//
// ********************************************************************
// * DISCLAIMER                                                       *
// *                                                                  *
// * The following disclaimer summarizes all the specific disclaimers *
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//
//
// $Id$
// GEANT4 tag $Name:  $
//
//
// class G4Mag_SpinEqRhs
//
// Class description:
//
// This is the equation of motion for a particle with spin in a pure
// magnetic field. The three components of the particle's spin are
// treated utilising BMT equation.

// History:
// - Created: J.Apostolakis, P.Gumplinger - February 8th, 1999.
// --------------------------------------------------------------------

#ifndef LEMuSRMAG_SPIN_EQRHS
#define LEMuSRMAG_SPIN_EQRHS

#include "G4Types.hh"
#include "G4Mag_EqRhs.hh"
#include "G4SteppingManager.hh"        // Include from 'tracking'
#include "G4TrackingManager.hh"        // Include from 'tracking'
#include "LEMuSRTrackingAction.hh"
#include "LEMuSRSteppingAction.hh"

class G4MagneticField;

class LEMuSRMag_SpinEqRhs : public G4Mag_EqRhs
{
   public:  // with description

     LEMuSRMag_SpinEqRhs( G4MagneticField* MagField );
    ~LEMuSRMag_SpinEqRhs();
       // Constructor and destructor. No actions.

     void SetChargeMomentumMass(G4double particleCharge, // in e+ units
                                G4double MomentumXc,
                                G4double mass); 
  
  //! Calculation of the derivatives
  /*! Given the value of the magnetic field B, this function 
   * calculates the value of the derivative dydx.
   */
  void EvaluateRhsGivenB( const  G4double y[],
                             const  G4double B[3],
                                    G4double dydx[] ) const;

   private:

     G4double omegac;
     G4double anomaly;
     G4double ParticleCharge;

     G4double E;
     G4double gamma;
     G4double beta; 
     G4double m_mass;

     LEMuSRTrackingAction* theTrackingAction;
 G4double oldomegac; //to remove
};

#endif /* LEMuSRMAG_SPIN_EQRHS */