Class XorShift1024Star

All Implemented Interfaces:
RandomLongSource, JumpableUniformRandomProvider, RestorableUniformRandomProvider, UniformRandomProvider
Direct Known Subclasses:
XorShift1024StarPhi

public class XorShift1024Star extends LongProvider implements JumpableUniformRandomProvider
A fast RNG implementing the XorShift1024* algorithm.

Note: This has been superseded by XorShift1024StarPhi. The sequences emitted by both generators are correlated.

Since:
1.0
See Also:
  • Field Details

    • SEED_SIZE

      private static final int SEED_SIZE
      Size of the state vector.
      See Also:
    • JUMP_COEFFICIENTS

      private static final long[] JUMP_COEFFICIENTS
      The coefficients for the jump function.
    • state

      private final long[] state
      State.
    • multiplier

      private final long multiplier
      The multiplier for the XorShift1024 algorithm.
    • index

      private int index
      Index in "state" array.
  • Constructor Details

    • XorShift1024Star

      public XorShift1024Star(long[] seed)
      Creates a new instance.
      Parameters:
      seed - Initial seed. If the length is larger than 16, only the first 16 elements will be used; if smaller, the remaining elements will be automatically set. A seed containing all zeros will create a non-functional generator.
    • XorShift1024Star

      protected XorShift1024Star(long[] seed, long multiplier)
      Creates a new instance.
      Parameters:
      seed - Initial seed. If the length is larger than 16, only the first 16 elements will be used; if smaller, the remaining elements will be automatically set. A seed containing all zeros will create a non-functional generator.
      multiplier - The multiplier for the XorShift1024 algorithm.
      Since:
      1.3
    • XorShift1024Star

      protected XorShift1024Star(XorShift1024Star source)
      Creates a copy instance.
      Parameters:
      source - Source to copy.
      Since:
      1.3
  • Method Details

    • getStateInternal

      protected byte[] getStateInternal()
      Creates a snapshot of the RNG state.
      Overrides:
      getStateInternal in class LongProvider
      Returns:
      the internal state.
    • setStateInternal

      protected void setStateInternal(byte[] s)
      Resets the RNG to the given state.
      Overrides:
      setStateInternal in class LongProvider
      Parameters:
      s - State (previously obtained by a call to BaseProvider.getStateInternal()).
      See Also:
    • setSeedInternal

      private void setSeedInternal(long[] seed)
      Seeds the RNG.
      Parameters:
      seed - Seed.
    • next

      public long next()
      Return the next random value.
      Specified by:
      next in interface RandomLongSource
      Returns:
      the next random value.
    • jump

      public UniformRandomProvider jump()
      Creates a copy of the UniformRandomProvider and then advances the state of the current instance. The copy is returned.

      The current state will be advanced in a single operation by the equivalent of a number of sequential calls to a method that updates the state of the provider. The size of the jump is implementation dependent.

      Repeat invocations of this method will create a series of generators that are uniformly spaced at intervals of the output sequence. Each generator provides non-overlapping output for the length of the jump for use in parallel computations.

      The jump size is the equivalent of 2512 calls to nextLong(). It can provide up to 2512 non-overlapping subsequences.

      Specified by:
      jump in interface JumpableUniformRandomProvider
      Returns:
      A copy of the current state.
      Since:
      1.3
    • copy

      protected XorShift1024Star copy()
      Create a copy.
      Returns:
      the copy
      Since:
      1.3
    • performJump

      private void performJump()
      Perform the jump to advance the generator state. Resets the cached state of the generator.