6 +4,13 @@
 cmake_minimum_required(VERSION 3.17...3.18 FATAL_ERROR)
 project(G4HepEm VERSION 0.1.0)
 
+#----------------------------------------------------------------------------
+# Option for enabling early exit
+option(G4HepEm_EARLY_TRACKING_EXIT "Enable user-defined early tracking exit" OFF)
+if(G4HepEm_EARLY_TRACKING_EXIT)
+  message(STATUS "User-defined early tracking exit is enabled")
+endif()
+
 # Local and Core Modules
 include(GNUInstallDirs)
 include(CheckLanguage)
@@ -30,6 +37,10 @@ function(g4hepem_add_library _name)
       $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
       $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/${PROJECT_NAME}>)
     target_link_libraries(${_name} PUBLIC ${_g4hepem_LINK})
+
+    if(G4HepEm_EARLY_TRACKING_EXIT)
+      target_compile_definitions(${_name} PUBLIC G4HepEm_EARLY_TRACKING_EXIT)
+    endif()
   endif()
 
   # Build static library, if enabled.
@@ -46,6 +57,10 @@ function(g4hepem_add_library _name)
       target_link_libraries(${_name}-static PUBLIC ${_lib}-static)
     endforeach()
 
+    if(G4HepEm_EARLY_TRACKING_EXIT)
+      target_compile_definitions(${_name}-static PUBLIC G4HepEm_EARLY_TRACKING_EXIT)
+    endif()
+
     # If only the static library, add alias targets for convenience.
     if(NOT BUILD_SHARED_LIBS)
       add_library(${_name} ALIAS ${_name}-static)

G4HepEm/G4HepEm/include/G4HepEmTrackingManager.hh

@@ -1,7 +1,9 @@
 #ifndef G4HepEmTrackingManager_h
 #define G4HepEmTrackingManager_h 1
 
+#include "G4EventManager.hh"
 #include "G4VTrackingManager.hh"
+
 #include "globals.hh"
 
 class G4HepEmRunManager;
@@ -22,13 +24,13 @@ class G4HepEmWoodcockHelper;
 class G4HepEmTrackingManager : public G4VTrackingManager {
 public:
   G4HepEmTrackingManager();
-  ~G4HepEmTrackingManager();
+  virtual ~G4HepEmTrackingManager();
 
   void BuildPhysicsTable(const G4ParticleDefinition &) override;
 
   void PreparePhysicsTable(const G4ParticleDefinition &) override;
 
-  void HandOverOneTrack(G4Track *aTrack) override;
+  virtual void HandOverOneTrack(G4Track *aTrack) override;
 
   void SetMultipleSteps(G4bool val) {
     fMultipleSteps = val;
@@ -47,11 +49,15 @@ public:
     fWDTRegionNames.push_back(regionName);
   }
 
+protected:
+  bool TrackElectron(G4Track *aTrack);
+  bool TrackGamma(G4Track *aTrack);
 
-private:
-  void TrackElectron(G4Track *aTrack);
-  void TrackGamma(G4Track *aTrack);
+  // Pointers to the fast simulation manager processes of the 3 particles if any
+  // [0] e-; [1] e+; [2] gamma; nullptr: no fast sim manager process attached
+  G4VProcess *fFastSimProcess[3];
 
+private:
   // Stacks secondaries created by HepEm physics (if any) and returns with the
   // energy deposit while stacking due to applying secondary production cuts
   double StackSecondaries(G4HepEmTLData* aTLData, G4Track* aG4PrimaryTrack,
@@ -77,6 +83,18 @@ private:
   //       no harm outside Athena.
   void InitXTRRelated();
 
+#ifdef G4HepEm_EARLY_TRACKING_EXIT
+  // Virtual function to check early tracking exit. This function allows user
+  // implementations to intercept the G4HepEm tracking loop based on
+  // user-defined conditions, e.g., when entering a GPU region To be implemented
+  // in derived classes by users, base implementation does nothing and returns
+  // false
+  virtual bool CheckEarlyTrackingExit(G4Track *track, G4EventManager *evtMgr,
+                                      G4UserTrackingAction *userTrackingAction,
+                                      G4TrackVector &secondaries) const {
+    return false;
+  }
+#endif
 
   G4HepEmRunManager *fRunManager;
   G4HepEmRandomEngine *fRandomEngine;
@@ -103,11 +121,6 @@ private:
   G4VProcess* fENucProcess;
   G4VProcess* fPNucProcess;
 
-
-  // Pointers to the fast simulation manager processes of the 3 particles if any
-  // [0] e-; [1] e+; [2] gamma; nullptr: no fast sim manager process attached
-  G4VProcess* fFastSimProcess[3];
-
   // ATLAS XTR RELATED:
   // Fields to store ptrs to the ATLAS XTR (transition radiation) process and
   // detector region that contain the tradiator volumes

G4HepEm/G4HepEm/src/G4HepEmTrackingManager.cc

@@ -192,7 +192,7 @@ void G4HepEmTrackingManager::PreparePhysicsTable(
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
-void G4HepEmTrackingManager::TrackElectron(G4Track *aTrack) {
+bool G4HepEmTrackingManager::TrackElectron(G4Track *aTrack) {
   TrackingManagerHelper::ChargedNavigation navigation;
 
   // Prepare for calling the user action.
@@ -307,6 +307,13 @@ void G4HepEmTrackingManager::TrackElectron(G4Track *aTrack) {
 
   while(aTrack->GetTrackStatus() == fAlive)
   {
+#ifdef G4HepEm_EARLY_TRACKING_EXIT
+    // check for user-defined early exit
+    if (CheckEarlyTrackingExit(aTrack, evtMgr, userTrackingAction, secondaries)) {
+      return false; 
+    }
+#endif
+
     // Beginning of this step: Prepare data structures.
     aTrack->IncrementCurrentStepNumber();
 
@@ -734,11 +741,12 @@ void G4HepEmTrackingManager::TrackElectron(G4Track *aTrack) {
   }
 
   evtMgr->StackTracks(&secondaries);
+  return true;
 }
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
-void G4HepEmTrackingManager::TrackGamma(G4Track *aTrack) {
+bool G4HepEmTrackingManager::TrackGamma(G4Track *aTrack) {
   TrackingManagerHelper::NeutralNavigation navigation;
 
   // Prepare for calling the user action.
@@ -848,6 +856,12 @@ void G4HepEmTrackingManager::TrackGamma(G4Track *aTrack) {
   // === StartTracking ===
 
   while (aTrack->GetTrackStatus() == fAlive) {
+#ifdef G4HepEm_EARLY_TRACKING_EXIT
+    // check for user-defined early exit
+    if (CheckEarlyTrackingExit(aTrack, evtMgr, userTrackingAction, secondaries)) {
+      return false; 
+    }
+#endif
 
     // Beginning of this step: Prepare data structures.
     aTrack->IncrementCurrentStepNumber();
@@ -1144,6 +1158,7 @@ void G4HepEmTrackingManager::TrackGamma(G4Track *aTrack) {
   }
 
   evtMgr->StackTracks(&secondaries);
+  return true;
 }
 
 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......