Geant4-11
G4MagIntegratorStepper.hh
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25//
26// G4MagIntegratorStepper
27//
28// Class description:
29//
30// Abstract base class for integrator of particle's equation of motion,
31// used in tracking in space dependent magnetic field
32//
33// A Stepper must integrate over NumberOfVariables elements,
34// and also copy (from input to output) any of NoStateVariables
35// not included in the NumberOfVariables.
36//
37// So it is expected that NoStateVariables >= NumberOfVariables
38
39// Author: J.Apostolakis, CERN - 15.01.1997
40// --------------------------------------------------------------------
41#ifndef G4MAGINTEGRATORSTEPPER_HH
42#define G4MAGINTEGRATORSTEPPER_HH
43
44#include "G4Types.hh"
45#include "G4EquationOfMotion.hh"
46
48{
49 public: // with description
50
52 G4int numIntegrationVariables,
53 G4int numStateVariables = 12,
54 G4bool isFSAL = false );
55
56 virtual ~G4MagIntegratorStepper() = default;
57 // Constructor and destructor. No actions.
58
61
62 virtual void Stepper( const G4double y[],
63 const G4double dydx[],
64 G4double h,
65 G4double yout[],
66 G4double yerr[] ) = 0;
67 // The stepper for the Runge Kutta integration.
68 // The stepsize is fixed, with the Step size given by h.
69 // Integrates ODE starting values y[0 to 6].
70 // Outputs yout[] and its estimated error yerr[].
71
72 virtual G4double DistChord() const = 0;
73 // Estimate the maximum distance of a chord from the true path
74 // over the segment last integrated.
75
76 inline void NormaliseTangentVector( G4double vec[6] );
77 // Simple utility function to (re)normalise 'unit velocity' vector.
78
79 inline void NormalisePolarizationVector( G4double vec[12] );
80 // Simple utility function to (re)normalise 'unit spin' vector.
81
82 inline void RightHandSide( const G4double y[], G4double dydx[] ) const;
83 // Utility method to supply the standard Evaluation of the
84 // Right Hand side of the associated equation.
85
86 inline void RightHandSide( const G4double y[],
87 G4double dydx[],
88 G4double field[] ) const;
89 // Calculate dydx and field at point y.
90
92 // Get the number of variables that the stepper will integrate over.
93
95 // Get the number of variables of state variables (>= above, integration)
96
97 virtual G4int IntegratorOrder() const = 0;
98 // Returns the order of the integrator
99 // i.e. its error behaviour is of the order O(h^order).
100
102 // Replacement method - using new data member
103
106 // As some steppers (eg RKG3) require other methods of Eq_Rhs
107 // this function allows for access to them.
108
109 inline void SetEquationOfMotion(G4EquationOfMotion* newEquation);
110
111 inline unsigned long GetfNoRHSCalls();
112 inline void ResetfNORHSCalls();
113 // Count number of calls to RHS method(s)
114
115 inline G4bool IsFSAL() const;
116
117 protected:
118
119 inline void SetIntegrationOrder(G4int order);
120 inline void SetFSAL(G4bool flag = true);
121
122 private:
123
125 const G4int fNoIntegrationVariables = 0; // Variables in integration
126 const G4int fNoStateVariables = 0; // Number required for FieldTrack
127
128 mutable unsigned long fNoRHSCalls = 0UL;
129 // Counter for calls to RHS method
130
131 // Parameters of a RK method -- must be shared by all steppers of a type
132 // -- Invariants for a class
133
134 G4int fIntegrationOrder = -1; // must be set by stepper !!!
135 // All ClassicalRK4 steppers are 4th order
137 // Depends on RK method & implementation
138};
139
141
142#endif /* G4MAGIntegratorSTEPPER */
double G4double
Definition: G4Types.hh:83
bool G4bool
Definition: G4Types.hh:86
int G4int
Definition: G4Types.hh:85
G4MagIntegratorStepper(G4EquationOfMotion *Equation, G4int numIntegrationVariables, G4int numStateVariables=12, G4bool isFSAL=false)
void NormalisePolarizationVector(G4double vec[12])
G4bool IsFSAL() const
unsigned long GetfNoRHSCalls()
G4EquationOfMotion * GetEquationOfMotion()
G4int GetNumberOfVariables() const
void RightHandSide(const G4double y[], G4double dydx[]) const
void NormaliseTangentVector(G4double vec[6])
virtual G4double DistChord() const =0
virtual ~G4MagIntegratorStepper()=default
G4EquationOfMotion * fEquation_Rhs
virtual void Stepper(const G4double y[], const G4double dydx[], G4double h, G4double yout[], G4double yerr[])=0
G4MagIntegratorStepper & operator=(const G4MagIntegratorStepper &)=delete
void SetIntegrationOrder(G4int order)
void SetEquationOfMotion(G4EquationOfMotion *newEquation)
const G4EquationOfMotion * GetEquationOfMotion() const
G4MagIntegratorStepper(const G4MagIntegratorStepper &)=delete
void SetFSAL(G4bool flag=true)
void RightHandSide(const G4double y[], G4double dydx[], G4double field[]) const
G4int GetNumberOfStateVariables() const
virtual G4int IntegratorOrder() const =0