RMGWorkerInitialization.hh

// Copyright (C) 2022 Luigi Pertoldi <https://orcid.org/0000-0002-0467-2571>
//
// This program is free software: you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option) any
// later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
// details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
#ifndef _RMG_WORKER_INITIALIZATION_HH_
#define _RMG_WORKER_INITIALIZATION_HH_
 
#include <type_traits>
 
#include "G4AutoLock.hh"
#include "G4StateManager.hh"
#include "G4UserTaskThreadInitialization.hh"
#include "Randomize.hh"
 
#include "RMGExceptionHandler.hh"
#include "RMGManager.hh"

namespace {
  G4Mutex RMGWorkerInitializationRNGMutex = G4MUTEX_INITIALIZER;
} // namespace

template<typename ThreadInitialization>
class RMGWorkerInitialization : public ThreadInitialization {
    static_assert(std::is_base_of_v<G4UserWorkerThreadInitialization, ThreadInitialization>);
 
  public:
 
    RMGWorkerInitialization() = default;
    ~RMGWorkerInitialization() = default;

    void SetupRNGEngine(const CLHEP::HepRandomEngine* aRNGEngine) const override {
      // Install our exception handler on this worker thread, mirroring the master-thread setup.
      // G4StateManager is thread-local in MT mode.
      if (G4StateManager::GetStateManager()->GetExceptionHandler() == nullptr) {
        G4StateManager::GetStateManager()->SetExceptionHandler(new RMGExceptionHandler());
      }
 
      G4AutoLock l(&RMGWorkerInitializationRNGMutex);
 
      auto rmg_man = RMGManager::Instance();
      // Implement custom logic if the user had chosen a random engine, otherwise apply Geant4's
      // default strategy.
      if (rmg_man->GetRandEngineSelected()) rmg_man->ApplyRandEngineForCurrentThread();
      else ThreadInitialization::SetupRNGEngine(aRNGEngine);
    }
};
 
#endif
 
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