| 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: $
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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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