| Geant4 Cross Reference |
1 // -*- C++ -*-
2 //
3 // -----------------------------------------------------------------------
4 // HEP Random
5 // --- RandPoisson ---
6 // class header file
7 // -----------------------------------------------------------------------
8 // This file is part of Geant4 (simulation toolkit for HEP).
9
10 // Class defining methods for shooting numbers according to the Poisson
11 // distribution, given a mean (Algorithm taken from "W.H.Press et al.,
12 // Numerical Recipes in C, Second Edition".
13 // Default mean value is set to 1, value used for operator()().
14
15 // =======================================================================
16 // Gabriele Cosmo - Created: 5th September 1995
17 // - Added not static Shoot() method: 17th May 1996
18 // - Algorithm now operates on doubles : 31st Oct 1996
19 // - Added methods to shoot arrays: 28th July 1997
20 // J.Marraffino - Added default mean as attribute and
21 // operator() with mean: 16th Feb 1998
22 // Gabriele Cosmo - Relocated static data from HepRandom: 5th Jan 1999
23 // M. Fischler - Moved meanMax and defaultMean from private to protected
24 // to accomodate derived classes RandPoissonQ & RandPoissonT
25 // M Fischler - put and get to/from streams 12/10/04
26 // =======================================================================
27
28 #ifndef RandPoisson_h
29 #define RandPoisson_h 1
30
31 #include "CLHEP/Random/Random.h"
32 #include "CLHEP/Utility/memory.h"
33 #include "CLHEP/Utility/thread_local.h"
34
35 namespace CLHEP {
36
37 /**
38 * @author
39 * @ingroup random
40 */
41 class RandPoisson : public HepRandom {
42
43 public:
44
45 inline RandPoisson ( HepRandomEngine& anEngine, double a1=1.0 );
46 inline RandPoisson ( HepRandomEngine* anEngine, double a1=1.0 );
47 // These constructors should be used to instantiate a RandPoisson
48 // distribution object defining a local engine for it.
49 // The static generator will be skipped using the non-static methods
50 // defined below.
51 // If the engine is passed by pointer the corresponding engine object
52 // will be deleted by the RandPoisson destructor.
53 // If the engine is passed by reference the corresponding engine object
54 // will not be deleted by the RandPoisson destructor.
55
56 virtual ~RandPoisson();
57 // Destructor
58
59 // Save and restore to/from streams
60
61 std::ostream & put ( std::ostream & os ) const;
62 std::istream & get ( std::istream & is );
63
64 // Static methods to shoot random values using the static generator
65
66 static long shoot( double mean=1.0 );
67
68 static void shootArray ( const int size, long* vect, double mean=1.0 );
69
70 // Static methods to shoot random values using a given engine
71 // by-passing the static generator.
72
73 static long shoot( HepRandomEngine* anEngine, double mean=1.0 );
74
75 static void shootArray ( HepRandomEngine* anEngine,
76 const int size, long* vect, double mean=1.0 );
77
78 // Methods using the localEngine to shoot random values, by-passing
79 // the static generator.
80
81 long fire();
82 long fire( double mean );
83
84 void fireArray ( const int size, long* vect );
85 void fireArray ( const int size, long* vect, double mean);
86
87 double operator()();
88 double operator()( double mean );
89
90 std::string name() const;
91 HepRandomEngine & engine();
92
93 static std::string distributionName() {return "RandPoisson";}
94 // Provides the name of this distribution class
95
96 protected:
97
98 double meanMax;
99 double defaultMean;
100
101 static double getOldMean() {return oldm_st;}
102
103 static double getMaxMean() {return meanMax_st;}
104
105 static void setOldMean( double val ){oldm_st = val;}
106
107 static double* getPStatus() {return status_st;}
108
109 static void setPStatus(double sq, double alxm, double g1) {
110 status_st[0] = sq; status_st[1] = alxm; status_st[2] = g1;
111 }
112
113 inline HepRandomEngine* getLocalEngine();
114
115 private:
116
117 std::shared_ptr<HepRandomEngine> localEngine;
118 double status[3], oldm;
119
120 // static data
121 static CLHEP_THREAD_LOCAL double status_st[3];
122 static CLHEP_THREAD_LOCAL double oldm_st;
123 static const double meanMax_st;
124
125 };
126
127 } // namespace CLHEP
128
129 #include "CLHEP/Random/RandPoisson.icc"
130
131 #endif
132