Gabriele Cosmo
118 lines
3.9 KiB
C++
118 lines
3.9 KiB
C++
// -*- C++ -*-
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//
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// -----------------------------------------------------------------------
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// HEP Random
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// --- Ranlux64Engine ---
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// class header file
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// -----------------------------------------------------------------------
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// The algorithm for this random engine has been taken from the notes of
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// a double-precision ranlux implementation by Martin Luscher, dated
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// November 1997.
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//
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// Like the previous ranlux generator, this one also has "luxury" levels,
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// determining how many pseudo-random numbers are discarded for every
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// twelve values used. Three levels are given, with the note that Luscher
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// himself advocates only the highest two levels for this engine.
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// level 0 (p=109): Throw away 109 values for every 12 used
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// level 1 (p=202): (default) Throw away 202 values for every 12 used
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// level 2 (p=397): Throw away 397 values for every 12 used
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//
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// The initialization is carried out using a Multiplicative Congruential
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// generator using formula constants of L'Ecuyer as described in "F.James,
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// Comp. Phys. Comm. 60 (1990) 329-344".
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// =======================================================================
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// Ken Smith - Created Initial draft: 14th Jul 1998
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// - Added conversion operators: 6th Aug 1998
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// Mark Fischler
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// 9/9/98 - Added update() routine to allow computation of many at once
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// - Replaced algorithm with jone exactly matching Luscher:
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// 48-bits generated
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// skip n-12 instead of n numbers
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// - Corrected protection agains overflow
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// 12/8/04 - Methods for instance save/restore
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// 12/27/04 - methods for anonymous save/restore 12/27/04
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//
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// =======================================================================
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#ifndef Ranlux64Engine_h
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#define Ranlux64Engine_h
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#include "CLHEP/Random/RandomEngine.h"
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namespace CLHEP {
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/**
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* @author
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* @ingroup random
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*/
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class Ranlux64Engine : public HepRandomEngine {
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public:
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Ranlux64Engine( std::istream& is );
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Ranlux64Engine();
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Ranlux64Engine( long seed, int lxr = 1 );
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Ranlux64Engine( int rowIndex, int colIndex, int lxr );
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virtual ~Ranlux64Engine();
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// Constructors and destructor
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double flat();
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// It returns a pseudo random number between 0 and 1,
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// excluding the end points.
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void flatArray (const int size, double* vect);
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// Fills the array "vect" of specified size with flat random values.
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void setSeed(long seed, int lxr=1);
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// Sets the state of the algorithm according to seed.
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void setSeeds(const long * seeds, int lxr=1);
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// Sets the state of the algorithm according to the zero terminated
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// array of seeds. Only the first seed is used.
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void saveStatus( const char filename[] = "Ranlux64.conf" ) const;
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// Saves in named file the current engine status.
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void restoreStatus( const char filename[] = "Ranlux64.conf" );
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// Reads from named file the last saved engine status and restores it.
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void showStatus() const;
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// Dumps the engine status on the screen.
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int getLuxury() const { return luxury; }
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// Gets the luxury level.
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virtual std::ostream & put (std::ostream & os) const;
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virtual std::istream & get (std::istream & is);
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static std::string beginTag ( );
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virtual std::istream & getState ( std::istream & is );
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std::string name() const;
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static std::string engineName() {return "Ranlux64Engine";}
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std::vector<unsigned long> put () const;
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bool get (const std::vector<unsigned long> & v);
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bool getState (const std::vector<unsigned long> & v);
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static const unsigned int VECTOR_STATE_SIZE = 30;
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private:
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void update();
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void advance(int dozens);
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int pDiscard; // separate sequence by p-r = p-12 discarded elements
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int pDozens; // pDiscard / 12;
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int endIters; // pDiscard % 12;
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int luxury;
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int index;
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double randoms[12]; // randoms [i] is the x[n-i] of Luscher's note
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double carry;
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}; // Ranlux64Engine
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} // namespace CLHEP
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#endif // Ranlux64Engine_h
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