include/Geant4/G4CachedMagneticField.hh

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0025 //
0026 // G4CachedMagneticField
0027 //
0028 // Class description:
0029 //
0030 // Caches Magnetic Field value, for field whose evaluation is expensive.
0031
0032 // Author: John Apostolakis (CERN), 20.07.2009.
0033 // --------------------------------------------------------------------
0034 #ifndef G4CACHED_MAGNETIC_FIELD_HH
0035 #define G4CACHED_MAGNETIC_FIELD_HH
0036
0037 #include "G4Types.hh"
0038 #include "G4ThreeVector.hh"
0039 #include "G4MagneticField.hh"
0040
0041 /**
0042  * @brief G4CachedMagneticField is a specialisation of G4MagneticField and
0043  * is used to cache the Magnetic Field value, for fields whose evaluation is
0044  * expensive.
0045  */
0046
0047 class G4CachedMagneticField : public G4MagneticField
0048 {
0049   public:
0050
0051     /**
0052      * Constructor for G4CachedMagneticField.
0053      *  @param[in] pMagField Pointer to the original magnetic field.
0054      *  @param[in] distance Distance for field evaluation, within
0055      *             which the field does not change.
0056      */
0057     G4CachedMagneticField(G4MagneticField* pMagField, G4double distance);
0058
0059     /**
0060      * Default Destructor.
0061      */
0062     ~G4CachedMagneticField() override = default;
0063
0064     /**
0065      * Copy constructor and assignment operator.
0066      */
0067     G4CachedMagneticField(const G4CachedMagneticField& r);
0068     G4CachedMagneticField& operator = (const G4CachedMagneticField& p);
0069
0070     /**
0071      * Returns the value of the field at the give 'Point'.
0072      *  @param[in] Point The given position time vector (x,y,z,t).
0073      *  @param[out] Bfield The returned field array.
0074      */
0075     void GetFieldValue( const G4double Point[4],
0076                               G4double* Bfield ) const override;
0077
0078     /**
0079      * Getter and setter for the distance within which field is constant.
0080      */
0081     inline G4double GetConstDistance() const { return fDistanceConst; }
0082     inline void SetConstDistance( G4double dist ) { fDistanceConst = dist;}
0083
0084     /**
0085      * Accessors.
0086      */
0087     inline G4int GetCountCalls() const { return fCountCalls; }
0088     inline G4int GetCountEvaluations() const { return fCountEvaluations; }
0089
0090     /**
0091      * Resets counters.
0092      */
0093     inline void ClearCounts() { fCountCalls = 0; fCountEvaluations=0; }
0094
0095     /**
0096      * Streams on standard output the values of counters.
0097      */
0098     void ReportStatistics();
0099
0100     /**
0101      * Returns a pointer of an allocated clone of the field.
0102      */
0103     G4Field* Clone() const override;
0104
0105   protected:
0106
0107     mutable G4int fCountCalls = 0, fCountEvaluations = 0;
0108
0109   private:
0110
0111     G4MagneticField* fpMagneticField = nullptr;
0112
0113     /** When the field is evaluated within this distance it will not change. */
0114     G4double fDistanceConst;
0115
0116     /** Caching state. */
0117     mutable G4ThreeVector fLastLocation;
0118     mutable G4ThreeVector fLastValue;
0119 };
0120
0121 #endif