G4Mag_UsualEqRhs.hh

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// $Id$
//
//
// class G4Mag_UsualEqRhs
//
// Class description:
//
// This is the standard right-hand side for equation of motion.
// The only case another is required is when using a moving reference
// frame ... or extending the class to include additional Forces,
// eg an electric field
 
// History:
// - Created: J. Apostolakis, January 13th 1997.
// --------------------------------------------------------------------
 
#ifndef G4MAG_USUAL_EQRHS
#define G4MAG_USUAL_EQRHS
 
#include "G4Mag_EqRhs.hh"
 
class G4MagneticField;
 
class G4Mag_UsualEqRhs : public G4Mag_EqRhs
{
   public:  // with description
 
     G4Mag_UsualEqRhs( G4MagneticField* MagField );
    ~G4Mag_UsualEqRhs();
       // Constructor and destructor. No actions.
 
     void EvaluateRhsGivenB( const G4double y[],
                             const G4double B[3],
                                   G4double dydx[] ) const;
       // Given the value of the magnetic field B, this function 
       // calculates the value of the derivative dydx.
 
     virtual void SetChargeMomentumMass( G4double particleCharge, // in e+ units
                                         G4double MomentumXc,
                                         G4double mass);
     
  private:
 
    G4double  fInvCurrentMomentumXc;   // OBSOLETE:
                            // This extra state was meant to save a square root 
                            // in a critical method.   But its use reduced
                            // robustness (it was unstable for large steps.)
};
 
#endif /* G4MAG_USUAL_EQRHS */