Package nl.tudelft.simulation.jstats.streams

Class RandomNumberGenerator

java.lang.Object
nl.tudelft.simulation.jstats.streams.RandomNumberGenerator
All Implemented Interfaces:
Serializable, StreamInterface
Direct Known Subclasses:
DX120Generator, MersenneTwister
public abstract class RandomNumberGenerator extends Object implements StreamInterface
The RandomNumberGenerator class provides an abstract basis for all pseudo random number generators.

Copyright (c) 2002-2024 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information https://simulation.tudelft.nl. The DSOL project is distributed under a three-clause BSD-style license, which can be found at https://https://simulation.tudelft.nl/dsol/docs/latest/license.html.

Author:
Alexander Verbraeck, Peter Jacobs
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected long
    seed
    The seed of the generator.

  • Constructor Summary

    Constructors
    Constructor
    Description
    RandomNumberGenerator()
    Construct a new RandomNumberGenerator.
    RandomNumberGenerator(long seed)
    Construct a new RandomNumberGenerator.

  • Method Summary

    Modifier and Type
    Method
    Description
    long
    getOriginalSeed()
    Return the original seed of the generator with which it has been first initialized.
    long
    getSeed()
    Return the seed of the generator.
    protected abstract long
    next(int bits)
    returns the next value in the stream.
    boolean
    nextBoolean()
    Return the next pseudo-random, uniformly distributed boolean value.
    double
    nextDouble()
    Return a pseudo-random number from the stream over the interval (0,1) using this stream, after advancing its state by one step.
    float
    nextFloat()
    Return a pseudo-random number from the stream over the interval (0,1) using this stream, after advancing its state by one step.
    int
    nextInt()
    Return a pseudo-random number from the stream over using this stream, after advancing its state by one step.
    int
    nextInt(int i, int j)
    Return pseudo-random number from the stream between the integers i (inclusive) and j (inclusive).
    long
    nextLong()
    Return a pseudo-random number from the stream over using this stream, after advancing its state by one step.
    void
    reset()
    Reset the stream to use the original seed with which it was initialized.
    void
    restoreState(byte[] state)
    Restore the state to an earlier saved state object.
    byte[]
    saveState()
    Save the state of the RNG into an object, e.g.
    abstract void
    setSeed(long seed)
    Set the seed of the generator.
    String
    toString()

    Methods inherited from class java.lang.Object

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

  • Field Details

    • seed

      protected long seed
      The seed of the generator.

  • Constructor Details

    • RandomNumberGenerator

      public RandomNumberGenerator()
      Construct a new RandomNumberGenerator. The seed value used in the rng is set to System.currentTimeMillis();

    • RandomNumberGenerator

      public RandomNumberGenerator(long seed)
      Construct a new RandomNumberGenerator.
      Parameters:
      seed - long; the seed of the generator.

  • Method Details

    • reset

      public void reset()
      Reset the stream to use the original seed with which it was initialized.
      Specified by:
      reset in interface StreamInterface

    • next

      protected abstract long next(int bits)
      returns the next value in the stream.
      Parameters:
      bits - int; the number of bits used
      Returns:
      the next value.

    • nextBoolean

      public boolean nextBoolean()
      Return the next pseudo-random, uniformly distributed boolean value.
      Specified by:
      nextBoolean in interface StreamInterface
      Returns:
      boolean; a pseudo-random boolean with 50/50 chance for true or false

    • nextDouble

      public double nextDouble()
      Return a pseudo-random number from the stream over the interval (0,1) using this stream, after advancing its state by one step.
      Specified by:
      nextDouble in interface StreamInterface
      Returns:
      double; the pseudo-random number

    • nextFloat

      public float nextFloat()
      Return a pseudo-random number from the stream over the interval (0,1) using this stream, after advancing its state by one step.
      Specified by:
      nextFloat in interface StreamInterface
      Returns:
      float; the pseudo-random number

    • nextInt

      public int nextInt()
      Return a pseudo-random number from the stream over using this stream, after advancing its state by one step.
      Specified by:
      nextInt in interface StreamInterface
      Returns:
      int; the pseudo-random number

    • nextInt

      public int nextInt(int i, int j)
      Return pseudo-random number from the stream between the integers i (inclusive) and j (inclusive).
      Specified by:
      nextInt in interface StreamInterface
      Parameters:
      i - int; the minimal value
      j - int; the maximum value
      Returns:
      int; a value between i and j

    • nextLong

      public long nextLong()
      Return a pseudo-random number from the stream over using this stream, after advancing its state by one step.
      Specified by:
      nextLong in interface StreamInterface
      Returns:
      long; the pseudo-random number

    • setSeed

      public abstract void setSeed(long seed)
      Set the seed of the generator.
      Specified by:
      setSeed in interface StreamInterface
      Parameters:
      seed - long; the new seed

    • getSeed

      public long getSeed()
      Return the seed of the generator.
      Specified by:
      getSeed in interface StreamInterface
      Returns:
      long; the seed

    • getOriginalSeed

      public long getOriginalSeed()
      Return the original seed of the generator with which it has been first initialized.
      Specified by:
      getOriginalSeed in interface StreamInterface
      Returns:
      long; the original seed of the generator when it was first initialized

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • saveState

      public byte[] saveState() throws StreamException
      Save the state of the RNG into an object, e.g. to roll it back to this state.
      Specified by:
      saveState in interface StreamInterface
      Returns:
      the state as an object specific to the RNG.
      Throws:
      StreamException - when getting the state fails.

    • restoreState

      public void restoreState(byte[] state) throws StreamException
      Restore the state to an earlier saved state object.
      Specified by:
      restoreState in interface StreamInterface
      Parameters:
      state - Object; the earlier saved state to which the RNG rolls back.
      Throws:
      StreamException - when resetting the state fails.