Gabriele Cosmo
110 lines
4.5 KiB
C++
110 lines
4.5 KiB
C++
//
|
|
// ********************************************************************
|
|
// * License and Disclaimer *
|
|
// * *
|
|
// * The Geant4 software is copyright of the Copyright Holders of *
|
|
// * the Geant4 Collaboration. It is provided under the terms and *
|
|
// * conditions of the Geant4 Software License, included in the file *
|
|
// * LICENSE and available at http://cern.ch/geant4/license . These *
|
|
// * include a list of copyright holders. *
|
|
// * *
|
|
// * 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. Please see the license in the file LICENSE and URL above *
|
|
// * for the full disclaimer and the limitation of liability. *
|
|
// * *
|
|
// * This code implementation is the result of the scientific and *
|
|
// * technical work of the GEANT4 collaboration. *
|
|
// * By using, copying, modifying or distributing the software (or *
|
|
// * any work based on the software) you agree to acknowledge its *
|
|
// * use in resulting scientific publications, and indicate your *
|
|
// * acceptance of all terms of the Geant4 Software license. *
|
|
// ********************************************************************
|
|
//
|
|
// G4VBiasingInteractionLaw
|
|
//
|
|
// Class Description:
|
|
//
|
|
// An abstract class to model interaction laws, not necessarily.
|
|
// exponential ones.
|
|
// These laws, p(l), are caraterized by their:
|
|
// - non-interaction probability over l:
|
|
// P_NI(l) = 1 - integral(0,l) p(s) ds
|
|
// - effective cross-section at l:
|
|
// sigma_eff(l) = p(l)/P_NI(l) (several forms exist)
|
|
// If several laws compete, the resulting net law has:
|
|
// - an non-interaction probability over a lenght l which
|
|
// is the product of the individual non-interaction probabilities.
|
|
// - an effective cross-section which is the
|
|
// sum on the individual effective cross-sections.
|
|
//
|
|
// Author: M.Verderi (LLR), November 2013
|
|
// --------------------------------------------------------------------
|
|
#ifndef G4VBiasingInteractionLaw_hh
|
|
#define G4VBiasingInteractionLaw_hh 1
|
|
|
|
#include "globals.hh"
|
|
#include <vector>
|
|
|
|
class G4BiasingProcessInterface;
|
|
|
|
class G4VBiasingInteractionLaw
|
|
{
|
|
public:
|
|
|
|
G4VBiasingInteractionLaw(const G4String& name)
|
|
: fName(name), fSampledInteractionLength(DBL_MAX) {}
|
|
virtual ~G4VBiasingInteractionLaw() = default;
|
|
|
|
const G4String& GetName() const { return fName; }
|
|
|
|
// -- Compute non-interaction probability and effective cross-section:
|
|
// -- (probability of interaction over dl = effective_cross-section* dl)
|
|
virtual G4double ComputeNonInteractionProbabilityAt(G4double length) const = 0;
|
|
virtual G4double ComputeEffectiveCrossSectionAt(G4double length) const = 0;
|
|
|
|
// -- Methods to deal with singularities : null cross sections or infinite ones.
|
|
// -- In such cases, weight can not always be computed.
|
|
// -- Tells if this interaction law has singularities:
|
|
virtual G4bool IsSingular() const { return false; }
|
|
// -- method interrogated only in case interaction law is IsSingular() == true:
|
|
virtual G4bool IsEffectiveCrossSectionInfinite() const { return false; }
|
|
|
|
// -----------------------------------------
|
|
// -- public interface to protected methods:
|
|
// -----------------------------------------
|
|
G4double Sample()
|
|
{
|
|
fSampledInteractionLength = SampleInteractionLength();
|
|
return fSampledInteractionLength;
|
|
}
|
|
G4double UpdateForStep(G4double truePathLength)
|
|
{
|
|
fSampledInteractionLength = UpdateInteractionLengthForStep(truePathLength);
|
|
return fSampledInteractionLength;
|
|
}
|
|
G4double GetSampledInteractionLength() const
|
|
{
|
|
return fSampledInteractionLength;
|
|
}
|
|
|
|
protected:
|
|
|
|
// -- Sample the distribution for point like interaction (PostStep ones)
|
|
virtual G4double SampleInteractionLength() = 0;
|
|
|
|
// -- Convenience method, used in many daughters classes :
|
|
// -- update the distribution for a made step of truePathLength size:
|
|
virtual G4double UpdateInteractionLengthForStep(G4double /* truePathLength */)
|
|
{ return DBL_MAX; }
|
|
|
|
private:
|
|
|
|
G4String fName;
|
|
G4double fSampledInteractionLength;
|
|
};
|
|
|
|
#endif
|