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: G4WeightWindowAlgorithm.cc,v 1.11 2007/11/09 15:43:07 ahoward Exp $ |
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28 | // GEANT4 tag $Name: geant4-09-04-beta-01 $ |
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29 | // |
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30 | // ---------------------------------------------------------------------- |
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31 | // GEANT 4 class source file |
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32 | // |
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33 | // G4WeightWindowAlgorithm.cc |
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34 | // |
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35 | // ---------------------------------------------------------------------- |
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36 | #include "G4WeightWindowAlgorithm.hh" |
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37 | #include "Randomize.hh" |
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38 | |
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39 | |
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40 | G4WeightWindowAlgorithm:: |
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41 | G4WeightWindowAlgorithm(G4double upperLimitFaktor, |
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42 | G4double survivalFaktor, |
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43 | G4int maxNumberOfSplits) : |
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44 | fUpperLimitFaktor(upperLimitFaktor), |
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45 | fSurvivalFaktor(survivalFaktor), |
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46 | fMaxNumberOfSplits(maxNumberOfSplits) |
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47 | {} |
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48 | |
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49 | G4WeightWindowAlgorithm::~G4WeightWindowAlgorithm() |
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50 | {} |
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51 | |
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52 | |
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53 | |
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54 | G4Nsplit_Weight |
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55 | G4WeightWindowAlgorithm::Calculate(G4double init_w, |
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56 | G4double lowerWeightBound) const { |
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57 | |
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58 | G4double survivalWeight = lowerWeightBound * fSurvivalFaktor; |
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59 | G4double upperWeight = lowerWeightBound * fUpperLimitFaktor; |
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60 | |
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61 | // initialize return value for case weight in window |
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62 | G4Nsplit_Weight nw; |
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63 | nw.fN = 1; |
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64 | nw.fW = init_w; |
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65 | |
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66 | if (init_w > upperWeight) { |
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67 | // splitting |
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68 | |
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69 | //TB G4double wi_ws = init_w/survivalWeight; |
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70 | //TB |
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71 | G4double temp_wi_ws = init_w/upperWeight; |
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72 | G4int split_i = static_cast<int>(temp_wi_ws); |
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73 | if(split_i != temp_wi_ws) split_i++; |
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74 | G4double wi_ws = init_w/split_i; |
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75 | |
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76 | //TB |
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77 | //TB G4int int_wi_ws = static_cast<int>(wi_ws); |
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78 | |
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79 | // values in case integer mode or in csae of double |
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80 | // mode and the lower number of splits will be diced |
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81 | //TB nw.fN = int_wi_ws; |
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82 | //TB nw.fW = survivalWeight; |
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83 | nw.fN = split_i; |
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84 | nw.fW = wi_ws; |
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85 | |
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86 | //TB if (wi_ws <= fMaxNumberOfSplits) { |
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87 | //TB if (wi_ws > int_wi_ws) { |
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88 | //TB // double mode |
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89 | //TB G4double p2 = wi_ws - int_wi_ws; |
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90 | //TB G4double r = G4UniformRand(); |
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91 | //TB if (r<p2) { |
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92 | //TB nw.fN = int_wi_ws + 1; |
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93 | //TB } |
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94 | //TB } |
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95 | //TB } |
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96 | //TB else { |
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97 | //TB // fMaxNumberOfSplits < wi_ws |
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98 | //TB nw.fN = fMaxNumberOfSplits; |
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99 | //TB nw.fW = init_w/fMaxNumberOfSplits; |
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100 | //TB } |
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101 | |
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102 | |
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103 | } else if (init_w < lowerWeightBound) { |
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104 | // Russian roulette |
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105 | G4double wi_ws = init_w/survivalWeight; |
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106 | G4double p = std::max(wi_ws,1./fMaxNumberOfSplits); |
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107 | G4double r = G4UniformRand(); |
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108 | if (r<p){ |
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109 | nw.fW = init_w/p; |
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110 | nw.fN = 1; |
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111 | } else { |
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112 | nw.fW = 0; |
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113 | nw.fN = 0; |
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114 | } |
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115 | } |
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116 | // else do nothing |
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117 | |
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118 | |
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119 | return nw; |
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120 | } |
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121 | |
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