Gabriele Cosmo
143 lines
4.3 KiB
C++
143 lines
4.3 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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// G4ImportanceAlgorithm implementation
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//
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// Author: Michael Dressel (CERN), 2002
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// ----------------------------------------------------------------------
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#include "G4Types.hh"
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#include <sstream>
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#include "Randomize.hh"
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#include "G4Threading.hh"
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#include "G4ImportanceAlgorithm.hh"
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#ifdef G4MULTITHREADED
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G4Mutex G4ImportanceAlgorithm::ImportanceMutex = G4MUTEX_INITIALIZER;
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#endif
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G4ImportanceAlgorithm::G4ImportanceAlgorithm()
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{
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}
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G4ImportanceAlgorithm::~G4ImportanceAlgorithm()
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{
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}
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G4Nsplit_Weight
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G4ImportanceAlgorithm::Calculate(G4double ipre,
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G4double ipost,
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G4double init_w) const
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{
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#ifdef G4MULTITHREADED
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G4MUTEXLOCK(&G4ImportanceAlgorithm::ImportanceMutex);
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#endif
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G4Nsplit_Weight nw;
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if (ipost>0.)
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{
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if (!(ipre>0.))
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{
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Error("Calculate() - ipre==0.");
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}
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G4double ipre_over_ipost = ipre/ipost;
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if ((ipre_over_ipost<0.25 || ipre_over_ipost> 4) && !fWarned)
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{
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std::ostringstream os;
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os << "Calculate() - ipre_over_ipost ! in [0.25, 4]." << G4endl
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<< "ipre_over_ipost = " << ipre_over_ipost << ".";
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Warning(os.str());
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fWarned = true;
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if (ipre_over_ipost<=0)
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{
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Error("Calculate() - ipre_over_ipost<=0.");
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}
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}
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if (init_w<=0.)
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{
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Error("Calculate() - iniitweight<= 0. found!");
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}
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// default geometrical splitting
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// in integer mode
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// for ipre_over_ipost <= 1
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G4double inv = 1./ipre_over_ipost;
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nw.fN = static_cast<G4int>(inv);
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nw.fW = init_w * ipre_over_ipost;
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// geometrical splitting for double mode
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if (ipre_over_ipost<1)
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{
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if ( static_cast<G4double>(nw.fN) != inv)
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{
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// double mode
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// probability p for splitting into n+1 tracks
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G4double p = inv - nw.fN;
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// get a random number out of [0,1)
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G4double r = G4UniformRand();
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if (r<p)
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{
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++nw.fN;
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}
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}
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}
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else if (ipre_over_ipost>1) // russian roulette
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{
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// probabiity for killing track
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G4double p = 1-inv;
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// get a random number out of [0,1)
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G4double r = G4UniformRand();
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if (r<p)
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{
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// kill track
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nw.fN = 0;
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nw.fW = 0;
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}
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else
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{
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nw.fN = 1;
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}
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}
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}
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#ifdef G4MULTITHREADED
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G4MUTEXUNLOCK(&G4ImportanceAlgorithm::ImportanceMutex);
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#endif
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return nw;
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}
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void G4ImportanceAlgorithm::Error(const G4String& msg) const
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{
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G4Exception("G4ImportanceAlgorithm::Error()",
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"GeomBias0002", FatalException, msg);
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}
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void G4ImportanceAlgorithm::Warning(const G4String& msg) const
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{
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G4Exception("G4ImportanceAlgorithm::Warning()",
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"GeomBias1001", JustWarning, msg);
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}
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