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// G4ParticleChangeForOccurenceBiasing
// --------------------------------------------------------------------

#include "G4ParticleChangeForOccurenceBiasing.hh"

G4ParticleChangeForOccurenceBiasing::
G4ParticleChangeForOccurenceBiasing(const G4String& name)
  : G4VParticleChange(),
    fName(name)
{}

void G4ParticleChangeForOccurenceBiasing::
SetWrappedParticleChange(G4VParticleChange* wpc)
{
  fWrappedParticleChange = wpc;
}

void G4ParticleChangeForOccurenceBiasing::StealSecondaries()
{
  SetNumberOfSecondaries( fWrappedParticleChange->GetNumberOfSecondaries() );
  for (G4int isecond = 0; isecond < fWrappedParticleChange->GetNumberOfSecondaries(); isecond++) 
  {
    G4Track* secondary =  fWrappedParticleChange->GetSecondary(isecond);
    secondary->SetWeight ( secondary->GetWeight() * fOccurenceWeightForInteraction );
    AddSecondary( secondary );
  }
  fWrappedParticleChange->Clear();
}

G4Step* G4ParticleChangeForOccurenceBiasing::UpdateStepForAtRest(G4Step* step)
{
  return step;
}

G4Step* G4ParticleChangeForOccurenceBiasing::UpdateStepForAlongStep(G4Step* step)
{
  // -- make particle change of wrapped process to apply its changes:
  if ( fWrappedParticleChange )
    fWrappedParticleChange->UpdateStepForAlongStep( step );

  // -- multiply parent weight by weight due to occurrence biasing:
  G4StepPoint* postStepPoint = step->GetPostStepPoint();
  postStepPoint->SetWeight( postStepPoint->GetWeight()*fOccurenceWeightForNonInteraction );

  return step;
}

G4Step* G4ParticleChangeForOccurenceBiasing::UpdateStepForPostStep(G4Step* step)
{
  // -- let make first wrapped process to apply its changes:
  fWrappedParticleChange->UpdateStepForPostStep(step);
  // -- then apply weight correction due to occurrence biasing:
  G4StepPoint* postStepPoint = step->GetPostStepPoint();
  postStepPoint->SetWeight( postStepPoint->GetWeight()*fOccurenceWeightForInteraction );

  return step;
}