include/Geant4/G4SimpleHeum.hh

0001 //
0002 // ********************************************************************
0003 // * License and Disclaimer                                           *
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0025 //
0026 // G4SimpleHeum
0027 //
0028 // Class description:
0029 //
0030 // Simple Heum stepper for magnetic field:
0031 //        x_1 = x_0  +
0032 //              h * 1/4 * dx(t0,x0)  +
0033 //                  3/4 * dx(t0+2/3*h, x0+2/3*h*(dx(t0+h/3,x0+h/3*dx(t0,x0))))
0034 //
0035 // Third order solver.
0036
0037 // Created: W.Wander <wwc@mit.edu>, 12/09/1997
0038 // -------------------------------------------------------------------
0039 #ifndef G4SIMPLEHEUM_HH
0040 #define G4SIMPLEHEUM_HH
0041
0042 #include "G4MagErrorStepper.hh"
0043
0044 class G4SimpleHeum : public G4MagErrorStepper
0045 {
0046   public:
0047
0048     G4SimpleHeum(G4EquationOfMotion* EqRhs, G4int num_variables = 6);
0049    ~G4SimpleHeum() override;
0050       // Constructor and destructor.
0051
0052     void DumbStepper( const G4double y[],
0053                       const G4double dydx[],
0054                             G4double h,
0055                             G4double yout[] ) override;
0056
0057     inline G4int IntegratorOrder() const override { return 3; }
0058
0059   private:
0060
0061     G4int fNumberOfVariables = 0;
0062
0063     G4double* dydxTemp = nullptr;
0064     G4double* dydxTemp2 = nullptr;
0065     G4double* yTemp = nullptr;
0066     G4double* yTemp2 = nullptr;
0067 };
0068
0069 #endif