librandom::KnuthLFG Class Reference

Built-in implementation of Knuth's Lagged Fibonacci generator. More...

#include <knuthlfg.h>

Inheritance diagram for librandom::KnuthLFG:

Public Member Functions
	KnuthLFG (unsigned long)
	Create generator with given seed. More...
	~KnuthLFG ()
RngPtr	clone (unsigned long s)
	clone a random number generator of same type initialized with given seed More...
Public Member Functions inherited from librandom::RandomGen
	RandomGen ()
virtual	~RandomGen ()
double	drand (void)
	The following functions implement the user interface of the RandomGen class, including buffer management. More...
double	operator() (void)
	draw from [0, 1) More...
double	drandpos (void)
	draw from (0, 1) More...
unsigned long	ulrand (const unsigned long)
	draw from [0, n-1] More...
void	seed (const unsigned long)
	set random seed to a new value More...
size_t	get_buffsize (void) const
	returns buffer size More...
void	set_buffsize (const size_t)
	set buffer size More...

Private Member Functions
void	seed_ (unsigned long)
	implements seeding for RandomGen More...
double	drand_ ()
	implements drawing a single [0,1) number for RandomGen More...
void	ran_array_ (std::vector< long > &rbuff)
	Generates numbers, refilling buffer. More...
void	ran_start_ (long seed)
	initializes buffer More...
long	ran_draw_ ()
	deliver integer random number from ran_buffer_ More...
void	self_test_ ()
	Perform minimal self-test given by Knuth. More...

Static Private Member Functions
static long	mod_diff_ (long, long)
	subtraction module MM More...
static bool	is_odd_ (long)

Private Attributes
std::vector< long >	ran_x_
	the generator state More...
std::vector< long >	ran_buffer_
	generated numbers, 0..KK-1 are shipped More...
const std::vector< long > ::const_iterator	end_
	marker past last to deliver More...
std::vector< long >::const_iterator	next_
	next number to deliver More...

Static Private Attributes
static const long	KK_ = 100
	the long lag More...
static const long	LL_ = 37
	the short lag More...
static const long	MM_ = 1L << 30
	the modulus More...
static const long	TT_ = 70
	guaranteed separation between streams More...
static const long	QUALITY_ = 1009
	number of RNGs to fill for each cycle More...
static const double	I2DFactor_ = 1.0 / librandom::KnuthLFG::MM_
	int to double factor More...

Additional Inherited Members
Static Public Member Functions inherited from librandom::RandomGen
static RngPtr	create_knuthlfg_rng (unsigned long)
	Create built-in Knuth Lagged Fibonacci random generator. More...
Static Public Attributes inherited from librandom::RandomGen
static const unsigned long	DefaultSeed = 0xd37ca59fUL
	Default value for seeding generators in places where no seed is supplied. More...

Detailed Description

Built-in implementation of Knuth's Lagged Fibonacci generator.

This implementation is directly derived from Knuth's C code and generates the same random number sequence as the GSL implementation.

Constructor & Destructor Documentation

librandom::KnuthLFG::KnuthLFG ( unsigned long  seed )

explicit

Create generator with given seed.

References ran_start_(), and self_test_().

Referenced by clone().

librandom::KnuthLFG::~KnuthLFG ( )

inline

Member Function Documentation

RngPtr librandom::KnuthLFG::clone ( unsigned long  long )

inlinevirtual

clone a random number generator of same type initialized with given seed

Implements librandom::RandomGen.

References KnuthLFG().

double librandom::KnuthLFG::drand_ ( void  )

inlineprivatevirtual

implements drawing a single [0,1) number for RandomGen

Implements librandom::RandomGen.

References I2DFactor_, and ran_draw_().

bool librandom::KnuthLFG::is_odd_ ( long  x )

inlinestaticprivate

long librandom::KnuthLFG::mod_diff_ ( long  x, long  y  )

inlinestaticprivate

subtraction module MM

References MM_.

void librandom::KnuthLFG::ran_array_ ( std::vector< long > &  rbuff )

private

Generates numbers, refilling buffer.

Note

Buffer must be passed as argument, since ran_start_() and self_test_() must pass other buffers than ran_buffer_.

References nest::names::n.

Referenced by ran_draw_().

long librandom::KnuthLFG::ran_draw_ ( )

inlineprivate

deliver integer random number from ran_buffer_

References end_, next_, ran_array_(), and ran_buffer_.

Referenced by drand_().

void librandom::KnuthLFG::ran_start_ ( long  seed )

private

initializes buffer

References nest::names::x.

Referenced by KnuthLFG(), and seed_().

void librandom::KnuthLFG::seed_ ( unsigned long  seed )

inlineprivatevirtual

implements seeding for RandomGen

Implements librandom::RandomGen.

References ran_start_().

void librandom::KnuthLFG::self_test_ ( )

private

Perform minimal self-test given by Knuth.

The test will break an assertion if it fails. This is acceptable, since failure indicates either lack of two's complement arithmetic or problems with the size of data types.

References assert().

Referenced by KnuthLFG().

Member Data Documentation

const std::vector<long>::const_iterator librandom::KnuthLFG::end_

private

marker past last to deliver

Referenced by ran_draw_().

const double librandom::KnuthLFG::I2DFactor_ = 1.0 / librandom::KnuthLFG::MM_

staticprivate

int to double factor

Referenced by drand_().

const long librandom::KnuthLFG::KK_ = 100

staticprivate

the long lag

const long librandom::KnuthLFG::LL_ = 37

staticprivate

the short lag

const long librandom::KnuthLFG::MM_ = 1L << 30

staticprivate

the modulus

Referenced by mod_diff_().

std::vector<long>::const_iterator librandom::KnuthLFG::next_

private

next number to deliver

Referenced by ran_draw_().

const long librandom::KnuthLFG::QUALITY_ = 1009

staticprivate

number of RNGs to fill for each cycle

std::vector<long> librandom::KnuthLFG::ran_buffer_

private

generated numbers, 0..KK-1 are shipped

Referenced by ran_draw_().

std::vector<long> librandom::KnuthLFG::ran_x_

private

the generator state

const long librandom::KnuthLFG::TT_ = 70

staticprivate

guaranteed separation between streams

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

• knuthlfg.h
• knuthlfg.cpp