 All Implemented Interfaces:
RandomGenerator
 Direct Known Subclasses:
EnhancedStreamableGenerator
RandomGenerator
for the purpose of adding all of the functionality of the RandomIndexer
,
RandomSampler
, and RandomVariates
. In this way, the EnhancedRandomGenerator can
be used as a dropin replacement for any of Java's random number generators, while substituting
more efficient algorithms in some cases, or adding functionality in others. Methods of the RandomGenerator
without equivalent replacements in one of RandomIndexer
, RandomSampler
, or RandomVariates
are simply delegated to the wrapped RandomGenerator
.
Enhanced Functionality provided by this class includes:
 Faster generation of random int values subject to a bound or bound and origin.
 Faster generation of random int values within an IntStream subject to a bound and origin.
 Faster generation of Gaussian distributed random doubles for Java's legacy random number generators.
 Additional distributions available beyond what is supported by the Java API's RandomGenerator classes, such as Binomial and Cauchy random vaiables.
 Ultrafast, but biased, nextBiasedInt methods that sacrifices uniformity for speed by excluding the rejection sampling necessary to ensure uniformity, as well as a biasedInts methods for generating streams of such integers.
 Methods for generating random pairs of integers without replacement, and random triples of integers without replacement.
 Methods for generating random samples of k integers without replacement from a range of integers.
 Methods to generate streams of numbers from distributions other than uniform, such as streams of random numbers from binomial distributions, Cauchy distributions, exponential distributions, and Gaussian distributions.
 Methods to generate streams of pairs of distinct integers, and streams of triples of distinct integers.
 Methods for shuffling the elements of arrays and Lists.

Nested Class Summary
Nested classes/interfaces inherited from interface java.util.random.RandomGenerator
RandomGenerator.ArbitrarilyJumpableGenerator, RandomGenerator.JumpableGenerator, RandomGenerator.LeapableGenerator, RandomGenerator.SplittableGenerator, RandomGenerator.StreamableGenerator

Constructor Summary
ConstructorDescriptionConstructs the EnhancedRandomGenerator to wrap an instance of the default random number generator as obtained via a call toRandomGenerator.getDefault()
.EnhancedRandomGenerator
(long seed) Constructs the EnhancedRandomGenerator to wrap an instance of a random number generator initialized with a specified seed to enable replicating the same sequence of random numbers during subsequent runs.EnhancedRandomGenerator
(String algorithmName) Constructs the EnhancedRandomGenerator to wrap an instance of any random number generator supported by your version of Java as specified by its name, as documented via theRandomGenerator.of(java.lang.String)
method.EnhancedRandomGenerator
(RandomGenerator generator) Constructs the EnhancedRandomGenerator from the RandomGenerator to wrap. 
Method Summary
Modifier and TypeMethodDescriptionfinal boolean[]
arrayMask
(int n) Generates an "array mask" of a specified length, where an "array mask" is an array of boolean values of the same length as another array.final boolean[]
arrayMask
(int n, double p) Generates an "array mask" of a specified length, where an "array mask" is an array of boolean values of the same length as another array.final boolean[]
arrayMask
(int n, int k) Generates an "array mask" of a specified length and specified number of true values, where an "array mask" is an array of boolean values of the same length as another array.final IntStream
biasedInts
(int randomNumberOrigin, int randomNumberBound) Returns an effectively unlimited stream of pseudorandom int values, each value random from the interval [randomNumberOrigin, randomNumberBound).final IntStream
biasedInts
(long streamSize, int randomNumberOrigin, int randomNumberBound) Returns a stream of pseudorandom int values, each value random from the interval [randomNumberOrigin, randomNumberBound).final IntStream
binomials
(int n, double p) Returns an effectively unlimited stream of pseudorandom int values, each value generated from a binomial distribution.final IntStream
binomials
(long streamSize, int n, double p) Returns a stream of pseudorandom int values, each value generated from a binomial distribution.final DoubleStream
cauchys
(double median, double scale) Returns an effectively unlimited stream of pseudorandom double values from a Cauchy distribution.final DoubleStream
cauchys
(long streamSize, double median, double scale) Returns a stream of pseudorandom double values from a Cauchy distribution.final DoubleStream
doubles()
Returns an effectively unlimited stream of pseudorandom double values, each value uniformly random from the interval [0.0, 1.0).final DoubleStream
doubles
(double randomNumberOrigin, double randomNumberBound) Returns an effectively unlimited stream of pseudorandom double values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).final DoubleStream
doubles
(long streamSize) Returns a stream of pseudorandom double values, each value uniformly random from the interval [0.0, 1.0).final DoubleStream
doubles
(long streamSize, double randomNumberOrigin, double randomNumberBound) Returns a stream of pseudorandom double values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).final DoubleStream
Returns an effectively unlimited stream of pseudorandom nonnegative double values from an exponential distribution with mean 1.final DoubleStream
exponentials
(long streamSize) Returns a stream of pseudorandom nonnegative double values from an exponential distribution with mean 1.final DoubleStream
Returns an effectively unlimited stream of pseudorandom double values from a Gaussian distribution with mean 0 and standard deviation 1.final DoubleStream
gaussians
(double mean, double stdev) Returns an effectively unlimited stream of pseudorandom double values from a Gaussian distribution with specified mean and standard deviation.final DoubleStream
gaussians
(long streamSize) Returns a stream of pseudorandom nonnegative double values from a Gaussian distribution with mean 0 and standard deviation 1.final DoubleStream
gaussians
(long streamSize, double mean, double stdev) Returns a stream of pseudorandom double values from a Gaussian distribution with specified mean and standard deviation.static EnhancedRandomGenerator
Gets an EnhancedRandomGenerator wrapping an instance of the default random number generator as obtained via a call toRandomGenerator.getDefault()
.final IntStream
ints()
Returns an effectively unlimited stream of pseudorandom int values.final IntStream
ints
(int randomNumberOrigin, int randomNumberBound) Returns an effectively unlimited stream of pseudorandom int values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).final IntStream
ints
(long streamSize) Returns a stream of pseudorandom int values.final IntStream
ints
(long streamSize, int randomNumberOrigin, int randomNumberBound) Returns a stream of pseudorandom int values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).final boolean
Return true if the implementation of the RandomGenerator (algorithm) that is wrapped by this EnhancedRandomGenerator has been marked for deprecation.final LongStream
longs()
Returns an effectively unlimited stream of pseudorandom long values.final LongStream
longs
(long streamSize) Returns a stream of pseudorandom long values.final LongStream
longs
(long randomNumberOrigin, long randomNumberBound) Returns an effectively unlimited stream of pseudorandom long values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).final LongStream
longs
(long streamSize, long randomNumberOrigin, long randomNumberBound) Returns a stream of pseudorandom long values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).final int
nextBiasedInt
(int bound) Generates a random integer in the interval: [0, bound).final int
nextBiasedInt
(int origin, int bound) Generates a random integer in the interval: [origin, bound).final int
nextBinomial
(int n, double p) Generates a pseudorandom integer from a binomial distribution.final boolean
Generates a pseudorandom boolean value.final void
nextBytes
(byte[] bytes) Fills a usersupplied byte array with byte values generated pseudorandomly uniformly distributed in the interval [128, 127].final double
nextCauchy
(double scale) Generates a pseudorandom number from a Cauchy distribution with median 0 and chosen scale parameter.final double
nextCauchy
(double median, double scale) Generates a pseudorandom number from a Cauchy distribution.final double
Generates a pseudorandom double value in the interval [0, 1).final double
nextDouble
(double bound) Generates a pseudorandom double value in the interval [0, bound).final double
nextDouble
(double origin, double bound) Generates a pseudorandom double value in the interval [origin, bound).final double
Generates a nonnegative pseudorandom number from an exponential distribution with mean 1.final float
Generates a pseudorandom float value in the interval [0, 1).final float
nextFloat
(float bound) Generates a pseudorandom float value in the interval [0, bound).final float
nextFloat
(float origin, float bound) Generates a pseudorandom float value in the interval [origin, bound).final double
Generates a random number from a Gaussian distribution with mean 0 and standard deviation 1.final double
nextGaussian
(double stddev) Generates a random number from a Gaussian distribution with mean 0 and standard deviation, stddev, of your choosing.final double
nextGaussian
(double mean, double stddev) Generates a random number from a Gaussian distribution with specified mean and standard deviation.final int
nextInt()
Generates a pseudorandom int value.final int
nextInt
(int bound) Generates a random integer uniformly distributed in the interval: [0, bound).final int
nextInt
(int origin, int bound) Generates a random integer uniformly distributed in the interval: [origin, bound).final IndexPair
nextIntPair
(int n) Generates a random sample of 2 integers, without replacement, from the set of integers in the interval [0, n).final int[]
nextIntPair
(int n, int[] result) Generates a random sample of 2 integers, without replacement, from the set of integers in the interval [0, n).final IndexTriple
nextIntTriple
(int n) Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n).final int[]
nextIntTriple
(int n, int[] result) Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n).final long
nextLong()
Generates a pseudorandom long value.final long
nextLong
(long bound) Generates a pseudorandom long value in the interval [0, bound).final long
nextLong
(long origin, long bound) Generates a pseudorandom long value in the interval [origin, bound).final IndexPair
nextSortedIntPair
(int n) Generates a random sample of 2 integers (i, j) without replacement, from the set of integers in the interval [0, n).final int[]
nextSortedIntPair
(int n, int[] result) Generates a random sample of 2 integers, without replacement, from the set of integers in the interval [0, n).final IndexTriple
nextSortedIntTriple
(int n) Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n).final int[]
nextSortedIntTriple
(int n, int[] result) Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n).final IndexPair
nextSortedWindowedIntPair
(int n, int window) Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and sorted such that i is less than j.final int[]
nextSortedWindowedIntPair
(int n, int window, int[] result) Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and sorted such that i is less than j.final IndexTriple
nextSortedWindowedIntTriple
(int n, int window) Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.final int[]
nextSortedWindowedIntTriple
(int n, int window, int[] result) Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.final IndexPair
nextWindowedIntPair
(int n, int window) Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window.final int[]
nextWindowedIntPair
(int n, int window, int[] result) Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window.final IndexTriple
nextWindowedIntTriple
(int n, int window) Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.final int[]
nextWindowedIntTriple
(int n, int window, int[] result) Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.static EnhancedRandomGenerator
Gets an EnhancedRandomGenerator wrapping an instance of any random number generator supported by your version of Java as specified by its name, as documented via theRandomGenerator.of(java.lang.String)
method.pairs
(int n) Returns an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).pairs
(long streamSize, int n) Returns a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).final int[]
sample
(int n, double p) Generates a random sample, without replacement, from the set of integers in the interval [0, n).final int[]
sample
(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n).final int[]
sampleInsertion
(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n).final int[]
samplePool
(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n).final int[]
sampleReservoir
(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n).final void
shuffle
(byte[] array) Randomizes the ordering of the elements of an array.final void
shuffle
(byte[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.final void
shuffle
(char[] array) Randomizes the ordering of the elements of an array.final void
shuffle
(char[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.final void
shuffle
(double[] array) Randomizes the ordering of the elements of an array.final void
shuffle
(double[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.final void
shuffle
(float[] array) Randomizes the ordering of the elements of an array.final void
shuffle
(float[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.final void
shuffle
(int[] array) Randomizes the ordering of the elements of an array.final void
shuffle
(int[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.final void
shuffle
(long[] array) Randomizes the ordering of the elements of an array.final void
shuffle
(long[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.final void
shuffle
(short[] array) Randomizes the ordering of the elements of an array.final void
shuffle
(short[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.final <T> void
Randomizes the ordering of the elements of a List.final <T> void
Randomizes the ordering of the elements of a portion of a List.final <T> void
shuffle
(T[] array) Randomizes the ordering of the elements of an array.final <T> void
shuffle
(T[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array.sortedPairs
(int n) Returns an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).sortedPairs
(long streamSize, int n) Returns a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).final Stream<IndexTriple>
sortedTriples
(int n) Returns an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n).final Stream<IndexTriple>
sortedTriples
(long streamSize, int n) Returns a stream of pseudorandom triples of int values, without replacement, from the interval [0, n).sortedWindowedPairs
(int n, int window) Returns an effectively unlimited stream of pseudorandom pairs (i, j) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and sorted such that i is less than j.sortedWindowedPairs
(long streamSize, int n, int window) Returns a stream of pseudorandom pairs of int values (i, j), without replacement, from the interval [0, n), such that ij ≤ window, and sorted such that i is less than j.final Stream<IndexTriple>
sortedWindowedTriples
(int n, int window) Returns an effectively unlimited stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.final Stream<IndexTriple>
sortedWindowedTriples
(long streamSize, int n, int window) Returns a stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.final Stream<IndexTriple>
triples
(int n) Returns an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n).final Stream<IndexTriple>
triples
(long streamSize, int n) Returns a stream of pseudorandom triples of int values, without replacement, from the interval [0, n).windowedPairs
(int n, int window) Returns an effectively unlimited stream of pseudorandom pairs (i, j) of int values, without replacement, from the interval [0, n), such that ij ≤ window.windowedPairs
(long streamSize, int n, int window) Returns a stream of pseudorandom pairs of int values (i, j), without replacement, from the interval [0, n), such that ij ≤ window.final Stream<IndexTriple>
windowedTriples
(int n, int window) Returns an effectively unlimited stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.final Stream<IndexTriple>
windowedTriples
(long streamSize, int n, int window) Returns a stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.

Constructor Details

EnhancedRandomGenerator
public EnhancedRandomGenerator()Constructs the EnhancedRandomGenerator to wrap an instance of the default random number generator as obtained via a call toRandomGenerator.getDefault()
. 
EnhancedRandomGenerator
public EnhancedRandomGenerator(long seed) Constructs the EnhancedRandomGenerator to wrap an instance of a random number generator initialized with a specified seed to enable replicating the same sequence of random numbers during subsequent runs. Parameters:
seed
 The seed for the random number generator.

EnhancedRandomGenerator
Constructs the EnhancedRandomGenerator from the RandomGenerator to wrap. Parameters:
generator
 The RandomGenerator to wrap, which serves as the source of randomness.

EnhancedRandomGenerator
Constructs the EnhancedRandomGenerator to wrap an instance of any random number generator supported by your version of Java as specified by its name, as documented via theRandomGenerator.of(java.lang.String)
method. Parameters:
algorithmName
 The name of the random number generator as documented by theRandomGenerator.of(java.lang.String)
method. Throws:
NullPointerException
 if algorithmName is null.IllegalArgumentException
 if algorithmName is not found.


Method Details

getDefault
Gets an EnhancedRandomGenerator wrapping an instance of the default random number generator as obtained via a call toRandomGenerator.getDefault()
. Returns:
 an EnhancedRandomGenerator wrapping an instance of the default random number generator

of
Gets an EnhancedRandomGenerator wrapping an instance of any random number generator supported by your version of Java as specified by its name, as documented via theRandomGenerator.of(java.lang.String)
method. Parameters:
algorithmName
 The name of the random number generator as documented by theRandomGenerator.of(java.lang.String)
method. Returns:
 an EnhancedRandomGenerator wrapping an instance of your chosen random number generator.
 Throws:
NullPointerException
 if algorithmName is null.IllegalArgumentException
 if algorithmName is not found.

arrayMask
public final boolean[] arrayMask(int n) Generates an "array mask" of a specified length, where an "array mask" is an array of boolean values of the same length as another array. Each position in the result is equally likely true or false. Enhanced Functionality.Runtime: O(n).
 Parameters:
n
 The length of the array mask. Returns:
 An array of n randomly generated boolean values.

arrayMask
public final boolean[] arrayMask(int n, int k) Generates an "array mask" of a specified length and specified number of true values, where an "array mask" is an array of boolean values of the same length as another array. Enhanced Functionality.Runtime: O(min(n, k^{2})), and it uses O(min(k, nk)) random numbers.
 Parameters:
n
 The length of the array mask.k
 The desired number of true values, which must be no greater than n. Returns:
 An array of n boolean values, exactly k of which are equal to true.

arrayMask
public final boolean[] arrayMask(int n, double p) Generates an "array mask" of a specified length, where an "array mask" is an array of boolean values of the same length as another array. Enhanced Functionality.Runtime: O(n), and it uses O(n) random doubles.
 Parameters:
n
 The length of the array mask.p
 The probability that an element of the result is true. Returns:
 An array of n boolean values, such that each element is true with probability p.

biasedInts
Returns an effectively unlimited stream of pseudorandom int values, each value random from the interval [randomNumberOrigin, randomNumberBound).Enhanced Functionality: Each int produced by the stream is generated by an implementation of a variation of the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019. The difference between this implementation and that algorithm is that we have removed the rejection sampling to create an ultrafast, but not strictly uniform, stream of random integers. If you require strict uniformity, then use the
ints(int, int)
method instead. Parameters:
randomNumberOrigin
 The lower bound, inclusive (must be less than bound)randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 an effectively unlimited stream of pseudorandom int values, random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound

biasedInts
Returns a stream of pseudorandom int values, each value random from the interval [randomNumberOrigin, randomNumberBound).Enhanced Functionality: Each int produced by the stream is generated by an implementation of a variation of the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019. The difference between this implementation and that algorithm is that we have removed the rejection sampling to create an ultrafast, but not strictly uniform, stream of random integers. If you require strict uniformity, then use the
ints(long, int, int)
method instead. Parameters:
streamSize
 The number of values in the stream.randomNumberOrigin
 The lower bound, inclusive (must be less than bound).randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 a stream of pseudorandom int values, random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound, or if streamSize is negative.

binomials
Returns an effectively unlimited stream of pseudorandom int values, each value generated from a binomial distribution. Enhanced Functionality. Parameters:
n
 Number of trials for the binomial distribution.p
 The probability of a successful trial. Returns:
 an effectively unlimited stream of pseudorandom int values generated from a binomial distribution.

binomials
Returns a stream of pseudorandom int values, each value generated from a binomial distribution. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 Number of trials for the binomial distribution.p
 The probability of a successful trial. Returns:
 a stream of pseudorandom int values generated from a binomial distribution.

cauchys
Returns an effectively unlimited stream of pseudorandom double values from a Cauchy distribution. Enhanced Functionality. Parameters:
median
 The median of the Cauchy distribution.scale
 The scale of the Cauchy distribution. Returns:
 an effectively unlimited stream of pseudorandom double values from a Cauchy distribution.

cauchys
Returns a stream of pseudorandom double values from a Cauchy distribution. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.median
 The median of the Cauchy distribution.scale
 The scale of the Cauchy distribution. Returns:
 a stream of pseudorandom double values from a Cauchy distribution.

exponentials
Returns an effectively unlimited stream of pseudorandom nonnegative double values from an exponential distribution with mean 1. Enhanced Functionality. Returns:
 an effectively unlimited stream of pseudorandom double values from an exponential distribution with mean 1.

exponentials
Returns a stream of pseudorandom nonnegative double values from an exponential distribution with mean 1. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream. Returns:
 a stream of pseudorandom double values from an exponential distribution with mean 1.

gaussians
Returns an effectively unlimited stream of pseudorandom double values from a Gaussian distribution with mean 0 and standard deviation 1. Enhanced Functionality. Returns:
 an effectively unlimited stream of pseudorandom double values from a Gaussian distribution with mean 0 and standard deviation 1.

gaussians
Returns an effectively unlimited stream of pseudorandom double values from a Gaussian distribution with specified mean and standard deviation. Enhanced Functionality. Parameters:
mean
 The mean of the Gaussian.stdev
 The standard deviation of the Gaussian. Returns:
 an effectively unlimited stream of pseudorandom double values from a Gaussian distribution with specified mean and standard deviation.

gaussians
Returns a stream of pseudorandom double values from a Gaussian distribution with specified mean and standard deviation. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.mean
 The mean of the Gaussian.stdev
 The standard deviation of the Gaussian. Returns:
 a stream of pseudorandom double values from a Gaussian distribution with specified mean and standard deviation.

gaussians
Returns a stream of pseudorandom nonnegative double values from a Gaussian distribution with mean 0 and standard deviation 1. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream. Returns:
 a stream of pseudorandom double values from a Gaussian distribution with mean 0 and standard deviation 1.

nextBiasedInt
public final int nextBiasedInt(int bound) Generates a random integer in the interval: [0, bound). Enhanced Functionality.The nextBiasedInt(bound) method computes a random int in the target interval but faster than nextInt(bound). It does not correct for bias via rejection sampling, and thus some values in the interval [0, bound) may be more likely than others. There is no bias for bound values that are powers of 2. Otherwise, the lower the value of bound, the less bias; and the higher the value of bound, the more bias. If your bound is relatively low, and if your application does not require strict uniformity, then this method is significantly faster than any approach that corrects for bias. We started with the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019. But we removed from it the rejection sampling portion.
 Parameters:
bound
 Upper bound, exclusive, on range of random integers (must be positive). Returns:
 a random integer between 0 (inclusive) and bound (exclusive).
 Throws:
IllegalArgumentException
 if the bound is not positive

nextBiasedInt
public final int nextBiasedInt(int origin, int bound) Generates a random integer in the interval: [origin, bound). Enhanced Functionality.The nextBiasedInt(origin, bound) method computes a random int in the target interval but faster than nextInt(origin, bound). It does not correct for bias via rejection sampling, and thus some values in the interval [origin, bound) may be more likely than others. There is no bias interval width is a power of 2. Otherwise, the smaller the interval, the less bias; and the larger the interval, the more bias. If your interval is relatively low, and if your application does not require strict uniformity, then this method is significantly faster than any approach that corrects for bias. We started with the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019. But we removed from it the rejection sampling portion.
 Parameters:
origin
 Lower bound, inclusive, on range of random integers.bound
 Upper bound, exclusive, on range of random integers (must be greater than origin). Returns:
 a random integer between origin (inclusive) and bound (exclusive).
 Throws:
IllegalArgumentException
 if the bound is not greater than origin

nextBinomial
public final int nextBinomial(int n, double p) Generates a pseudorandom integer from a binomial distribution. Enhanced Functionality. Parameters:
n
 Number of trials for the binomial distribution.p
 The probability of a successful trial. Returns:
 A pseudorandom integer from a binomial distribution.

nextCauchy
public final double nextCauchy(double scale) Generates a pseudorandom number from a Cauchy distribution with median 0 and chosen scale parameter. Enhanced Functionality. Parameters:
scale
 The scale parameter of the Cauchy. Returns:
 a pseudorandom number from a Cauchy distribution

nextCauchy
public final double nextCauchy(double median, double scale) Generates a pseudorandom number from a Cauchy distribution. Enhanced Functionality. Parameters:
median
 The median of the Cauchy.scale
 The scale parameter of the Cauchy. Returns:
 a pseudorandom number from a Cauchy distribution

nextGaussian
public final double nextGaussian(double stddev) Generates a random number from a Gaussian distribution with mean 0 and standard deviation, stddev, of your choosing.Enhanced Functionality: This method is a convenience method for nextGaussian(mean, stdev), with a mean of 0. If the wrapped RandomGenerator is one of the legacy classes
Random
orSecureRandom
, then this method uses our implementation of the original ziggurat algorithm. In all other cases, it uses the Java API's implementation from the RandomGenerator interface, which is the modified ziggurat algorithm, which is faster than the original. For more information as well as experimental comparison, see the following report:Vincent A. Cicirello. 2024. Fast Gaussian Distributed Pseudorandom Number Generation in Java via the Ziggurat Algorithm. arXiv:2405.19493, May 2024. doi:10.48550/arXiv.2405.19493. [PDF]
 Parameters:
stddev
 The standard deviation of the Gaussian. Returns:
 A random number from a Gaussian distribution with mean 0 and standard deviation stddev.

nextIntPair
public final int[] nextIntPair(int n, int[] result) Generates a random sample of 2 integers, without replacement, from the set of integers in the interval [0, n). All n choose 2 combinations are equally likely. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from.result
 An array to hold the pair that is generated. If result is null or if result.length is less than 2, then this method will construct an array for the result. Returns:
 An array containing the pair of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 2.

nextIntPair
Generates a random sample of 2 integers, without replacement, from the set of integers in the interval [0, n). All n choose 2 combinations are equally likely. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from. Returns:
 A pair of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 2.

nextIntTriple
public final int[] nextIntTriple(int n, int[] result) Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n). All n choose 3 combinations are equally likely. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from.result
 An array to hold the triple that is generated. If result is null or if result.length is less than 3, then this method will construct an array for the result. Returns:
 An array containing the triple of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 3.

nextIntTriple
Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n). All n choose 3 combinations are equally likely. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from. Returns:
 A triple of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 3.

nextSortedIntPair
public final int[] nextSortedIntPair(int n, int[] result) Generates a random sample of 2 integers, without replacement, from the set of integers in the interval [0, n). The result is sorted with the minimum first followed by the maximum. All n choose 2 combinations are equally likely. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from.result
 An array to hold the pair that is generated. If result is null or if result.length is less than 2, then this method will construct an array for the result. Returns:
 An array containing the pair of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 2.

nextSortedIntPair
Generates a random sample of 2 integers (i, j) without replacement, from the set of integers in the interval [0, n). The pair is sorted such that i is the minimum and j is the maximum. All n choose 2 combinations are equally likely. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from. Returns:
 A pair of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 2.

nextSortedIntTriple
public final int[] nextSortedIntTriple(int n, int[] result) Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n). All n choose 3 combinations are equally likely. The result is sorted in increasing order. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from.result
 An array to hold the triple that is generated. If result is null or if result.length is less than 3, then this method will construct an array for the result. Returns:
 An array containing the triple of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 3.

nextSortedIntTriple
Generates a random sample of 3 integers, without replacement, from the set of integers in the interval [0, n). All n choose 3 combinations are equally likely. The result is sorted in increasing order. Enhanced Functionality.The runtime of this method is O(1), and it uses an algorithm described in:
Vincent A. Cicirello. 2024. Algorithms for Generating Small Random Samples. Software: Practice and Experience, September 2024. doi:10.1002/spe.3379 [PDF]
 Parameters:
n
 The number of integers to choose from. Returns:
 A triple of randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if n < 3.

nextSortedWindowedIntPair
public final int[] nextSortedWindowedIntPair(int n, int window, int[] result) Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and sorted such that i is less than j. All pairs that satisfy the window constraint are equally likely. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the pair.result
 An array to hold the pair that is generated. If result is null or if result.length is less than 2, then this method will construct an array for the result. Returns:
 An array containing the pair of randomly chosen integers, i, j, from the interval [0, n), such that ij ≤ window.
 Throws:
IllegalArgumentException
 if window < 1 or n < 2.

nextSortedWindowedIntPair
Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and sorted such that i is less than j. All pairs that satisfy the window constraint are equally likely. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the pair. Returns:
 A pair of randomly chosen integers, i, j, from the interval [0, n), such that ij ≤ window.
 Throws:
IllegalArgumentException
 if window < 1 or n < 2.

nextSortedWindowedIntTriple
public final int[] nextSortedWindowedIntTriple(int n, int window, int[] result) Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. All triples that satisfy the window constraint are equally likely. The result is sorted in increasing order. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the triple.result
 An array to hold the triple that is generated. If result is null or if result.length is less than 3, then this method will construct an array for the result. Returns:
 An array containing the triple of randomly chosen integers, i, j, k from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.
 Throws:
IllegalArgumentException
 if window < 2 or n < 3.

nextSortedWindowedIntTriple
Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. All triples that satisfy the window constraint are equally likely. The result is sorted in increasing order. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the triple. Returns:
 A triple of randomly chosen integers, i, j, k from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.
 Throws:
IllegalArgumentException
 if window < 2 or n < 3.

nextWindowedIntPair
public final int[] nextWindowedIntPair(int n, int window, int[] result) Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window. All pairs that satisfy the window constraint are equally likely. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the pair.result
 An array to hold the pair that is generated. If result is null or if result.length is less than 2, then this method will construct an array for the result. Returns:
 An array containing the pair of randomly chosen integers, i, j, from the interval [0, n), such that ij ≤ window.
 Throws:
IllegalArgumentException
 if window < 1 or n < 2.

nextWindowedIntPair
Generates a random sample of 2 integers, i, j, without replacement, from the set of integers in the interval [0, n), such that ij ≤ window. All pairs that satisfy the window constraint are equally likely. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the pair. Returns:
 A pair of randomly chosen integers, i, j, from the interval [0, n), such that ij ≤ window.
 Throws:
IllegalArgumentException
 if window < 1 or n < 2.

nextWindowedIntTriple
public final int[] nextWindowedIntTriple(int n, int window, int[] result) Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. All triples that satisfy the window constraint are equally likely. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the triple.result
 An array to hold the triple that is generated. If result is null or if result.length is less than 3, then this method will construct an array for the result. Returns:
 An array containing the triple of randomly chosen integers, i, j, k from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.
 Throws:
IllegalArgumentException
 if window < 2 or n < 3.

nextWindowedIntTriple
Generates a random sample of 3 integers, i, j, k without replacement, from the set of integers in the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. All triples that satisfy the window constraint are equally likely. Enhanced Functionality.The runtime is O(1).
 Parameters:
n
 The number of integers to choose from.window
 The maximum difference between the integers of the triple. Returns:
 A triple of randomly chosen integers, i, j, k from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window.
 Throws:
IllegalArgumentException
 if window < 2 or n < 3.

pairs
Returns an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n). Enhanced Functionality. Parameters:
n
 bound on random values, exclusive. Returns:
 an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

pairs
Returns a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n). Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive. Returns:
 a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

sample
public final int[] sample(int n, double p) Generates a random sample, without replacement, from the set of integers in the interval [0, n). Each of the n integers has a probability p of inclusion in the sample. Enhanced Functionality. Parameters:
n
 The number of integers to choose from.p
 The probability that each of the n integers is included in the sample. Returns:
 An array containing the sample.

sample
public final int[] sample(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n). All n choose k combinations are equally likely. Enhanced Functionality.This method chooses among the
samplePool(int, int, int[])
,sampleReservoir(int, int, int[])
, andsampleInsertion(int, int, int[])
methods based on the values of n and k.This approach combining reservoir sampling, pool sampling, and insertion sampling was described in: Vincent A. Cicirello. 2022. Cycle Mutation: Evolving Permutations via Cycle Induction, Applied Sciences, 12(11), Article 5506 (June 2022). doi:10.3390/app12115506
The runtime is O(min(n, k^{2})) and it generates O(min(k, nk)) random numbers.
 Parameters:
n
 The number of integers to choose from.k
 The size of the desired sample.result
 An array to hold the sample that is generated. If result is null or if result.length is less than k, then this method will construct an array for the result. Returns:
 An array containing the sample of k randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if k > n.NegativeArraySizeException
 if k < 0.

sampleInsertion
public final int[] sampleInsertion(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n). All n choose k combinations are equally likely. Enhanced Functionality.This implements the insertion sampling algorithm described in:
Vincent A. Cicirello. 2022. Cycle Mutation: Evolving Permutations via Cycle Induction, Applied Sciences, 12(11), Article 5506 (June 2022). doi:10.3390/app12115506
The runtime is O(k^{2}) and it generates O(k) random numbers. Thus, it is a better choice than both sampleReservoir and samplePool when k^{2} < n. Just like sampleReservoir, the sampleInsertion method only requires O(1) extra space, while samplePool requires O(n) extra space.
 Parameters:
n
 The number of integers to choose from.k
 The size of the desired sample.result
 An array to hold the sample that is generated. If result is null or if result.length is less than k, then this method will construct an array for the result. Returns:
 An array containing the sample of k randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if k > n.NegativeArraySizeException
 if k < 0.

samplePool
public final int[] samplePool(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n). All n choose k combinations are equally likely. Enhanced Functionality.This implements the algorithm SELECT of S. Goodman and S. Hedetniemi, as described in: J Ernvall, O Nevalainen, "An Algorithm for Unbiased Random Sampling," The Computer Journal, 25(1):4547, 1982.
The runtime is O(n) and it generates O(k) random numbers. Thus, it is a better choice than sampleReservoir when k < nk. However, this uses O(n) extra space, whereas the reservoir algorithm uses no extra space.
 Parameters:
n
 The number of integers to choose from.k
 The size of the desired sample.result
 An array to hold the sample that is generated. If result is null or if result.length is less than k, then this method will construct an array for the result. Returns:
 An array containing the sample of k randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if k > n.NegativeArraySizeException
 if k < 0.

sampleReservoir
public final int[] sampleReservoir(int n, int k, int[] result) Generates a random sample of k integers, without replacement, from the set of integers in the interval [0, n). All n choose k combinations are equally likely. Enhanced Functionality.Uses the reservoir sampling algorithm (Algorithm R) from J. Vitter's 1985 article "Random Sampling with a Reservoir" from ACM Transactions on Mathematical Software.
The runtime is O(n) and it generates O(nk) random numbers. Thus, it is an especially good choice as k approaches n. Only constant extra space required.
 Parameters:
n
 The number of integers to choose from.k
 The size of the desired sample.result
 An array to hold the sample that is generated. If result is null or if result.length is less than k, then this method will construct an array for the result. Returns:
 An array containing the sample of k randomly chosen integers from the interval [0, n).
 Throws:
IllegalArgumentException
 if k > n.NegativeArraySizeException
 if k < 0.

shuffle
public final void shuffle(byte[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shuffle

shuffle
public final void shuffle(byte[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
public final void shuffle(char[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shuffle

shuffle
public final void shuffle(char[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
public final void shuffle(double[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shuffle

shuffle
public final void shuffle(double[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
public final void shuffle(float[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shuffle

shuffle
public final void shuffle(float[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
public final void shuffle(int[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shuffle

shuffle
public final void shuffle(int[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
public final void shuffle(long[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shuffle

shuffle
public final void shuffle(long[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
public final void shuffle(short[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shuffle

shuffle
public final void shuffle(short[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
public final <T> void shuffle(T[] array) Randomizes the ordering of the elements of an array. All possible reorderings are equally likely. Enhanced Functionality. Type Parameters:
T
 type of array elements Parameters:
array
 the array to shuffle

shuffle
public final <T> void shuffle(T[] array, int first, int last) Randomizes the ordering of the elements within a portion of an array. All possible reorderings are equally likely. Enhanced Functionality. Type Parameters:
T
 type of array elements Parameters:
array
 the array to shufflefirst
 the first element (inclusive) of the part of the array to shufflelast
 the last element (exclusive) of the part of the array to shuffle Throws:
ArrayIndexOutOfBoundsException
 if first is less than 0 or if last is greater than array.length

shuffle
Randomizes the ordering of the elements of a List. All possible reorderings are equally likely. Enhanced Functionality. Type Parameters:
T
 type of List elements Parameters:
list
 the List to shuffle

shuffle
Randomizes the ordering of the elements of a portion of a List. All possible reorderings are equally likely. Enhanced Functionality. Type Parameters:
T
 type of List elements Parameters:
list
 the List to shufflefirst
 the first element (inclusive) of the part of the List to shufflelast
 the last element (exclusive) of the part of the List to shuffle

sortedPairs
Returns an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n). Each pair is sorted such that i is the minimum and j is the maximum of the pair. Enhanced Functionality. Parameters:
n
 bound on random values, exclusive. Returns:
 an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

sortedPairs
Returns a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n). Each pair is sorted such that i is the minimum and j is the maximum of the pair. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive. Returns:
 a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

sortedTriples
Returns an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n). Each triple is sorted in increasing order. Enhanced Functionality. Parameters:
n
 bound on random values, exclusive. Returns:
 an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

sortedTriples
Returns a stream of pseudorandom triples of int values, without replacement, from the interval [0, n). Each triple is sorted in increasing order. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive. Returns:
 a stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

sortedWindowedPairs
Returns an effectively unlimited stream of pseudorandom pairs (i, j) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and sorted such that i is less than j. All pairs that satisfy the window constraint are equally likely. Enhanced Functionality. Parameters:
n
 bound on random values, exclusive.window
 The maximum difference between the integers of the pair. Returns:
 an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

sortedWindowedPairs
Returns a stream of pseudorandom pairs of int values (i, j), without replacement, from the interval [0, n), such that ij ≤ window, and sorted such that i is less than j. All pairs that satisfy the window constraint are equally likely.. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive.window
 The maximum difference between the integers of the pair. Returns:
 a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

sortedWindowedTriples
Returns an effectively unlimited stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. Each triple is sorted in increasing order. All triples that satisfy the window constraint are equally likely. Enhanced Functionality. Parameters:
n
 bound on random values, exclusive.window
 The maximum difference between the integers of the triple. Returns:
 an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

sortedWindowedTriples
Returns a stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. Each triple is sorted in increasing order. All triples that satisfy the window constraint are equally likely. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive.window
 The maximum difference between the integers of the triple. Returns:
 a stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

triples
Returns an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n). Enhanced Functionality. Parameters:
n
 bound on random values, exclusive. Returns:
 an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

triples
Returns a stream of pseudorandom triples of int values, without replacement, from the interval [0, n). Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive. Returns:
 a stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

windowedPairs
Returns an effectively unlimited stream of pseudorandom pairs (i, j) of int values, without replacement, from the interval [0, n), such that ij ≤ window. All pairs that satisfy the window constraint are equally likely. Enhanced Functionality. Parameters:
n
 bound on random values, exclusive.window
 The maximum difference between the integers of the pair. Returns:
 an effectively unlimited stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

windowedPairs
Returns a stream of pseudorandom pairs of int values (i, j), without replacement, from the interval [0, n), such that ij ≤ window. All pairs that satisfy the window constraint are equally likely.. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive.window
 The maximum difference between the integers of the pair. Returns:
 a stream of pseudorandom pairs of int values, without replacement, from the interval [0, n).

windowedTriples
Returns an effectively unlimited stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. All triples that satisfy the window constraint are equally likely. Enhanced Functionality. Parameters:
n
 bound on random values, exclusive.window
 The maximum difference between the integers of the triple. Returns:
 an effectively unlimited stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

windowedTriples
Returns a stream of pseudorandom triples (i, j , k) of int values, without replacement, from the interval [0, n), such that ij ≤ window, and ik ≤ window, and kj ≤ window. All triples that satisfy the window constraint are equally likely. Enhanced Functionality. Parameters:
streamSize
 The number of values in the stream.n
 bound on random values, exclusive.window
 The maximum difference between the integers of the triple. Returns:
 a stream of pseudorandom triples of int values, without replacement, from the interval [0, n).

nextGaussian
public final double nextGaussian()Generates a random number from a Gaussian distribution with mean 0 and standard deviation 1.Enhanced Functionality: If the wrapped RandomGenerator is one of the legacy classes
Random
orSecureRandom
, then this method enhances Gaussian generation by using our implementation of the original ziggurat algorithm. In all other cases, it delegates to the Java API's implementation from the RandomGenerator interface, which is the modified ziggurat algorithm, which is faster than the original. For more information as well as experimental comparison, see the following report:Vincent A. Cicirello. 2024. Fast Gaussian Distributed Pseudorandom Number Generation in Java via the Ziggurat Algorithm. arXiv:2405.19493, May 2024. doi:10.48550/arXiv.2405.19493. [PDF]
 Specified by:
nextGaussian
in interfaceRandomGenerator
 Returns:
 A random number from a Gaussian distribution with mean 0 and standard deviation 1.

nextGaussian
public final double nextGaussian(double mean, double stddev) Generates a random number from a Gaussian distribution with specified mean and standard deviation.Enhanced Functionality: If the wrapped RandomGenerator is one of the legacy classes
Random
orSecureRandom
, then this method enhances Gaussian generation by using our implementation of the original ziggurat algorithm. In all other cases, it delegates to the Java API's implementation from the RandomGenerator interface, which is the modified ziggurat algorithm, which is faster than the original. For more information as well as experimental comparison, see the following report:Vincent A. Cicirello. 2024. Fast Gaussian Distributed Pseudorandom Number Generation in Java via the Ziggurat Algorithm. arXiv:2405.19493, May 2024. doi:10.48550/arXiv.2405.19493. [PDF]
 Specified by:
nextGaussian
in interfaceRandomGenerator
 Parameters:
mean
 The mean of the Gaussian.stddev
 The standard deviation of the Gaussian. Returns:
 A random number from a Gaussian distribution with mean 0 and standard deviation stddev.

nextInt
public final int nextInt(int bound) Generates a random integer uniformly distributed in the interval: [0, bound).Enhanced Functionality: This method is an implementation of the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019.
 Specified by:
nextInt
in interfaceRandomGenerator
 Parameters:
bound
 Upper bound, exclusive, on range of random integers (must be positive). Returns:
 a random integer between 0 (inclusive) and bound (exclusive).
 Throws:
IllegalArgumentException
 if the bound is not positive

nextInt
public final int nextInt(int origin, int bound) Generates a random integer uniformly distributed in the interval: [origin, bound).Enhanced Functionality: This method is an implementation of the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019.
 Specified by:
nextInt
in interfaceRandomGenerator
 Parameters:
origin
 The lower bound, inclusive (must be less than bound)bound
 Upper bound, exclusive, on range of random integers. Returns:
 a random integer between 0 (inclusive) and bound (exclusive).
 Throws:
IllegalArgumentException
 if the origin is greater than or equal to bound

ints
Returns an effectively unlimited stream of pseudorandom int values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).Enhanced Functionality: Each int produced by the stream is generated by an implementation of the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019.
 Specified by:
ints
in interfaceRandomGenerator
 Parameters:
randomNumberOrigin
 The lower bound, inclusive (must be less than bound)randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 an effectively unlimited stream of pseudorandom int values, uniformly random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound

ints
Returns a stream of pseudorandom int values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound).Enhanced Functionality: Each int produced by the stream is generated by an implementation of the algorithm proposed in the article: Daniel Lemire, "Fast Random Integer Generation in an Interval," ACM Transactions on Modeling and Computer Simulation, 29(1), 2019.
 Specified by:
ints
in interfaceRandomGenerator
 Parameters:
streamSize
 The number of values in the stream.randomNumberOrigin
 The lower bound, inclusive (must be less than bound).randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 a stream of pseudorandom int values, uniformly random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound, or if streamSize is negative.

doubles
Returns an effectively unlimited stream of pseudorandom double values, each value uniformly random from the interval [0.0, 1.0). Delegates implementation to the wrapped object. Specified by:
doubles
in interfaceRandomGenerator
 Returns:
 an effectively unlimited stream of pseudorandom double values, uniformly random from the interval [0.0, 1.0).

doubles
Returns an effectively unlimited stream of pseudorandom double values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound). Delegates implementation to the wrapped object. Specified by:
doubles
in interfaceRandomGenerator
 Parameters:
randomNumberOrigin
 The lower bound, inclusive (must be less than bound)randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 an effectively unlimited stream of pseudorandom double values, uniformly random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound, or if randomNumberOrigin is not finite. or if randomNumberBound is not finite.

doubles
Returns a stream of pseudorandom double values, each value uniformly random from the interval [0.0, 1.0). Delegates implementation to the wrapped object. Specified by:
doubles
in interfaceRandomGenerator
 Parameters:
streamSize
 The number of values in the stream. Returns:
 a stream of pseudorandom double values, uniformly random from the interval [0.0, 1.0).
 Throws:
IllegalArgumentException
 if streamSize is negative.

doubles
public final DoubleStream doubles(long streamSize, double randomNumberOrigin, double randomNumberBound) Returns a stream of pseudorandom double values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound). Delegates implementation to the wrapped object. Specified by:
doubles
in interfaceRandomGenerator
 Parameters:
streamSize
 The number of values in the stream.randomNumberOrigin
 The lower bound, inclusive (must be less than bound).randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 a stream of pseudorandom double values, uniformly random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound, or if streamSize is negative.

ints
Returns an effectively unlimited stream of pseudorandom int values. Delegates implementation to the wrapped object. Specified by:
ints
in interfaceRandomGenerator
 Returns:
 an effectively unlimited stream of pseudorandom int values.

ints
Returns a stream of pseudorandom int values. Delegates implementation to the wrapped object. Specified by:
ints
in interfaceRandomGenerator
 Parameters:
streamSize
 The number of values in the stream. Returns:
 a stream of pseudorandom int values.
 Throws:
IllegalArgumentException
 if streamSize is negative.

isDeprecated
public final boolean isDeprecated()Return true if the implementation of the RandomGenerator (algorithm) that is wrapped by this EnhancedRandomGenerator has been marked for deprecation. Delegates implementation to the wrapped object. Specified by:
isDeprecated
in interfaceRandomGenerator
 Returns:
 true if the implementation of the RandomGenerator (algorithm) that is wrapped by this EnhancedRandomGenerator has been marked for deprecation

longs
Returns an effectively unlimited stream of pseudorandom long values. Delegates implementation to the wrapped object. Specified by:
longs
in interfaceRandomGenerator
 Returns:
 an effectively unlimited stream of pseudorandom long values.

longs
Returns an effectively unlimited stream of pseudorandom long values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound). Delegates implementation to the wrapped object. Specified by:
longs
in interfaceRandomGenerator
 Parameters:
randomNumberOrigin
 The lower bound, inclusive (must be less than bound)randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 an effectively unlimited stream of pseudorandom long values, uniformly random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound

longs
Returns a stream of pseudorandom long values. Delegates implementation to the wrapped object. Specified by:
longs
in interfaceRandomGenerator
 Parameters:
streamSize
 The number of values in the stream. Returns:
 a stream of pseudorandom long values.
 Throws:
IllegalArgumentException
 if streamSize is negative.

longs
Returns a stream of pseudorandom long values, each value uniformly random from the interval [randomNumberOrigin, randomNumberBound). Delegates implementation to the wrapped object. Specified by:
longs
in interfaceRandomGenerator
 Parameters:
streamSize
 The number of values in the stream.randomNumberOrigin
 The lower bound, inclusive (must be less than bound).randomNumberBound
 Upper bound, exclusive, on range of random integers. Returns:
 a stream of pseudorandom long values, uniformly random from the interval [randomNumberOrigin, randomNumberBound).
 Throws:
IllegalArgumentException
 if the randomNumberOrigin is greater than or equal to randomNumberBound, or if streamSize is negative.

nextBoolean
public final boolean nextBoolean()Generates a pseudorandom boolean value. Delegates implementation to the wrapped object. Specified by:
nextBoolean
in interfaceRandomGenerator
 Returns:
 a pseudorandom boolean value

nextBytes
public final void nextBytes(byte[] bytes) Fills a usersupplied byte array with byte values generated pseudorandomly uniformly distributed in the interval [128, 127]. Delegates implementation to the wrapped object. Specified by:
nextBytes
in interfaceRandomGenerator
 Parameters:
bytes
 The byte array to fill with random bytes. Throws:
NullPointerException
 if bytes is null

nextDouble
public final double nextDouble()Generates a pseudorandom double value in the interval [0, 1). Delegates implementation to the wrapped object. Specified by:
nextDouble
in interfaceRandomGenerator
 Returns:
 a pseudorandom double in [0, 1).

nextDouble
public final double nextDouble(double bound) Generates a pseudorandom double value in the interval [0, bound). Delegates implementation to the wrapped object. Specified by:
nextDouble
in interfaceRandomGenerator
 Parameters:
bound
 The upper bound, exclusive. Must be positive and finite. Returns:
 a pseudorandom double in [0, bound).
 Throws:
IllegalArgumentException
 if bound is not finite or not positive.

nextDouble
public final double nextDouble(double origin, double bound) Generates a pseudorandom double value in the interval [origin, bound). Delegates implementation to the wrapped object. Specified by:
nextDouble
in interfaceRandomGenerator
 Parameters:
origin
 The lower bound, inclusive.bound
 The upper bound, exclusive. Returns:
 a pseudorandom double in [origin, bound).
 Throws:
IllegalArgumentException
 if origin is greater than or equal to bound, or if origin is not finite or if bound is not finite.

nextExponential
public final double nextExponential()Generates a nonnegative pseudorandom number from an exponential distribution with mean 1. Delegates implementation to the wrapped object. Specified by:
nextExponential
in interfaceRandomGenerator
 Returns:
 a nonnegative pseudorandom number from an exponential distribution

nextFloat
public final float nextFloat()Generates a pseudorandom float value in the interval [0, 1). Delegates implementation to the wrapped object. Specified by:
nextFloat
in interfaceRandomGenerator
 Returns:
 a pseudorandom float in [0, 1).

nextFloat
public final float nextFloat(float bound) Generates a pseudorandom float value in the interval [0, bound). Delegates implementation to the wrapped object. Specified by:
nextFloat
in interfaceRandomGenerator
 Parameters:
bound
 The upper bound, exclusive. Must be positive and finite. Returns:
 a pseudorandom float in [0, bound).
 Throws:
IllegalArgumentException
 if bound is not finite or not positive.

nextFloat
public final float nextFloat(float origin, float bound) Generates a pseudorandom float value in the interval [origin, bound). Delegates implementation to the wrapped object. Specified by:
nextFloat
in interfaceRandomGenerator
 Parameters:
origin
 The lower bound, inclusive.bound
 The upper bound, exclusive. Returns:
 a pseudorandom float in [origin, bound).
 Throws:
IllegalArgumentException
 if origin is greater than or equal to bound, or if origin is not finite or if bound is not finite.

nextInt
public final int nextInt()Generates a pseudorandom int value. Delegates implementation to the wrapped object. Specified by:
nextInt
in interfaceRandomGenerator
 Returns:
 a pseudorandom int

nextLong
public final long nextLong()Generates a pseudorandom long value. Delegates implementation to the wrapped object. Specified by:
nextLong
in interfaceRandomGenerator
 Returns:
 a pseudorandom long

nextLong
public final long nextLong(long bound) Generates a pseudorandom long value in the interval [0, bound). Delegates implementation to the wrapped object. Specified by:
nextLong
in interfaceRandomGenerator
 Parameters:
bound
 The upper bound, exclusive (must be positive). Returns:
 a pseudorandom long in [0, bound).
 Throws:
IllegalArgumentException
 if bound is not positive.

nextLong
public final long nextLong(long origin, long bound) Generates a pseudorandom long value in the interval [origin, bound). Delegates implementation to the wrapped object. Specified by:
nextLong
in interfaceRandomGenerator
 Parameters:
origin
 The lower bound, inclusive.bound
 The upper bound, exclusive. Returns:
 a pseudorandom long in [origin, bound).
 Throws:
IllegalArgumentException
 if origin is greater than or equal to bound.
