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RandBinomial.h
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1 // -*- C++ -*-
2 //
3 // -----------------------------------------------------------------------
4 // HEP Random
5 // --- RandBinomial ---
6 // class header file
7 // -----------------------------------------------------------------------
8 
9 // Class defining methods for shooting binomial distributed random values,
10 // given a sample size n (default=1) and a probability p (default=0.5).
11 // Default values are used for operator()().
12 //
13 // Valid input values satisfy the relation n*min(p,1-p) > 0. When invalid
14 // values are presented, the code silently returns -1.0.
15 
16 // =======================================================================
17 // John Marraffino - Created: 12th May 1998 Based on the C-Rand package
18 // by Ernst Stadlober and Franz Niederl of the Technical
19 // University of Graz, Austria.
20 // Gabriele Cosmo - Removed useless methods and data: 5th Jan 1999
21 // M Fischler - put and get to/from streams 12/10/04
22 // =======================================================================
23 
24 #ifndef RandBinomial_h
25 #define RandBinomial_h 1
26 
27 #include "CLHEP/Random/Random.h"
28 #include "CLHEP/Utility/memory.h"
29 
30 namespace CLHEP {
31 
36 class RandBinomial : public HepRandom {
37 
38 public:
39 
40  inline RandBinomial ( HepRandomEngine& anEngine, long n=1,
41  double p=0.5 );
42  inline RandBinomial ( HepRandomEngine* anEngine, long n=1,
43  double p=0.5 );
44  // These constructors should be used to instantiate a RandBinomial
45  // distribution object defining a local engine for it.
46  // The static generator will be skipped using the non-static methods
47  // defined below.
48  // If the engine is passed by pointer the corresponding engine object
49  // will be deleted by the RandBinomial destructor.
50  // If the engine is passed by reference the corresponding engine object
51  // will not be deleted by the RandBinomial destructor.
52 
53  virtual ~RandBinomial();
54  // Destructor
55 
56  // Static methods to shoot random values using the static generator
57 
58  static inline double shoot();
59 
60  static double shoot( long n, double p );
61 
62  static void shootArray ( const int size, double* vect,
63  long n=1, double p=0.5 );
64 
65  // Static methods to shoot random values using a given engine
66  // by-passing the static generator.
67 
68  static inline double shoot( HepRandomEngine* anEngine );
69 
70  static double shoot( HepRandomEngine* anEngine,
71  long n, double p );
72 
73  static void shootArray ( HepRandomEngine* anEngine, const int size,
74  double* vect, long n=1,
75  double p=0.5 );
76 
77  // Methods using the localEngine to shoot random values, by-passing
78  // the static generator.
79 
80  inline double fire();
81 
82  double fire( long n, double p );
83 
84  void fireArray ( const int size, double* vect);
85  void fireArray ( const int size, double* vect,
86  long n, double p );
87  inline double operator()();
88  inline double operator()( long n, double p );
89 
90  // Save and restore to/from streams
91 
92  std::ostream & put ( std::ostream & os ) const;
93  std::istream & get ( std::istream & is );
94 
95  std::string name() const;
96  HepRandomEngine & engine();
97 
98  static std::string distributionName() {return "RandBinomial";}
99  // Provides the name of this distribution class
100 
101 private:
102 
103  static double genBinomial( HepRandomEngine *anEngine, long n, double p );
104 
105  std::shared_ptr<HepRandomEngine> localEngine;
106  long defaultN;
107  double defaultP;
108 
109 };
110 
111 } // namespace CLHEP
112 
113 #include "CLHEP/Random/RandBinomial.icc"
114 
115 #endif