SplittableRandom
class SplittableRandom : RandomGenerator, RandomGenerator.SplittableGenerator
A generator of uniform pseudorandom values (with period 264) applicable for use in (among other contexts) isolated parallel computations that may generate subtasks. Class SplittableRandom supports methods for producing pseudorandom numbers of type int, long, and double with similar usages as for class java.util.Random but differs in the following ways:
- Series of generated values pass the DieHarder suite testing independence and uniformity properties of random number generators. (Most recently validated with version 3.31.1.) These tests validate only the methods for certain types and ranges, but similar properties are expected to hold, at least approximately, for others as well. The period (length of any series of generated values before it repeats) is 264.
- Method #split constructs and returns a new SplittableRandom instance that shares no mutable state with the current instance. However, with very high probability, the values collectively generated by the two objects have the same statistical properties as if the same quantity of values were generated by a single thread using a single
SplittableRandom object.
- Instances of SplittableRandom are not thread-safe. They are designed to be split, not shared, across threads. For example, a
fork/join-style computation using random numbers might include a construction of the form new Subtask(aSplittableRandom.split()).fork().
- This class provides additional methods for generating random streams, that employ the above techniques when used in
stream.parallel() mode.
Instances of SplittableRandom are not cryptographically secure. Consider instead using java.security.SecureRandom in security-sensitive applications. Additionally, default-constructed instances do not use a cryptographically random seed unless the java.lang.System#getProperty java.util.secureRandomSeed is set to true.
Summary
| Public constructors |
|
Creates a new SplittableRandom instance using the specified initial seed.
|
|
Creates a new SplittableRandom instance that is likely to generate sequences of values that are statistically independent of those of any other instances in the current program; and may, and typically does, vary across program invocations.
|
| Public methods |
| DoubleStream! |
Returns a stream producing the given streamSize number of pseudorandom double values from this generator and/or one split from it; each value is between zero (inclusive) and one (exclusive).
|
| DoubleStream! |
Returns an effectively unlimited stream of pseudorandom double values from this generator and/or one split from it; each value is between zero (inclusive) and one (exclusive).
|
| DoubleStream! |
Returns a stream producing the given streamSize number of pseudorandom double values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
|
| DoubleStream! |
Returns an effectively unlimited stream of pseudorandom double values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
|
| IntStream! |
Returns a stream producing the given streamSize number of pseudorandom int values from this generator and/or one split from it.
|
| IntStream! |
Returns an effectively unlimited stream of pseudorandom int values from this generator and/or one split from it.
|
| IntStream! |
ints(streamSize: Long, randomNumberOrigin: Int, randomNumberBound: Int)Returns a stream producing the given streamSize number of pseudorandom int values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
|
| IntStream! |
ints(randomNumberOrigin: Int, randomNumberBound: Int)Returns an effectively unlimited stream of pseudorandom int values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
|
| LongStream! |
Returns a stream producing the given streamSize number of pseudorandom long values from this generator and/or one split from it.
|
| LongStream! |
Returns an effectively unlimited stream of pseudorandom long values from this generator and/or one split from it.
|
| LongStream! |
Returns a stream producing the given streamSize number of pseudorandom long values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
|
| LongStream! |
Returns an effectively unlimited stream of pseudorandom long values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
|
| Unit |
Fills a user-supplied byte array with generated byte values pseudorandomly chosen uniformly from the range of values between -128 (inclusive) and 127 (inclusive).
|
| Int |
|
| Long |
|
| SplittableRandom! |
Constructs and returns a new SplittableRandom instance that shares no mutable state with this instance.
|
| SplittableRandom! |
Returns a new pseudorandom number generator, split off from this one, that implements the RandomGenerator and SplittableGenerator interfaces.
|
| Stream<RandomGenerator.SplittableGenerator!>! |
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the SplittableGenerator interface.
|
| Stream<RandomGenerator.SplittableGenerator!>! |
Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the SplittableGenerator interface.
|
| Stream<RandomGenerator.SplittableGenerator!>! |
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the SplittableGenerator interface.
|
| Stream<RandomGenerator.SplittableGenerator!>! |
Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the SplittableGenerator interface.
|
| Inherited functions |
From class RandomGenerator
Boolean |
isDeprecated()
Return true if the implementation of RandomGenerator (algorithm) has been marked for deprecation.
|
Boolean |
nextBoolean()
Returns a pseudorandomly chosen boolean value.
The default implementation tests the high-order bit (sign bit) of a value produced by nextInt(), on the grounds that some algorithms for pseudorandom number generation produce values whose high-order bits have better statistical quality than the low-order bits.
|
Double |
nextDouble()
Returns a pseudorandom double value between zero (inclusive) and one (exclusive).
|
Double |
nextDouble(bound: Double)
Returns a pseudorandomly chosen double value between zero (inclusive) and the specified bound (exclusive).
|
Double |
nextDouble(origin: Double, bound: Double)
Returns a pseudorandomly chosen double value between the specified origin (inclusive) and the specified bound (exclusive).
|
Double |
nextExponential()
Returns a nonnegative double value pseudorandomly chosen from an exponential distribution whose mean is 1.
|
Float |
nextFloat()
Returns a pseudorandom float value between zero (inclusive) and one (exclusive).
|
Float |
nextFloat(bound: Float)
Returns a pseudorandomly chosen float value between zero (inclusive) and the specified bound (exclusive).
|
Float |
nextFloat(origin: Float, bound: Float)
Returns a pseudorandomly chosen float value between the specified origin (inclusive) and the specified bound (exclusive).
|
Double |
nextGaussian()
Returns a double value pseudorandomly chosen from a Gaussian (normal) distribution whose mean is 0 and whose standard deviation is 1.
|
Double |
nextGaussian(mean: Double, stddev: Double)
Returns a double value pseudorandomly chosen from a Gaussian (normal) distribution with a mean and standard deviation specified by the arguments.
|
Int |
nextInt(bound: Int)
Returns a pseudorandomly chosen int value between zero (inclusive) and the specified bound (exclusive).
|
Int |
nextInt(origin: Int, bound: Int)
Returns a pseudorandomly chosen int value between the specified origin (inclusive) and the specified bound (exclusive).
|
Long |
nextLong(bound: Long)
Returns a pseudorandomly chosen long value between zero (inclusive) and the specified bound (exclusive).
|
Long |
nextLong(origin: Long, bound: Long)
Returns a pseudorandomly chosen long value between the specified origin (inclusive) and the specified bound (exclusive).
|
|
From class SplittableGenerator
Stream<RandomGenerator!>! |
rngs()
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the RandomGenerator interface. Ideally the generators in the stream will appear to be statistically independent.
|
Stream<RandomGenerator!>! |
rngs(streamSize: Long)
Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the RandomGenerator interface. Ideally the generators in the stream will appear to be statistically independent.
|
|
Public constructors
SplittableRandom
SplittableRandom(seed: Long)
Creates a new SplittableRandom instance using the specified initial seed. SplittableRandom instances created with the same seed in the same program generate identical sequences of values.
| Parameters |
seed |
Long: the initial seed |
SplittableRandom
SplittableRandom()
Creates a new SplittableRandom instance that is likely to generate sequences of values that are statistically independent of those of any other instances in the current program; and may, and typically does, vary across program invocations.
Public methods
doubles
fun doubles(streamSize: Long): DoubleStream!
Returns a stream producing the given streamSize number of pseudorandom double values from this generator and/or one split from it; each value is between zero (inclusive) and one (exclusive).
| Parameters |
streamSize |
Long: the number of values to generate |
| Exceptions |
java.lang.IllegalArgumentException |
if streamSize is less than zero |
doubles
fun doubles(): DoubleStream!
Returns an effectively unlimited stream of pseudorandom double values from this generator and/or one split from it; each value is between zero (inclusive) and one (exclusive).
doubles
fun doubles(
streamSize: Long,
randomNumberOrigin: Double,
randomNumberBound: Double
): DoubleStream!
Returns a stream producing the given streamSize number of pseudorandom double values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
| Parameters |
streamSize |
Long: the number of values to generate |
randomNumberOrigin |
Double: the origin (inclusive) of each random value |
randomNumberBound |
Double: the bound (exclusive) of each random value |
| Return |
DoubleStream! |
a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive) |
| Exceptions |
java.lang.IllegalArgumentException |
if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound |
doubles
fun doubles(
randomNumberOrigin: Double,
randomNumberBound: Double
): DoubleStream!
Returns an effectively unlimited stream of pseudorandom double values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
| Parameters |
randomNumberOrigin |
Double: the origin (inclusive) of each random value |
randomNumberBound |
Double: the bound (exclusive) of each random value |
| Return |
DoubleStream! |
a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive) |
| Exceptions |
java.lang.IllegalArgumentException |
if randomNumberOrigin is greater than or equal to randomNumberBound |
ints
fun ints(streamSize: Long): IntStream!
Returns a stream producing the given streamSize number of pseudorandom int values from this generator and/or one split from it.
| Parameters |
streamSize |
Long: the number of values to generate |
| Return |
IntStream! |
a stream of pseudorandom int values |
| Exceptions |
java.lang.IllegalArgumentException |
if streamSize is less than zero |
ints
fun ints(): IntStream!
Returns an effectively unlimited stream of pseudorandom int values from this generator and/or one split from it.
| Return |
IntStream! |
a stream of pseudorandom int values |
ints
fun ints(
streamSize: Long,
randomNumberOrigin: Int,
randomNumberBound: Int
): IntStream!
Returns a stream producing the given streamSize number of pseudorandom int values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
| Parameters |
streamSize |
Long: the number of values to generate |
randomNumberOrigin |
Int: the origin (inclusive) of each random value |
randomNumberBound |
Int: the bound (exclusive) of each random value |
| Return |
IntStream! |
a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive) |
| Exceptions |
java.lang.IllegalArgumentException |
if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound |
ints
fun ints(
randomNumberOrigin: Int,
randomNumberBound: Int
): IntStream!
Returns an effectively unlimited stream of pseudorandom int values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
| Parameters |
randomNumberOrigin |
Int: the origin (inclusive) of each random value |
randomNumberBound |
Int: the bound (exclusive) of each random value |
| Return |
IntStream! |
a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive) |
| Exceptions |
java.lang.IllegalArgumentException |
if randomNumberOrigin is greater than or equal to randomNumberBound |
longs
fun longs(streamSize: Long): LongStream!
Returns a stream producing the given streamSize number of pseudorandom long values from this generator and/or one split from it.
| Parameters |
streamSize |
Long: the number of values to generate |
| Return |
LongStream! |
a stream of pseudorandom long values |
| Exceptions |
java.lang.IllegalArgumentException |
if streamSize is less than zero |
longs
fun longs(): LongStream!
Returns an effectively unlimited stream of pseudorandom long values from this generator and/or one split from it.
| Return |
LongStream! |
a stream of pseudorandom long values |
longs
fun longs(
streamSize: Long,
randomNumberOrigin: Long,
randomNumberBound: Long
): LongStream!
Returns a stream producing the given streamSize number of pseudorandom long values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
| Parameters |
streamSize |
Long: the number of values to generate |
randomNumberOrigin |
Long: the origin (inclusive) of each random value |
randomNumberBound |
Long: the bound (exclusive) of each random value |
| Return |
LongStream! |
a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive) |
| Exceptions |
java.lang.IllegalArgumentException |
if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound |
longs
fun longs(
randomNumberOrigin: Long,
randomNumberBound: Long
): LongStream!
Returns an effectively unlimited stream of pseudorandom long values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive).
| Parameters |
randomNumberOrigin |
Long: the origin (inclusive) of each random value |
randomNumberBound |
Long: the bound (exclusive) of each random value |
| Return |
LongStream! |
a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive) |
| Exceptions |
java.lang.IllegalArgumentException |
if randomNumberOrigin is greater than or equal to randomNumberBound |
nextBytes
fun nextBytes(bytes: ByteArray!): Unit
Fills a user-supplied byte array with generated byte values pseudorandomly chosen uniformly from the range of values between -128 (inclusive) and 127 (inclusive).
| Parameters |
bytes |
ByteArray!: the byte array to fill with pseudorandom bytes |
| Exceptions |
java.lang.NullPointerException |
if bytes is null |
nextInt
fun nextInt(): Int
| Return |
Int |
a pseudorandomly chosen int value |
nextLong
fun nextLong(): Long
| Return |
Long |
a pseudorandomly chosen long value |
split
fun split(): SplittableRandom!
Constructs and returns a new SplittableRandom instance that shares no mutable state with this instance. However, with very high probability, the set of values collectively generated by the two objects has the same statistical properties as if the same quantity of values were generated by a single thread using a single SplittableRandom object. Either or both of the two objects may be further split using the split() method, and the same expected statistical properties apply to the entire set of generators constructed by such recursive splitting.
splits
fun splits(): Stream<RandomGenerator.SplittableGenerator!>!
Returns an effectively unlimited stream of new pseudorandom number generators, each of which implements the SplittableGenerator interface.
This pseudorandom number generator may be used as a source of pseudorandom bits used to initialize the state the new ones.
splits
fun splits(streamSize: Long): Stream<RandomGenerator.SplittableGenerator!>!
Returns a stream producing the given streamSize number of new pseudorandom number generators, each of which implements the SplittableGenerator interface.
This pseudorandom number generator may be used as a source of pseudorandom bits used to initialize the state the new ones.
| Parameters |
streamSize |
Long: the number of values to generate |
| Exceptions |
java.lang.IllegalArgumentException |
if streamSize is less than zero |
