Class CMWC4096RNG

java.lang.Object
java.util.Random
org.uncommons.maths.random.CMWC4096RNG
All Implemented Interfaces:
Serializable, RandomGenerator, RepeatableRNG

public class CMWC4096RNG extends Random implements RepeatableRNG

A Java version of George Marsaglia's Complementary Multiply With Carry (CMWC) RNG. This is a very fast PRNG with an extremely long period (2^131104). It should be used in preference to the MersenneTwisterRNG when a very long period is required.

One potential drawback of this RNG is that it requires significantly more seed data than the other RNGs provided by Uncommons Maths. It requires just over 16 kilobytes, which may be a problem if your are obtaining seed data from a slow or limited entropy source. In contrast, the Mersenne Twister requires only 128 bits of seed data.

NOTE: Because instances of this class require 16-kilobyte seeds, it is not possible to seed this RNG using the Random.setSeed(long) method inherited from Random. Calls to this method will have no effect. Instead the seed must be set by a constructor.

Since:
1.2
See Also:
  • Field Details

    • SEED_SIZE_BYTES

      private static final int SEED_SIZE_BYTES
      See Also:
    • A

      private static final long A
      See Also:
    • seed

      private final byte[] seed
    • state

      private final int[] state
    • carry

      private int carry
    • index

      private int index
    • lock

      private final ReentrantLock lock
  • Constructor Details

    • CMWC4096RNG

      public CMWC4096RNG()
      Creates a new RNG and seeds it using the default seeding strategy.
    • CMWC4096RNG

      public CMWC4096RNG(SeedGenerator seedGenerator) throws SeedException
      Seed the RNG using the provided seed generation strategy.
      Parameters:
      seedGenerator - The seed generation strategy that will provide the seed value for this RNG.
      Throws:
      SeedException - If there is a problem generating a seed.
    • CMWC4096RNG

      public CMWC4096RNG(byte[] seed)
      Creates an RNG and seeds it with the specified seed data.
      Parameters:
      seed - The seed data used to initialise the RNG.
  • Method Details

    • getSeed

      public byte[] getSeed()
      Specified by:
      getSeed in interface RepeatableRNG
      Returns:
      The seed data used to initialise this pseudo-random number generator.
    • next

      protected int next(int bits)
      Overrides:
      next in class Random