include/Geant4/G4RK547FEq2.hh

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0024 //
0025 // G4RK547FEq2
0026 //
0027 // Class description:
0028 //
0029 // An implementation of the 7 stage embedded Runge-Kutta 4,5 pair (RK547FEq2)
0030 // from the paper:
0031 //   D. J. Higham and G. Hall,
0032 //   "Embedded Runge-Kutta formulae with stable equilibrium states",
0033 //   J. Comput. Appl. Math., vol. 29, no. 1, pp. 25-33, 1990.
0034
0035 // Author: Dmitry Sorokin, Google Summer of Code 2017
0036 // Supervision: John Apostolakis, CERN
0037 // --------------------------------------------------------------------
0038 #ifndef G4RK547FEQ2_HH
0039 #define G4RK547FEQ2_HH
0040
0041 #include "G4MagIntegratorStepper.hh"
0042 #include "G4FieldTrack.hh"
0043
0044 class G4RK547FEq2 : public G4MagIntegratorStepper
0045 {
0046   public:
0047
0048     G4RK547FEq2(G4EquationOfMotion* EqRhs, G4int integrationVariables = 6);
0049
0050     G4RK547FEq2 (const G4RK547FEq2&) = delete;
0051     G4RK547FEq2& operator = (const G4RK547FEq2&) = delete;
0052
0053     void Stepper( const G4double yInput[],
0054                   const G4double dydx[],
0055                         G4double hstep,
0056                         G4double yOutput[],
0057                         G4double yError[] ) override;
0058
0059     void Stepper( const G4double yInput[],
0060                   const G4double dydx[],
0061                         G4double hstep,
0062                         G4double yOutput[],
0063                         G4double yError[],
0064                         G4double dydxOutput[] );
0065
0066     G4double DistChord() const override;
0067     G4int IntegratorOrder() const override { return 4; }
0068
0069   private:
0070
0071     void makeStep( const G4double yInput[],
0072                    const G4double dydx[],
0073                    const G4double hstep,
0074                          G4double yOutput[],
0075                          G4double* dydxOutput = nullptr,
0076                          G4double* yError = nullptr ) const;
0077
0078   private:
0079
0080     G4double fyIn[G4FieldTrack::ncompSVEC],
0081              fdydx[G4FieldTrack::ncompSVEC],
0082              fyOut[G4FieldTrack::ncompSVEC],
0083              fdydxOut[G4FieldTrack::ncompSVEC];
0084
0085     G4double fhstep= -1.0;
0086 };
0087
0088 #endif