field04/include/F04GlobalField.hh

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0026 //
0027 /// \file field/field04/include/F04GlobalField.hh
0028 /// \brief Definition of the F04GlobalField class
0029 //
0030
0031 #ifndef F04GlobalField_h
0032 #define F04GlobalField_h 1
0033
0034 #include "F04DetectorConstruction.hh"
0035 #include "F04ElementField.hh"
0036 #include "F04FieldMessenger.hh"
0037
0038 #include "G4ChordFinder.hh"
0039 #include "G4ElectroMagneticField.hh"
0040 #include "G4EqEMFieldWithSpin.hh"
0041 #include "G4EqMagElectricField.hh"
0042 #include "G4FieldManager.hh"
0043 #include "G4MagIntegratorStepper.hh"
0044 #include "G4Mag_EqRhs.hh"
0045 #include "G4Mag_SpinEqRhs.hh"
0046 #include "G4MagneticField.hh"
0047 #include "G4PropagatorInField.hh"
0048
0049 #include <vector>
0050
0051 //  F04GlobalField - handles the global ElectroMagnetic field
0052 //
0053 //  There is a single G04GlobalField object.
0054 //
0055 //  The field from each individual beamline element is given by a
0056 //  ElementField object. Any number of overlapping ElementField
0057 //  objects can be added to the global field. Any element that
0058 //  represents an element with an EM field must add the appropriate
0059 //  ElementField to the global GlobalField object.
0060
0061 using FieldList = std::vector<F04ElementField*>;
0062
0063 class F04GlobalField : public G4ElectroMagneticField
0064 {
0065     // class F04GlobalField : public G4MagneticField {
0066
0067   private:
0068     F04GlobalField(F04DetectorConstruction* const);
0069     F04GlobalField(const F04GlobalField&);
0070
0071     F04GlobalField& operator=(const F04GlobalField&);
0072
0073     void SetupArray();
0074
0075   public:
0076     ~F04GlobalField() override;
0077
0078     /// GetObject() returns the single F04GlobalField object.
0079     /// It is constructed, if necessary.
0080     static F04GlobalField* GetObject(F04DetectorConstruction* const);
0081     static F04GlobalField* GetObject();
0082
0083     /// GetFieldValue() returns the field value at a given point[].
0084     /// field is really field[6]: Bx,By,Bz,Ex,Ey,Ez.
0085     /// point[] is in global coordinates: x,y,z,t.
0086     void GetFieldValue(const G4double* point, G4double* field) const override;
0087
0088     /// DoesFieldChangeEnergy() returns true.
0089     G4bool DoesFieldChangeEnergy() const override { return true; }
0090
0091     /// AddElementField() adds the ElementField object for a single
0092     /// element to the global field.
0093     void AddElementField(F04ElementField* f)
0094     {
0095       if (fFields) fFields->push_back(f);
0096     }
0097
0098     /// Clear() removes all ElementField-s from the global object,
0099     /// and destroys them. Used before the geometry is completely
0100     /// re-created.
0101     void Clear();
0102
0103     /// constructs all field tracking objects
0104     void ConstructField();
0105
0106     /// Set the Stepper types
0107     void SetStepperType(G4int i) { fStepperType = i; }
0108
0109     /// Set the Stepper
0110     void SetStepper();
0111
0112     /// Set the minimum step length
0113     void SetMinStep(G4double stp) { fMinStep = stp; }
0114
0115     /// Set the delta chord length
0116     void SetDeltaChord(G4double dcr) { fDeltaChord = dcr; }
0117
0118     /// Set the delta one step length
0119     void SetDeltaOneStep(G4double stp) { fDeltaOneStep = stp; }
0120
0121     /// Set the delta intersection length
0122     void SetDeltaIntersection(G4double its) { fDeltaIntersection = its; }
0123
0124     /// Set the minimum eps length
0125     void SetEpsMin(G4double eps) { fEpsMin = eps; }
0126
0127     /// Set the maximum eps length
0128     void SetEpsMax(G4double eps) { fEpsMax = eps; }
0129
0130     /// Return the list of Element Fields
0131     FieldList* GetFields() { return fFields; }
0132
0133   protected:
0134     /// Get the global field manager
0135     G4FieldManager* GetGlobalFieldManager();
0136
0137   private:
0138     static G4ThreadLocal F04GlobalField* fObject;
0139
0140     G4int fNfp = 0;
0141     G4bool fFirst = true;
0142
0143     FieldList* fFields = nullptr;
0144
0145     const F04ElementField** fFp = nullptr;
0146
0147   private:
0148     // A. INVARIANTS:
0149     // --------------
0150     // INVARIANT: an integer to indicate the type of RK integration method ('stepper') used
0151     G4int fStepperType = 4;  // ClassicalRK4 is default stepper;
0152
0153     // INVARIANTS: Accuracy parameters of field propagation (and the integration it uses.)
0154     // 1. These values are lengths - initialised in src
0155     G4double fMinStep = 0.01 * CLHEP::mm;
0156     G4double fDeltaChord = 3.0 * CLHEP::mm;
0157     G4double fDeltaOneStep = 0.01 * CLHEP::mm;
0158     G4double fDeltaIntersection = 0.1 * CLHEP::mm;
0159     // 2. Dimensionless numbers - can initialise here
0160     G4double fEpsMin = 2.5e-7;  // Relative accuracy of integration (minimum)
0161     G4double fEpsMax = 0.001;  // Relative accuracy of integration (maximum)
0162
0163     // B. STATE: objects which carry out the propagation and are modified during tracking
0164     // --------
0165     //  G4Mag_EqRhs*            fEquation;
0166     //  G4Mag_SpinEqRhs*        fEquation;
0167
0168     //  G4EqMagElectricField*   fEquation;
0169     G4EqEMFieldWithSpin* fEquation = nullptr;
0170
0171     G4FieldManager* fFieldManager = nullptr;
0172     G4PropagatorInField* fFieldPropagator = nullptr;
0173     G4MagIntegratorStepper* fStepper = nullptr;
0174     G4ChordFinder* fChordFinder = nullptr;
0175
0176     // INVARIANTS during tracking: Auxiliary class & information - used for setup
0177     F04FieldMessenger* fFieldMessenger;
0178     F04DetectorConstruction* fDetectorConstruction = nullptr;
0179 };
0180
0181 #endif