Package org.hipparchus.random

Class Well19937a

java.lang.Object
org.hipparchus.random.AbstractWell
org.hipparchus.random.Well19937a
All Implemented Interfaces:
Serializable, RandomGenerator
public class Well19937a extends AbstractWell
This class implements the WELL19937a pseudo-random number generator from François Panneton, Pierre L'Ecuyer and Makoto Matsumoto.

This generator is described in a paper by François Panneton, Pierre L'Ecuyer and Makoto Matsumoto Improved Long-Period Generators Based on Linear Recurrences Modulo 2 ACM Transactions on Mathematical Software, 32, 1 (2006). The errata for the paper are in wellrng-errata.txt.

See Also:

  • Nested Class Summary

    Nested classes/interfaces inherited from class org.hipparchus.random.AbstractWell

    AbstractWell.IndexTable

  • Field Summary

    Fields inherited from class org.hipparchus.random.AbstractWell

    index, v

  • Constructor Summary

    Constructors
    Constructor
    Description
    Well19937a()
    Creates a new random number generator.
    Well19937a(int seed)
    Creates a new random number generator using a single int seed.
    Well19937a(int[] seed)
    Creates a new random number generator using an int array seed.
    Well19937a(long seed)
    Creates a new random number generator using a single long seed.

  • Method Summary

    Modifier and Type
    Method
    Description
    protected void
    clearCache()
    Clears the cache used by the default implementation of RandomGenerator.nextGaussian().
    boolean
    nextBoolean()
    Returns the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence.
    void
    nextBytes(byte[] bytes)
    Generates random bytes and places them into a user-supplied byte array.
    void
    nextBytes(byte[] bytes, int start, int len)
    Generates random bytes and places them into a user-supplied byte array.
    double
    nextDouble()
    Returns the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.
    float
    nextFloat()
    Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.
    double
    nextGaussian()
    Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
    int
    nextInt()
    Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence.
    int
    nextInt(int n)
    Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
    long
    nextLong()
    Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence.
    long
    nextLong(long n)
    Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
    void
    setSeed(int seed)
    Sets the seed of the underlying random number generator using an int seed.
    void
    setSeed(long seed)
    Sets the seed of the underlying random number generator using a long seed.
    String
    toString()

    Methods inherited from class org.hipparchus.random.AbstractWell

    setSeed

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Well19937a

      public Well19937a()
      Creates a new random number generator.

      The instance is initialized using the current time as the seed.

    • Well19937a

      public Well19937a(int seed)
      Creates a new random number generator using a single int seed.
      Parameters:
      seed - the initial seed (32 bits integer)

    • Well19937a

      public Well19937a(int[] seed)
      Creates a new random number generator using an int array seed.
      Parameters:
      seed - the initial seed (32 bits integers array), if null the seed of the generator will be related to the current time

    • Well19937a

      public Well19937a(long seed)
      Creates a new random number generator using a single long seed.
      Parameters:
      seed - the initial seed (64 bits integer)

  • Method Details

    • nextInt

      public int nextInt()
      Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence.

      All 232 possible int values should be produced with (approximately) equal probability.

      Specified by:
      nextInt in interface RandomGenerator
      Returns:
      the next pseudorandom, uniformly distributed int value from this random number generator's sequence

    • nextBoolean

      public boolean nextBoolean()
      Returns the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence.
      Returns:
      the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence

    • nextDouble

      public double nextDouble()
      Returns the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence.
      Returns:
      the next pseudorandom, uniformly distributed double value between 0.0 and 1.0 from this random number generator's sequence

    • nextFloat

      public float nextFloat()
      Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.
      Returns:
      the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence

    • nextLong

      public long nextLong()
      Returns the next pseudorandom, uniformly distributed long value from this random number generator's sequence. All 264 possible long values should be produced with (approximately) equal probability.
      Returns:
      the next pseudorandom, uniformly distributed long value from this random number generator's sequence

    • nextBytes

      public void nextBytes(byte[] bytes)
      Generates random bytes and places them into a user-supplied byte array. The number of random bytes produced is equal to the length of the byte array.
      Parameters:
      bytes - the non-null byte array in which to put the random bytes

    • nextBytes

      public void nextBytes(byte[] bytes, int start, int len)
      Generates random bytes and places them into a user-supplied byte array.
      Parameters:
      bytes - the non-null byte array in which to put the random bytes
      start - the starting index for inserting the generated bytes into the array
      len - the number of bytes to generate

    • setSeed

      public void setSeed(int seed)
      Sets the seed of the underlying random number generator using an int seed.

      Sequences of values generated starting with the same seeds should be identical.

      Specified by:
      setSeed in interface RandomGenerator
      Parameters:
      seed - the seed value

    • setSeed

      public void setSeed(long seed)
      Sets the seed of the underlying random number generator using a long seed.

      Sequences of values generated starting with the same seeds should be identical.

      Specified by:
      setSeed in interface RandomGenerator
      Parameters:
      seed - the seed value

    • nextInt

      public int nextInt(int n) throws IllegalArgumentException
      Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
      Specified by:
      nextInt in interface RandomGenerator
      Parameters:
      n - the bound on the random number to be returned. Must be positive.
      Returns:
      a pseudorandom, uniformly distributed int value between 0 (inclusive) and n (exclusive).
      Throws:
      IllegalArgumentException - if n is not positive.

    • nextLong

      public long nextLong(long n)
      Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.
      Specified by:
      nextLong in interface RandomGenerator
      Parameters:
      n - the bound on the random number to be returned. Must be positive.
      Returns:
      a pseudorandom, uniformly distributed int value between 0 (inclusive) and n (exclusive).

    • nextGaussian

      public double nextGaussian()
      Returns the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence.
      Specified by:
      nextGaussian in interface RandomGenerator
      Returns:
      the next pseudorandom, Gaussian ("normally") distributed double value with mean 0.0 and standard deviation 1.0 from this random number generator's sequence

    • clearCache

      protected void clearCache()
      Clears the cache used by the default implementation of RandomGenerator.nextGaussian().

    • toString

      public String toString()
      Overrides:
      toString in class Object