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>> 1 // This code implementation is the intellectual property of >> 2 // the GEANT4 collaboration. 1 // 3 // 2 // ******************************************* << 4 // By copying, distributing or modifying the Program (or any work 3 // * License and Disclaimer << 5 // based on the Program) you indicate your acceptance of this statement, 4 // * << 6 // and all its terms. 5 // * The Geant4 software is copyright of th << 6 // * the Geant4 Collaboration. It is provided << 7 // * conditions of the Geant4 Software License << 8 // * LICENSE and available at http://cern.ch/ << 9 // * include a list of copyright holders. << 10 // * << 11 // * Neither the authors of this software syst << 12 // * institutes,nor the agencies providing fin << 13 // * work make any representation or warran << 14 // * regarding this software system or assum << 15 // * use. Please see the license in the file << 16 // * for the full disclaimer and the limitatio << 17 // * << 18 // * This code implementation is the result << 19 // * technical work of the GEANT4 collaboratio << 20 // * By using, copying, modifying or distri << 21 // * any work based on the software) you ag << 22 // * use in resulting scientific publicati << 23 // * acceptance of all terms of the Geant4 Sof << 24 // ******************************************* << 25 // 7 // 26 // G4HelixExplicitEuler implementation << 8 // $Id: G4HelixExplicitEuler.cc,v 1.3 2000/04/12 18:29:26 japost Exp $ >> 9 // GEANT4 tag $Name: geant4-03-00 $ 27 // 10 // 28 // Helix Explicit Euler: x_1 = x_0 + helix(h) << 29 // with helix(h) being a helix piece of lengt << 30 // Most simple approach for solving linear di << 31 // Take the current derivative and add it to << 32 // << 33 // Author: W.Wander <wwc@mit.edu>, 12.09.1997 << 34 // ------------------------------------------- << 35 << 36 #include "G4HelixExplicitEuler.hh" 11 #include "G4HelixExplicitEuler.hh" 37 #include "G4PhysicalConstants.hh" << 38 #include "G4ThreeVector.hh" 12 #include "G4ThreeVector.hh" 39 13 40 G4HelixExplicitEuler::G4HelixExplicitEuler(G4M << 14 // 41 : G4MagHelicalStepper(EqRhs) << 15 // Helix Explicit Euler: x_1 = x_0 + helix(h) 42 { << 16 // with helix(h) being a helix piece of length h 43 } << 17 // W.Wander <wwc@mit.edu> 12/09/97 44 << 18 // 45 G4HelixExplicitEuler::~G4HelixExplicitEuler() << 46 19 47 void G4HelixExplicitEuler::Stepper( const G4do << 20 // ------------------------------------------------------------------------- 48 const G4do << 49 G4do << 50 G4do << 51 G4do << 52 { << 53 // Estimation of the Stepping Angle << 54 // << 55 G4ThreeVector Bfld; << 56 MagFieldEvaluate(yInput, Bfld); << 57 << 58 const G4int nvar = 6 ; << 59 G4double yTemp[8], yIn[8] ; << 60 G4ThreeVector Bfld_midpoint; << 61 21 62 // Saving yInput because yInput and yOut can << 22 // most simple approach for solving linear differential equations. 63 // << 23 // Take the current derivative and add it to the current position. 64 for(G4int i=0; i<nvar; ++i) << 24 // 65 { << 66 yIn[i] = yInput[i]; << 67 } << 68 << 69 G4double h = Step * 0.5; << 70 << 71 // Do full step and two half steps << 72 // << 73 G4double yTemp2[7]; << 74 AdvanceHelix(yIn, Bfld, h, yTemp2,yTemp); << 75 MagFieldEvaluate(yTemp2, Bfld_midpoint) ; << 76 AdvanceHelix(yTemp2, Bfld_midpoint, h, yOut) << 77 SetAngCurve(GetAngCurve() * 2); << 78 << 79 // Error estimation << 80 // << 81 for(G4int i=0; i<nvar; ++i) << 82 { << 83 yErr[i] = yOut[i] - yTemp[i]; << 84 } << 85 } << 86 25 87 G4double G4HelixExplicitEuler::DistChord() c << 26 void >> 27 G4HelixExplicitEuler::DumbStepper( const G4double yIn[], >> 28 G4ThreeVector Bfld, >> 29 G4double h, >> 30 G4double yOut[]) 88 { 31 { 89 // Implementation : must check whether h/R > << 32 AdvanceHelix(yIn, Bfld, h, yOut); 90 // If( h/R < pi) use G4LineSection::DistL << 91 // Else DistChord=R_helix << 92 // << 93 G4double distChord; << 94 G4double Ang_curve=GetAngCurve(); << 95 << 96 33 97 if(Ang_curve<=pi) << 34 // NormaliseTangentVector( yOut ); // this could harm more than it helps 98 { << 35 return ; 99 distChord=GetRadHelix()*(1-std::cos(0.5*An << 100 } << 101 else if(Ang_curve<twopi) << 102 { << 103 distChord=GetRadHelix()*(1+std::cos(0.5*(t << 104 } << 105 else << 106 { << 107 distChord=2.*GetRadHelix(); << 108 } << 109 << 110 return distChord; << 111 } << 112 << 113 void G4HelixExplicitEuler::DumbStepper( const << 114 << 115 << 116 << 117 { << 118 AdvanceHelix(yIn, Bfld, h, yOut); << 119 } 36 } 120 37