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.


Ken Smith

See also

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

Distributions: HepRandom, RandBinomial, RandBit, RandBreitWigner, RandChiSquare, RandExponential, RandFlat, RandGamma, RandGauss, RandGaussQ, RandGaussT, RandGeneral, RandLandau, RandPoisson, RandPoissonQ, RandPoissonT, RandStudentT

Functions: HepStat


#include "CLHEP/Random/TripleRand.h"

class TripleRand: public HepRandomEngine

Public Member Functions

TripleRand(long seed)
TripleRand(HepInt rowIndex, HepInt colIndex)
TripleRand(HepStd::istream& is)
Copy constructor
TripleRand(const TripleRand & p)
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)
HepDouble flat()
Returns a pseudo random number between 0 and 1
(excluding the end points)
void flatArray(const HepInt size, HepDouble* vect)
Fills an array vect of specified size with flat random values.
void restoreStatus(const char filename[] = "TripleRand.conf")
Reads from named file the last saved engine status and restores it.
void saveStatus(const char filename[] = "TripleRand.conf") const
Saves on named file the current engine status.
void setSeed(long seed, HepInt)
Sets the state of the algorithm according to seed.
void setSeeds(const long * seeds, HepInt)
Sets the state of the algorithm according to the zero-terminated array of seeds.
void showStatus() const
Dumps the current engine status on the screen.

Non-Member Functions

HepStd::ostream & operator<< (HepStd::ostream & os, const TripleRand & e)
Output to a stream.
HepStd::istream & operator>> (HepStd::istream & is, TripleRand & e)
Input from a stream.



15 May 2000