Package io.github.olyutorskii.aletojio.rng.lcg

Class LcgRndInt31

java.lang.Object

io.github.olyutorskii.aletojio.rng.lcg.AbstractLcg

io.github.olyutorskii.aletojio.rng.lcg.LcgRndInt31

All Implemented Interfaces:

RndInt31

public class LcgRndInt31
extends AbstractLcg
implements RndInt31

Implementation of 31bit output Linear congruential generator(LCG).

LCG is a commonly used random number generator in the past.

* LCG implementations on CPU without 64-bit remainders often output only 31-bit random numbers.

Recurrence relation sequences : X(n+1) = (X(n) * Mul + Inc) mod Mod

• Mul : Multiplier
• Inc : Increment
• Mod : Modulus

See Also:

• Linear congruential generator (Wikipedia)

Field Summary

Fields inherited from class io.github.olyutorskii.aletojio.rng.lcg.AbstractLcg

MASK_B31, MASK_B32

Constructor Summary

Constructors

Constructor	Description
LcgRndInt31(long mulArg, long incArg, long modArg)	Constructor.

Method Summary

Modifier and Type	Method	Description
int	nextInt31()	Return next random number as 31bit int from LSB without sign-bit.
protected int	seedToResult()	Calculate result number from seed.

Methods inherited from class io.github.olyutorskii.aletojio.rng.lcg.AbstractLcg

getSeed, nextIntImpl, nextSeed, setSeed

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

LcgRndInt31

public LcgRndInt31(long mulArg,
 long incArg,
 long modArg)
            throws IllegalArgumentException

Constructor.

• Multiplier must be 1 or greatrer.
• Increment must be 0 or greatrer.
• Modulus must be 2 or greater.

Parameters:

mulArg - multiplier

incArg - increment

modArg - modulus

Throws:

IllegalArgumentException - illegal argument

Method Details

seedToResult

protected int seedToResult()

Calculate result number from seed.

result(31bit) reflects seed[0:30]

Specified by:

seedToResult in class AbstractLcg

Returns:

result number

nextInt31

public int nextInt31()

Return next random number as 31bit int from LSB without sign-bit.

Only positive or zero value returned.

* LCG implementations on CPU without 64-bit remainders often output only 31-bit random numbers.

Specified by:

nextInt31 in interface RndInt31

Returns:

random number