G4AtlasUserWorkerInitialization.h

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef G4ATLASALG_G4ATLASUSERWORKERINITIALIZATION_H
#define G4ATLASALG_G4ATLASUSERWORKERINITIALIZATION_H
 
#include <G4FastSimulationManagerProcess.hh>
#include <G4ParticleDefinition.hh>
#include <G4ParticleTable.hh>
#include <G4ProcessManager.hh>
#include <G4UserWorkerInitialization.hh>
 
class G4AtlasUserWorkerInitialization : public G4UserWorkerInitialization {
public:
  struct Config {
    bool m_activateFastSimulation{false}; 
  };
 
  explicit G4AtlasUserWorkerInitialization(const Config& config)
      : G4UserWorkerInitialization(), m_config(config) {}
 
  void WorkerRunStart() const override
  {
    if(!m_config.m_activateFastSimulation)
      return;
    // Enable fast simulation processes for all particle types
    // Initialized here because it needs to happen after Geant4 physics initialization to access the particle table
    G4FastSimulationManagerProcess* fastSimManagerProcess = new G4FastSimulationManagerProcess;
    G4ParticleTable* theParticleTable = G4ParticleTable::GetParticleTable();
    G4ParticleTable::G4PTblDicIterator* theParticleIterator = theParticleTable->GetIterator();
 
    theParticleIterator->reset();
    while( (*theParticleIterator)() ){
      G4ParticleDefinition* particle = theParticleIterator->value();
      G4ProcessManager* pmanager = particle->GetProcessManager();
      pmanager->AddProcess(fastSimManagerProcess, -1, 1, 1);
    }
  }
 
private:
  Config m_config;
};
#endif