include/Geant4/G4FSALIntegrationDriver.hh

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0025 //
0026 // G4FSALIntegrationDriver
0027 //
0028 // Class description:
0029 //
0030 // Driver class which controls the integration error of a Runge-Kutta stepper
0031
0032 // Created: D.Sorokin, 2017
0033 // --------------------------------------------------------------------
0034 #ifndef G4FSALINTEGRATIONDRIVER_HH
0035 #define G4FSALINTEGRATIONDRIVER_HH
0036
0037 #include "G4RKIntegrationDriver.hh"
0038 #include "G4ChordFinderDelegate.hh"
0039
0040 template <class T>
0041 class G4FSALIntegrationDriver : public G4RKIntegrationDriver<T>,
0042                        public G4ChordFinderDelegate<G4FSALIntegrationDriver<T>>
0043 {
0044   public:
0045
0046     G4FSALIntegrationDriver(G4double hminimum,
0047                             T*       stepper,
0048                             G4int    numberOfComponents = 6,
0049                             G4int    statisticsVerbosity = 1);
0050
0051    ~G4FSALIntegrationDriver() override;
0052
0053     G4FSALIntegrationDriver(const G4FSALIntegrationDriver&) = delete;
0054     G4FSALIntegrationDriver& operator=(const G4FSALIntegrationDriver&) = delete;
0055
0056     G4double AdvanceChordLimited(G4FieldTrack& track,
0057                                  G4double hstep,
0058                                  G4double eps,
0059                                  G4double chordDistance) override;
0060
0061     void OnStartTracking() override
0062     {
0063       ChordFinderDelegate::ResetStepEstimate();
0064     }
0065
0066     void OnComputeStep(const G4FieldTrack* /*track*/ = nullptr) override {}
0067
0068     G4bool DoesReIntegrate() const override { return true; }
0069
0070     G4bool AccurateAdvance( G4FieldTrack& track,
0071                             G4double hstep,
0072                             G4double eps, // Requested y_err/hstep
0073                             G4double hinitial = 0.0) override;
0074       // Integrates ODE from current s (s=s0) to s=s0+h with accuracy eps.
0075       // On output track is replaced by value at end of interval.
0076       // The concept is similar to the odeint routine from NRC p.721-722.
0077
0078     G4bool QuickAdvance(       G4FieldTrack& fieldTrack,
0079                          const G4double dydx[],
0080                                G4double hstep,
0081                                G4double& dchord_step,
0082                                G4double& dyerr ) override;
0083       // QuickAdvance just tries one Step - it does not ensure accuracy.
0084
0085     void SetVerboseLevel(G4int newLevel) override;
0086     G4int GetVerboseLevel() const override;
0087
0088     void StreamInfo( std::ostream& os ) const override;
0089      // Write out the parameters / state of the driver
0090
0091     // Accessors
0092
0093     G4double GetMinimumStep() const;
0094     void SetMinimumStep(G4double newval);
0095
0096     void OneGoodStep(G4double y[],  // InOut
0097                      G4double dydx[],
0098                      G4double& curveLength,
0099                      G4double htry,
0100                      G4double eps,
0101                      G4double& hdid,
0102                      G4double& hnext);
0103       // This takes one Step that is of size htry, or as large
0104       // as possible while satisfying the accuracy criterion of:
0105       //     yerr < eps * |y_end-y_start|
0106
0107     G4double GetSmallestFraction() const;
0108     void SetSmallestFraction(G4double val);
0109
0110   protected:
0111
0112     void IncrementQuickAdvanceCalls();
0113
0114   private:
0115
0116     void CheckStep(const G4ThreeVector& posIn,
0117                    const G4ThreeVector& posOut,
0118                          G4double hdid);
0119
0120     G4double fMinimumStep;
0121       // Minimum Step allowed in a Step (in absolute units)
0122
0123     G4double fSmallestFraction{1e-12};
0124       // Smallest fraction of (existing) curve length - in relative units
0125       // below this fraction the current step will be the last
0126       // Expected range: smaller than 0.1 * epsilon and bigger than 5e-13
0127       //    ( Note: this range is not enforced. )
0128
0129     G4int fVerboseLevel;
0130       // Verbosity level for printing (debug, ..)
0131       // Could be varied during tracking - to help identify issues
0132
0133     G4int fNoQuickAvanceCalls{0};
0134     G4int fNoAccurateAdvanceCalls{0};
0135     G4int fNoAccurateAdvanceBadSteps{0};
0136     G4int fNoAccurateAdvanceGoodSteps{0};
0137
0138     using Base = G4RKIntegrationDriver<T>;
0139     using ChordFinderDelegate = G4ChordFinderDelegate<G4FSALIntegrationDriver<T>>;
0140 };
0141
0142 #include "G4FSALIntegrationDriver.icc"
0143
0144 #endif