Interface RandomGenerator.ArbitrarilyJumpableGenerator

All Superinterfaces:: RandomGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.LeapableGenerator, RandomGenerator.StreamableGenerator

Enclosing interface:: RandomGenerator

public static interface RandomGenerator.ArbitrarilyJumpableGenerator extends RandomGenerator.LeapableGenerator

This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can easily jump forward, by an arbitrary amount, to a distant point in the state cycle.

Ideally, all RandomGenerator.ArbitrarilyJumpableGenerator objects produced by iterative jumping from a single original RandomGenerator.ArbitrarilyJumpableGenerator object are statistically independent of one another and individually uniform, provided that they do not traverse overlapping portions of the state cycle. In practice, one must settle for some approximation to independence and uniformity. In particular, a specific implementation may assume that each generator in a stream produced by the jump() method is used to produce a number of values no larger than the jump distance specified. Implementors are advised to use algorithms whose period is at least 2¹²⁷.

For many applications, it suffices to jump forward by a power of two or some small multiple of a power of two, but this power of two may not be representable as a long value. To avoid the use of BigInteger values as jump distances, double values are used instead.

Methods are provided to perform a single jump operation and also to produce a stream of generators produced from the original by iterative copying and jumping of internal state. A typical strategy for a multithreaded application is to create a single RandomGenerator.ArbitrarilyJumpableGenerator object, call its jump() method exactly once, and then parcel out generators from the resulting stream, one to each thread. However, each generator produced also has type RandomGenerator.ArbitrarilyJumpableGenerator; with care, different jump distances can be used to traverse the entire state cycle in various ways.

Objects that implement RandomGenerator.ArbitrarilyJumpableGenerator are typically not cryptographically secure. Consider instead using SecureRandom to get a cryptographically secure pseudo-random number generator for use by security-sensitive applications.

Since:: 17

Nested Class Summary

Nested classes/interfaces declared in interface RandomGenerator

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

Modifier and Type	Interface	Description
`static interface`	`RandomGenerator.ArbitrarilyJumpableGenerator`	This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can easily jump forward, by an arbitrary amount, to a distant point in the state cycle.
`static interface`	`RandomGenerator.JumpableGenerator`	This interface is designed to provide a common protocol for objects that generate pseudorandom values and can easily jump forward, by a moderate amount (ex. 2⁶⁴) to a distant point in the state cycle.
`static interface`	`RandomGenerator.LeapableGenerator`	This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can easily not only jump but also leap forward, by a large amount (ex. 2¹²⁸), to a very distant point in the state cycle.
`static interface`	`RandomGenerator.SplittableGenerator`	This interface is designed to provide a common protocol for objects that generate sequences of pseudorandom values and can be split into two objects (the original one and a new one) each of which obey that same protocol (and therefore can be recursively split indefinitely).
`static interface`	`RandomGenerator.StreamableGenerator`	The `RandomGenerator.StreamableGenerator` interface augments the `RandomGenerator` interface to provide methods that return streams of `RandomGenerator` objects.

Method Summary

Modifier and Type	Method	Description
`RandomGenerator.ArbitrarilyJumpableGenerator`	`copy()`	Returns a new generator whose internal state is an exact copy of this generator (therefore their future behavior should be identical if subjected to the same series of operations).
`default RandomGenerator.ArbitrarilyJumpableGenerator`	`copyAndJump(double distance)`	Copy this generator, jump this generator forward, then return the copy.
`default void`	`jump()`	Alter the state of this pseudorandom number generator so as to jump forward a large, fixed distance (typically 2⁶⁴ or more) within its state cycle.
`void`	`jump(double distance)`	Alter the state of this pseudorandom number generator so as to jump forward a specified distance within its state cycle.
`void`	`jumpPowerOfTwo(int logDistance)`	Alter the state of this pseudorandom number generator so as to jump forward a distance equal to 2^logDistance within its state cycle.
`default Stream<RandomGenerator.ArbitrarilyJumpableGenerator>`	`jumps(double distance)`	Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the `RandomGenerator.ArbitrarilyJumpableGenerator` interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.
`default Stream<RandomGenerator.ArbitrarilyJumpableGenerator>`	`jumps(long streamSize, double distance)`	Returns a stream producing the given `streamSize` number of new pseudorandom number generators, each of which implements the `RandomGenerator.ArbitrarilyJumpableGenerator` interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.
`default void`	`leap()`	Alter the state of this pseudorandom number generator so as to jump forward a very large, fixed distance (typically 2¹²⁸ or more) within its state cycle.
`static RandomGenerator.ArbitrarilyJumpableGenerator`	`of(String name)`	Returns an instance of `RandomGenerator.ArbitrarilyJumpableGenerator` that utilizes the `name` algorithm.

Methods declared in interface RandomGenerator

doubles, doubles, doubles, doubles, equiDoubles, ints, ints, ints, ints, isDeprecated, longs, longs, longs, longs, nextBoolean, nextBytes, nextDouble, nextDouble, nextDouble, nextExponential, nextFloat, nextFloat, nextFloat, nextGaussian, nextGaussian, nextInt, nextInt, nextInt, nextLong, nextLong, nextLong

Modifier and Type	Method	Description
`default DoubleStream`	`doubles()`	Returns an effectively unlimited stream of pseudorandomly chosen `double` values.
`default DoubleStream`	`doubles(double randomNumberOrigin, double randomNumberBound)`	Returns an effectively unlimited stream of pseudorandomly chosen `double` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default DoubleStream`	`doubles(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `double` values.
`default DoubleStream`	`doubles(long streamSize, double randomNumberOrigin, double randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `double` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default DoubleStream`	`equiDoubles(double left, double right, boolean isLeftIncluded, boolean isRightIncluded)`	Returns an effectively unlimited stream of pseudorandomly chosen `double` values, where each value is between the specified `left` boundary and the specified `right` boundary.
`default IntStream`	`ints()`	Returns an effectively unlimited stream of pseudorandomly chosen `int` values.
`default IntStream`	`ints(int randomNumberOrigin, int randomNumberBound)`	Returns an effectively unlimited stream of pseudorandomly chosen `int` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default IntStream`	`ints(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `int` values.
`default IntStream`	`ints(long streamSize, int randomNumberOrigin, int randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `int` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default boolean`	`isDeprecated()`	Return true if the implementation of RandomGenerator (algorithm) has been marked for deprecation.
`default LongStream`	`longs()`	Returns an effectively unlimited stream of pseudorandomly chosen `long` values.
`default LongStream`	`longs(long streamSize)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `long` values.
`default LongStream`	`longs(long randomNumberOrigin, long randomNumberBound)`	Returns an effectively unlimited stream of pseudorandomly chosen `long` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default LongStream`	`longs(long streamSize, long randomNumberOrigin, long randomNumberBound)`	Returns a stream producing the given `streamSize` number of pseudorandomly chosen `long` values, where each value is between the specified origin (inclusive) and the specified bound (exclusive).
`default boolean`	`nextBoolean()`	Returns a pseudorandomly chosen `boolean` value.
`default void`	`nextBytes(byte[] bytes)`	Fills a user-supplied byte array with generated byte values pseudorandomly chosen uniformly from the range of values between -128 (inclusive) and 127 (inclusive).
`default double`	`nextDouble()`	Returns a pseudorandom `double` value between zero (inclusive) and one (exclusive).
`default double`	`nextDouble(double bound)`	Returns a pseudorandomly chosen `double` value between zero (inclusive) and the specified bound (exclusive).
`default double`	`nextDouble(double origin, double bound)`	Returns a pseudorandomly chosen `double` value between the specified origin (inclusive) and the specified bound (exclusive).
`default double`	`nextExponential()`	Returns a nonnegative `double` value pseudorandomly chosen from an exponential distribution whose mean is 1.
`default float`	`nextFloat()`	Returns a pseudorandom `float` value between zero (inclusive) and one (exclusive).
`default float`	`nextFloat(float bound)`	Returns a pseudorandomly chosen `float` value between zero (inclusive) and the specified bound (exclusive).
`default float`	`nextFloat(float origin, float bound)`	Returns a pseudorandomly chosen `float` value between the specified origin (inclusive) and the specified bound (exclusive).
`default double`	`nextGaussian()`	Returns a `double` value pseudorandomly chosen from a Gaussian (normal) distribution whose mean is 0 and whose standard deviation is 1.
`default double`	`nextGaussian(double mean, double stddev)`	Returns a `double` value pseudorandomly chosen from a Gaussian (normal) distribution with a mean and standard deviation specified by the arguments.
`default int`	`nextInt()`	Returns a pseudorandomly chosen `int` value.
`default int`	`nextInt(int bound)`	Returns a pseudorandomly chosen `int` value between zero (inclusive) and the specified bound (exclusive).
`default int`	`nextInt(int origin, int bound)`	Returns a pseudorandomly chosen `int` value between the specified origin (inclusive) and the specified bound (exclusive).
`long`	`nextLong()`	Returns a pseudorandomly chosen `long` value.
`default long`	`nextLong(long bound)`	Returns a pseudorandomly chosen `long` value between zero (inclusive) and the specified bound (exclusive).
`default long`	`nextLong(long origin, long bound)`	Returns a pseudorandomly chosen `long` value between the specified origin (inclusive) and the specified bound (exclusive).

Methods declared in interface RandomGenerator.JumpableGenerator

copyAndJump, jumpDistance, jumps, jumps, rngs, rngs

Modifier and Type	Method	Description
`default RandomGenerator`	`copyAndJump()`	Copy this generator, jump this generator forward, then return the copy.
`double`	`jumpDistance()`	Returns the distance by which the `jump`() method will jump forward within the state cycle of this generator object.
`default Stream<RandomGenerator>`	`jumps()`	Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.
`default Stream<RandomGenerator>`	`jumps(long streamSize)`	Returns a stream producing the given `streamSize` number of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.
`default Stream<RandomGenerator>`	`rngs()`	Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.
`default Stream<RandomGenerator>`	`rngs(long streamSize)`	Returns a stream producing the given `streamSize` number of new pseudorandom number generators, each of which implements the `RandomGenerator` interface.

Methods declared in interface RandomGenerator.LeapableGenerator

copyAndLeap, leapDistance, leaps, leaps

Modifier and Type	Method	Description
`default RandomGenerator.JumpableGenerator`	`copyAndLeap()`	Copy this generator, leap this generator forward, then return the copy.
`double`	`leapDistance()`	Returns the distance by which the `leap`() method will leap forward within the state cycle of this generator object.
`default Stream<RandomGenerator.JumpableGenerator>`	`leaps()`	Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the `RandomGenerator.JumpableGenerator` interface.
`default Stream<RandomGenerator.JumpableGenerator>`	`leaps(long streamSize)`	Returns a stream producing the given `streamSize` number of new pseudorandom number generators, each of which implements the `RandomGenerator.JumpableGenerator` interface.

Method Details

of

static RandomGenerator.ArbitrarilyJumpableGenerator of(String name)

Returns an instance of RandomGenerator.ArbitrarilyJumpableGenerator that utilizes the name algorithm.

Parameters:: name - Name of random number generator algorithm
Returns:: An instance of RandomGenerator.ArbitrarilyJumpableGenerator
Throws:: NullPointerException - if name is null; IllegalArgumentException - if the named algorithm is not found

copy

RandomGenerator.ArbitrarilyJumpableGenerator copy()

Returns a new generator whose internal state is an exact copy of this generator (therefore their future behavior should be identical if subjected to the same series of operations).

Specified by:: copy in interface RandomGenerator.JumpableGenerator
Specified by:: copy in interface RandomGenerator.LeapableGenerator
Returns:: a new object that is a copy of this generator

jumpPowerOfTwo

void jumpPowerOfTwo(int logDistance)

Alter the state of this pseudorandom number generator so as to jump forward a distance equal to 2^logDistance within its state cycle.

Parameters:: logDistance - the base-2 logarithm of the distance to jump forward within the state cycle
Throws:: IllegalArgumentException - if logDistance is 2^logDistance is greater than the period of this generator

jump

void jump(double distance)

Alter the state of this pseudorandom number generator so as to jump forward a specified distance within its state cycle.

Parameters:: distance - the distance to jump forward within the state cycle
Throws:: IllegalArgumentException - if distance is not greater than or equal to 0.0, or is greater than the period of this generator

jump

default void jump()

Alter the state of this pseudorandom number generator so as to jump forward a large, fixed distance (typically 2⁶⁴ or more) within its state cycle. The distance used is that returned by method jumpDistance().

Specified by:: jump in interface RandomGenerator.JumpableGenerator
Implementation Requirements:: The default implementation invokes jump(jumpDistance()).

jumps

default Stream<RandomGenerator.ArbitrarilyJumpableGenerator> jumps(double distance)

Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the RandomGenerator.ArbitrarilyJumpableGenerator interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.

Implementation Requirements:: The default implementation is equivalent to jumps (Long.MAX_VALUE).
Parameters:: distance - a distance to jump forward within the state cycle
Returns:: a stream of objects that implement the RandomGenerator interface
Throws:: IllegalArgumentException - if distance is not greater than or equal to 0.0, or is greater than the period of this generator

jumps

default Stream<RandomGenerator.ArbitrarilyJumpableGenerator> jumps(long streamSize, double distance)

Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the RandomGenerator.ArbitrarilyJumpableGenerator interface, produced by jumping copies of this generator by different integer multiples of the specified jump distance.

Implementation Requirements:: The default implementation is equivalent to jumps(distance).limit(streamSize).
Parameters:: streamSize - the number of generators to generate; distance - a distance to jump forward within the state cycle
Returns:: a stream of objects that implement the RandomGenerator interface
Throws:: IllegalArgumentException - if streamSize is less than zero or if distance is not greater than or equal to 0.0, or is greater than the period of this generator

leap

default void leap()

Alter the state of this pseudorandom number generator so as to jump forward a very large, fixed distance (typically 2¹²⁸ or more) within its state cycle. The distance used is that returned by method leapDistance().

Specified by:: leap in interface RandomGenerator.LeapableGenerator

copyAndJump

default RandomGenerator.ArbitrarilyJumpableGenerator copyAndJump(double distance)

Copy this generator, jump this generator forward, then return the copy.

Implementation Requirements:: The default implementation copies this, jumps(distance) and then returns the copy.
Parameters:: distance - a distance to jump forward within the state cycle
Returns:: a copy of this generator object before the jump occurred
Throws:: IllegalArgumentException - if distance is not greater than or equal to 0.0, or is greater than the period of this generator

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