Gabriele Cosmo
145 lines
5.2 KiB
C++
145 lines
5.2 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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//
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// ------------------------------------------------------------
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// GEANT 4 class header file
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//
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// ---------------- G4SampleResonance ----------------
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// by Henning Weber, March 2001.
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// helper class for sampling resonance masses
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// ------------------------------------------------------------
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#include "globals.hh"
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#include <iostream>
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#include "G4SampleResonance.hh"
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#include "G4DecayTable.hh"
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#include "Randomize.hh"
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#include "G4HadronicException.hh"
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G4ThreadLocal G4SampleResonance::minMassMapType *G4SampleResonance::minMassCache_G4MT_TLS_ = 0;
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G4double G4SampleResonance::GetMinimumMass(const G4ParticleDefinition* p) const
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{ ;;; if (!minMassCache_G4MT_TLS_) minMassCache_G4MT_TLS_ = new G4SampleResonance::minMassMapType ; G4SampleResonance::minMassMapType &minMassCache = *minMassCache_G4MT_TLS_; ;;;
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G4double minResonanceMass = DBL_MAX;
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if ( p->IsShortLived() )
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{
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minMassMapIterator iter = minMassCache.find(p);
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if ( iter!=minMassCache.end() )
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{
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minResonanceMass = (*iter).second;
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}
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else
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{
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// G4cout << "--> request for " << p->GetParticleName() << G4endl;
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const G4DecayTable* theDecays = const_cast<G4ParticleDefinition*>(p)->GetDecayTable();
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const G4int nDecays = theDecays->entries();
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for (G4int i=0; i<nDecays; i++)
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{
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const G4VDecayChannel* aDecay = theDecays->GetDecayChannel(i);
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const G4int nDaughters = aDecay->GetNumberOfDaughters();
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G4double minChannelMass = 0;
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for (G4int j=0; j<nDaughters; j++)
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{
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const G4ParticleDefinition* aDaughter = const_cast<G4VDecayChannel*>(aDecay)->GetDaughter(j);
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G4double minMass = GetMinimumMass(aDaughter);
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if (!minMass) minMass = DBL_MAX; // exclude gamma channel;
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minChannelMass+=minMass;
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}
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// G4cout << "channel mass for the above is " << minChannelMass/MeV << G4endl;
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if (minChannelMass < minResonanceMass) minResonanceMass = minChannelMass;
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}
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// replace this as soon as the compiler supports mutable!!
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G4SampleResonance* self = const_cast<G4SampleResonance*>(this);
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//Andrea Dotti (13Jan2013): Change needed for G4MT
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//(self->minMassCache)[p] = minResonanceMass;
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self->minMassCache_G4MT_TLS_->operator[](p) = minResonanceMass;
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}
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}
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else
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{
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minResonanceMass = p->GetPDGMass();
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}
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// G4cout << "minimal mass for " << p->GetParticleName() << " is " << minResonanceMass/MeV << G4endl;
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return minResonanceMass;
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}
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G4double G4SampleResonance::SampleMass(const G4ParticleDefinition* p, const G4double maxMass) const
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{ if (!minMassCache_G4MT_TLS_) minMassCache_G4MT_TLS_ = new G4SampleResonance::minMassMapType ;
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return SampleMass(p->GetPDGMass(), p->GetPDGWidth(), GetMinimumMass(p), maxMass);
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}
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G4double G4SampleResonance::SampleMass(const G4double poleMass,
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const G4double gamma,
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const G4double minMass,
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const G4double maxMass) const
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{ if (!minMassCache_G4MT_TLS_) minMassCache_G4MT_TLS_ = new G4SampleResonance::minMassMapType ;
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// Chooses a mass randomly between minMass and maxMass
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// according to a Breit-Wigner function with constant
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// width gamma and pole poleMass
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if ( minMass > maxMass )
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{
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throw G4HadronicException(__FILE__, __LINE__,
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"SampleResonanceMass: mass range negative (minMass>maxMass)");
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}
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G4double returnMass;
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if ( gamma < DBL_EPSILON )
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{
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returnMass = std::max(minMass, std::min(maxMass, poleMass));
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}
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else
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{
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double fmin = BrWigInt0(minMass, gamma, poleMass);
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double fmax = BrWigInt0(maxMass, gamma, poleMass);
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double f = fmin + (fmax-fmin)*G4UniformRand();
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returnMass = BrWigInv(f, gamma, poleMass);
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}
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return returnMass;
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}
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