Gabriele Cosmo
110 lines
3.4 KiB
C++
110 lines
3.4 KiB
C++
//
|
|
// ********************************************************************
|
|
// * DISCLAIMER *
|
|
// * *
|
|
// * The following disclaimer summarizes all the specific disclaimers *
|
|
// * of contributors to this software. The specific disclaimers,which *
|
|
// * govern, are listed with their locations in: *
|
|
// * http://cern.ch/geant4/license *
|
|
// * *
|
|
// * Neither the authors of this software system, nor their employing *
|
|
// * institutes,nor the agencies providing financial support for this *
|
|
// * work make any representation or warranty, express or implied, *
|
|
// * regarding this software system or assume any liability for its *
|
|
// * use. *
|
|
// * *
|
|
// * This code implementation is the intellectual property of the *
|
|
// * GEANT4 collaboration. *
|
|
// * By copying, distributing or modifying the Program (or any work *
|
|
// * based on the Program) you indicate your acceptance of this *
|
|
// * statement, and all its terms. *
|
|
// ********************************************************************
|
|
//
|
|
//
|
|
// $Id: G4WeightWindowAlgorithm.cc,v 1.7 2003/08/19 15:16:56 dressel Exp $
|
|
// GEANT4 tag $Name: geant4-07-01 $
|
|
//
|
|
// ----------------------------------------------------------------------
|
|
// GEANT 4 class source file
|
|
//
|
|
// G4WeightWindowAlgorithm.cc
|
|
//
|
|
// ----------------------------------------------------------------------
|
|
#include "G4WeightWindowAlgorithm.hh"
|
|
#include "Randomize.hh"
|
|
|
|
|
|
G4WeightWindowAlgorithm::
|
|
G4WeightWindowAlgorithm(G4double upperLimitFaktor,
|
|
G4double survivalFaktor,
|
|
G4int maxNumberOfSplits) :
|
|
fUpperLimitFaktor(upperLimitFaktor),
|
|
fSurvivalFaktor(survivalFaktor),
|
|
fMaxNumberOfSplits(maxNumberOfSplits)
|
|
{}
|
|
|
|
G4WeightWindowAlgorithm::~G4WeightWindowAlgorithm()
|
|
{}
|
|
|
|
|
|
|
|
G4Nsplit_Weight
|
|
G4WeightWindowAlgorithm::Calculate(G4double init_w,
|
|
G4double lowerWeightBound) const {
|
|
|
|
G4double survivalWeight = lowerWeightBound * fSurvivalFaktor;
|
|
G4double upperWeight = lowerWeightBound * fUpperLimitFaktor;
|
|
|
|
// initialize return value for case weight in window
|
|
G4Nsplit_Weight nw;
|
|
nw.fN = 1;
|
|
nw.fW = init_w;
|
|
|
|
if (init_w > upperWeight) {
|
|
// splitting
|
|
|
|
G4double wi_ws = init_w/survivalWeight;
|
|
G4int int_wi_ws = static_cast<int>(wi_ws);
|
|
|
|
// values in case integer mode or in csae of double
|
|
// mode and the lower number of splits will be diced
|
|
nw.fN = int_wi_ws;
|
|
nw.fW = survivalWeight;
|
|
|
|
if (wi_ws <= fMaxNumberOfSplits) {
|
|
if (wi_ws > int_wi_ws) {
|
|
// double mode
|
|
G4double p2 = wi_ws - int_wi_ws;
|
|
G4double r = G4UniformRand();
|
|
if (r<p2) {
|
|
nw.fN = int_wi_ws + 1;
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
// fMaxNumberOfSplits < wi_ws
|
|
nw.fN = fMaxNumberOfSplits;
|
|
nw.fW = init_w/fMaxNumberOfSplits;
|
|
}
|
|
|
|
|
|
} else if (init_w < lowerWeightBound) {
|
|
// Russian roulette
|
|
G4double wi_ws = init_w/survivalWeight;
|
|
G4double p = std::max(wi_ws,1./fMaxNumberOfSplits);
|
|
G4double r = G4UniformRand();
|
|
if (r<p){
|
|
nw.fW = init_w/p;
|
|
nw.fN = 1;
|
|
} else {
|
|
nw.fW = 0;
|
|
nw.fN = 0;
|
|
}
|
|
}
|
|
// else do nothing
|
|
|
|
|
|
return nw;
|
|
}
|
|
|