include/Geant4/G4SimpleRunge.hh

0001 //
0002 // ********************************************************************
0003 // * License and Disclaimer                                           *
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0024 // ********************************************************************
0025 //
0026 // G4SimpleRunge
0027 //
0028 // Class description:
0029 //
0030 // Simple Runge:
0031 //
0032 //        x_1 = x_0 + h * ( dx( t_0+h/2, x_0 + h/2 * dx( t_0, x_0) ) )
0033 //
0034 // Second order solver.
0035 // Takes the derivative at a position to be assumed at the middle of the
0036 // Step and adds it to the current position.
0037
0038 // Created: W.Wander <wwc@mit.edu>, 12/09/1997
0039 // -------------------------------------------------------------------
0040 #ifndef G4SIMPLERUNGE_HH
0041 #define G4SIMPLERUNGE_HH
0042
0043 #include "G4MagErrorStepper.hh"
0044
0045 class G4SimpleRunge : public G4MagErrorStepper
0046 {
0047   public:
0048
0049     G4SimpleRunge(G4EquationOfMotion* EquationRhs, G4int numberOfVariables = 6);
0050    ~G4SimpleRunge() override;
0051       // Constructor and destructor.
0052
0053     void DumbStepper( const G4double y[],
0054                       const G4double dydx[],
0055                             G4double h,
0056                             G4double yout[] ) override;
0057
0058     inline G4int IntegratorOrder() const override { return 2; }
0059
0060   private:
0061
0062     G4int fNumberOfVariables = 0;
0063
0064     G4double* dydxTemp = nullptr;
0065     G4double* yTemp = nullptr;
0066 };
0067
0068 #endif