| Geant4 Cross Reference |
1 // -*- C++ -*-
2 //
3 // -----------------------------------------------------------------------
4 // HEP Random
5 // --- MTwistEngine ---
6 // class header file
7 // -----------------------------------------------------------------------
8 // A "fast, compact, huge-period generator" based on M. Matsumoto and
9 // T. Nishimura, "Mersenne Twister: A 623-dimensionally equidistributed
10 // uniform pseudorandom number generator", to appear in ACM Trans. on
11 // Modeling and Computer Simulation. It is a twisted GFSR generator
12 // with a Mersenne-prime period of 2^19937-1, uniform on open interval (0,1)
13 // For further information, see http://www.math.keio.ac.jp/~matumoto/emt.html
14 // =======================================================================
15 // Ken Smith - Started initial draft: 14th Jul 1998
16 // - Optimized to get pow() out of flat() method: 21st Jul
17 // - Added conversion operators: 6th Aug 1998
18 // M Fischler - Changes in way powers of two are kept: 16-Sep-1998
19 // Mark Fischler - Methods for distrib. instance save/restore 12/8/04
20 // Mark Fischler methods for anonymous save/restore 12/27/04
21 // =======================================================================
22
23 #ifndef MTwistEngine_h
24 #define MTwistEngine_h
25
26 #include "CLHEP/Random/RandomEngine.h"
27
28 namespace CLHEP {
29
30 /**
31 * @author
32 * @ingroup random
33 */
34 class MTwistEngine : public HepRandomEngine {
35
36 public:
37
38 MTwistEngine();
39 MTwistEngine( long seed );
40 MTwistEngine( int rowIndex, int colIndex );
41 MTwistEngine( std::istream & is );
42 virtual ~MTwistEngine();
43 // Constructors and destructor.
44
45 double flat();
46 // Returns a pseudo random number between 0 and 1 (excluding the end points).
47
48 void flatArray(const int size, double* vect);
49 // Fills an array "vect" of specified size with flat random values.
50
51 void setSeed(long seed, int);
52 // Sets the state of the algorithm according to seed.
53
54 void setSeeds(const long * seeds, int);
55 // Sets the state of the algorithm according to the zero terminated
56 // array of seeds. It is allowed to ignore one or many seeds in this array.
57
58 void saveStatus( const char filename[] = "MTwist.conf") const;
59 // Saves the current engine status in the named file
60
61 void restoreStatus( const char filename[] = "MTwist.conf" );
62 // Reads from named file the the last saved engine status and restores it.
63
64 void showStatus() const;
65 // Dumps the current engine status on the screen.
66
67 operator double(); // Returns same as flat()
68 operator float(); // returns flat, without worrying about filling bits
69 operator unsigned int(); // 32-bit flat, quickest of all
70
71 virtual std::ostream & put (std::ostream & os) const;
72 virtual std::istream & get (std::istream & is);
73 static std::string beginTag ( );
74 virtual std::istream & getState ( std::istream & is );
75
76 std::string name() const;
77 static std::string engineName() {return "MTwistEngine";}
78
79 std::vector<unsigned long> put () const;
80 bool get (const std::vector<unsigned long> & v);
81 bool getState (const std::vector<unsigned long> & v);
82
83 static const unsigned int VECTOR_STATE_SIZE = 626;
84
85 private:
86
87 unsigned int mt[624];
88 int count624;
89
90 enum{ NminusM = 227, M = 397, N = 624};
91
92 }; // MTwistEngine
93
94 } // namespace CLHEP
95
96 #endif // MTwistEngine_h
97