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: G4SimpleHeum.cc,v 1.8 2006/06/29 18:24:51 gunter Exp $ |
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28 | // GEANT4 tag $Name: $ |
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29 | // |
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30 | // Simple Heum: |
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31 | // x_1 = x_0 + h * |
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32 | // 1/4 * dx(t0,x0) + |
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33 | // 3/4 * dx(t0+2/3*h, x0+2/3*h*(dx(t0+h/3,x0+h/3*dx(t0,x0)))) |
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34 | // |
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35 | // Third order solver. |
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36 | // |
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37 | // W.Wander <wwc@mit.edu> 12/09/97 |
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38 | // ------------------------------------------------------------------- |
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39 | |
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40 | #include "G4SimpleHeum.hh" |
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41 | #include "G4ThreeVector.hh" |
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42 | |
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43 | /////////////////////////////////////////////////////////////////////////// |
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44 | // |
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45 | // Constructor |
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46 | |
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47 | G4SimpleHeum::G4SimpleHeum(G4EquationOfMotion *EqRhs, G4int num_variables): |
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48 | G4MagErrorStepper(EqRhs, num_variables), |
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49 | fNumberOfVariables(num_variables) |
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50 | { |
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51 | dydxTemp = new G4double[fNumberOfVariables] ; |
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52 | dydxTemp2 = new G4double[fNumberOfVariables] ; |
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53 | yTemp = new G4double[fNumberOfVariables] ; |
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54 | yTemp2 = new G4double[fNumberOfVariables] ; |
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55 | } |
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56 | |
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57 | |
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58 | ////////////////////////////////////////////////////////////////////////// |
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59 | // |
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60 | // Destructor |
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61 | |
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62 | G4SimpleHeum::~G4SimpleHeum() |
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63 | { |
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64 | delete[] dydxTemp; |
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65 | delete[] dydxTemp2; |
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66 | delete[] yTemp; |
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67 | delete[] yTemp2; |
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68 | } |
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69 | |
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70 | |
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71 | ////////////////////////////////////////////////////////////////////// |
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72 | // |
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73 | // |
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74 | |
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75 | void |
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76 | G4SimpleHeum::DumbStepper( const G4double yIn[], |
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77 | const G4double dydx[], |
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78 | G4double h, |
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79 | G4double yOut[]) |
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80 | { |
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81 | // const G4int nvar = 6 ; |
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82 | |
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83 | G4int i; |
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84 | |
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85 | for( i = 0; i < fNumberOfVariables; i++ ) |
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86 | { |
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87 | yTemp[i] = yIn[i] + (1.0/3.0) * h * dydx[i] ; |
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88 | } |
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89 | |
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90 | RightHandSide(yTemp,dydxTemp); |
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91 | |
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92 | for( i = 0; i < fNumberOfVariables; i++ ) |
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93 | { |
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94 | yTemp2[i] = yIn[i] + (2.0/3.0) * h * dydxTemp[i] ; |
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95 | } |
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96 | |
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97 | RightHandSide(yTemp2,dydxTemp2); |
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98 | |
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99 | for( i = 0; i < fNumberOfVariables; i++ ) |
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100 | { |
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101 | yOut[i] = yIn[i] + h * ( 0.25 * dydx[i] + |
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102 | 0.75 * dydxTemp2[i]); |
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103 | } |
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104 | |
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105 | // NormaliseTangentVector( yOut ); |
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106 | } |
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