include/Geant4/G4MagErrorStepper.hh

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0025 //
0026 // G4MagErrorStepper
0027 //
0028 // Class description:
0029 //
0030 // Abstract base class for integrator of particle's equation of motion,
0031 // used in tracking in space dependent magnetic field.
0032
0033 // Author: W.Wander (MIT), 09.12.1997
0034 // --------------------------------------------------------------------
0035 #ifndef G4MAGERRORSTEPPER_HH
0036 #define G4MAGERRORSTEPPER_HH
0037
0038 #include "G4Types.hh"
0039 #include "G4MagIntegratorStepper.hh"
0040 #include "G4Mag_EqRhs.hh"
0041 #include "G4ThreeVector.hh"
0042
0043 /**
0044  * @brief G4MagErrorStepper is an abstract base class for integrator of
0045  * particle's equation of motion, used in tracking in space dependent
0046  * magnetic field.
0047  */
0048
0049 class G4MagErrorStepper : public G4MagIntegratorStepper
0050 {
0051   public:
0052
0053     /**
0054      * Constructor for G4MagErrorStepper.
0055      *  @param[in] EqRhs Pointer to the provided equation of motion.
0056      *  @param[in] numberOfVariables The number of integration variables.
0057      *  @param[in] numberOfVariables The number of state variables.
0058      */
0059     G4MagErrorStepper(G4EquationOfMotion*EqRhs,
0060                       G4int numberOfVariables,
0061                       G4int numStateVariables = 12);
0062
0063     /**
0064      * Destructor.
0065      */
0066     ~G4MagErrorStepper() override;
0067
0068     /**
0069      * Copy constructor and assignment operator not allowed.
0070      */
0071     G4MagErrorStepper(const G4MagErrorStepper&) = delete;
0072     G4MagErrorStepper& operator=(const G4MagErrorStepper&) = delete;
0073
0074     /**
0075      * The stepper for the Runge Kutta integration.
0076      * The stepsize is fixed, with the step size given by 'h'.
0077      * Integrates ODE starting values y[0 to 6].
0078      * Outputs yout[] and its estimated error yerr[].
0079      *  @param[in] y Starting values array of integration variables.
0080      *  @param[in] dydx Derivatives array.
0081      *  @param[in] h The given step size.
0082      *  @param[out] yout Integration output.
0083      *  @param[out] yerr The estimated error.
0084      */
0085     void Stepper( const G4double y[],
0086                   const G4double dydx[],
0087                         G4double h,
0088                         G4double yout[],
0089                         G4double yerr[] ) override;
0090
0091     /**
0092      * Same as Stepper() function above, but should perform a 'dump' step
0093      * without error calculation. To be implemented in concrete derived classes.
0094      */
0095     virtual void DumbStepper( const G4double y[],
0096                               const G4double dydx[],
0097                                     G4double h,
0098                                     G4double yout[] ) = 0;
0099
0100     /**
0101      * Estimates the maximum distance of curved solution and chord.
0102      */
0103     G4double DistChord() const override;
0104
0105   private:
0106
0107     /** Data stored in order to find the chord. */
0108     G4ThreeVector fInitialPoint, fMidPoint, fFinalPoint;
0109
0110     /** Arrays used only for temporary storage; they are allocated at the
0111         class level only for efficiency, so that calls to new and delete are
0112         not made in Stepper(). */
0113     G4double *yInitial, *yMiddle, *dydxMid, *yOneStep;
0114 };
0115
0116 #include  "G4MagErrorStepper.icc"
0117
0118 #endif