1 | // |
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2 | // ******************************************************************** |
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3 | // * License and Disclaimer * |
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4 | // * * |
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5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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7 | // * conditions of the Geant4 Software License, included in the file * |
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8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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9 | // * include a list of copyright holders. * |
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10 | // * * |
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11 | // * Neither the authors of this software system, nor their employing * |
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12 | // * institutes,nor the agencies providing financial support for this * |
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13 | // * work make any representation or warranty, express or implied, * |
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14 | // * regarding this software system or assume any liability for its * |
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15 | // * use. Please see the license in the file LICENSE and URL above * |
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16 | // * for the full disclaimer and the limitation of liability. * |
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17 | // * * |
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18 | // * This code implementation is the result of the scientific and * |
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19 | // * technical work of the GEANT4 collaboration. * |
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20 | // * By using, copying, modifying or distributing the software (or * |
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21 | // * any work based on the software) you agree to acknowledge its * |
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22 | // * use in resulting scientific publications, and indicate your * |
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23 | // * acceptance of all terms of the Geant4 Software license. * |
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24 | // ******************************************************************** |
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25 | // |
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26 | // |
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27 | // $Id: G4ClassicalRK4.hh,v 1.10 2006/06/29 18:21:55 gunter Exp $ |
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28 | // GEANT4 tag $Name: HEAD $ |
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29 | // |
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30 | // |
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31 | // class G4ClassicalRK4 |
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32 | // |
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33 | // Class description: |
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34 | // |
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35 | // Integrate the equations of the motion of a particle in a magnetic field |
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36 | // using the classical 4th Runge-Kutta method. |
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37 | |
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38 | // History: |
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39 | // - Created: J.Apostolakis, V.Grichine - 30.1.97 |
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40 | // - Moved into G4MagErrorStepper: W.Wander <wwc@mit.edu> - 12/09/97 |
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41 | // ------------------------------------------------------------------- |
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42 | |
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43 | #include "G4MagErrorStepper.hh" |
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44 | |
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45 | class G4ClassicalRK4 : public G4MagErrorStepper |
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46 | { |
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47 | public: // with description |
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48 | |
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49 | G4ClassicalRK4(G4EquationOfMotion *EquationMotion, G4int numberOfVariables = 6) ; |
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50 | |
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51 | ~G4ClassicalRK4() ; |
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52 | |
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53 | // A stepper that does not know about errors. |
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54 | // It is used by the MagErrorStepper stepper. |
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55 | |
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56 | void DumbStepper( const G4double yIn[], |
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57 | const G4double dydx[], |
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58 | G4double h, |
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59 | G4double yOut[] ) ; |
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60 | // Given values for the variables y[0,..,n-1] and their derivatives |
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61 | // dydx[0,...,n-1] known at x, use the classical 4th Runge-Kutta |
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62 | // method to advance the solution over an interval h and return the |
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63 | // incremented variables as yout[0,...,n-1], which not be a distinct |
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64 | // array from y. The user supplies the routine RightHandSide(x,y,dydx), |
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65 | // which returns derivatives dydx at x. The source is routine rk4 from |
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66 | // NRC p. 712-713 . |
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67 | |
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68 | public: // without description |
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69 | |
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70 | G4int IntegratorOrder() const { return 4; } |
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71 | |
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72 | private: |
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73 | |
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74 | void StepWithEst( const G4double yIn[], |
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75 | const G4double dydx[], |
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76 | G4double h, |
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77 | G4double yOut[], |
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78 | G4double& alpha2, |
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79 | G4double& beta2, |
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80 | const G4double B1[], |
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81 | G4double B2[] ); |
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82 | // No longer used. Obsolete. |
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83 | |
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84 | G4ClassicalRK4(const G4ClassicalRK4&); |
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85 | G4ClassicalRK4& operator=(const G4ClassicalRK4&); |
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86 | // Private copy constructor and assignment operator. |
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87 | |
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88 | private: |
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89 | |
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90 | // G4int fNumberOfVariables ; // is set default to 6 in constructor |
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91 | |
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92 | G4double *dydxm, *dydxt, *yt; // scratch space - not state |
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93 | }; |
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