DRand48Engine

Random engine using drand48() and srand48() functions from C standard library to implement the flat() basic distribution and for setting seeds respectively.

DRand48Engine uses the seed48() function from C standard library to retrieve the current internal status of the generator, which is represented by 3 short values. Copies of an object of this kind are not allowed. The engine state can be streamed through ad-hoc defined stream operator<< and operator>>.

For Windows/NT platforms (WIN32), the code for drand48() has been extracted from the GNU C Library 2.0.1 and adapted for the native types.

Author

See also

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

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

Declaration

#include "CLHEP/Random/DRand48Engine.h"

class DRand48Engine : public HepRandomEngine

Public Member Functions

Constructors

DRand48Engine()

DRand48Engine(long seed)

DRand48Engine(HepInt rowIndex, HepInt colIndex)

DRand48Engine(std::istream& is)

Destructor

virtual ~DRand48Engine()

flat

HepDouble flat()

It returns a pseudo random number between 0 and 1, according to the standard stdlib random function drand48() but excluding the end points.

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[] = "DRand48.conf")

Reads from file DRand48.conf the last saved engine status and restores it.

saveStatus

void saveStatus(const char filename[] = "DRand48.conf") const

Saves on file DRand48.conf the current engine status.

setSeed

void setSeed(long seed, HepInt dum=0)

Sets the state of the algorithm according to seed.

setSeeds

void setSeeds(const long * seeds, HepInt dum=0)

Sets the state of the algorithm according to the zero terminated array of seeds. Only the first seed is used.

showStatus

void showStatus() const

Dumps the engine status on the screen.

Non-Member Functions

<<

std::ostream & operator<< (std::ostream & os, const DRand48Engine & e)

Output to a stream.

>>

std::istream & operator>> (std::istream & is, DRand48Engine & e)

Input from a stream.

Example