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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