Package io.github.olyutorskii.aletojio.rng.mwc

Class Cmwc

java.lang.Object

io.github.olyutorskii.aletojio.rng.mwc.Mwc

io.github.olyutorskii.aletojio.rng.mwc.Cmwc

All Implemented Interfaces:

RndInt32

public class Cmwc
extends Mwc

Complementary-multiply-with-carry random number generator.

Random sequence X(n) is derived as follows with parameter a(multiplier), b(divisor).

• T(n) = a * X(n-r) + C(n-1)
• C(n) = T(n) / b
• Y(n) = T(n) mod b
• X(n) = b - 1 - Y(n)

r is the length of the record that stores past results. "carry" comes from C(n-1).

See Also:

• Multiply-with-carry pseudorandom number generator (Wikipedia)

Constructor Summary

Constructors

Constructor	Description
Cmwc()	Constructor.
Cmwc(int recLen, long mulArg, long divArg)	Constructor.

Method Summary

Modifier and Type	Method	Description
protected int	funcRndFromTval(long tVal)	Function that takes T-value as an argument and returns random result.

Methods inherited from class io.github.olyutorskii.aletojio.rng.mwc.Mwc

funcCarryFromTval, funcTval, getCarry, getOldest, getRecords, nextInt32, pushLatest, setCarry, setSeeds

Methods inherited from class java.lang.Object

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

Constructor Details

Cmwc

public Cmwc(int recLen,
 long mulArg,
 long divArg)
     throws IllegalArgumentException

Constructor.

• record length must be greater than 0.
• multiplier must be greater than 1.
• divisor must be greater than 1.

If you want 32-bit uniformly distributed random numbers, the divisor must be 2**32, but you can compromise with 2**32 -1.

Parameters:

recLen - records length

mulArg - multiplier

divArg - divisor

Throws:

IllegalArgumentException - illegal argument

Cmwc

public Cmwc()
     throws IllegalArgumentException

Constructor.

• Default record length = 1024
• Default multiplier value = 987769338
• Default divisor value = 2**32 - 1

* Caution : If you don't provide your entropy to seeds, it takes over million trials until the seed is scrambled.

Throws:

IllegalArgumentException - illegal argument

See Also:

• Random Number Generators

Method Details

funcRndFromTval

protected int funcRndFromTval(long tVal)

Function that takes T-value as an argument and returns random result.

Overrides:

funcRndFromTval in class Mwc

Parameters:

tVal - T-value

Returns:

random result