Package it.unimi.dsi.util

Class XorShift64StarRandomGenerator

  • All Implemented Interfaces:
    org.apache.commons.math3.random.RandomGenerator
    @Deprecated
public class XorShift64StarRandomGenerator
extends org.apache.commons.math3.random.AbstractRandomGenerator
    Deprecated.
    Use SplitMix64RandomGenerator instead.
    A fast, good-quality pseudorandom number generator that combines George Marsaglia's Xorshift generators (described in “Xorshift RNGs”, Journal of Statistical Software, 8:1−6, 2003) with a multiplication.

    • Method Summary

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

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

        clear, nextGaussian, setSeed, setSeed

    • Constructor Detail

      • XorShift64StarRandomGenerator

        public XorShift64StarRandomGenerator()
        Deprecated.
        Creates a new generator seeded using Util.randomSeed().

      • XorShift64StarRandomGenerator

        public XorShift64StarRandomGenerator​(long seed)
        Deprecated.
        Creates a new generator using a given seed.
        Parameters:
        seed - a nonzero seed for the generator (if zero, the generator will be seeded with Long.MIN_VALUE).

    • Method Detail

      • nextLong

        public long nextLong()
        Deprecated.
        Specified by:
        nextLong in interface org.apache.commons.math3.random.RandomGenerator
        Overrides:
        nextLong in class org.apache.commons.math3.random.AbstractRandomGenerator

      • nextInt

        public int nextInt()
        Deprecated.
        Specified by:
        nextInt in interface org.apache.commons.math3.random.RandomGenerator
        Overrides:
        nextInt in class org.apache.commons.math3.random.AbstractRandomGenerator

      • nextInt

        public int nextInt​(int n)
        Deprecated.
        Returns a pseudorandom, approximately uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.

        The hedge “approximately” is due to the fact that to be always faster than ThreadLocalRandom we return the upper 63 bits of nextLong() modulo n instead of using Random's fancy algorithm (which nextLong(long) uses though). This choice introduces a bias: the numbers from 0 to 263 mod n are slightly more likely than the other ones. In the worst case, “more likely” means 1.00000000023 times more likely, which is in practice undetectable. If for some reason you need truly uniform generation, just use nextLong(long).

        Specified by:
        nextInt in interface org.apache.commons.math3.random.RandomGenerator
        Overrides:
        nextInt in class org.apache.commons.math3.random.AbstractRandomGenerator
        Parameters:
        n - the positive bound on the random number to be returned.
        Returns:
        the next pseudorandom int value between 0 (inclusive) and n (exclusive).

      • nextLong

        public long nextLong​(long n)
        Deprecated.
        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()
        Deprecated.
        Specified by:
        nextDouble in interface org.apache.commons.math3.random.RandomGenerator
        Specified by:
        nextDouble in class org.apache.commons.math3.random.AbstractRandomGenerator

      • nextFloat

        public float nextFloat()
        Deprecated.
        Specified by:
        nextFloat in interface org.apache.commons.math3.random.RandomGenerator
        Overrides:
        nextFloat in class org.apache.commons.math3.random.AbstractRandomGenerator

      • nextBoolean

        public boolean nextBoolean()
        Deprecated.
        Specified by:
        nextBoolean in interface org.apache.commons.math3.random.RandomGenerator
        Overrides:
        nextBoolean in class org.apache.commons.math3.random.AbstractRandomGenerator

      • nextBytes

        public void nextBytes​(byte[] bytes)
        Deprecated.
        Specified by:
        nextBytes in interface org.apache.commons.math3.random.RandomGenerator
        Overrides:
        nextBytes in class org.apache.commons.math3.random.AbstractRandomGenerator

      • setSeed

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

        The seed will be passed through HashCommon.murmurHash3(long). In this way, if the user passes a small value we will avoid the short irregular transient associated with states with a very small number of bits set.

        Specified by:
        setSeed in interface org.apache.commons.math3.random.RandomGenerator
        Specified by:
        setSeed in class org.apache.commons.math3.random.AbstractRandomGenerator
        Parameters:
        seed - a nonzero seed for this generator (if zero, the generator will be seeded with Long.MIN_VALUE).

      • setState

        public void setState​(long state)
        Deprecated.
        Sets the state of this generator.
        Parameters:
        state - the new state for this generator (must be nonzero).