it.unimi.dsi.util

Class SplitMix64RandomGenerator

java.lang.Object

org.apache.commons.math3.random.AbstractRandomGenerator

it.unimi.dsi.util.SplitMix64RandomGenerator

All Implemented Interfaces:

RandomGenerator

public class SplitMix64RandomGenerator
extends AbstractRandomGenerator

A fast, top-quality, non-splittable version of the SplitMix pseudorandom number generator used by Java 8's SplittableRandom. Due to the fixed increment constant and to different strategies in generating finite ranges, the methods of this generator are usually faster than those of SplittableRandom.

Note that this generator has a relatively short period (2⁶⁴) so it should not be used to generate very long sequences (the rule of thumb to have a period greater than the square of the length of the sequence you want to generate).

See Also:

it.unimi.dsi.util, RandomGenerator, SplitMix64Random

Constructor Summary

Constructors

Constructor and Description
SplitMix64RandomGenerator() Creates a new generator seeded using Util.randomSeed().
SplitMix64RandomGenerator(long seed) Creates a new generator using a given seed.

Method Summary

Modifier and Type	Method and Description
static void	main(String[] arg)
boolean	nextBoolean()
void	nextBytes(byte[] bytes)
double	nextDouble()
float	nextFloat()
int	nextInt()
int	nextInt(int n)
long	nextLong()
long	nextLong(long n) Returns a pseudorandom uniformly distributed long value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
void	setSeed(long seed) Sets the seed of this generator.
void	setState(long state) Sets the state of this generator.

Methods inherited from class org.apache.commons.math3.random.AbstractRandomGenerator

clear, nextGaussian, setSeed, setSeed

Methods inherited from class java.lang.Object

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

Constructor Detail

SplitMix64RandomGenerator

public SplitMix64RandomGenerator()

Creates a new generator seeded using Util.randomSeed().

SplitMix64RandomGenerator

public SplitMix64RandomGenerator(long seed)

Creates a new generator using a given seed.

Parameters:

seed - a nonzero seed for the generator (if zero, the generator will be seeded with -1).

Method Detail

nextLong

public long nextLong()

Specified by:

nextLong in interface RandomGenerator

Overrides:

nextLong in class AbstractRandomGenerator

nextInt

public int nextInt()

Specified by:

nextInt in interface RandomGenerator

Overrides:

nextInt in class AbstractRandomGenerator

nextInt

public int nextInt(int n)

Specified by:

nextInt in interface RandomGenerator

Overrides:

nextInt in class AbstractRandomGenerator

nextLong

public long nextLong(long n)

Returns a pseudorandom uniformly distributed long value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence. The algorithm used to generate the value guarantees that the result is uniform, provided that the sequence of 64-bit values produced by this generator is.

Parameters:

n - the positive bound on the random number to be returned.

Returns:

the next pseudorandom long value between 0 (inclusive) and n (exclusive).

nextDouble

public double nextDouble()

Specified by:

nextDouble in interface RandomGenerator

Specified by:

nextDouble in class AbstractRandomGenerator

nextFloat

public float nextFloat()

Specified by:

nextFloat in interface RandomGenerator

Overrides:

nextFloat in class AbstractRandomGenerator

nextBoolean

public boolean nextBoolean()

Specified by:

nextBoolean in interface RandomGenerator

Overrides:

nextBoolean in class AbstractRandomGenerator

nextBytes

public void nextBytes(byte[] bytes)

Specified by:

nextBytes in interface RandomGenerator

Overrides:

nextBytes in class AbstractRandomGenerator

setSeed

public void setSeed(long seed)

Sets the seed of this generator.

The seed will be passed through HashCommon.murmurHash3(long).

Specified by:

setSeed in interface RandomGenerator

Specified by:

setSeed in class AbstractRandomGenerator

Parameters:

seed - a seed for this generator.

setState

public void setState(long state)

Sets the state of this generator.

Parameters:

state - the new state for this generator (must be nonzero).

main

public static void main(String[] arg)