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// $Id: G4EmMultiModel.cc,v 1.8 2010/08/17 17:36:59 vnivanch Exp $
// GEANT4 tag $Name: emutils-V09-03-23 $
//
// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:   G4EmMultiModel
//
// Author:        Vladimir Ivanchenko
// 
// Creation date: 03.05.2004
//
// Modifications: 
// 15-04-05 optimize internal interface (V.Ivanchenko)
// 04-07-10 updated interfaces according to g4 9.4 (V.Ivanchenko)
//


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#include "G4EmMultiModel.hh"
#include "Randomize.hh"

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G4EmMultiModel::G4EmMultiModel(const G4String& nam)
  : G4VEmModel(nam), nModels(0)
{
  model.clear();
  cross_section.clear();
}

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G4EmMultiModel::~G4EmMultiModel()
{}

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void G4EmMultiModel::AddModel(G4VEmModel* p)
{
  cross_section.push_back(0.0);
  model.push_back(p);
  ++nModels;
}

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void G4EmMultiModel::Initialise(const G4ParticleDefinition* p, 
                                const G4DataVector& cuts)
{
  if(nModels > 0) {
    G4cout << "### Initialisation of EM MultiModel " << GetName()
	   << " including following list of models:" << G4endl;
    for(G4int i=0; i<nModels; ++i) {
      G4cout << "    " << (model[i])->GetName();
      (model[i])->SetParticleChange(pParticleChange, GetModelOfFluctuations());
      (model[i])->Initialise(p, cuts);
    }
    G4cout << G4endl;
  }
}

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G4double G4EmMultiModel::ComputeDEDX(const G4MaterialCutsCouple* couple,
                                     const G4ParticleDefinition* p,
				     G4double kineticEnergy,
				     G4double cutEnergy)
{
  SetCurrentCouple(couple);
  G4double dedx = 0.0;

  if(nModels > 0) {
    for(G4int i=0; i<nModels; i++) {
      dedx += (model[i])->ComputeDEDX(couple, p, cutEnergy, kineticEnergy);
    }
  } 

  return dedx;
}

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G4double G4EmMultiModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition* p,
						    G4double kinEnergy,
						    G4double Z,
						    G4double A,
						    G4double cutEnergy,
						    G4double maxEnergy)
{
  G4double cross = 0.0;
  if(nModels>0) {
    for(G4int i=0; i<nModels; ++i) {
      (model[i])->SetCurrentCouple(CurrentCouple());
      cross += (model[i])->ComputeCrossSectionPerAtom(p, kinEnergy, Z, A, 
						      cutEnergy, maxEnergy);
    }
  } 
  return cross;
}

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void G4EmMultiModel::SampleSecondaries(std::vector<G4DynamicParticle*>* vdp,
				       const G4MaterialCutsCouple* couple,
				       const G4DynamicParticle* dp,
				       G4double minEnergy,
				       G4double maxEnergy)
{
  SetCurrentCouple(couple);
  if(nModels > 0) {
    G4int i;
    G4double cross = 0.0;
    for(i=0; i<nModels; ++i) {
      cross += (model[i])->CrossSection(couple, dp->GetParticleDefinition(), 
                                        dp->GetKineticEnergy(), minEnergy, maxEnergy);
      cross_section[i] = cross;
    }

    cross *= G4UniformRand();

    for(i=0; i<nModels; ++i) {
      if(cross <= cross_section[i]) {
        (model[i])->SampleSecondaries(vdp, couple, dp, minEnergy, maxEnergy);
        return;
      }
    }
  } 
}

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