G4BlineTracer.cc

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/// \file field/BlineTracer/src/G4BlineTracer.cc
/// \brief Implementation of the G4BlineTracer class
//
//
//
//
// --------------------------------------------------------------------
//
// G4BlineTracer implementation
//
// --------------------------------------------------------------------
// Author: Laurent Desorgher (desorgher@phim.unibe.ch)
//         Created - 2003-10-06
// --------------------------------------------------------------------
 
#include "G4BlineTracer.hh"
#include "G4BlineTracerMessenger.hh"
#include "G4BlinePrimaryGeneratorAction.hh"
#include "G4BlineEventAction.hh"
#include "G4BlineSteppingAction.hh"
#include "G4BlineEquation.hh"
 
#include "G4RunManager.hh"
#include "G4TransportationManager.hh"
#include "G4FieldManager.hh"
#include "G4PropagatorInField.hh"
#include "G4MagIntegratorDriver.hh"
#include "G4CashKarpRKF45.hh"
#include "G4LogicalVolumeStore.hh"
#include "G4ChordFinder.hh"
#include "G4SystemOfUnits.hh"
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4BlineTracer::G4BlineTracer()
{
  fMessenger = new G4BlineTracerMessenger(this);
  fSteppingAction = new G4BlineSteppingAction(this) ;
  fEventAction = new G4BlineEventAction(this);
  fPrimaryGeneratorAction = new G4BlinePrimaryGeneratorAction();
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4BlineTracer::~G4BlineTracer()
{
  delete fMessenger;
  delete fSteppingAction;
  delete fEventAction;
  delete fPrimaryGeneratorAction;
  for (size_t i=0; i< fVecEquationOfMotion.size();i++)
  {
    if (fVecEquationOfMotion[i]) delete fVecEquationOfMotion[i];
    if (fVecChordFinders[i]) delete fVecChordFinders[i];
  }
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4BlineTracer::BeginOfRunAction(const G4Run*)
{
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4BlineTracer::EndOfRunAction(const G4Run*)
{
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4BlineTracer::ComputeBlines(G4int n_of_lines)
{
  //the first time ResetChordFinders should be called
  //
  if (!fWas_ResetChordFinders_already_called)
  {
    ResetChordFinders();
    fWas_ResetChordFinders_already_called=true;
  }
 
  // Replace the user action by the ad-hoc actions for Blines
 
  G4RunManager* theRunManager =  G4RunManager::GetRunManager();
  auto  user_run_action =
    (G4UserRunAction*)theRunManager->GetUserRunAction();
  theRunManager->SetUserAction(this);
 
  auto  user_stepping_action =
    (G4UserSteppingAction*)theRunManager->GetUserSteppingAction();
  theRunManager->SetUserAction(fSteppingAction);
 
  auto  userPrimaryAction =
    (G4VUserPrimaryGeneratorAction*)theRunManager->GetUserPrimaryGeneratorAction();
  if (userPrimaryAction)
    fPrimaryGeneratorAction->SetUserPrimaryAction(userPrimaryAction);
  theRunManager->SetUserAction(fPrimaryGeneratorAction);
 
  auto  user_event_action =
    (G4UserEventAction*)theRunManager->GetUserEventAction();
  theRunManager->SetUserAction(fEventAction);
 
  auto  user_tracking_action =
    (G4UserTrackingAction*)theRunManager->GetUserTrackingAction();
  G4UserTrackingAction* aNullTrackingAction = nullptr;
  theRunManager->SetUserAction(aNullTrackingAction);
 
  auto  user_stacking_action =
    (G4UserStackingAction*)theRunManager->GetUserStackingAction();
  G4UserStackingAction* aNullStackingAction = nullptr;
  theRunManager->SetUserAction(aNullStackingAction);
 
  // replace the user defined chordfinder by the element of fVecChordFinders
 
  std::vector<G4ChordFinder*> user_chord_finders;
  std::vector<G4double> user_largest_acceptable_step;
  for (size_t i=0;i<fVecChordFinders.size();i++)
  {
    user_largest_acceptable_step.push_back(-1.);
    if (fVecChordFinders[i])
    {
      user_chord_finders.push_back(fVecFieldManagers[i]->GetChordFinder());
      fVecChordFinders[i]->SetDeltaChord(user_chord_finders[i]->GetDeltaChord());
      fVecFieldManagers[i]->SetChordFinder(fVecChordFinders[i]);
    }
    else user_chord_finders.push_back(nullptr);
  }
 
  // I have tried to use the smooth line filter ability but I could not obtain
  // a smooth trajectory in the G4TrajectoryContainer after an event
  // Another solution for obtaining a smooth trajectory is to limit
  // the LargestAcceptableStep in the G4PropagatorInField object.
  // This is the solution I used.
 
  // Old solution:
  // G4TransportationManager::GetTransportationManager()
  //     ->GetPropagatorInField()->SetTrajectoryFilter(fTrajectoryFilter);
 
  // New solution:
  // set the largest_acceptable_step to max_step:length
 
  G4TransportationManager* tmanager =
    G4TransportationManager::GetTransportationManager();
  G4double previous_largest_acceptable_step =
    tmanager->GetPropagatorInField()->GetLargestAcceptableStep();
 
  tmanager->GetPropagatorInField()
          ->SetLargestAcceptableStep(fMaxTrackingStep);
 
  // Start the integration of n_of_lines different magnetic field lines
 
  for (G4int il=0; il<n_of_lines;il++)
  {
    // for each magnetic field line we integrate once backward and once
    // forward from the same starting point
 
    // backward integration
 
    for (size_t i=0; i< fVecEquationOfMotion.size();i++)
    {
      if (fVecEquationOfMotion[i])
        fVecEquationOfMotion[i]->SetBackwardDirectionOfIntegration(true);
    }
    theRunManager->BeamOn(1);
 
    // forward integration
 
    for (size_t i=0; i < fVecEquationOfMotion.size();i++)
    {
      if (fVecEquationOfMotion[i])
        fVecEquationOfMotion[i]->SetBackwardDirectionOfIntegration(false);
    }
    theRunManager->BeamOn(1);
  }
 
  // Remove trajectory filter to PropagatorInField
  // It was for old solution when using smooth trajectory filter
 
  // tmanager->GetPropagatorInField()->SetTrajectoryFilter(0);
 
  // back to User defined actions and other parameters
  // -------------------------------------------------
 
  tmanager->GetPropagatorInField()
          ->SetLargestAcceptableStep(previous_largest_acceptable_step);
 
  // return to User actions
 
  theRunManager->SetUserAction(user_run_action);
  theRunManager->SetUserAction(user_event_action);
  theRunManager->SetUserAction(userPrimaryAction);
  theRunManager->SetUserAction(user_stepping_action);
  theRunManager->SetUserAction(user_tracking_action);
  theRunManager->SetUserAction(user_stacking_action);
 
  // set user defined chord finders and largest acceptable step
 
  for (size_t i=0;i<fVecFieldManagers.size();i++)
  {
    if (user_chord_finders[i])
      fVecFieldManagers[i]->SetChordFinder(user_chord_finders[i]);
  }
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
////////////////////////////////////////////////////////////////
 
/*
G4bool G4BlineTracer::CheckMagneticFields()
{
  // Check FieldManagers
 
  G4TransportationManager* tmanager =
    G4TransportationManager::GetTransportationManager();
 
  if (fVecFieldManagers[0] != tmanager->GetFieldManager())
    return false;
  if (fVecMagneticFields[0] != tmanager->GetFieldManager()->GetDetectorField())
    return false;
  G4LogicalVolumeStore* theVolumeStore = G4LogicalVolumeStore::GetInstance();
 
  std::vector<G4FieldManagers*> LogicalVolumeFields;
  size_t j=0;
  for (size_t i=0; i<theVolumeStore.size();i++)
  {
    if (theVolumeStore[i]->GetFieldManager())
    {
      j++;
      if (j >= fVecFieldManagers.size()) return false;
      if (fVecFieldManagers[j] != theVolumeStore[i]->GetFieldManager())
        return false;
      if (fVecMagneticFields[j] !=
          theVolumeStore[i]->GetFieldManager()->GetDetectorField())
        return false;
    }
  }
  if (j<fVecFieldManagers.size()) return false;
 
 return true;
}
*/
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4BlineTracer::ResetChordFinders()
{
  for (size_t i=0; i<fVecEquationOfMotion.size();i++)
  {
    delete fVecEquationOfMotion[i];
    delete fVecChordFinders[i];
  }
 
  fVecChordFinders.clear();
  fVecFieldManagers.clear();
  fVecMagneticFields.clear();
  fVecEquationOfMotion.clear();
 
  // global field
 
  fVecChordFinders.push_back(nullptr);
  fVecMagneticFields.push_back(nullptr);
  fVecEquationOfMotion.push_back(nullptr);
  fVecFieldManagers.push_back(G4TransportationManager::GetTransportationManager()
                             ->GetFieldManager());
  if (fVecFieldManagers[0])
  {
    fVecMagneticFields[0] =
      (G4MagneticField*) fVecFieldManagers[0]->GetDetectorField();
    if (fVecMagneticFields[0])
    {
      fVecEquationOfMotion[0] = new G4BlineEquation(fVecMagneticFields[0]);
      auto  pStepper = new G4CashKarpRKF45(fVecEquationOfMotion[0]);
      auto  pIntgrDriver =
        new G4MagInt_Driver(0.01*mm,pStepper,pStepper->GetNumberOfVariables());
      fVecChordFinders[0] = new G4ChordFinder(pIntgrDriver);
    }
  }
 
  // local fields
 
  G4LogicalVolumeStore* theVolumeStore = G4LogicalVolumeStore::GetInstance();
 
  size_t j=0;
  for (size_t i=0; i<theVolumeStore->size();i++)
  {
    if ((*theVolumeStore)[i]->GetFieldManager())
    {
      j++;
      fVecFieldManagers.push_back(((*theVolumeStore)[i])->GetFieldManager());
      fVecMagneticFields.push_back((G4MagneticField*)
                                   fVecFieldManagers[j]->GetDetectorField());
      fVecEquationOfMotion.push_back(nullptr);
      fVecChordFinders.push_back(nullptr);
      if (fVecMagneticFields[j])
      {
        fVecEquationOfMotion[j]= new G4BlineEquation(fVecMagneticFields[j]);
        auto  pStepper = new G4CashKarpRKF45(fVecEquationOfMotion[j]);
        auto  pIntgrDriver =
          new G4MagInt_Driver(.01*mm,pStepper,pStepper->GetNumberOfVariables());
        fVecChordFinders[j] = new G4ChordFinder(pIntgrDriver);
      }
    }
  }
}