Gabriele Cosmo
118 lines
3.3 KiB
C++
118 lines
3.3 KiB
C++
// -*- C++ -*-
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//
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// -----------------------------------------------------------------------
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// HEP Random
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// --- RandLandau ---
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// class header file
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// -----------------------------------------------------------------------
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// This file is part of Geant4 (simulation toolkit for HEP).
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// Class defining methods for shooting or firing Landau distributed
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// random values.
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//
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// The Landau distribution is parameterless and describes the fluctuations
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// in energy loss of a particle, making certain assumptions. For
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// definitions and algorithms, the following papers could be read:
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//
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// Landau, Jour Phys VIII, No. 4, p. 201 (1944)
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// Borsh-Supan, Jour Res. of NBS 65B NO. 4 p. 245 (1961)
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// Kolbig & Schorr Comp Phys Comm 31 p. 97 (1984)
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//
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// The algorithm implemented comes form RANLAN in CERNLIB.
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// =======================================================================
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// M. Fischler - Created: 5th January 2000
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// M Fischler - put and get to/from streams 12/10/04
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//
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// =======================================================================
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#ifndef RandLandau_h
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#define RandLandau_h 1
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#include "CLHEP/Random/Random.h"
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#include "CLHEP/Utility/memory.h"
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namespace CLHEP {
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/**
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* @author
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* @ingroup random
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*/
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class RandLandau : public HepRandom {
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public:
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inline RandLandau ( HepRandomEngine& anEngine );
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inline RandLandau ( HepRandomEngine* anEngine );
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// These constructors should be used to instantiate a RandLandau
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// distribution object defining a local engine for it.
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// The static generator will be skipped using the non-static methods
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// defined below.
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// If the engine is passed by pointer the corresponding engine object
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// will be deleted by the RandLandau destructor.
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// If the engine is passed by reference the corresponding engine object
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// will not be deleted by the RandLandau destructor.
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virtual ~RandLandau();
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// Destructor
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// Save and restore to/from streams
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std::ostream & put ( std::ostream & os ) const;
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std::istream & get ( std::istream & is );
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//
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// Methods to generate Landau-distributed random deviates.
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//
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// These deviates are accurate to the actual Landau distribution to
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// one part in 10**5 or better.
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// Static methods to shoot random values using the static generator
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static inline double shoot();
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static void shootArray ( const int size, double* vect );
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// Static methods to shoot random values using a given engine
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// by-passing the static generator.
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static inline double shoot( HepRandomEngine* anotherEngine );
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static void shootArray ( HepRandomEngine* anotherEngine,
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const int size,
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double* vect );
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// Instance methods using the localEngine to instead of the static
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// generator, and the default mean and stdDev established at construction
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inline double fire();
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void fireArray ( const int size, double* vect);
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inline double operator()();
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std::string name() const;
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HepRandomEngine & engine();
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static std::string distributionName() {return "RandLandau";}
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// Provides the name of this distribution class
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protected:
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static double transform (double r);
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static double transformSmall (double r);
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private:
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std::shared_ptr<HepRandomEngine> localEngine;
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};
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} // namespace CLHEP
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#include "CLHEP/Random/RandLandau.icc"
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#endif
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