| Geant4 Cross Reference |
>> 1 // $Id:$
1 // -*- C++ -*- 2 // -*- C++ -*-
2 // 3 //
3 // ------------------------------------------- 4 // -----------------------------------------------------------------------
4 // HEP Random 5 // HEP Random
5 // --- RanshiEngine --- 6 // --- RanshiEngine ---
6 // class header file 7 // class header file
7 // ------------------------------------------- 8 // -----------------------------------------------------------------------
8 // 9 //
9 // 10 //
10 // The algorithm for this random engine was ta 11 // The algorithm for this random engine was taken from "F.Gutbrod, Comp.
11 // Phys. Comm. 87 (1995) 291-306". 12 // Phys. Comm. 87 (1995) 291-306".
12 // 13 //
13 // The algorithm can be imagined as a physical 14 // The algorithm can be imagined as a physical system as follows: Imagine
14 // 512 "black balls" each with their own uniqu 15 // 512 "black balls" each with their own unique spin, and positions char-
15 // acterized by disrete angles, where the spin 16 // acterized by disrete angles, where the spin is a 32-bit unsigned integer.
16 // A "red ball" collides based upon the angle 17 // A "red ball" collides based upon the angle determined by the last 8 bits
17 // of its spin, and the spin of the colliding 18 // of its spin, and the spin of the colliding ball is taken as the output
18 // random number. The spin of the colliding ba 19 // random number. The spin of the colliding ball is replaced then with the
19 // left circular shift of the black ball's spi 20 // left circular shift of the black ball's spin XOR'd with the red ball's
20 // spin. The black ball's old spin becomes the 21 // spin. The black ball's old spin becomes the red ball's.
21 // 22 //
22 // To avoid the traps presented, two measures 23 // To avoid the traps presented, two measures are taken: first, the red
23 // ball will oscillate between hitting the low 24 // ball will oscillate between hitting the lower half of the buffer on one
24 // turn and the upper half on another; second, 25 // turn and the upper half on another; second, the red ball's spin is
25 // incremented by a counter of the number of r 26 // incremented by a counter of the number of random numbers produced.
26 // 27 //
27 // The result is scaled to a double precision 28 // The result is scaled to a double precision floating point number to which
28 // is added another random double further scal 29 // is added another random double further scaled 2^(53-32) places to the
29 // right in order to ensure that the remaining 30 // right in order to ensure that the remaining bits of the result are not
30 // left empty due to the mere 32 bits represen 31 // left empty due to the mere 32 bits representation used internally.
31 32
32 // =========================================== 33 // =======================================================================
33 // Ken Smith - Created: 9th June 1998 34 // Ken Smith - Created: 9th June 1998
34 // - Removed pow() from flat me 35 // - Removed pow() from flat method: 21st Jul 1998
35 // - Added conversion operators 36 // - Added conversion operators: 6th Aug 1998
36 // Mark Fischler Methods put, get for insta 37 // Mark Fischler Methods put, get for instance save/restore 12/8/04
37 // Mark Fischler methods for anonymous save 38 // Mark Fischler methods for anonymous save/restore 12/27/04
38 // =========================================== 39 // =======================================================================
39 40
40 #ifndef HepRanshiEngine_h 41 #ifndef HepRanshiEngine_h
41 #define HepRanshiEngine_h 42 #define HepRanshiEngine_h
42 43
43 #include "CLHEP/Random/RandomEngine.h" 44 #include "CLHEP/Random/RandomEngine.h"
44 45
45 namespace CLHEP { 46 namespace CLHEP {
46 47
47 /** 48 /**
48 * @author 49 * @author
49 * @ingroup random 50 * @ingroup random
50 */ 51 */
51 class RanshiEngine: public HepRandomEngine { 52 class RanshiEngine: public HepRandomEngine {
52 53
53 public: 54 public:
54 55
55 RanshiEngine(); 56 RanshiEngine();
56 RanshiEngine(std::istream &is); 57 RanshiEngine(std::istream &is);
57 RanshiEngine(long seed); 58 RanshiEngine(long seed);
58 RanshiEngine(int rowIndex, int colIndex); 59 RanshiEngine(int rowIndex, int colIndex);
59 virtual ~RanshiEngine(); 60 virtual ~RanshiEngine();
60 // Constructors and destructor 61 // Constructors and destructor
61 62
62 double flat(); 63 double flat();
63 // Returns a pseudo random number between 64 // Returns a pseudo random number between 0 and 1
64 65
65 void flatArray(const int size, double* vec 66 void flatArray(const int size, double* vect);
66 // Fills the array "vect" of specified siz 67 // Fills the array "vect" of specified size with flat random values
67 68
68 void setSeed(long seed, int); 69 void setSeed(long seed, int);
69 // Sets the state of the algorithm accordi 70 // Sets the state of the algorithm according to seed.
70 71
71 void setSeeds(const long* seeds, int); 72 void setSeeds(const long* seeds, int);
72 // Sets the state of the algorithm accordi 73 // Sets the state of the algorithm according to the zero-terminated
73 // array of seeds. 74 // array of seeds.
74 75
75 void saveStatus(const char filename[] = "R 76 void saveStatus(const char filename[] = "RanshiEngine.conf") const;
76 // Saves on named file the current engine 77 // Saves on named file the current engine status
77 78
78 void restoreStatus(const char filename[] = 79 void restoreStatus(const char filename[] = "RanshiEngine.conf");
79 // Reads from named file the last saved en 80 // Reads from named file the last saved engine status
80 // and restores it. 81 // and restores it.
81 82
82 void showStatus() const; 83 void showStatus() const;
83 // Dumps the engine status on the screen 84 // Dumps the engine status on the screen
84 85
85 operator double(); // Returns same a << 86 operator float(); // flat value, without worrying about filling bits
86 operator float(); // flat value, wi << 87 operator unsigned int(); // 32-bit flat value, quickest of all
87 operator unsigned int(); // 32-bit flat va << 88
88 << 89 virtual std::ostream & put (std::ostream & os) const;
89 virtual std::ostream & put (std::ostream & << 90 virtual std::istream & get (std::istream & is);
90 virtual std::istream & get (std::istream & << 91 static std::string beginTag ( );
91 static std::string beginTag ( ); << 92 virtual std::istream & getState ( std::istream & is );
92 virtual std::istream & getState ( std::ist << 93
93 << 94 std::string name() const;
94 std::string name() const; << 95 static std::string engineName() {return "RanshiEngine";}
95 static std::string engineName() {return "R << 96
96 << 97 std::vector<unsigned long> put () const;
97 std::vector<unsigned long> put () const; << 98 bool get (const std::vector<unsigned long> & v);
98 bool get (const std::vector<unsigned long> << 99 bool getState (const std::vector<unsigned long> & v);
99 bool getState (const std::vector<unsigned <<
100 100
101 private: 101 private:
102 enum {numBuff = 512}; 102 enum {numBuff = 512};
103 103
104 unsigned int halfBuff, numFlats; 104 unsigned int halfBuff, numFlats;
105 unsigned int buffer[numBuff]; 105 unsigned int buffer[numBuff];
106 unsigned int redSpin; 106 unsigned int redSpin;
107 107
108 static const unsigned int VECTOR_STATE_SIZ 108 static const unsigned int VECTOR_STATE_SIZE = numBuff + 4;
109 109
110 }; // RanshiEngine 110 }; // RanshiEngine
111 111
112 } // namespace CLHEP 112 } // namespace CLHEP
113 113
114 #endif // HepRanshiEngine_h 114 #endif // HepRanshiEngine_h
115 115