source: trunk/source/geometry/biasing/src/G4WeightWindowAlgorithm.cc@ 1169

Last change on this file since 1169 was 1058, checked in by garnier, 17 years ago

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1//
2// ********************************************************************
3// * License and Disclaimer *
4// * *
5// * The Geant4 software is copyright of the Copyright Holders of *
6// * the Geant4 Collaboration. It is provided under the terms and *
7// * conditions of the Geant4 Software License, included in the file *
8// * LICENSE and available at http://cern.ch/geant4/license . These *
9// * include a list of copyright holders. *
10// * *
11// * Neither the authors of this software system, nor their employing *
12// * institutes,nor the agencies providing financial support for this *
13// * work make any representation or warranty, express or implied, *
14// * regarding this software system or assume any liability for its *
15// * use. Please see the license in the file LICENSE and URL above *
16// * for the full disclaimer and the limitation of liability. *
17// * *
18// * This code implementation is the result of the scientific and *
19// * technical work of the GEANT4 collaboration. *
20// * By using, copying, modifying or distributing the software (or *
21// * any work based on the software) you agree to acknowledge its *
22// * use in resulting scientific publications, and indicate your *
23// * acceptance of all terms of the Geant4 Software license. *
24// ********************************************************************
25//
26//
27// $Id: G4WeightWindowAlgorithm.cc,v 1.11 2007/11/09 15:43:07 ahoward Exp $
28// GEANT4 tag $Name: geant4-09-02-ref-02 $
29//
30// ----------------------------------------------------------------------
31// GEANT 4 class source file
32//
33// G4WeightWindowAlgorithm.cc
34//
35// ----------------------------------------------------------------------
36#include "G4WeightWindowAlgorithm.hh"
37#include "Randomize.hh"
38
39
40G4WeightWindowAlgorithm::
41G4WeightWindowAlgorithm(G4double upperLimitFaktor,
42 G4double survivalFaktor,
43 G4int maxNumberOfSplits) :
44 fUpperLimitFaktor(upperLimitFaktor),
45 fSurvivalFaktor(survivalFaktor),
46 fMaxNumberOfSplits(maxNumberOfSplits)
47{}
48
49G4WeightWindowAlgorithm::~G4WeightWindowAlgorithm()
50{}
51
52
53
54G4Nsplit_Weight
55G4WeightWindowAlgorithm::Calculate(G4double init_w,
56 G4double lowerWeightBound) const {
57
58 G4double survivalWeight = lowerWeightBound * fSurvivalFaktor;
59 G4double upperWeight = lowerWeightBound * fUpperLimitFaktor;
60
61 // initialize return value for case weight in window
62 G4Nsplit_Weight nw;
63 nw.fN = 1;
64 nw.fW = init_w;
65
66 if (init_w > upperWeight) {
67 // splitting
68
69 //TB G4double wi_ws = init_w/survivalWeight;
70 //TB
71 G4double temp_wi_ws = init_w/upperWeight;
72 G4int split_i = static_cast<int>(temp_wi_ws);
73 if(split_i != temp_wi_ws) split_i++;
74 G4double wi_ws = init_w/split_i;
75
76 //TB
77//TB G4int int_wi_ws = static_cast<int>(wi_ws);
78
79 // values in case integer mode or in csae of double
80 // mode and the lower number of splits will be diced
81 //TB nw.fN = int_wi_ws;
82 //TB nw.fW = survivalWeight;
83 nw.fN = split_i;
84 nw.fW = wi_ws;
85
86//TB if (wi_ws <= fMaxNumberOfSplits) {
87//TB if (wi_ws > int_wi_ws) {
88//TB // double mode
89//TB G4double p2 = wi_ws - int_wi_ws;
90//TB G4double r = G4UniformRand();
91//TB if (r<p2) {
92//TB nw.fN = int_wi_ws + 1;
93//TB }
94//TB }
95//TB }
96//TB else {
97//TB // fMaxNumberOfSplits < wi_ws
98//TB nw.fN = fMaxNumberOfSplits;
99//TB nw.fW = init_w/fMaxNumberOfSplits;
100//TB }
101
102
103 } else if (init_w < lowerWeightBound) {
104 // Russian roulette
105 G4double wi_ws = init_w/survivalWeight;
106 G4double p = std::max(wi_ws,1./fMaxNumberOfSplits);
107 G4double r = G4UniformRand();
108 if (r<p){
109 nw.fW = init_w/p;
110 nw.fN = 1;
111 } else {
112 nw.fW = 0;
113 nw.fN = 0;
114 }
115 }
116 // else do nothing
117
118
119 return nw;
120}
121
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