squidpony.squidmath

Class TricycleRNG

java.lang.Object

squidpony.squidmath.TricycleRNG

All Implemented Interfaces:

java.io.Serializable, RandomnessSource

public class TricycleRNG
extends java.lang.Object
implements RandomnessSource, java.io.Serializable

A RandomnessSource with three long states that changes its state with three ways it can connect states to other states. This has been backported from jdkgdxds, which got this from SquidSquad originally. This generator has an unknown period that is statistically extremely likely to be very long (more than 2 to the 64), and no combinations of states are known that put it in a bad starting state or one with a shorter period. It is a very fast generator, particularly on Java 16 and newer. It has passed 64TB of PractRand testing with no anomalies, and 4PB of hwd testing.
TricycleRNG, it's got three states and it cycles changes between them.
Created by Tommy Ettinger on 7/13/2021.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
long	stateA Can be any long value.
long	stateB Can be any long value.
long	stateC Can be any long value.

Constructor Summary

Constructors

Constructor and Description
TricycleRNG() Creates a new generator seeded using Math.random.
TricycleRNG(long seed)
TricycleRNG(long seedA, long seedB, long seedC)

Method Summary

Modifier and Type	Method and Description
TricycleRNG	copy() Produces a copy of this RandomnessSource that, if next() and/or nextLong() are called on this object and the copy, both will generate the same sequence of random numbers from the point copy() was called.
boolean	equals(java.lang.Object o)
long	getStateA() Get the "A" part of the internal state as a long.
long	getStateB() Get the "B" part of the internal state as a long.
long	getStateC() Get the "C" part of the internal state as a long.
int	hashCode()
int	next(int bits) Using this method, any algorithm that might use the built-in Java Random can interface with this randomness source.
long	nextLong() Using this method, any algorithm that needs to efficiently generate more than 32 bits of random data can interface with this randomness source.
long	previousLong()
void	setSeed(long seed) This initializes all 3 states of the generator to random values based on the given seed.
void	setStateA(long stateA) Set the "A" part of the internal state with a long.
void	setStateB(long stateB) Set the "B" part of the internal state with a long.
void	setStateC(long stateC) Set the "C" part of the internal state with a long.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

stateA

public long stateA

Can be any long value.

stateB

public long stateB

Can be any long value.

stateC

public long stateC

Can be any long value.

Constructor Detail

TricycleRNG

public TricycleRNG()

Creates a new generator seeded using Math.random.

TricycleRNG

public TricycleRNG(long seed)

TricycleRNG

public TricycleRNG(long seedA,
                   long seedB,
                   long seedC)

Method Detail

setSeed

public void setSeed(long seed)

This initializes all 3 states of the generator to random values based on the given seed. (2 to the 64) possible initial generator states can be produced here, all with a different first value returned by nextLong() (because stateA is guaranteed to be different for every different seed).

Parameters:

seed - the initial seed; may be any long

getStateA

public long getStateA()

Get the "A" part of the internal state as a long.

Returns:

the current internal state of this object.

setStateA

public void setStateA(long stateA)

Set the "A" part of the internal state with a long.

Parameters:

stateA - any 64-bit long

getStateB

public long getStateB()

Get the "B" part of the internal state as a long.

Returns:

the current internal "B" state of this object.

setStateB

public void setStateB(long stateB)

Set the "B" part of the internal state with a long.

Parameters:

stateB - any 64-bit long

getStateC

public long getStateC()

Get the "C" part of the internal state as a long.

Returns:

the current internal "C" state of this object.

setStateC

public void setStateC(long stateC)

Set the "C" part of the internal state with a long.

Parameters:

stateC - any 64-bit long

nextLong

public long nextLong()

Description copied from interface: RandomnessSource

Using this method, any algorithm that needs to efficiently generate more than 32 bits of random data can interface with this randomness source. Get a random long between Long.MIN_VALUE and Long.MAX_VALUE (both inclusive).

Specified by:

nextLong in interface RandomnessSource

Returns:

a random long between Long.MIN_VALUE and Long.MAX_VALUE (both inclusive)

previousLong

public long previousLong()

next

public int next(int bits)

Description copied from interface: RandomnessSource

Using this method, any algorithm that might use the built-in Java Random can interface with this randomness source.

Specified by:

next in interface RandomnessSource

Parameters:

bits - the number of bits to be returned

Returns:

the integer containing the appropriate number of bits

copy

public TricycleRNG copy()

Produces a copy of this RandomnessSource that, if next() and/or nextLong() are called on this object and the copy, both will generate the same sequence of random numbers from the point copy() was called. This just need to copy the state so it isn't shared, usually, and produce a new value with the same exact state.

Specified by:

copy in interface RandomnessSource

Returns:

a copy of this RandomnessSource

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object