TripleRand

A canopy pseudo-random number generator. Using the Tausworthe exclusive-or shift register, a simple Integer Coungruence generator, and the Hurd 288 total bit shift register, all XOR'd with each other, we provide an engine that should be a fairly good "mother" generator.

This is similar to DualRand, with the addition of the Hurd288Engine. From DualRand, we have the following:

Exclusive or of a feedback shift register and integer congruence random number generator. The feedback shift register uses offsets 127 and 97. The integer congruence generator uses a different multiplier for each stream. The multipliers are chosen to give full period and maximum "potency" for modulo 2^32. The period of the combined random number generator is 2^159 - 2^32, and the sequences are different for each stream (not just started in a different place).

The above is then amended to also add in the exclusive or of the 288-total bit Hurd engine which in this case is a series of 32 interconnected 9-bit shift registers, with the newest bit of each register formed by the XOR of the previous bit and some bit b-d from a previous register where d is chosen to create a primitive polynomial to maximize the period.

Author

See also

Engines: HepRandomEngine, DRand48Engine , DualRand HepJamesRandom Hurd160Engine Hurd288Engine MTwistEngine RandEngine RanecuEngine RanluxEngine Ranlux64Engine RanshiEngine

Distributions: HepRandom, RandBinomial RandBreitWigner RandChiSquare RandExponential RandFlat RandGamma RandGauss RandGeneral RandPoisson RandStudentT

Declaration

#include "CLHEP/Random/TripleRand.h"

class TripleRand: public HepRandomEngine

Public Member Functions

Constructors

TripleRand()

TripleRand(long seed)

TripleRand(HepInt rowIndex, HepInt colIndex)

TripleRand(std::istream& is)

Copy constructor

TripleRand(const TripleRand & p)

Destructor

virtual ~TripleRand()

Conversion operators

operator HepFloat()

Flat value, without worrying about filling bits

operator unsigned int()

32-bit flat value, quickest of all

=

TripleRand & operator=(const TripleRand & p)

Assignment

Cong

IntegerCong & Cong()

Accessor function, to retrieve the constituent engine for input

ConstCong

const IntegerCong & ConstCong() const

Accessor function, necessary for output

ConstHurd

const Hurd288Engine & ConstHurd() const

Accessor function, necessary for output

ConstTaus

const Tausworthe & ConstTaus() const

Accessor function, necessary for output

flat

HepDouble flat()

Returns a pseudo random number between 0 and 1

flatArray

void flatArray(const HepInt size, HepDouble* vect)

Fills an array vect of specified size with flat random values.

Hurd

Hurd288Engine & Hurd()

Accessor function, to retrieve the constituent engine for input

restoreStatus

void restoreStatus(const char filename[] = "TripleRand.conf")

Reads from named file the last saved engine status and restores it.

saveStatus

void saveStatus(const char filename[] = "TripleRand.conf") const

Saves on named file the current engine status.

setSeed

void setSeed(long seed, HepInt)

Sets the state of the algorithm according to seed.

setSeeds

void setSeeds(const long * seeds, HepInt)

Sets the state of the algorithm according to the zero-terminated array of seeds.

showStatus

void showStatus() const

Dumps the current engine status on the screen.