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25 //
26 // G4FSALIntegrationDriver
27 //
28 // Class description:
29 //
30 // Driver class which controls the integration error of a Runge-Kutta stepper
31
32 // Created: D.Sorokin, 2017
33 // --------------------------------------------------------------------
34 #ifndef G4FSALINTEGRATIONDRIVER_HH
35 #define G4FSALINTEGRATIONDRIVER_HH
36
37 #include "G4RKIntegrationDriver.hh"
38 #include "G4ChordFinderDelegate.hh"
39
40 template <class T>
41 class G4FSALIntegrationDriver : public G4RKIntegrationDriver<T>,
42 public G4ChordFinderDelegate<G4FSALIntegrationDriver<T>>
43 {
44 public:
45
46 G4FSALIntegrationDriver(G4double hminimum,
47 T* stepper,
48 G4int numberOfComponents = 6,
49 G4int statisticsVerbosity = 1);
50
51 ~G4FSALIntegrationDriver() override;
52
53 G4FSALIntegrationDriver(const G4FSALIntegrationDriver&) = delete;
54 G4FSALIntegrationDriver& operator=(const G4FSALIntegrationDriver&) = delete;
55
56 G4double AdvanceChordLimited(G4FieldTrack& track,
57 G4double hstep,
58 G4double eps,
59 G4double chordDistance) override;
60
61 void OnStartTracking() override
62 {
63 ChordFinderDelegate::ResetStepEstimate();
64 }
65
66 void OnComputeStep(const G4FieldTrack* /*track*/ = nullptr) override {}
67
68 G4bool DoesReIntegrate() const override { return true; }
69
70 G4bool AccurateAdvance( G4FieldTrack& track,
71 G4double hstep,
72 G4double eps, // Requested y_err/hstep
73 G4double hinitial = 0.0) override;
74 // Integrates ODE from current s (s=s0) to s=s0+h with accuracy eps.
75 // On output track is replaced by value at end of interval.
76 // The concept is similar to the odeint routine from NRC p.721-722.
77
78 G4bool QuickAdvance( G4FieldTrack& fieldTrack,
79 const G4double dydx[],
80 G4double hstep,
81 G4double& dchord_step,
82 G4double& dyerr ) override;
83 // QuickAdvance just tries one Step - it does not ensure accuracy.
84
85 void SetVerboseLevel(G4int newLevel) override;
86 G4int GetVerboseLevel() const override;
87
88 void StreamInfo( std::ostream& os ) const override;
89 // Write out the parameters / state of the driver
90
91 // Accessors
92
93 G4double GetMinimumStep() const;
94 void SetMinimumStep(G4double newval);
95
96 void OneGoodStep(G4double y[], // InOut
97 G4double dydx[],
98 G4double& curveLength,
99 G4double htry,
100 G4double eps,
101 G4double& hdid,
102 G4double& hnext);
103 // This takes one Step that is of size htry, or as large
104 // as possible while satisfying the accuracy criterion of:
105 // yerr < eps * |y_end-y_start|
106
107 G4double GetSmallestFraction() const;
108 void SetSmallestFraction(G4double val);
109
110 protected:
111
112 void IncrementQuickAdvanceCalls();
113
114 private:
115
116 void CheckStep(const G4ThreeVector& posIn,
117 const G4ThreeVector& posOut,
118 G4double hdid);
119
120 G4double fMinimumStep;
121 // Minimum Step allowed in a Step (in absolute units)
122
123 G4double fSmallestFraction{1e-12};
124 // Smallest fraction of (existing) curve length - in relative units
125 // below this fraction the current step will be the last
126 // Expected range: smaller than 0.1 * epsilon and bigger than 5e-13
127 // ( Note: this range is not enforced. )
128
129 G4int fVerboseLevel;
130 // Verbosity level for printing (debug, ..)
131 // Could be varied during tracking - to help identify issues
132
133 G4int fNoQuickAvanceCalls{0};
134 G4int fNoAccurateAdvanceCalls{0};
135 G4int fNoAccurateAdvanceBadSteps{0};
136 G4int fNoAccurateAdvanceGoodSteps{0};
137
138 using Base = G4RKIntegrationDriver<T>;
139 using ChordFinderDelegate = G4ChordFinderDelegate<G4FSALIntegrationDriver<T>>;
140 };
141
142 #include "G4FSALIntegrationDriver.icc"
143
144 #endif
145