DualRand


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).

Author

Doug Toussaint

See also

Engines: HepRandomEngine, DRand48Engine , 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/DualRand.h"

class DualRand: public HepRandomEngine

Public Member Functions

Constructors
DualRand()
DualRand(long seed)
DualRand(HepInt rowIndex, HepInt colIndex)
DualRand(std::istream& is)
Copy constructor
DualRand(const DualRand & p)
Destructor
virtual ~DualRand()
Conversion operators
operator HepFloat()
Flat value, without worrying about filling bits

operator unsigned int()
32-bit flat value, quickest of all
=
DualRand & operator=(const DualRand & p)
Assignment
flat
HepDouble flat()
Returns a pseudo random number between 0 and 1 (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[] = "DualRand.conf")
Reads from named file the last saved engine status and restores it.
saveStatus
void saveStatus(const char filename[] = "DualRand.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 DualRand & e)
Output to a stream.
>>
std::istream & operator>> (std::istream & is, DualRand & e)
Input from a stream.

Example

CLHEP/test/testRandom.cc


04 May 1999
EVC