RNG::LFIB4 Class Reference

A lagged Fibonacci random number generator by George Marsaglia (1999; internet posting). More...

#include <rng.h>

Inheritance diagram for RNG::LFIB4:

Collaboration diagram for RNG::LFIB4:

Public Member Functions
virtual std::string	to_string () const
rngint_t	value ()
	~LFIB4 ()
void	vec_reseed (const std::vector< rngint_t > &seeds)
int	nseed ()
Public Member Functions inherited from RNG::Table256
	~Table256 ()
Public Member Functions inherited from RNG::UniformInteger
virtual	~UniformInteger ()
rngint_t	value_in_range (rngint_t range)
virtual double	realvalue (bool include_zero=true, bool include_one=true)
	Return a random value in the interval [0,1], (0,1], [0,1), or (0,1) More...
void	reseed ()
void	reseed (rngint_t)
void	reseed (rngint_t, rngint_t)
void	reseed (rngint_t, rngint_t, rngint_t)
void	reseed (rngint_t, rngint_t, rngint_t, rngint_t)

Static Public Member Functions
static LFIB4 *	construct ()
static LFIB4 *	construct (const std::vector< rngint_t > &seeds)

Protected Member Functions
	LFIB4 ()
Protected Member Functions inherited from RNG::Table256
	Table256 ()

Additional Inherited Members
Protected Attributes inherited from RNG::Table256
UniformInteger *	seeder_
rngint_t	t [256]
unsigned char	c

Detailed Description

A lagged Fibonacci random number generator by George Marsaglia (1999; internet posting).

Here is an excerpt from the posting describing this generator: LFIB4 is an extension of the class that I have previously defined as lagged Fibonacci generators: x(n)=x(n-r) op x(n-s), with the x's in a finite set over which there is a binary operation op, such as +,- on integers mod 232, * on odd such integers, exclusive-or (xor) on binary vectors. Except for those using multiplication, lagged Fibonacci generators fail various tests of randomness, unless the lags are very long. To see if more than two lags would serve to overcome the problems of 2- lag generators using +,- or xor, I have developed the 4-lag generator LFIB4: x(n)=x(n-256)+x(n-179)+x(n-119)+x(n-55) mod 232. Its period is 2³¹*(2²⁵⁶-1), about 2²⁸⁷, and it seems to pass all tests—in particular, those of the kind for which 2-lag generators using +,-,xor seem to fail. For even more confidence in its suitability, LFIB4 can be combined with KISS, with a resulting period of about 2⁴¹⁰: just use (KISS+LFIB4) in any C expression.

Definition at line 400 of file rng.h.

Constructor & Destructor Documentation

RNG::LFIB4::LFIB4 ( )

protected

RNG::LFIB4::~LFIB4

(

)

Member Function Documentation

static LFIB4* RNG::LFIB4::construct ( )

static

static LFIB4* RNG::LFIB4::construct ( const std::vector< rngint_t > &  seeds )

static

int RNG::LFIB4::nseed ( )

virtual

Reimplemented from RNG::Table256.

virtual std::string RNG::LFIB4::to_string ( ) const

inlinevirtual

Definition at line 407 of file rng.h.

rngint_t RNG::LFIB4::value ( )

inlinevirtual

Implements RNG::UniformInteger.

Definition at line 418 of file rng.h.

References RNG::UniformInteger::nseed(), and RNG::UniformInteger::vec_reseed().

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void RNG::LFIB4::vec_reseed ( const std::vector< rngint_t > &  seeds )

virtual

Reimplemented from RNG::Table256.

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The documentation for this class was generated from the following file:

• sstmac/common/rng.h