include/Geant4/G4DormandPrinceRK78.hh

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0025 //
0026 // G4DormandPrinceRK78
0027 //
0028 // Class description:
0029 //
0030 // Dormand-Prince 8(7)13M non-FSAL RK method, a 13 stage embedded
0031 // explicit Runge-Kutta method, using a pair of 7th and 8th order formulae.
0032 //
0033 // Paper proposing this RK scheme:
0034 // P.J. Prince, J.R. Dormand, "High order embedded Runge-Kutta formulae",
0035 // Journal of Computational and Applied Mathematics, Volume 7, Issue 1, 1981,
0036 // Pages 67-75, ISSN 0377-0427, DOI: 10.1016/0771-050X(81)90010-3
0037
0038 // Created: Somnath Banerjee, Google Summer of Code 2015, 28 June 2015
0039 // Supervision: John Apostolakis, CERN
0040 // --------------------------------------------------------------------
0041 #ifndef G4DORMAND_PRINCE_RK78_HH
0042 #define G4DORMAND_PRINCE_RK78_HH
0043
0044 #include "G4MagIntegratorStepper.hh"
0045
0046 class G4DormandPrinceRK78 : public G4MagIntegratorStepper
0047 {
0048   public:
0049
0050     G4DormandPrinceRK78(G4EquationOfMotion* EqRhs,
0051                         G4int numberOfVariables = 6,
0052                         G4bool primary = true);
0053     ~G4DormandPrinceRK78() override;
0054
0055     G4DormandPrinceRK78(const G4DormandPrinceRK78&) = delete;
0056     G4DormandPrinceRK78& operator=(const G4DormandPrinceRK78&) = delete;
0057
0058     void Stepper( const G4double y[],
0059                   const G4double dydx[],
0060                         G4double h,
0061                         G4double yout[],
0062                         G4double yerr[]) override ;
0063
0064     G4double  DistChord() const override;
0065     inline G4int IntegratorOrder() const override { return 7; }
0066
0067  private :
0068
0069     G4double *ak2,   *ak3,  *ak4,  *ak5,  *ak6,  *ak7, *ak8,
0070              *ak9,   *ak10, *ak11, *ak12, *ak13,
0071              *yTemp, *yIn;
0072
0073     G4double fLastStepLength = -1.0;
0074     G4double *fLastInitialVector, *fLastFinalVector,
0075              *fLastDyDx, *fMidVector, *fMidError;
0076       // For DistChord calculations
0077
0078     G4DormandPrinceRK78* fAuxStepper = nullptr;
0079 };
0080
0081 #endif