include/Geant4/G4HelixSimpleRunge.hh

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0025 //
0026 // G4HelixSimpleRunge
0027 //
0028 // Class description:
0029 //
0030 // Helix Simple Runge-Kutta stepper for magnetic field:
0031 //       x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) )
0032 //
0033 // Second order solver.
0034 // Take the derivative at a position to be assumed at the middle of the
0035 // Step and add it to the current position.
0036
0037 // Author: W.Wander (MIT), 03.12.1998
0038 // -------------------------------------------------------------------
0039 #ifndef G4HELIXSIMPLERUNGE_HH
0040 #define G4HELIXSIMPLERUNGE_HH
0041
0042 #include "G4MagHelicalStepper.hh"
0043
0044 /**
0045  * @brief G4HelixSimpleRunge implements a simple Helix stepper for magnetic
0046  * field with 2nd order solver.
0047  */
0048
0049 class G4HelixSimpleRunge : public G4MagHelicalStepper
0050 {
0051   public:
0052
0053     /**
0054      * Constructor for G4HelixSimpleRunge.
0055      *  @param[in] EqRhs Pointer to the provided equation of motion.
0056      */
0057     G4HelixSimpleRunge(G4Mag_EqRhs* EqRhs);
0058
0059     /**
0060      * Default Destructor.
0061      */
0062     ~G4HelixSimpleRunge() override = default;
0063
0064     /**
0065      * The stepper function for the integration.
0066      *  @param[in] y Starting values array of integration variables.
0067      *  @param[in] Bfld The field vector.
0068      *  @param[in] h The given step size.
0069      *  @param[out] yout Integration output.
0070      */
0071     void  DumbStepper( const G4double y[],
0072                              G4ThreeVector Bfld,
0073                              G4double h,
0074                              G4double yout[] ) override;
0075
0076     /**
0077      * Returns the order, 2, of integration.
0078      */
0079     inline G4int IntegratorOrder() const override { return 2; }
0080
0081     /**
0082      * Returns the stepper type-ID, "kHelixSimpleRunge".
0083      */
0084     inline G4StepperType StepperType() const override { return kHelixSimpleRunge; }
0085 };
0086
0087 #endif