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00001 // $Id: Hurd288Engine.h,v 1.3.4.2 2005/04/15 16:32:52 garren Exp $ 00002 // -*- C++ -*- 00003 // 00004 // ----------------------------------------------------------------------- 00005 // HEP Random 00006 // --- Hurd288Engine --- 00007 // class header file 00008 // ----------------------------------------------------------------------- 00009 // The starting point for the Hurd Random algorithm is the paper in 00010 // IEEE Transactions on Computers c23, 2 Feb 1974. The algorithm is 00011 // essentially a series of 32 interconnected b-bit registers. The basic 00012 // property is that at each step, bit 1 becomes bit 0, bit 2 the new bit 1, 00013 // bit b the new bit b-1. This is modified so that the new bit b0 is the old 00014 // bit b1 XOR'd with some bit b-d from the previous bit register. The values 00015 // of d can be chosen so as to generate a primitive polynomial, a maximal 00016 // length sequence through all bit patterns except the zero pattern. 00017 // 00018 // This generator, Hurd288, use values based upon Table I of the afore- 00019 // mentioned paper, such that we have 288 total bits, representing 32 00020 // 9-bit registers (actually implemented as an array of 9 32-bit words) 00021 // ======================================================================= 00022 // 07-23-98 KLS Initial draft started 00023 // Ken Smith - Added conversion operators: 6th Aug 1998 00024 // Mark Fischler - methods for distrib. instacne save/restore 12/8/04 00025 // Mark Fischler - methods for anonymous save/restore 12/27/04 00026 // ======================================================================= 00027 00028 #ifndef Hurd288Engine_h 00029 #define Hurd288Engine_h 00030 00031 #include "CLHEP/Random/defs.h" 00032 #include "CLHEP/Random/RandomEngine.h" 00033 00034 namespace CLHEP { 00035 00040 class Hurd288Engine: public HepRandomEngine { 00041 00042 public: 00043 00044 Hurd288Engine(); 00045 Hurd288Engine( std::istream &is ); 00046 Hurd288Engine( long seed ); 00047 Hurd288Engine( int rowIndex, int colIndex ); 00048 virtual ~Hurd288Engine(); 00049 // Constructors and destructor. 00050 00051 Hurd288Engine( const Hurd288Engine &p ); 00052 Hurd288Engine & operator = ( const Hurd288Engine &p ); 00053 // Copy constructor and operator=. 00054 00055 double flat(); 00056 // Returns a pseudo random number between 0 and 1 00057 00058 void flatArray( const int size, double* vect ); 00059 // Fills the array "vect" of specified size with flat random values. 00060 00061 void setSeed( long seed, int ); 00062 // Sets the state of the algorithm according to seed. 00063 00064 void setSeeds( const long* seeds, int ); 00065 // Sets the state of the algorithm according to the zero-terminated 00066 // array of seeds. 00067 00068 void saveStatus( const char filename[] = "Hurd288Engine.conf" ) const; 00069 // Saves on named file the current engine status 00070 00071 void restoreStatus( const char filename[] = "Hurd288Engine.conf" ); 00072 // Reads from named file the last saved engine status 00073 // and restores it. 00074 00075 void showStatus() const; 00076 // Dumps the engine status on the screen 00077 00078 operator float(); // flat value, without worrying about filling bits 00079 operator unsigned int(); // 32-bit flat value, quickest of all 00080 00081 virtual std::ostream & put (std::ostream & os) const; 00082 virtual std::istream & get (std::istream & is); 00083 static std::string beginTag ( ); 00084 virtual std::istream & getState ( std::istream & is ); 00085 00086 std::string name() const; 00087 static std::string engineName() {return "Hurd288Engine";} 00088 00089 std::vector<unsigned long> put () const; 00090 bool get (const std::vector<unsigned long> & v); 00091 bool getState (const std::vector<unsigned long> & v); 00092 00093 static const unsigned int VECTOR_STATE_SIZE = 11; 00094 00095 private: 00096 static int numEngines; 00097 static int maxIndex; 00098 00099 static double twoToMinus_32; 00100 static double twoToMinus_53; 00101 static double nearlyTwoToMinus_54; 00102 void powersOfTwo(); 00103 void advance(); 00104 00105 int wordIndex; 00106 unsigned int words[9]; 00107 00108 }; // Hurd288Engine 00109 00110 } // namespace CLHEP 00111 00112 #ifdef ENABLE_BACKWARDS_COMPATIBILITY 00113 // backwards compatibility will be enabled ONLY in CLHEP 1.9 00114 using namespace CLHEP; 00115 #endif 00116 00117 #endif // Hurd288Engine_h