squidpony.squidmath

Class DistributedRNG

java.lang.Object

squidpony.squidmath.AbstractRNG

squidpony.squidmath.DistributedRNG

All Implemented Interfaces:

java.io.Serializable, IRNG, IStatefulRNG, RandomnessSource, StatefulRandomness

public class DistributedRNG
extends AbstractRNG
implements IStatefulRNG, StatefulRandomness, java.io.Serializable

An implementation of IRNG that allows specifying a distribution for all random numbers it produces via a IDistribution.SimpleDistribution value. You can adapt any IDistribution to a SimpleDistribution with the static methods in SimpleDistribution, like IDistribution.SimpleDistribution.fractionalDistribution(IDistribution). If no distribution is specified, this uses CurvedBoundedDistribution.instance.
This uses a MoonwalkRNG internally to handle the number generation that the distribution requests. While you can call methods on rng that are specific to MoonwalkRNG, many distributions will get multiple random numbers where a normal RNG would only get one, and this makes the state-jumping features of MoonwalkRNG less useful here. It's still a fast generator when it comes to generating doubles, which is why it's used here; GWT-oriented generators would be slower at generating doubles on desktop and many mobile platforms.
Created by Tommy Ettinger on 11/27/2019.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
IDistribution.SimpleDistribution	distribution
MoonwalkRNG	rng

Constructor Summary

Constructors

Constructor and Description
DistributedRNG()
DistributedRNG(long state)
DistributedRNG(long state, IDistribution.SimpleDistribution distribution)

Method Summary

Modifier and Type	Method and Description
DistributedRNG	copy() Creates a copy of this IRNG; it will generate the same random numbers, given the same calls in order, as this IRNG at the point copy() is called.
long	getState() Get the current internal state of the StatefulRandomness as a long.
int	next(int bits) Get up to 32 bits (inclusive) of random output; the int this produces will not require more than bits bits to represent.
boolean	nextBoolean() Get a random bit of state, interpreted as true or false with approximately equal likelihood.
double	nextDouble() Gets a random double between 0.0 inclusive and 1.0 exclusive.
float	nextFloat() Gets a random float between 0.0f inclusive and 1.0f exclusive.
int	nextInt() Get a random integer between Integer.MIN_VALUE to Integer.MAX_VALUE (both inclusive).
int	nextInt(int bound) Returns a random non-negative integer below the given bound, or 0 if the bound is 0 or negative.
long	nextLong() Get a random long between Long.MIN_VALUE to Long.MAX_VALUE (both inclusive).
long	nextLong(long bound) Exclusive on bound (which must be positive), with an inner bound of 0.
int	nextSignedInt(int outerBound) Returns a random non-negative integer between 0 (inclusive) and the given bound (exclusive), or 0 if the bound is 0.
long	nextSignedLong(long outerBound) Exclusive on bound (which may be positive or negative), with an inner bound of 0.
void	setState(long state) Set the current internal state of this StatefulRandomness with a long; this accepts a state of 0 with no issues.
java.io.Serializable	toSerializable() Gets a view of this IRNG in a way that implements Serializable, which may simply be this IRNG if it implements Serializable as well as IRNG.

Methods inherited from class squidpony.squidmath.AbstractRNG

between, between, between, getRandomElement, getRandomElement, getRandomElement, nextDouble, nextFloat, randomOrdering, randomOrdering, randomPortion, shuffle, shuffle, shuffle, shuffle, shuffleInPlace, shuffleInPlace, swap

Methods inherited from class java.lang.Object

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

Methods inherited from interface squidpony.squidmath.IRNG

between, between, between, getRandomElement, getRandomElement, getRandomElement, nextDouble, nextFloat, randomOrdering, randomOrdering, randomPortion, shuffle, shuffle, shuffle, shuffle, shuffleInPlace, shuffleInPlace

Field Detail

distribution

public IDistribution.SimpleDistribution distribution

rng

public MoonwalkRNG rng

Constructor Detail

DistributedRNG

public DistributedRNG()

DistributedRNG

public DistributedRNG(long state)

DistributedRNG

public DistributedRNG(long state,
                      IDistribution.SimpleDistribution distribution)

Method Detail

next

public final int next(int bits)

Get up to 32 bits (inclusive) of random output; the int this produces will not require more than bits bits to represent.

Specified by:

next in interface IRNG

Specified by:

next in interface RandomnessSource

Specified by:

next in class AbstractRNG

Parameters:

bits - an int between 1 and 32, both inclusive

Returns:

a random number that fits in the specified number of bits

nextInt

public int nextInt()

Get a random integer between Integer.MIN_VALUE to Integer.MAX_VALUE (both inclusive).

Specified by:

nextInt in interface IRNG

Specified by:

nextInt in class AbstractRNG

Returns:

a 32-bit random int.

nextLong

public long nextLong()

Get a random long between Long.MIN_VALUE to Long.MAX_VALUE (both inclusive). This implementation has "holes" in its range, numbers that it cannot produce regardless of distribution.

Specified by:

nextLong in interface IRNG

Specified by:

nextLong in interface RandomnessSource

Specified by:

nextLong in class AbstractRNG

Returns:

a 64-bit random long.

nextBoolean

public boolean nextBoolean()

Get a random bit of state, interpreted as true or false with approximately equal likelihood.

Specified by:

nextBoolean in interface IRNG

Specified by:

nextBoolean in class AbstractRNG

Returns:

a random boolean.

nextDouble

public double nextDouble()

Gets a random double between 0.0 inclusive and 1.0 exclusive. This returns a maximum of 0.9999999999999999 because that is the largest double value that is less than 1.0 .

Specified by:

nextDouble in interface IRNG

Specified by:

nextDouble in class AbstractRNG

Returns:

a double between 0.0 (inclusive) and 0.9999999999999999 (inclusive)

nextFloat

public float nextFloat()

Gets a random float between 0.0f inclusive and 1.0f exclusive. This returns a maximum of 0.99999994 because that is the largest float value that is less than 1.0f .

Specified by:

nextFloat in interface IRNG

Specified by:

nextFloat in class AbstractRNG

Returns:

a float between 0f (inclusive) and 0.99999994f (inclusive)

nextInt

public int nextInt(int bound)

Returns a random non-negative integer below the given bound, or 0 if the bound is 0 or negative.

Specified by:

nextInt in interface IRNG

Overrides:

nextInt in class AbstractRNG

Parameters:

bound - the upper bound (exclusive)

Returns:

the found number

nextLong

public long nextLong(long bound)

Exclusive on bound (which must be positive), with an inner bound of 0. If bound is negative or 0 this always returns 0.

Specified by:

nextLong in interface IRNG

Overrides:

nextLong in class AbstractRNG

Parameters:

bound - the outer exclusive bound; should be positive, otherwise this always returns 0L

Returns:

a random long between 0 (inclusive) and bound (exclusive)

nextSignedLong

public long nextSignedLong(long outerBound)

Exclusive on bound (which may be positive or negative), with an inner bound of 0. If bound is negative this returns a negative long; if bound is positive this returns a positive long. The bound can even be 0, which will cause this to return 0L every time.

Specified by:

nextSignedLong in interface IRNG

Overrides:

nextSignedLong in class AbstractRNG

Parameters:

outerBound - the outer exclusive bound; can be positive or negative

Returns:

a random long between 0 (inclusive) and bound (exclusive)

nextSignedInt

public int nextSignedInt(int outerBound)

Returns a random non-negative integer between 0 (inclusive) and the given bound (exclusive), or 0 if the bound is 0. The bound can be negative, which will produce 0 or a negative result.

Specified by:

nextSignedInt in interface IRNG

Overrides:

nextSignedInt in class AbstractRNG

Parameters:

outerBound - the outer bound (exclusive), can be negative or positive

Returns:

the found number

copy

public DistributedRNG copy()

Creates a copy of this IRNG; it will generate the same random numbers, given the same calls in order, as this IRNG at the point copy() is called. The copy will not share references with this IRNG, except to distribution, which usually shouldn't change much.

Specified by:

copy in interface RandomnessSource

Specified by:

copy in interface StatefulRandomness

Specified by:

copy in class AbstractRNG

Returns:

a copy of this IRNG

toSerializable

public java.io.Serializable toSerializable()

Gets a view of this IRNG in a way that implements Serializable, which may simply be this IRNG if it implements Serializable as well as IRNG.

Specified by:

toSerializable in interface IRNG

Specified by:

toSerializable in class AbstractRNG

Returns:

a Serializable view of this IRNG or a similar one; may be this

getState

public long getState()

Get the current internal state of the StatefulRandomness as a long.

Specified by:

getState in interface StatefulRandomness

Returns:

the current internal state of this object.

setState

public void setState(long state)

Set the current internal state of this StatefulRandomness with a long; this accepts a state of 0 with no issues.

Specified by:

setState in interface StatefulRandomness

Parameters:

state - a 64-bit long.