| Geant4 Cross Reference |
1 // -*- C++ -*-
2 //
3 // -----------------------------------------------------------------------
4 // HEP Random
5 // --- RandGamma ---
6 // class header file
7 // -----------------------------------------------------------------------
8
9 // Class defining methods for shooting gamma distributed random values,
10 // given a k (default=1) and specifying also a lambda (default=1).
11 // Default values are used for operator()().
12
13 // Valid input values are k > 0 and lambda > 0. When invalid values are
14 // 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 RandGamma_h
25 #define RandGamma_h 1
26
27 #include "CLHEP/Random/Random.h"
28 #include "CLHEP/Utility/memory.h"
29
30 namespace CLHEP {
31
32 /**
33 * @author
34 * @ingroup random
35 */
36 class RandGamma : public HepRandom {
37
38 public:
39
40 inline RandGamma ( HepRandomEngine& anEngine, double k=1.0,
41 double lambda=1.0 );
42 inline RandGamma ( HepRandomEngine* anEngine, double k=1.0,
43 double lambda=1.0 );
44 // These constructors should be used to instantiate a RandGamma
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 RandGamma destructor.
50 // If the engine is passed by reference the corresponding engine object
51 // will not be deleted by the RandGamma destructor.
52
53 virtual ~RandGamma();
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( double k, double lambda );
61
62 static void shootArray ( const int size, double* vect,
63 double k=1.0, double lambda=1.0 );
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 double k, double lambda );
72
73 static void shootArray ( HepRandomEngine* anEngine, const int size,
74 double* vect, double k=1.0,
75 double lambda=1.0 );
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( double k, double lambda );
83
84 void fireArray ( const int size, double* vect);
85 void fireArray ( const int size, double* vect,
86 double k, double lambda );
87 inline double operator()();
88 inline double operator()( double k, double lambda );
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 "RandGamma";}
99 // Provides the name of this distribution class
100
101
102 private:
103
104 static double genGamma( HepRandomEngine *anEngine, double k,
105 double lambda );
106
107 std::shared_ptr<HepRandomEngine> localEngine;
108 double defaultK;
109 double defaultLambda;
110
111 };
112
113 } // namespace CLHEP
114
115 #include "CLHEP/Random/RandGamma.icc"
116
117 #endif
118