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: G4HelixHeum.cc,v 1.6 2006/06/29 18:24:04 gunter Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-02-cand-01 $ |
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29 | // |
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30 | // |
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31 | // Simple Heum: |
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32 | // x_1 = x_0 + h * |
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33 | // 1/4 * dx(t0,x0) + |
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34 | // 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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35 | // |
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36 | // Third order solver. |
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37 | // |
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38 | // W.Wander <wwc@mit.edu> 12/09/97 |
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39 | // ------------------------------------------------------------------- |
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40 | |
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41 | #include "G4HelixHeum.hh" |
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42 | #include "G4ThreeVector.hh" |
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43 | |
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44 | void |
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45 | G4HelixHeum::DumbStepper( const G4double yIn[], |
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46 | G4ThreeVector Bfld, |
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47 | G4double h, |
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48 | G4double yOut[]) |
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49 | { |
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50 | const G4int nvar = 6 ; |
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51 | |
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52 | G4ThreeVector Bfield_Temp, Bfield_Temp2; |
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53 | G4double yTemp[6], yAdd1[6], yAdd2[6] , yTemp2[6]; |
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54 | |
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55 | G4int i; |
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56 | |
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57 | AdvanceHelix( yIn, Bfld, h, yAdd1 ); |
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58 | |
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59 | AdvanceHelix( yIn, Bfld, h/3.0, yTemp ); |
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60 | MagFieldEvaluate(yTemp,Bfield_Temp); |
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61 | |
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62 | AdvanceHelix( yIn, Bfield_Temp, (2.0 / 3.0) * h, yTemp2 ); |
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63 | |
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64 | MagFieldEvaluate(yTemp2,Bfield_Temp2); |
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65 | |
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66 | AdvanceHelix( yIn, Bfield_Temp2, h, yAdd2 ); |
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67 | |
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68 | for( i = 0; i < nvar; i++ ) { |
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69 | yOut[i] = ( 0.25 * yAdd1[i] + 0.75 * yAdd2[i]); |
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70 | } |
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71 | |
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72 | // NormaliseTangentVector( yOut ); |
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73 | } |
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