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// $Id: G4HelixSimpleRunge.hh,v 1.7 2006/06/29 18:22:41 gunter Exp $
// GEANT4 tag $Name: geant4-09-03 $
//
//
// class G4HelixSimpleRunge
//
// Class description:
//
//  Helix Simple Runge-Kutta stepper for magnetic field:
//        x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) )
//
//  Second order solver.
//  Take the derivative at a position to be assumed at the middle of the
//  Step and add it to the current position.

// W. Wander <wwc@mit.edu> 03/12/98
// -------------------------------------------------------------------

#ifndef G4HELIXSIMPLERUNGE_HH
#define G4HELIXSIMPLERUNGE_HH
#include "G4MagHelicalStepper.hh"

class G4HelixSimpleRunge : public G4MagHelicalStepper
{
  public:  // with description

    G4HelixSimpleRunge(G4Mag_EqRhs *EqRhs)
      : G4MagHelicalStepper(EqRhs){}

    ~G4HelixSimpleRunge(){}
  
    void  DumbStepper(  const G4double y[],
                              G4ThreeVector   Bfld,
                              G4double        h,
                              G4double        yout[]);

  public:  // without description
  
    G4int IntegratorOrder() const { return 2; }
};

#endif /* G4HELIXSIMPLERUNGE_HH */
