Files
geant4/source/externals/clhep/include/CLHEP/Random/Ranlux64Engine.h
T
2018-12-07 15:15:39 +01:00

118 lines
3.9 KiB
C++

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