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// $Id: G4StokesVector.hh,v 1.4 2007/11/01 17:32:34 schaelic Exp $
// GEANT4 tag $Name: geant4-09-03 $
//
// GEANT4 Class header file
//
// File name:     G4StokesVector
//
// Author:        Andreas Schaelicke
//
// Creation date: 01.05.2005
//
// Modifications:
// 27-07-06 added some test routines (P.Starovoitov)
// 25-08-06 modified name of test routines (A.Schaelicke)
//
// Class Description:
//
// Provides Stokesvector representation employed in implementation of
// polarized processes.
//
// aim:
//   - store three components of a stokesvector
//   - distinguish between boson or fermion state (different transformations)
//   - provide unique definition of reference frame (cf. G4PolarizationHelper)
//

#ifndef G4StokesVector_h
#define G4StokesVector_h 1

#include "G4ThreeVector.hh"
#include "G4RotationMatrix.hh"


class G4StokesVector: public G4ThreeVector
{
 public:
  // standard vectors:
  static const G4StokesVector ZERO;
  static const G4StokesVector P1;
  static const G4StokesVector P2;
  static const G4StokesVector P3;
  static const G4StokesVector M1;
  static const G4StokesVector M2;
  static const G4StokesVector M3;
public:
  G4StokesVector();
  G4StokesVector(const G4ThreeVector & v);
  virtual ~G4StokesVector();
public:
  inline G4double p1() const { return x(); }
  inline G4double p2() const { return y(); }
  inline G4double p3() const { return z(); }

  inline G4bool IsZero() const { return *this==ZERO; } 
  inline G4double Transverse() const { return perp(); } 

  inline G4ThreeVector PolSqr() const { 
    return G4ThreeVector(x()*x(),y()*y(),z()*z()); 
  }
  inline G4ThreeVector PolSqrt() const { 
    return G4ThreeVector(std::sqrt(x()),std::sqrt(y()),std::sqrt(z())); 
  }
  G4ThreeVector PolError(const G4StokesVector & sum2, long n);

  // Ratio of 3-vectors.
  G4ThreeVector PolDiv( const G4StokesVector & );

  inline void SetPhoton() { isPhoton=true; }

  void RotateAz(G4ThreeVector nInteractionFrame, 
		G4ThreeVector particleDirection);
  void InvRotateAz(G4ThreeVector nInteractionFrame, 
		   G4ThreeVector particleDirection);
  void RotateAz(G4double cosphi, G4double sinphi);
  G4double GetBeta();

  void DiceUniform();
  void DiceP1();
  void DiceP2();
  void DiceP3();

  void FlipP3();
private:
  G4bool isPhoton;
};


#endif
