field04/include/F04GlobalField.hh

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0025 //
0026 /// \file F04GlobalField.hh
0027 /// \brief Definition of the F04GlobalField class
0028
0029 #ifndef F04GlobalField_h
0030 #define F04GlobalField_h 1
0031
0032 #include "F04DetectorConstruction.hh"
0033 #include "F04ElementField.hh"
0034 #include "F04FieldMessenger.hh"
0035
0036 #include "G4ChordFinder.hh"
0037 #include "G4ElectroMagneticField.hh"
0038 #include "G4EqEMFieldWithSpin.hh"
0039 #include "G4EqMagElectricField.hh"
0040 #include "G4FieldManager.hh"
0041 #include "G4MagIntegratorStepper.hh"
0042 #include "G4Mag_EqRhs.hh"
0043 #include "G4Mag_SpinEqRhs.hh"
0044 #include "G4MagneticField.hh"
0045 #include "G4PropagatorInField.hh"
0046
0047 #include <vector>
0048
0049 //  F04GlobalField - handles the global ElectroMagnetic field
0050 //
0051 //  There is a single G04GlobalField object.
0052 //
0053 //  The field from each individual beamline element is given by a
0054 //  ElementField object. Any number of overlapping ElementField
0055 //  objects can be added to the global field. Any element that
0056 //  represents an element with an EM field must add the appropriate
0057 //  ElementField to the global GlobalField object.
0058
0059 using FieldList = std::vector<F04ElementField*>;
0060
0061 class F04GlobalField : public G4ElectroMagneticField
0062 {
0063     // class F04GlobalField : public G4MagneticField {
0064
0065   private:
0066     F04GlobalField(F04DetectorConstruction* const);
0067     F04GlobalField(const F04GlobalField&);
0068
0069     F04GlobalField& operator=(const F04GlobalField&);
0070
0071     void SetupArray();
0072
0073   public:
0074     ~F04GlobalField() override;
0075
0076     /// GetObject() returns the single F04GlobalField object.
0077     /// It is constructed, if necessary.
0078     static F04GlobalField* GetObject(F04DetectorConstruction* const);
0079     static F04GlobalField* GetObject();
0080
0081     /// GetFieldValue() returns the field value at a given point[].
0082     /// field is really field[6]: Bx,By,Bz,Ex,Ey,Ez.
0083     /// point[] is in global coordinates: x,y,z,t.
0084     void GetFieldValue(const G4double* point, G4double* field) const override;
0085
0086     /// DoesFieldChangeEnergy() returns true.
0087     G4bool DoesFieldChangeEnergy() const override { return true; }
0088
0089     /// AddElementField() adds the ElementField object for a single
0090     /// element to the global field.
0091     void AddElementField(F04ElementField* f)
0092     {
0093       if (fFields) fFields->push_back(f);
0094     }
0095
0096     /// Clear() removes all ElementField-s from the global object,
0097     /// and destroys them. Used before the geometry is completely
0098     /// re-created.
0099     void Clear();
0100
0101     /// constructs all field tracking objects
0102     void ConstructField();
0103
0104     /// Set the Stepper types
0105     void SetStepperType(G4int i) { fStepperType = i; }
0106
0107     /// Set the Stepper
0108     void SetStepper();
0109
0110     /// Set the minimum step length
0111     void SetMinStep(G4double stp) { fMinStep = stp; }
0112
0113     /// Set the delta chord length
0114     void SetDeltaChord(G4double dcr) { fDeltaChord = dcr; }
0115
0116     /// Set the delta one step length
0117     void SetDeltaOneStep(G4double stp) { fDeltaOneStep = stp; }
0118
0119     /// Set the delta intersection length
0120     void SetDeltaIntersection(G4double its) { fDeltaIntersection = its; }
0121
0122     /// Set the minimum eps length
0123     void SetEpsMin(G4double eps) { fEpsMin = eps; }
0124
0125     /// Set the maximum eps length
0126     void SetEpsMax(G4double eps) { fEpsMax = eps; }
0127
0128     /// Return the list of Element Fields
0129     FieldList* GetFields() { return fFields; }
0130
0131   protected:
0132     /// Get the global field manager
0133     G4FieldManager* GetGlobalFieldManager();
0134
0135   private:
0136     static G4ThreadLocal F04GlobalField* fObject;
0137
0138     G4int fNfp = 0;
0139     G4bool fFirst = true;
0140
0141     FieldList* fFields = nullptr;
0142
0143     const F04ElementField** fFp = nullptr;
0144
0145   private:
0146     // A. INVARIANTS:
0147     // --------------
0148     // INVARIANT: an integer to indicate the type of RK integration method ('stepper') used
0149     G4int fStepperType = 4;  // ClassicalRK4 is default stepper;
0150
0151     // INVARIANTS: Accuracy parameters of field propagation (and the integration it uses.)
0152     // 1. These values are lengths - initialised in src
0153     G4double fMinStep = 0.01 * CLHEP::mm;
0154     G4double fDeltaChord = 3.0 * CLHEP::mm;
0155     G4double fDeltaOneStep = 0.01 * CLHEP::mm;
0156     G4double fDeltaIntersection = 0.1 * CLHEP::mm;
0157     // 2. Dimensionless numbers - can initialise here
0158     G4double fEpsMin = 2.5e-7;  // Relative accuracy of integration (minimum)
0159     G4double fEpsMax = 0.001;  // Relative accuracy of integration (maximum)
0160
0161     // B. STATE: objects which carry out the propagation and are modified during tracking
0162     // --------
0163     //  G4Mag_EqRhs*            fEquation;
0164     //  G4Mag_SpinEqRhs*        fEquation;
0165
0166     //  G4EqMagElectricField*   fEquation;
0167     G4EqEMFieldWithSpin* fEquation = nullptr;
0168
0169     G4FieldManager* fFieldManager = nullptr;
0170     G4PropagatorInField* fFieldPropagator = nullptr;
0171     G4MagIntegratorStepper* fStepper = nullptr;
0172     G4ChordFinder* fChordFinder = nullptr;
0173
0174     // INVARIANTS during tracking: Auxiliary class & information - used for setup
0175     F04FieldMessenger* fFieldMessenger;
0176     F04DetectorConstruction* fDetectorConstruction = nullptr;
0177 };
0178
0179 #endif