include/Geant4/G4TCachedMagneticField.hh

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0025 //
0026 // G4TCachedMagneticField
0027
0028 // Author: Josh Xie (CERN, Google Summer of Code 2014), June 2014
0029 // Supervisors:  Sandro Wenzel, John Apostolakis (CERN)
0030 // --------------------------------------------------------------------
0031 #ifndef G4TCACHED_MAGNETIC_FIELD_HH
0032 #define G4TCACHED_MAGNETIC_FIELD_HH
0033
0034 #include "G4Types.hh"
0035 #include "G4ThreeVector.hh"
0036 #include "G4MagneticField.hh"
0037
0038 /**
0039  * @brief G4TCachedMagneticField is a templated implementation for a specialisation
0040  * of G4MagneticField used to cache the Magnetic Field value.
0041  */
0042
0043 template <class T_Field>
0044 class G4TCachedMagneticField : public G4MagneticField
0045 {
0046   public:
0047
0048     G4TCachedMagneticField(T_Field* pTField, G4double distance)
0049       : G4MagneticField()
0050       , fLastLocation(DBL_MAX, DBL_MAX, DBL_MAX)
0051       , fLastValue(DBL_MAX, DBL_MAX, DBL_MAX)
0052       , fCountCalls(0)
0053       , fCountEvaluations(0)
0054     {
0055       fpMagneticField = pTField;
0056       fDistanceConst  = distance;
0057
0058       this->ClearCounts();
0059     }
0060
0061     virtual ~G4TCachedMagneticField() = default;
0062
0063     G4TCachedMagneticField(const G4TCachedMagneticField<T_Field>& rightCMF)
0064     {
0065       fpMagneticField = rightCMF.fpMagneticField;
0066       fDistanceConst  = rightCMF.fDistanceConst;
0067       fLastLocation   = rightCMF.fLastLocation;
0068       fLastValue      = rightCMF.fLastValue;
0069       this->ClearCounts();
0070     }
0071
0072     G4TCachedMagneticField& operator=(const G4TCachedMagneticField& right)
0073     {
0074       if(&right == this) { return *this; }
0075
0076       fpMagneticField = right.fpMagneticField;
0077
0078       fDistanceConst= right.fDistanceConst;
0079       fLastLocation = right.fLastLocation;
0080       fLastValue = right.fLastValue;
0081
0082       fCountCalls = 0;
0083       fCountEvaluations = 0;
0084
0085       return *this;
0086     }
0087
0088     G4TCachedMagneticField* Clone() const
0089     {
0090       G4cout << "Clone is called" << G4endl;
0091       // Cannot use copy constructor: I need to clone associated magnetic field
0092       T_Field* aF = this->fpMagneticField->T_Field::Clone();
0093       G4TCachedMagneticField* cloned = new G4TCachedMagneticField(aF, this->fDistanceConst);
0094       cloned->fLastLocation = this->fLastLocation;
0095       cloned->fLastValue    = this->fLastValue;
0096       return cloned;
0097     }
0098
0099     void ReportStatistics()
0100     {
0101       G4cout << " Cached field: " << G4endl
0102              << "   Number of calls:        " << fCountCalls << G4endl
0103              << "   Number of evaluations : " << fCountEvaluations << G4endl;
0104     }
0105
0106     virtual void GetFieldValue(const G4double Point[4], G4double* Bfield) const
0107     {
0108       G4ThreeVector newLocation(Point[0], Point[1], Point[2]);
0109
0110       G4double distSq = (newLocation - fLastLocation).mag2();
0111       fCountCalls++;
0112       if(distSq < fDistanceConst * fDistanceConst)
0113       {
0114         Bfield[0] = fLastValue.x();
0115         Bfield[1] = fLastValue.y();
0116         Bfield[2] = fLastValue.z();
0117       }
0118       else
0119       {
0120         fpMagneticField->T_Field::GetFieldValue(Point, Bfield);
0121         fCountEvaluations++;
0122         fLastLocation = G4ThreeVector(Point[0], Point[1], Point[2]);
0123         fLastValue = G4ThreeVector(Bfield[0], Bfield[1], Bfield[2]);
0124       }
0125     }
0126
0127     G4double GetConstDistance() const { return fDistanceConst; }
0128     void SetConstDistance(G4double dist) { fDistanceConst = dist; }
0129
0130     G4int GetCountCalls() const { return fCountCalls; }
0131     G4int GetCountEvaluations() const { return fCountEvaluations; }
0132     void ClearCounts()
0133     {
0134       fCountCalls       = 0;
0135       fCountEvaluations = 0;
0136     }
0137
0138   protected:
0139
0140     mutable G4int fCountCalls, fCountEvaluations;
0141
0142   private:
0143
0144     T_Field* fpMagneticField;
0145
0146     /** When the field is evaluated within this distance it will not change. */
0147     G4double fDistanceConst;
0148
0149     /** Caching state. */
0150     mutable G4ThreeVector fLastLocation;
0151     mutable G4ThreeVector fLastValue;
0152 };
0153
0154 #endif