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//
// File name:     G4VPolarizedCrossSection
//
// Author:        Andreas Schaelicke
//
// Creation date: 15.05.2005
//
// Modifications:
//
// Class Description:
//   (pure virtual) interface class
//
//   provides readable but efficient routines to determine 
//   polarization for the final state of a given process
//   empoying the differential cross section
//

#ifndef G4VPolarizedCrossSection_h
#define G4VPolarizedCrossSection_h 1

#include "G4StokesVector.hh"


class G4VPolarizedCrossSection
{
public:
  G4VPolarizedCrossSection();
  virtual ~G4VPolarizedCrossSection();

public:
  virtual void Initialize(G4double, G4double, G4double,
			  const G4StokesVector & p0,const G4StokesVector & p1,
 			  G4int flag=0); 
  virtual G4double XSection(const G4StokesVector & pol2,const G4StokesVector & pol3) = 0; 
  virtual G4double TotalXSection(G4double xmin, G4double xmax, G4double y,
				 const G4StokesVector & pol0,
				 const G4StokesVector & pol1);
  
  // return expected mean polarisation
  virtual G4StokesVector GetPol2();
  virtual G4StokesVector GetPol3();

  // return basic kinematics properties
  //   minimal gamma value in TotalXSection
  inline G4double GetYmin() {return fYmin; } 
  //   minimal energy fraction in TotalXSection
  virtual G4double GetXmin(G4double y);
  //   maximal energy fraction in TotalXSection 
  virtual G4double GetXmax(G4double y);

  // return appropriate distribute polarisation states;
//  void DicePolarization();
//   G4StokesVector DicedPol2();
//   G4StokesVector DicedPol3();
  inline void SetMaterial(G4double A, G4double Z, G4double coul) 
  { theA=A; theZ=Z; fCoul=coul; }
protected:
  // define kinematics properties
  inline void SetXmin(G4double xmin) { fXmin=xmin;}
  inline void SetXmax(G4double xmax) { fXmax=xmax;}
  inline void SetYmin(G4double ymin) { fYmin=ymin;}

  // kinematic properties
  G4double fXmin, fXmax, fYmin;
  // material properties
  G4double theA, theZ;
  G4double fCoul;
};


#endif
