| Geant4 Cross Reference |
1 //
2 // ********************************************************************
3 // * License and Disclaimer *
4 // * *
5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. *
10 // * *
11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitation of liability. *
17 // * *
18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboration. *
20 // * By using, copying, modifying or distributing the software (or *
21 // * any work based on the software) you agree to acknowledge its *
22 // * use in resulting scientific publications, and indicate your *
23 // * acceptance of all terms of the Geant4 Software license. *
24 // ********************************************************************
25 //
26 // G4ExactHelixStepper
27 //
28 // Class description:
29 //
30 // Concrete class for particle motion in constant magnetic field.
31 // Helix a-la-Explicity Euler: x_1 = x_0 + helix(h)
32 // with helix(h) being a helix piece of length h.
33 // simplest approach for solving linear differential equations.
34 // Take the current derivative and add it to the current position.
35 //
36 // As the field is assumed constant, an error is not calculated.
37
38 // Author: J.Apostolakis, 28.01.2005.
39 // Implementation adapted from ExplicitEuler by W.Wander
40 // --------------------------------------------------------------------
41 #ifndef G4EXACTHELIXSTEPPER_HH
42 #define G4EXACTHELIXSTEPPER_HH
43
44 #include "G4Types.hh"
45 #include "G4ThreeVector.hh"
46
47 #include "G4MagIntegratorStepper.hh"
48 #include "G4MagHelicalStepper.hh"
49 #include "G4Mag_EqRhs.hh"
50
51 class G4ExactHelixStepper : public G4MagHelicalStepper
52 {
53 public:
54
55 G4ExactHelixStepper(G4Mag_EqRhs* EqRhs);
56 ~G4ExactHelixStepper() override;
57
58 G4ExactHelixStepper(const G4ExactHelixStepper&) = delete;
59 G4ExactHelixStepper& operator=(const G4ExactHelixStepper&) = delete;
60
61 void Stepper( const G4double y[],
62 const G4double dydx[],
63 G4double h,
64 G4double yout[],
65 G4double yerr[] ) override;
66 // Step 'integration' for step size 'h'
67 // Provides helix starting at y[0 to 6]
68 // Outputs yout[] and ZERO estimated error yerr[]=0.
69
70 void DumbStepper( const G4double y[],
71 G4ThreeVector Bfld,
72 G4double h,
73 G4double yout[] ) override;
74 // Performs a 'dump' Step without error calculation.
75
76 G4double DistChord() const override;
77 // Estimate maximum distance of curved solution and chord ...
78
79 G4int IntegratorOrder() const override;
80
81 private:
82
83 G4ThreeVector fBfieldValue;
84 // Initial value of field at last step
85 };
86
87 #endif
88