Package com.github.tommyettinger.random

Class Goblin3Random

java.lang.Object

java.util.Random

com.github.tommyettinger.random.EnhancedRandom

com.github.tommyettinger.random.Goblin3Random

All Implemented Interfaces:

Externalizable, Serializable, RandomGenerator

public class Goblin3Random
extends EnhancedRandom

A 64-bit-native generator with 192 bits of state. Period is 2 to the 192. This is exactly 1D-equidistributed.
This operates like an extended version of OrbitalRandom, making use of BitConversion.countLeadingZeros(long) to produce longer cycles. It runs its last state's value through a mixer that is like Moremur (which is what DistinctRandom uses), but also XORs in the other states at two points in the Moremur mixer. It also uses "non-magic" constants, which actually work fine here: stateA uses 7777777777777777777L as its increment for a counter, and the complicated hex constants used by Moremur are replaced by 5555555555555555555L and 3333333333333333333L.
This passes 128TB of PractRand with no anomalies. It also passes Initial Correlation Evaluator tests (and their Immediate variants).
This is the 3-long-state version of the Goblin generator.

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.random.RandomGenerator

RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.LeapableGenerator, RandomGenerator.SplittableGenerator, RandomGenerator.StreamableGenerator

Field Summary

Fields

Modifier and Type	Field	Description
protected long	stateA	The first state; can be any long.
protected long	stateB	The second state; can be any long.
protected long	stateC	The third state; can be any long.

Constructor Summary

Constructors

Constructor	Description
Goblin3Random()	Creates a new Goblin3Random with a random state.
Goblin3Random(long seed)	Creates a new Goblin3Random with the given seed; all long values are permitted.
Goblin3Random(long stateA, long stateB)	Creates a new Goblin3Random with the given two states; all long values are permitted.
Goblin3Random(long stateA, long stateB, long stateC)	Creates a new Goblin3Random with the given three states; all long values are permitted.

Method Summary

Modifier and Type	Method	Description
Goblin3Random	copy()	Creates a new EnhancedRandom with identical states to this one, so if the same EnhancedRandom methods are called on this object and its copy (in the same order), the same outputs will be produced.
boolean	equals(Object o)
BigInteger	getMinimumPeriod()	2 to the 192.
long	getSelectedState(int selection)	Gets the state determined by selection, as-is.
long	getStateA()
long	getStateB()
long	getStateC()
int	getStateCount()	This generator has 3 long states, so this returns 3.
String	getTag()	Gets the tag used to identify this type of EnhancedRandom, as a String.
int	next(int bits)	Generates the next pseudorandom number with a specific maximum size in bits (not a max number).
long	nextLong()	Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence.
long	previousLong()	Optional; moves the state to its previous value and returns the previous long that would have been produced by EnhancedRandom.nextLong().
void	setSeed(long seed)	This initializes all 3 states of the generator to random values based on the given seed.
void	setSelectedState(int selection, long value)	Sets one of the states, determined by selection, to value, as-is.
void	setState(long stateA, long stateB)	Equivalent to setState(stateA, stateB, 1L).
void	setState(long stateA, long stateB, long stateC)	Sets the state completely to the given three state variables.
void	setStateA(long stateA)	Sets the first part of the state.
void	setStateB(long stateB)	Sets the second part of the state.
void	setStateC(long stateC)	Sets the third part of the state.
String	toString()

Methods inherited from class com.github.tommyettinger.random.EnhancedRandom

appendSerialized, appendSerialized, areEqual, fixGamma, fixGamma, lcm, mainlyGeneratesInt, maxDoubleOf, maxFloatOf, maxIntOf, maxLongOf, minDoubleOf, minFloatOf, minIntOf, minLongOf, nextBoolean, nextBoolean, nextBytes, nextDouble, nextDouble, nextDouble, nextExclusiveDouble, nextExclusiveDouble, nextExclusiveDouble, nextExclusiveDoubleEquidistant, nextExclusiveFloat, nextExclusiveFloat, nextExclusiveFloat, nextExclusiveFloatEquidistant, nextExclusiveSignedDouble, nextExclusiveSignedFloat, nextExponential, nextFloat, nextFloat, nextFloat, nextGaussian, nextGaussian, nextGaussianFloat, nextGaussianFloat, nextInclusiveDouble, nextInclusiveDouble, nextInclusiveDouble, nextInclusiveFloat, nextInclusiveFloat, nextInclusiveFloat, nextInt, nextInt, nextInt, nextLong, nextLong, nextSign, nextSignedInt, nextSignedInt, nextSignedLong, nextSignedLong, nextTriangular, nextTriangular, nextTriangular, nextTriangular, nextUnsignedInt, previousInt, probit, processSignedInt32, processUnsignedInt32, randomElement, randomElement, rateGamma, readExternal, seedFromMath, setSeed, setSeed, setState, setState, setState, setState, setState, setState, setState, setState, setState, setWith, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, shuffle, skip, stringDeserialize, stringDeserialize, stringSerialize, stringSerialize, writeExternal

Methods inherited from class java.util.Random

doubles, doubles, doubles, doubles, from, ints, ints, ints, ints, longs, longs, longs, longs

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.random.RandomGenerator

isDeprecated

Field Details

stateA

protected long stateA

The first state; can be any long.

stateB

protected long stateB

The second state; can be any long.

stateC

protected long stateC

The third state; can be any long.

Constructor Details

Goblin3Random

public Goblin3Random()

Creates a new Goblin3Random with a random state.

Goblin3Random

public Goblin3Random(long seed)

Creates a new Goblin3Random with the given seed; all long values are permitted. The seed will be passed to setSeed(long) to attempt to adequately distribute the seed randomly.

Parameters:

seed - any long value

Goblin3Random

public Goblin3Random(long stateA,
 long stateB)

Creates a new Goblin3Random with the given two states; all long values are permitted. These states will be used verbatim for stateA and stateB. stateC will be assigned 1.

Parameters:

stateA - any long value

stateB - any long value

Goblin3Random

public Goblin3Random(long stateA,
 long stateB,
 long stateC)

Creates a new Goblin3Random with the given three states; all long values are permitted. These states will be used verbatim.

Parameters:

stateA - any long value

stateB - any long value

stateC - any long value

Method Details

getTag

public String getTag()

Description copied from class: EnhancedRandom

Gets the tag used to identify this type of EnhancedRandom, as a String. This tag should be unique, and for uniformity purposes, all tags used in this library are 4 characters long. User-defined tags should have a different length.

Specified by:

getTag in class EnhancedRandom

Returns:

a unique String identifier for this type of EnhancedRandom; usually 4 chars long.

getMinimumPeriod

public BigInteger getMinimumPeriod()

2 to the 192.

Overrides:

getMinimumPeriod in class EnhancedRandom

Returns:

2 to the 192

getStateCount

public int getStateCount()

This generator has 3 long states, so this returns 3.

Overrides:

getStateCount in class EnhancedRandom

Returns:

3 (three)

getSelectedState

public long getSelectedState(int selection)

Gets the state determined by selection, as-is. The value for selection should be between 0 and 2, inclusive; if it is any other value this gets state C as if 2 was given.

Overrides:

getSelectedState in class EnhancedRandom

Parameters:

selection - used to select which state variable to get; generally 0, 1, or 2

Returns:

the value of the selected state

setSelectedState

public void setSelectedState(int selection,
 long value)

Sets one of the states, determined by selection, to value, as-is. Selections 0, 1, and 2 refer to states A, B, and C, and if the selection is anything else, this ignores it and sets nothing.

Overrides:

setSelectedState in class EnhancedRandom

Parameters:

selection - used to select which state variable to set; generally 0, 1, or 2

value - the exact value to use for the selected state, if valid

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, though there are (2 to the 192) possible states in total.

Specified by:

setSeed in class EnhancedRandom

Parameters:

seed - the initial seed; may be any long

getStateA

public long getStateA()

setStateA

public void setStateA(long stateA)

Sets the first part of the state.

Parameters:

stateA - can be any long

getStateB

public long getStateB()

setStateB

public void setStateB(long stateB)

Sets the second part of the state.

Parameters:

stateB - can be any long

getStateC

public long getStateC()

setStateC

public void setStateC(long stateC)

Sets the third part of the state.

Parameters:

stateC - can be any long

setState

public void setState(long stateA,
 long stateB)

Equivalent to setState(stateA, stateB, 1L).

Overrides:

setState in class EnhancedRandom

Parameters:

stateA - the long value to use for stateA

stateB - the long value to use for stateB

setState

public void setState(long stateA,
 long stateB,
 long stateC)

Sets the state completely to the given three state variables. This is the same as calling setStateA(long), setStateB(long), and setStateC(long) as a group.

Overrides:

setState in class EnhancedRandom

Parameters:

stateA - the first state; can be any long

stateB - the second state; can be any long

stateC - the third state; can be any long

nextLong

public long nextLong()

Description copied from class: EnhancedRandom

Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence. The general contract of nextLong is that one long value is pseudorandomly generated and returned.
The only methods that need to be implemented by this interface are this and EnhancedRandom.copy(), though other methods can be implemented as appropriate for generators that, for instance, natively produce ints rather than longs.

Specified by:

nextLong in interface RandomGenerator

Specified by:

nextLong in class EnhancedRandom

Returns:

the next pseudorandom, uniformly distributed long value from this random number generator's sequence

previousLong

public long previousLong()

Description copied from class: EnhancedRandom

Optional; moves the state to its previous value and returns the previous long that would have been produced by EnhancedRandom.nextLong(). This can be equivalent to calling EnhancedRandom.skip(long) with -1L, but not always; many generators can't efficiently skip long distances, but can step back by one value.
Generators that natively generate int results typically produce long values by generating an int for the high 32 bits and an int for the low 32 bits. When producing the previous long, the order the high and low bits are generated, such as by EnhancedRandom.previousInt(), should be reversed. Generators that natively produce long values usually don't need to implement EnhancedRandom.previousInt(), but those that produce int usually should implement it, and may optionally call previousInt() twice in this method.
If you know how to implement the reverse of a particular random number generator, it is recommended you do so here, rather than rely on skip(). This isn't always easy, but should always be possible for any decent PRNG (some historical PRNGs, such as the Middle-Square PRNG, cannot be reversed at all). If a generator cannot be reversed because multiple initial states can transition to the same subsequent state, it is known to have statistical problems that are not necessarily present in a generator that matches one initial state to one subsequent state.
The public implementation calls EnhancedRandom.skip(long) with -1L, and if skip() has not been implemented differently, then it will throw an UnsupportedOperationException.

Overrides:

previousLong in class EnhancedRandom

Returns:

the previous number this would have produced with EnhancedRandom.nextLong()

next

public int next(int bits)

Description copied from class: EnhancedRandom

Generates the next pseudorandom number with a specific maximum size in bits (not a max number). If you want to get a random number in a range, you should usually use EnhancedRandom.nextInt(int) instead. For some specific cases, this method is more efficient and less biased than EnhancedRandom.nextInt(int). For bits values between 1 and 30, this should be similar in effect to nextInt(1 << bits); though it won't typically produce the same values, they will have the correct range. If bits is 31, this can return any non-negative int; note that nextInt(1 << 31) won't behave this way because 1 << 31 is negative. If bits is 32 (or 0), this can return any int.

The general contract of next is that it returns an int value and if the argument bits is between 1 and 32 (inclusive), then that many low-order bits of the returned value will be (approximately) independently chosen bit values, each of which is (approximately) equally likely to be 0 or 1.

Note that you can give this values for bits that are outside its expected range of 1 to 32, but the value used, as long as bits is positive, will effectively be bits % 32. As stated before, a value of 0 for bits is the same as a value of 32.

Overrides:

next in class EnhancedRandom

Parameters:

bits - the amount of random bits to request, from 1 to 32

Returns:

the next pseudorandom value from this random number generator's sequence

copy

public Goblin3Random copy()

Description copied from class: EnhancedRandom

Creates a new EnhancedRandom with identical states to this one, so if the same EnhancedRandom methods are called on this object and its copy (in the same order), the same outputs will be produced. This is not guaranteed to copy the inherited state of any parent class, so if you call methods that are only implemented by a superclass (like Random) and not this one, the results may differ.

Specified by:

copy in class EnhancedRandom

Returns:

a deep copy of this EnhancedRandom.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object