CLHEP/Random/RanecuEngine.h

00001 // $Id: RanecuEngine.h,v 1.14 2002/04/12 15:02:45 evc Exp $
00002 // -*- C++ -*-
00003 //
00004 // -----------------------------------------------------------------------
00005 //                             HEP Random
00006 //                         --- RanecuEngine ---
00007 //                          class header file
00008 // -----------------------------------------------------------------------
00009 // This file is part of Geant4 (simulation toolkit for HEP).
00010 //
00011 // RANECU Random Engine - algorithm originally written in FORTRAN77
00012 //                        as part of the MATHLIB HEP library.
00013 // The initialisation is carried out using a Multiplicative Congruential
00014 // generator using formula constants of L'Ecuyer as described in "F.James,
00015 // Comp. Phys. Comm. 60 (1990) 329-344".
00016 // Seeds are taken from a seed table given an index, the getSeed() method
00017 // returns the current index in the seed table, the getSeeds() method
00018 // returns a pointer to the couple of seeds stored in the local table of
00019 // seeds at the current index.
00020 
00021 // =======================================================================
00022 // Gabriele Cosmo - Created: 2nd February 1996
00023 //                - Minor corrections: 31st October 1996
00024 //                - Added methods for engine status: 19th November 1996
00025 //                - setSeed() now has default dummy argument
00026 //                  set to zero: 11th July 1997
00027 //                - Added default index to setSeeds(): 16th Oct 1997
00028 // J.Marraffino   - Added stream operators and related constructor.
00029 //                  Added automatic seed selection from seed table and
00030 //                  engine counter: 16th Feb 1998
00031 // Ken Smith      - Added conversion operators:  6th Aug 1998
00032 // =======================================================================
00033 
00034 #ifndef RanecuEngine_h
00035 #define RanecuEngine_h 1
00036 
00037 #include "CLHEP/Random/RandomEngine.h"
00038 
00043 class RanecuEngine : public HepRandomEngine {
00044 
00045 public:
00046 
00047   RanecuEngine(HepStd::istream& is);
00048   RanecuEngine();
00049   RanecuEngine(int index);
00050   virtual ~RanecuEngine();
00051   // Constructors and destructor.
00052 
00053   RanecuEngine(const RanecuEngine &p);
00054   // Copy constructor
00055 
00056   RanecuEngine & operator = (const RanecuEngine &p);
00057   // Overloaded assignment operator, to retrieve the engine status.
00058 
00059   double flat();
00060   // Returns a pseudo random number between 0 and 1 
00061   // (excluding the end points)
00062 
00063   void flatArray (const int size, double* vect);
00064   // Fills an array "vect" of specified size with flat random values.
00065 
00066   void setIndex (long index);
00067   // Sets the state of the algorithm according to "index", the position
00068   // in the local table of seeds.
00069  
00070   void setSeed (long index, int dum=0);
00071   // Resets the state of the algorithm according to "index", the position
00072   // in the static table of seeds stored in HepRandom.
00073 
00074   void setSeeds (const long* seeds, int index=-1);
00075   // Sets the state of the algorithm according to the array of seeds
00076   // "seeds" containing two seed values to be stored in the local table at
00077   // "index" position.
00078 
00079   void saveStatus( const char filename[] = "Ranecu.conf" ) const;
00080   // Saves on file Ranecu.conf the current engine status.
00081 
00082   void restoreStatus( const char filename[] = "Ranecu.conf" );
00083   // Reads from file Ranecu.conf the last saved engine status
00084   // and restores it.
00085 
00086   void showStatus() const;
00087   // Dumps the engine status on the screen.
00088 
00089   operator unsigned int();
00090   // 32-bit int flat, faster in this case
00091 
00092   friend HepStd::ostream& operator<< (HepStd::ostream& os, const RanecuEngine& e);
00093   friend HepStd::istream& operator>> (HepStd::istream& is,       RanecuEngine& e);
00094 
00095 protected:
00096 
00097   // Suggested L'ecuyer coefficients for portable 32 bits generators.
00098   
00099   const int ecuyer_a, ecuyer_b, ecuyer_c, ecuyer_d, ecuyer_e, ecuyer_f;
00100   const int shift1, shift2;
00101   const double prec;
00102 
00103 private:
00104 
00105   // Members defining the current state of the generator.
00106 
00107   const int maxSeq;
00108   long table[215][2];
00109   int seq;
00110   static int numEngines;
00111 
00112 };
00113 
00114 #endif

Class Library for High Energy Physics (version 1.8)