Gabriele Cosmo
121 lines
3.9 KiB
C++
121 lines
3.9 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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// $Id: G4WeightWindowAlgorithm.cc 66356 2012-12-18 09:02:32Z gcosmo $
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//
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// ----------------------------------------------------------------------
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// GEANT 4 class source file
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//
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// G4WeightWindowAlgorithm.cc
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//
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// ----------------------------------------------------------------------
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#include "G4WeightWindowAlgorithm.hh"
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#include "Randomize.hh"
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G4WeightWindowAlgorithm::
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G4WeightWindowAlgorithm(G4double upperLimitFaktor,
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G4double survivalFaktor,
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G4int maxNumberOfSplits) :
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fUpperLimitFaktor(upperLimitFaktor),
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fSurvivalFaktor(survivalFaktor),
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fMaxNumberOfSplits(maxNumberOfSplits)
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{}
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G4WeightWindowAlgorithm::~G4WeightWindowAlgorithm()
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{}
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G4Nsplit_Weight
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G4WeightWindowAlgorithm::Calculate(G4double init_w,
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G4double lowerWeightBound) const {
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G4double survivalWeight = lowerWeightBound * fSurvivalFaktor;
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G4double upperWeight = lowerWeightBound * fUpperLimitFaktor;
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// initialize return value for case weight in window
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G4Nsplit_Weight nw;
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nw.fN = 1;
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nw.fW = init_w;
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if (init_w > upperWeight) {
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// splitting
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//TB G4double wi_ws = init_w/survivalWeight;
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//TB
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G4double temp_wi_ws = init_w/upperWeight;
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G4int split_i = static_cast<int>(temp_wi_ws);
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if(split_i != temp_wi_ws) split_i++;
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G4double wi_ws = init_w/split_i;
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//TB
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//TB G4int int_wi_ws = static_cast<int>(wi_ws);
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// values in case integer mode or in csae of double
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// mode and the lower number of splits will be diced
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//TB nw.fN = int_wi_ws;
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//TB nw.fW = survivalWeight;
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nw.fN = split_i;
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nw.fW = wi_ws;
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//TB if (wi_ws <= fMaxNumberOfSplits) {
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//TB if (wi_ws > int_wi_ws) {
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//TB // double mode
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//TB G4double p2 = wi_ws - int_wi_ws;
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//TB G4double r = G4UniformRand();
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//TB if (r<p2) {
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//TB nw.fN = int_wi_ws + 1;
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//TB }
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//TB }
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//TB }
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//TB else {
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//TB // fMaxNumberOfSplits < wi_ws
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//TB nw.fN = fMaxNumberOfSplits;
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//TB nw.fW = init_w/fMaxNumberOfSplits;
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//TB }
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} else if (init_w < lowerWeightBound) {
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// Russian roulette
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G4double wi_ws = init_w/survivalWeight;
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G4double p = std::max(wi_ws,1./fMaxNumberOfSplits);
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G4double r = G4UniformRand();
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if (r<p){
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nw.fW = init_w/p;
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nw.fN = 1;
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} else {
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nw.fW = 0;
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nw.fN = 0;
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}
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}
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// else do nothing
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return nw;
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}
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