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00001 // $Id: RandGamma.h,v 1.3.4.1 2005/03/18 22:26:48 garren Exp $ 00002 // -*- C++ -*- 00003 // 00004 // ----------------------------------------------------------------------- 00005 // HEP Random 00006 // --- RandGamma --- 00007 // class header file 00008 // ----------------------------------------------------------------------- 00009 00010 // Class defining methods for shooting gamma distributed random values, 00011 // given a k (default=1) and specifying also a lambda (default=1). 00012 // Default values are used for operator()(). 00013 00014 // Valid input values are k > 0 and lambda > 0. When invalid values are 00015 // presented, the code silently returns -1.0. 00016 00017 // ======================================================================= 00018 // John Marraffino - Created: 12th May 1998 Based on the C-Rand package 00019 // by Ernst Stadlober and Franz Niederl of the Technical 00020 // University of Graz, Austria. 00021 // Gabriele Cosmo - Removed useless methods and data: 5th Jan 1999 00022 // M Fischler - put and get to/from streams 12/10/04 00023 // ======================================================================= 00024 00025 #ifndef RandGamma_h 00026 #define RandGamma_h 1 00027 00028 #include "CLHEP/Random/defs.h" 00029 #include "CLHEP/Random/Random.h" 00030 00031 namespace CLHEP { 00032 00037 class RandGamma : public HepRandom { 00038 00039 public: 00040 00041 inline RandGamma ( HepRandomEngine& anEngine, double k=1.0, 00042 double lambda=1.0 ); 00043 inline RandGamma ( HepRandomEngine* anEngine, double k=1.0, 00044 double lambda=1.0 ); 00045 // These constructors should be used to instantiate a RandGamma 00046 // distribution object defining a local engine for it. 00047 // The static generator will be skipped using the non-static methods 00048 // defined below. 00049 // If the engine is passed by pointer the corresponding engine object 00050 // will be deleted by the RandGamma destructor. 00051 // If the engine is passed by reference the corresponding engine object 00052 // will not be deleted by the RandGamma destructor. 00053 00054 virtual ~RandGamma(); 00055 // Destructor 00056 00057 // Static methods to shoot random values using the static generator 00058 00059 static inline double shoot(); 00060 00061 static double shoot( double k, double lambda ); 00062 00063 static void shootArray ( const int size, double* vect, 00064 double k=1.0, double lambda=1.0 ); 00065 00066 // Static methods to shoot random values using a given engine 00067 // by-passing the static generator. 00068 00069 static inline double shoot( HepRandomEngine* anEngine ); 00070 00071 static double shoot( HepRandomEngine* anEngine, 00072 double k, double lambda ); 00073 00074 static void shootArray ( HepRandomEngine* anEngine, const int size, 00075 double* vect, double k=1.0, 00076 double lambda=1.0 ); 00077 00078 // Methods using the localEngine to shoot random values, by-passing 00079 // the static generator. 00080 00081 inline double fire(); 00082 00083 double fire( double k, double lambda ); 00084 00085 void fireArray ( const int size, double* vect); 00086 void fireArray ( const int size, double* vect, 00087 double k, double lambda ); 00088 inline double operator()(); 00089 inline double operator()( double k, double lambda ); 00090 00091 // Save and restore to/from streams 00092 00093 std::ostream & put ( std::ostream & os ) const; 00094 std::istream & get ( std::istream & is ); 00095 00096 std::string name() const; 00097 HepRandomEngine & engine(); 00098 00099 static std::string distributionName() {return "RandGamma";} 00100 // Provides the name of this distribution class 00101 00102 00103 private: 00104 00105 // Private copy constructor. Defining it here disallows use. 00106 RandGamma(const RandGamma& d); 00107 00108 static double genGamma( HepRandomEngine *anEngine, double k, 00109 double lambda ); 00110 00111 HepRandomEngine* localEngine; 00112 bool deleteEngine; 00113 double defaultK; 00114 double defaultLambda; 00115 00116 }; 00117 00118 } // namespace CLHEP 00119 00120 #ifdef ENABLE_BACKWARDS_COMPATIBILITY 00121 // backwards compatibility will be enabled ONLY in CLHEP 1.9 00122 using namespace CLHEP; 00123 #endif 00124 00125 #include "CLHEP/Random/RandGamma.icc" 00126 00127 #endif