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25 //
26 // G4VIntegrationDriver
27 //
28 // Class description:
29 //
30 // Abstract base class for 'driver' classes which are responsible for
31 // undertaking integration of an state given an equation of motion and
32 // within acceptable error bound(s).
33 //
34 // Different integration methods are meant to be provided via this
35 // common interface, and can span the original type (explicit Runge Kutta
36 // methods), enhanced RK methods and alternatives such as the
37 // Bulirsch-Stoer and multi-step methods.
38 //
39 // The drivers' key mission is to insure that the error is below set values.
40
41 // Author: Dmitry Sorokin, Google Summer of Code 2017
42 // Supervision: John Apostolakis, CERN
43 // --------------------------------------------------------------------
44 #ifndef G4VINTEGRATION_DRIVER_HH
45 #define G4VINTEGRATION_DRIVER_HH
46
47 #include "G4Types.hh"
48 #include "G4FieldTrack.hh"
49 #include "G4EquationOfMotion.hh"
50
51 class G4MagIntegratorStepper;
52
53 class G4VIntegrationDriver
54 {
55 public:
56
57 virtual ~G4VIntegrationDriver() = default;
58
59 virtual G4double AdvanceChordLimited(G4FieldTrack& track,
60 G4double hstep,
61 G4double eps,
62 G4double chordDistance) = 0;
63
64 virtual G4bool AccurateAdvance(G4FieldTrack& track,
65 G4double hstep,
66 G4double eps, // Requested y_err/hstep
67 G4double hinitial = 0 ) = 0;
68
69 virtual void SetEquationOfMotion(G4EquationOfMotion* equation) = 0;
70 virtual G4EquationOfMotion* GetEquationOfMotion() = 0;
71
72 virtual void RenewStepperAndAdjust(G4MagIntegratorStepper* pItsStepper);
73 // Method for compatibility -- relevant only for G4MagIntegratorDriver
74
75 virtual void SetVerboseLevel(G4int level) = 0;
76 virtual G4int GetVerboseLevel() const = 0;
77
78 virtual void OnComputeStep(const G4FieldTrack* /*track*/ = nullptr) = 0;
79
80 virtual void OnStartTracking() = 0;
81
82 public: // without description
83
84 //[[deprecated("will be removed")]]
85 virtual G4bool QuickAdvance(G4FieldTrack& /*track*/, // INOUT
86 const G4double /*dydx*/[],
87 G4double /*hstep*/,
88 G4double& /*dchord_step*/,
89 G4double& /*dyerr*/) { return false; }
90
91 //[[deprecated("will be removed")]]
92 virtual void GetDerivatives(const G4FieldTrack& track,
93 G4double dydx[]) const = 0;
94
95 //[[deprecated("will be removed")]]
96 virtual void GetDerivatives(const G4FieldTrack& track,
97 G4double dydx[],
98 G4double field[]) const = 0;
99
100 //[[deprecated("use GetEquationOfMotion() instead of GetStepper()->GetEquationOfMotion()")]]
101 virtual const G4MagIntegratorStepper* GetStepper() const = 0;
102 virtual G4MagIntegratorStepper* GetStepper() = 0;
103
104 //[[deprecated("will be removed")]]
105 virtual G4double ComputeNewStepSize(G4double errMaxNorm, // normalised error
106 G4double hstepCurrent) = 0;
107 // Taking the last step's normalised error, calculate
108 // a step size for the next step.
109 // - Can limit the next step's size within a factor of the current one.
110
111 virtual G4bool DoesReIntegrate() const = 0;
112 // Whether the driver implementates re-integration
113 // - original Integration driver will re-start and re-calculate interval => yes
114 // - Interpolation Driver does not recalculate (it interpolates)
115 // Basically answer: does this driver *Recalculate* when AccurateAdvance is called ?
116
117 virtual void StreamInfo( std::ostream& os ) const = 0;
118 // Write out the parameters / state of the driver
119
120 friend std::ostream& operator<<( std::ostream& os, const G4VIntegrationDriver& id);
121
122 protected:
123
124 static constexpr G4double max_stepping_increase = 5;
125 static constexpr G4double max_stepping_decrease = 0.1;
126 };
127
128 #endif
129