Hurd160Engine

The starting point for the Hurd Random algorithm is the paper in IEEE Transactions on Computers c23, 2 Feb 1974. The algorithm is essentially a series of 32 interconnected b-bit registers. The basic property is that at each step, bit 1 becomes bit 0, bit 2 the new bit 1, bit b the new bit b-1. This is modified so that the new bit b0 is the old bit b1 XOR'd with some bit b-d from the previous bit register. The values of d can be chosen so as to generate a primitive polynomial, a maximal length sequence through all bit patterns except the zero pattern.

This generator, Hurd160 use values based upon Table I of the afore mentioned paper, such that we have 160 total bits, representing 32 5-bit registers (actually implemented as an array of 5 32-bit words)

Author

See also

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

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

Declaration

#include "CLHEP/Random/Hurd160Engine.h"

class Hurd160Engine: public HepRandomEngine

Public Member Functions

Constructors

Hurd160Engine()

Hurd160Engine(long seed)

Hurd160Engine(HepInt rowIndex, HepInt colIndex)

Hurd160Engine(std::istream& is)

Copy constructor

Hurd160Engine(const Hurd160Engine & p)

Destructor

virtual ~Hurd160Engine()

Conversion operators

operator HepFloat()

Flat value, without worrying about filling bits

operator unsigned int()

32-bit flat value, quickest of all

=

Hurd160Engine & operator=(const Hurd160Engine & p)

Assignment

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.

restoreStatus

void restoreStatus(const char filename[] = "Hurd160Engine.conf")

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

saveStatus

void saveStatus(const char filename[] = "Hurd160Engine.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.

Non-Member Functions

<<

std::ostream & operator<< (std::ostream & os, const Hurd160Engine & e)

Output to a stream.

>>

std::istream & operator>> (std::istream & is, Hurd160Engine & e)

Input from a stream.

Example