Package it.unimi.dsi.util

Class SplitMix64Random

java.lang.Object
java.util.Random
it.unimi.dsi.util.SplitMix64Random
All Implemented Interfaces:
Serializable, java.util.random.RandomGenerator
public class SplitMix64Random extends Random
A fast, high-quality, non-splittable version of the SplitMix pseudorandom number generator used by 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:

  • Nested Class Summary

    Nested classes/interfaces inherited from interface java.util.random.RandomGenerator

    java.util.random.RandomGenerator.ArbitrarilyJumpableGenerator, java.util.random.RandomGenerator.JumpableGenerator, java.util.random.RandomGenerator.LeapableGenerator, java.util.random.RandomGenerator.SplittableGenerator, java.util.random.RandomGenerator.StreamableGenerator

  • Constructor Summary

    Constructors
    Constructor
    Description
    SplitMix64Random()
    Creates a new generator seeded using Util.randomSeed().
    SplitMix64Random(long seed)
    Creates a new generator using a given seed.

  • Method Summary

    Modifier and Type
    Method
    Description
    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 java.util.Random

    doubles, doubles, doubles, doubles, from, ints, ints, ints, ints, longs, longs, longs, longs, next, nextGaussian

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface java.util.random.RandomGenerator

    isDeprecated, nextDouble, nextDouble, nextExponential, nextFloat, nextFloat, nextGaussian, nextInt, nextLong

  • Constructor Details

    • SplitMix64Random

      public SplitMix64Random()
      Creates a new generator seeded using Util.randomSeed().

    • SplitMix64Random

      public SplitMix64Random(long seed)
      Creates a new generator using a given seed.
      Parameters:
      seed - a seed for the generator.

  • Method Details

    • nextLong

      public long nextLong()
      Specified by:
      nextLong in interface java.util.random.RandomGenerator
      Overrides:
      nextLong in class Random

    • nextInt

      public int nextInt()
      Specified by:
      nextInt in interface java.util.random.RandomGenerator
      Overrides:
      nextInt in class Random

    • nextInt

      public int nextInt(int n)
      Specified by:
      nextInt in interface java.util.random.RandomGenerator
      Overrides:
      nextInt in class Random

    • 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 java.util.random.RandomGenerator
      Overrides:
      nextDouble in class Random

    • nextFloat

      public float nextFloat()
      Specified by:
      nextFloat in interface java.util.random.RandomGenerator
      Overrides:
      nextFloat in class Random

    • nextBoolean

      public boolean nextBoolean()
      Specified by:
      nextBoolean in interface java.util.random.RandomGenerator
      Overrides:
      nextBoolean in class Random

    • nextBytes

      public void nextBytes(byte[] bytes)
      Specified by:
      nextBytes in interface java.util.random.RandomGenerator
      Overrides:
      nextBytes in class Random

    • setSeed

      public void setSeed(long seed)
      Sets the seed of this generator.

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

      Overrides:
      setSeed in class Random
      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).