include/Geant4/G4ExplicitEuler.hh

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0025 //
0026 // G4ExplicitEuler
0027 //
0028 // Class description:
0029 //
0030 // Explicit Euler stepper for magnetic field: x_1 = x_0 + h * dx_0.
0031 // The most simple approach for solving linear differential equations.
0032 // Take the current derivative and add it to the current position.
0033
0034 // Author: W.Wander (MIT), 12.09.1997
0035 // -------------------------------------------------------------------
0036 #ifndef G4EXPLICITEULER_HH
0037 #define G4EXPLICITEULER_HH
0038
0039 #include "G4MagErrorStepper.hh"
0040
0041 /**
0042  * @brief G4ExplicitEuler implements an Explicit Euler stepper for magnetic
0043  * field: x_1 = x_0 + h * dx_0. The most simple approach for solving linear
0044  * differential equations. Takes the current derivative and adds it to the
0045  * current position.
0046  */
0047
0048 class G4ExplicitEuler : public G4MagErrorStepper
0049 {
0050   public:
0051
0052     /**
0053      * Constructor for G4ExplicitEuler.
0054      *  @param[in] EqRhs Pointer to the provided equation of motion.
0055      *  @param[in] numberOfVariables The number of integration variables.
0056      */
0057     G4ExplicitEuler(G4EquationOfMotion* EqRhs,
0058                     G4int numberOfVariables = 6) ;
0059
0060     /**
0061      * Default Destructor.
0062      */
0063     ~G4ExplicitEuler() override = default;
0064
0065     /**
0066      * The stepper function for the integration.
0067      *  @param[in] y Starting values array of integration variables.
0068      *  @param[in] dydx Derivatives array.
0069      *  @param[in] h The given step size.
0070      *  @param[out] yout Integration output.
0071      */
0072     void DumbStepper( const G4double y[],
0073                        const G4double dydx[],
0074                              G4double h,
0075                              G4double yout[] ) override;
0076
0077     /**
0078      * Returns the order, 1, of integration.
0079      */
0080     inline G4int IntegratorOrder() const override { return 1; }
0081
0082     /**
0083      * Returns the stepper type-ID, "kExplicitEuler".
0084      */
0085     inline G4StepperType StepperType() const override { return kExplicitEuler; }
0086 };
0087
0088 #endif