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// $Id$
//
// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4EmElementSelector
//
// Author:        Vladimir Ivanchenko
//
// Creation date: 29.05.2008
//
// Modifications:
//
//
// Class Description:
//
// Generic helper class for the random selection of an element

// -------------------------------------------------------------------
//

#ifndef G4EmElementSelector_h
#define G4EmElementSelector_h 1

#include "globals.hh"
#include "G4ParticleDefinition.hh"
#include "G4Material.hh"
#include "G4Element.hh"
#include "G4ElementVector.hh"
#include "G4PhysicsLogVector.hh"
#include "Randomize.hh"
#include <vector>

class G4VEmModel;

class G4EmElementSelector
{

public:

  G4EmElementSelector(G4VEmModel*, const G4Material*, G4int bins, 
		      G4double emin, G4double emax, 
		      G4bool spline = true);

  ~G4EmElementSelector();

  void Initialise(const G4ParticleDefinition*, G4double cut = 0.0);

  void Dump(const G4ParticleDefinition* p = 0);

  inline const G4Element* SelectRandomAtom(G4double kineticEnergy);

  inline const G4Material* GetMaterial() const;

private:

  //  hide assignment operator
  G4EmElementSelector & operator=(const  G4EmElementSelector &right);
  G4EmElementSelector(const  G4EmElementSelector&);

  G4VEmModel*       model;
  const G4Material* material;
  const G4Element*  element;
  const G4ElementVector* theElementVector;

  G4int    nElmMinusOne;
  G4int    nbins;

  G4double cutEnergy;
  G4double lowEnergy;
  G4double highEnergy;

  std::vector<G4PhysicsLogVector*> xSections;
  
};

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.....
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.....

inline const G4Element* G4EmElementSelector::SelectRandomAtom(G4double e)
{
  if (nElmMinusOne > 0) {
    G4double x = G4UniformRand();
    element = (*theElementVector)[nElmMinusOne];
    for(G4int i=0; i<nElmMinusOne; ++i) {
      if (x <= (xSections[i])->Value(e)) {
	element = (*theElementVector)[i];
	break;
      }
    }
  }
  return element;
}

inline const G4Material* G4EmElementSelector::GetMaterial() const
{
  return material;
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.....

#endif