G4BOptrForceCollision.cc

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#include "G4BOptrForceCollision.hh"
#include "G4BiasingProcessInterface.hh"

#include "G4BOptnForceCommonTruncatedExp.hh"
#include "G4ILawCommonTruncatedExp.hh"
#include "G4BOptnForceFreeFlight.hh"
#include "G4BOptnCloning.hh"

#include "G4Step.hh"
#include "G4StepPoint.hh"
#include "G4VProcess.hh"

#include "G4ParticleDefinition.hh"
#include "G4ParticleTable.hh"

#include "G4SystemOfUnits.hh"


G4BOptrForceCollision::G4BOptrForceCollision(G4String particleName, G4String name)
  : G4VBiasingOperator(name),
    fSetup(true)
{
  fSharedForceInteractionOperation = new G4BOptnForceCommonTruncatedExp("SharedForceInteraction");
  fCloningOperation                = new G4BOptnCloning("Cloning");
  fParticleToBias = G4ParticleTable::GetParticleTable()->FindParticle(particleName);
  
  if ( fParticleToBias == 0 )
    {
      G4ExceptionDescription ed;
      ed << " Particle `" << particleName << "' not found !" << G4endl;
      G4Exception(" G4BOptrForceCollision::G4BOptrForceCollision(...)",
                  "BIAS.GEN.07",
                  JustWarning,
                  ed);
    }
}


G4BOptrForceCollision::G4BOptrForceCollision(const G4ParticleDefinition* particle, G4String name)
  : G4VBiasingOperator(name),
    fSetup(true)
{
  fSharedForceInteractionOperation = new G4BOptnForceCommonTruncatedExp("SharedForceInteraction");
  fCloningOperation                = new G4BOptnCloning("Cloning");
  fParticleToBias                  = particle;
}


G4BOptrForceCollision::~G4BOptrForceCollision()
{
  for ( std::map< const G4BiasingProcessInterface*, G4BOptnForceFreeFlight* >::iterator it = fFreeFlightOperations.begin() ;
        it != fFreeFlightOperations.end() ;
        it++ ) delete (*it).second;
  delete fSharedForceInteractionOperation;
  delete fCloningOperation;
}


void G4BOptrForceCollision::StartRun()
{
  // -- start by remembering processes under biasing, and create needed biasing operations:
  if ( fSetup )
    {
      const G4ProcessManager* processManager = fParticleToBias->GetProcessManager();
      const G4BiasingProcessSharedData* sharedData =
        G4BiasingProcessInterface::GetSharedData( processManager );
      if (sharedData ) // -- sharedData tested, as is can happen a user attaches an operator to a volume but without defined BiasingProcessInterface processes.
        {
          for ( size_t i = 0 ; i < (sharedData->GetPhysicsBiasingProcessInterfaces()).size(); i++ )
            {
              const G4BiasingProcessInterface* wrapperProcess =
                (sharedData->GetPhysicsBiasingProcessInterfaces())[i];
              G4String operationName = "FreeFlight-"+wrapperProcess->GetWrappedProcess()->GetProcessName();
              fFreeFlightOperations[wrapperProcess] = new G4BOptnForceFreeFlight(operationName);
            }
        }
      fSetup = false;
    }
}


G4VBiasingOperation* G4BOptrForceCollision::ProposeOccurenceBiasingOperation(const G4Track* track, const G4BiasingProcessInterface* callingProcess)
{
  if ( track->GetDefinition() != fParticleToBias ) return 0;
  
  
  // -- Send force interaction operation to the callingProcess:
  // ----------------------------------------------------------
  // -- at this level, a copy of the track entering the volume was
  // -- generated (borned) earlier. This copy will make the forced
  // -- interaction in the volume.
  if ( GetBirthOperation( track ) == fCloningOperation )
    {
      // -- forced interaction already occured, abort.
      // -- [Note that if ones would redo a forced interaction, it
      // -- would require an other cloning before, if one wants to conserve
      // -- the weight.]
      if ( fSharedForceInteractionOperation->GetInteractionOccured() ) return 0;

      // -- Remember if this calling process is the first of the physics wrapper in
      // -- the PostStepGPIL loop (using default argument of method below):
      G4bool isFirstPhysGPIL = callingProcess-> GetIsFirstPostStepGPILInterface();
      
      // -- [*first process*] Initialize or update force interaction operation:
      if ( isFirstPhysGPIL )
        {
          // -- first step of cloned track, initialize the forced interaction operation:
          if ( track->GetCurrentStepNumber() == 1 ) fSharedForceInteractionOperation->Initialize( track );
          else
            {
              if ( fSharedForceInteractionOperation->GetInitialMomentum() != track->GetMomentum() )
                {
                  // -- means that some other physics process, not under control of the forced interaction operation,
                  // -- has occured, need to re-initialize the operation as distance to boundary has changed.
                  // -- [ Note the re-initialization is only possible for a Markovian law. ]
                  fSharedForceInteractionOperation->Initialize( track );
                }
              else
                {
                  // -- means that some other non-physics process (biasing or not, like step limit), has occured,
                  // -- but track conserves its momentum direction, only need to reduced the maximum distance for
                  // -- forced interaction.
                  // -- [ Note the update is only possible for a Markovian law. ]
                  fSharedForceInteractionOperation->UpdateForStep( track->GetStep() );
                }
            }
        }
      
      // -- [*all processes*] Sanity check : it may happen in limit cases that distance to
      // -- out is zero, weight would be infinite in this case: abort forced interaction.
      if ( fSharedForceInteractionOperation->GetMaximumDistance() < DBL_MIN ) return 0;
      
      // -- [* first process*] collect cross-sections and sample force law to determine interaction length
      // -- and winning process:
      if ( isFirstPhysGPIL )
        {
          // -- collect cross-sections:
          // -- ( Remember that the first of the G4BiasingProcessInterface triggers the update
          // --   of these cross-sections )
          const G4BiasingProcessSharedData* sharedData = callingProcess->GetSharedData();
          for ( size_t i = 0 ; i < (sharedData->GetPhysicsBiasingProcessInterfaces()).size() ; i++ )
            {
              const G4BiasingProcessInterface* wrapperProcess = ( sharedData->GetPhysicsBiasingProcessInterfaces() )[i];
              G4double interactionLength = wrapperProcess->GetWrappedProcess()->GetCurrentInteractionLength();
              // -- keep only well defined cross-section (*§*):
              if ( interactionLength < DBL_MAX/10. )
                fSharedForceInteractionOperation->AddCrossSection( wrapperProcess->GetWrappedProcess(),  1.0/interactionLength );
            }
          // -- sample the shared law (interaction length, and winning process:
          if ( fSharedForceInteractionOperation->GetNumberOfSharing() > 0 ) fSharedForceInteractionOperation->Sample();
        }
      
      // -- [*all processes*] Send operation, after sanity check (same criterium than (*§*) !):
      G4double      currentInteractionLength =  callingProcess->GetWrappedProcess()->GetCurrentInteractionLength();
      G4VBiasingOperation* operationToReturn = 0;
      if ( currentInteractionLength < DBL_MAX/10. )  operationToReturn = fSharedForceInteractionOperation;


      return operationToReturn;

    } // -- end of " if ( GetBirthOperation( track ) == fCloningOperation ) "
  
  
  
  // -- Send force free flight to the callingProcess:
  // ------------------------------------------------
  // -- At this point a track cloning happened in the previous step,
  // -- we request the continuing/current track to be forced flight.
  // -- Note this track will fly with 0.0 weight during its forced flight:
  // -- it is to forbid the double counting with the force interaction track.
  // -- Its weight is restored at the end of its free flight, this weight
  // -- being its initial weight * the weight for the free flight travel,
  // -- this last one being per process. The initial weight is common, and is
  // -- arbitrary asked to the first operation to take care of it.
  if ( fPreviousOperationApplied == fCloningOperation )
    {
      G4BOptnForceFreeFlight* operation =  fFreeFlightOperations[callingProcess];
      if ( callingProcess->GetWrappedProcess()->GetCurrentInteractionLength() < DBL_MAX/10. )
        {
          // -- the initial track weight will be restored only by the first DoIt free flight:
          operation->ResetInitialTrackWeight(fInitialTrackWeight);
          return operation;
        }
    }
  // -- If forced flight was already requested for the calling process, this flight
  // -- may have been interupted by some other non-physics process : request
  // -- process to continue with same forced flight:
  // -- ** ?? ** Incorrect here in case of flight interrupted by a *physics process*. Ie case
  // -- ** ?? ** of a subset of physics processes forced is not treated correctly here ** ?? **
  else if ( callingProcess->GetPreviousOccurenceBiasingOperation() == fFreeFlightOperations[callingProcess] )
    {
      return fFreeFlightOperations[callingProcess];
    }
  
  // -- other cases here: particle appearing in the volume by some
  // -- previous interaction : we decide to not bias these.
  return 0;
  
}


G4VBiasingOperation* G4BOptrForceCollision::ProposeNonPhysicsBiasingOperation(const G4Track* track,
                                                                              const G4BiasingProcessInterface* /* callingProcess */)
{
  if ( track->GetDefinition() != fParticleToBias ) return 0;
  
  // -- bias only tracks entering the volume.
  // -- A "cloning" is done:
  // --  - the primary will be forced flight under a zero weight up to volume exit,
  // --    where the weight will be restored with proper weight for free flight
  // --  - the clone will be forced to interact in the volume.
  if ( track->GetStep()->GetPreStepPoint()->GetStepStatus() == fGeomBoundary )
    {
      fSharedForceInteractionOperation->SetInteractionOccured( false );
      fInitialTrackWeight = track->GetWeight();
      fCloningOperation->SetCloneWeights(0.0, fInitialTrackWeight);
      return fCloningOperation;
    }

  // -- for all other cases: does nothing
  return 0;
}


G4VBiasingOperation* G4BOptrForceCollision::ProposeFinalStateBiasingOperation(const G4Track*, const G4BiasingProcessInterface* callingProcess)
{
  // -- Propose at final state generation the same operation which was proposed at GPIL level,
  // -- (which is either the force free flight or the force interaction operation).
  // -- count on the process interface to collect this operation:
  return callingProcess->GetCurrentOccurenceBiasingOperation();
}


void G4BOptrForceCollision::StartTracking( const G4Track* )
{
  fPreviousOperationApplied = 0;
}


void G4BOptrForceCollision::ExitBiasing( const G4Track* track, const G4BiasingProcessInterface* /*callingProcess*/ )
{
  fPreviousOperationApplied = 0;
  // -- clean-up track for what happens with this operator:
  ForgetTrack ( track );
}


void G4BOptrForceCollision::OperationApplied( const G4BiasingProcessInterface*   callingProcess, G4BiasingAppliedCase,
                                              G4VBiasingOperation*             operationApplied, const G4VParticleChange* particleChangeProduced )
{
  fPreviousOperationApplied = operationApplied;
  if ( operationApplied == fCloningOperation )
    RememberSecondaries( callingProcess, operationApplied, particleChangeProduced );
}