[831] | 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 | // class G4HelixMixedStepper |
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| 27 | // |
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| 28 | // Class description: |
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| 29 | // |
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| 30 | // G4HelixMixedStepper split the Method used for Integration in two: |
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| 31 | // |
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| 32 | // If Stepping Angle ( h / R_curve) < pi/3 |
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| 33 | // use Stepper for small step(ClassicalRK4 by default) |
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| 34 | // Else use HelixExplicitEuler Stepper |
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| 35 | // |
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| 36 | // History: |
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| 37 | // Derived from ExactHelicalStepper 18/05/07 |
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| 38 | // |
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| 39 | // ------------------------------------------------------------------------- |
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| 40 | |
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| 41 | #include "G4HelixMixedStepper.hh" |
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| 42 | #include "G4ClassicalRK4.hh" |
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| 43 | #include "G4CashKarpRKF45.hh" |
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| 44 | #include "G4SimpleRunge.hh" |
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| 45 | #include "G4HelixImplicitEuler.hh" |
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| 46 | #include "G4HelixExplicitEuler.hh" |
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| 47 | #include "G4HelixSimpleRunge.hh" |
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| 48 | #include "G4ExactHelixStepper.hh" |
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| 49 | #include "G4ExplicitEuler.hh" |
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| 50 | #include "G4ImplicitEuler.hh" |
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| 51 | #include "G4SimpleHeum.hh" |
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| 52 | #include "G4RKG3_Stepper.hh" |
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| 53 | |
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| 54 | #include "G4ThreeVector.hh" |
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| 55 | #include "G4LineSection.hh" |
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| 56 | G4HelixMixedStepper::G4HelixMixedStepper(G4Mag_EqRhs *EqRhs,G4int fStepperNumber) |
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| 57 | : G4MagHelicalStepper(EqRhs) |
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| 58 | |
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| 59 | { |
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| 60 | SetVerbose(1); fNumCallsRK4=0; fNumCallsHelix=0; |
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| 61 | if(!fStepperNumber) fStepperNumber=4; |
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| 62 | fRK4Stepper = SetupStepper(EqRhs, fStepperNumber); |
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| 63 | } |
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| 64 | |
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| 65 | |
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| 66 | G4HelixMixedStepper::~G4HelixMixedStepper() { |
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| 67 | |
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| 68 | delete(fRK4Stepper); |
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| 69 | if (fVerbose>0){ PrintCalls();}; |
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| 70 | } |
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| 71 | void G4HelixMixedStepper::Stepper( const G4double yInput[7], |
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| 72 | const G4double dydx[7], |
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| 73 | G4double Step, |
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| 74 | G4double yOut[7], |
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| 75 | G4double yErr[]) |
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| 76 | |
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| 77 | { |
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| 78 | |
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| 79 | //Estimation of the Stepping Angle |
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| 80 | |
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| 81 | G4ThreeVector Bfld; |
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| 82 | MagFieldEvaluate(yInput, Bfld); |
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| 83 | |
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| 84 | G4double Bmag = Bfld.mag(); |
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| 85 | const G4double *pIn = yInput+3; |
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| 86 | G4ThreeVector initVelocity= G4ThreeVector( pIn[0], pIn[1], pIn[2]); |
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| 87 | G4double velocityVal = initVelocity.mag(); |
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| 88 | G4double R_1; |
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| 89 | G4double Ang_curve; |
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| 90 | |
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| 91 | R_1=std::abs(GetInverseCurve(velocityVal,Bmag)); |
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| 92 | Ang_curve=R_1*Step; |
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| 93 | SetAngCurve(Ang_curve); |
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| 94 | SetCurve(std::abs(1/R_1)); |
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| 95 | |
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| 96 | |
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| 97 | if(Ang_curve<0.33*pi){ |
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| 98 | fNumCallsRK4++; |
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| 99 | fRK4Stepper->Stepper(yInput,dydx,Step,yOut,yErr); |
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| 100 | |
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| 101 | |
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| 102 | } |
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| 103 | else{ |
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| 104 | fNumCallsHelix++; |
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| 105 | const G4int nvar = 6 ; |
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| 106 | G4int i; |
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| 107 | G4double yTemp[7], yIn[7] ; |
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| 108 | G4double yTemp2[7]; |
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| 109 | G4ThreeVector Bfld_midpoint; |
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| 110 | // Saving yInput because yInput and yOut can be aliases for same array |
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| 111 | for(i=0;i<nvar;i++) yIn[i]=yInput[i]; |
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| 112 | |
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| 113 | G4double h = Step * 0.5; |
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| 114 | // Do two half steps and full step |
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| 115 | AdvanceHelix(yIn, Bfld, h, yTemp,yTemp2); |
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| 116 | MagFieldEvaluate(yTemp, Bfld_midpoint) ; |
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| 117 | AdvanceHelix(yTemp, Bfld_midpoint, h, yOut); |
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| 118 | // Error estimation |
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| 119 | for(i=0;i<nvar;i++) { |
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| 120 | yErr[i] = yOut[i] - yTemp2[i] ; |
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| 121 | |
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| 122 | } |
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| 123 | } |
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| 124 | |
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| 125 | |
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| 126 | |
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| 127 | |
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| 128 | } |
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| 129 | |
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| 130 | void |
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| 131 | G4HelixMixedStepper::DumbStepper( const G4double yIn[], |
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| 132 | G4ThreeVector Bfld, |
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| 133 | G4double h, |
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| 134 | G4double yOut[]) |
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| 135 | { |
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| 136 | |
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| 137 | |
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| 138 | AdvanceHelix(yIn, Bfld, h, yOut); |
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| 139 | |
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| 140 | |
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| 141 | |
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| 142 | } |
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| 143 | |
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| 144 | G4double G4HelixMixedStepper::DistChord() const |
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| 145 | { |
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| 146 | // Implementation : must check whether h/R > 2 pi !! |
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| 147 | // If( h/R < pi) use G4LineSection::DistLine |
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| 148 | // Else DistChord=R_helix |
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| 149 | // |
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| 150 | G4double distChord; |
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| 151 | G4double Ang_curve=GetAngCurve(); |
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| 152 | |
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| 153 | |
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| 154 | if(Ang_curve<=pi){ |
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| 155 | distChord=GetRadHelix()*(1-std::cos(0.5*Ang_curve)); |
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| 156 | } |
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| 157 | else |
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| 158 | if(Ang_curve<twopi){ |
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| 159 | distChord=GetRadHelix()*(1+std::cos(0.5*(twopi-Ang_curve))); |
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| 160 | } |
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| 161 | else{ |
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| 162 | distChord=2.*GetRadHelix(); |
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| 163 | } |
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| 164 | |
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| 165 | |
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| 166 | |
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| 167 | return distChord; |
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| 168 | |
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| 169 | } |
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| 170 | // --------------------------------------------------------------------------- |
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| 171 | void G4HelixMixedStepper::PrintCalls() |
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| 172 | { |
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| 173 | G4cout<<"In HelixMixedStepper::Number of calls to smallStepStepper = "<<fNumCallsRK4 |
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| 174 | <<" and Number of calls to Helix = "<<fNumCallsHelix<<G4endl; |
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| 175 | } |
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| 176 | |
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| 177 | |
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| 178 | |
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| 179 | G4MagIntegratorStepper* G4HelixMixedStepper:: SetupStepper(G4Mag_EqRhs* pE, G4int StepperNumber) |
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| 180 | { |
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| 181 | G4MagIntegratorStepper* pStepper; |
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| 182 | if (fVerbose>0)G4cout<<"In G4HelixMixedStepper Stepper for small steps is "; |
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| 183 | switch ( StepperNumber ) |
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| 184 | { |
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| 185 | case 0: pStepper = new G4ExplicitEuler( pE ); if (fVerbose>0)G4cout<<"G4ExplicitEuler"<<G4endl; break; |
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| 186 | case 1: pStepper = new G4ImplicitEuler( pE ); if (fVerbose>0)G4cout<<"G4ImplicitEuler"<<G4endl; break; |
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| 187 | case 2: pStepper = new G4SimpleRunge( pE ); if (fVerbose>0)G4cout<<"G4SimpleRunge"<<G4endl; break; |
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| 188 | case 3: pStepper = new G4SimpleHeum( pE ); if (fVerbose>0)G4cout<<"G4SimpleHeum"<<G4endl;break; |
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| 189 | case 4: pStepper = new G4ClassicalRK4( pE ); if (fVerbose>0)G4cout<<"G4ClassicalRK4"<<G4endl; break; |
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| 190 | case 5: pStepper = new G4HelixExplicitEuler( pE ); if (fVerbose>0)G4cout<<"G4HelixExplicitEuler"<<G4endl; break; |
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| 191 | case 6: pStepper = new G4HelixImplicitEuler( pE ); if (fVerbose>0)G4cout<<"G4HelixImplicitEuler"<<G4endl; break; |
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| 192 | case 7: pStepper = new G4HelixSimpleRunge( pE ); if (fVerbose>0)G4cout<<"G4HelixSimpleRunge"<<G4endl; break; |
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| 193 | case 8: pStepper = new G4CashKarpRKF45( pE ); if (fVerbose>0)G4cout<<"G4CashKarpRKF45"<<G4endl; break; |
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| 194 | case 9: pStepper = new G4ExactHelixStepper( pE ); if (fVerbose>0)G4cout<<"G4ExactHelixStepper"<<G4endl; break; |
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| 195 | case 10: pStepper = new G4RKG3_Stepper( pE ); if (fVerbose>0)G4cout<<"G4RKG3_Stepper"<<G4endl; break; |
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| 196 | |
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| 197 | default: pStepper = new G4ClassicalRK4( pE );G4cout<<"Default G4ClassicalRK4"<<G4endl; break; |
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| 198 | |
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| 199 | } |
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| 200 | return pStepper; |
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| 201 | } |
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