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// $Id: G4UniversalFluctuation.hh,v 1.6 2008/10/22 16:04:33 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-02 $
//
// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:     G4UniversalFluctuation
//
// Author:        Vladimir Ivanchenko
//
// Creation date: 03.01.2002
//
// Modifications:
//
// 09-12-02 remove warnings (V.Ivanchenko)
// 28-12-02 add method Dispersion (V.Ivanchenko)
// 07-02-03 change signature (V.Ivanchenko)
// 13-02-03 Add name (V.Ivanchenko)
// 16-10-03 Changed interface to Initialisation (V.Ivanchenko)
// 07-02-05 define problim = 5.e-3 (mma)
//
// Class Description:
//
// Implementation of energy loss fluctuations

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

#ifndef G4UniversalFluctuation_h
#define G4UniversalFluctuation_h 1


#include "G4VEmFluctuationModel.hh"
#include "G4ParticleDefinition.hh"

class G4UniversalFluctuation : public G4VEmFluctuationModel
{

public:

  G4UniversalFluctuation(const G4String& nam = "UniFluc");

  virtual ~G4UniversalFluctuation();

  G4double SampleFluctuations(const G4Material*,
                          const G4DynamicParticle*,
 				G4double&,
                                G4double&,
                                G4double&);

  G4double Dispersion(    const G4Material*,
                          const G4DynamicParticle*,
 				G4double&,
                                G4double&);

  void InitialiseMe(const G4ParticleDefinition*);

  // Initialisation prestep
  inline void SetParticleAndCharge(const G4ParticleDefinition*, G4double q2);

protected:

private:

  // hide assignment operator
  G4UniversalFluctuation & operator=(const  G4UniversalFluctuation &right);
  G4UniversalFluctuation(const  G4UniversalFluctuation&);

  const G4ParticleDefinition* particle;
  const G4Material* lastMaterial;

  G4double particleMass;
  G4double chargeSquare;

  // data members to speed up the fluctuation calculation
  G4double ipotFluct;
  G4double electronDensity;
  
  G4double f1Fluct;
  G4double f2Fluct;
  G4double e1Fluct;
  G4double e2Fluct;
  G4double e1LogFluct;
  G4double e2LogFluct;
  G4double ipotLogFluct;
  G4double e0;

  G4double facwidth;
  G4double oldloss;
  G4double samestep;
  G4double e1,e2;

  G4double minNumberInteractionsBohr;
  G4double theBohrBeta2;
  G4double minLoss;
  G4double nmaxCont1;
  G4double nmaxCont2;

};

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

inline void 
G4UniversalFluctuation::SetParticleAndCharge(const G4ParticleDefinition* part,
					     G4double q2)
{
  if(part != particle) {
    particle       = part;
    particleMass   = part->GetPDGMass();
  }
  chargeSquare = q2;
}

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

#endif

