Class XoRoShiRo128Plus

java.lang.Object
org.apache.commons.rng.core.BaseProvider
org.apache.commons.rng.core.source64.LongProvider
org.apache.commons.rng.core.source64.XoRoShiRo128Plus
All Implemented Interfaces:
RandomLongSource, JumpableUniformRandomProvider, LongJumpableUniformRandomProvider, RestorableUniformRandomProvider, UniformRandomProvider
public class XoRoShiRo128Plus extends LongProvider
A fast 64-bit generator suitable for double generation. This is slightly faster than the all-purpose generator XoRoShiRo128StarStar.

This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 128 bits and the period is 2128-1. Speed is expected to be similar to XoShiRo256Plus.

Since:
1.3
See Also:

  • Field Details

    • state0

      protected long state0
      State 0 of the generator.

    • state1

      protected long state1
      State 1 of the generator.

  • Constructor Details

    • XoRoShiRo128Plus

      public XoRoShiRo128Plus(long[] seed)
      Creates a new instance.
      Parameters:
      seed - Initial seed. If the length is larger than 2, only the first 2 elements will be used; if smaller, the remaining elements will be automatically set. A seed containing all zeros will create a non-functional generator.

    • XoRoShiRo128Plus

      public XoRoShiRo128Plus(long seed0, long seed1)
      Creates a new instance using a 2 element seed. A seed containing all zeros will create a non-functional generator.
      Parameters:
      seed0 - Initial seed element 0.
      seed1 - Initial seed element 1.

    • XoRoShiRo128Plus

      protected XoRoShiRo128Plus(XoRoShiRo128Plus source)
      Creates a copy instance.
      Parameters:
      source - Source to copy.

  • Method Details

    • nextOutput

      protected long nextOutput()
      Use the current state to compute the next output from the generator. The output function shall vary with respect to different generators. This method is called from RandomLongSource.next() before the current state is updated.
      Returns:
      the next output

    • copy

      protected XoRoShiRo128Plus copy()
      Create a copy.
      Returns:
      the copy

    • 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:

    • 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 264 calls to nextLong(). It can provide up to 264 non-overlapping subsequences.

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

    • longJump

      public JumpableUniformRandomProvider longJump()
      Creates a copy of the JumpableUniformRandomProvider 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 long 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 long jump for use in parallel computations.

      The returned copy may be jumped m / n times before overlap with the current instance where m is the long jump length and n is the jump length of the JumpableUniformRandomProvider.jump() method.

      The jump size is the equivalent of 296 calls to nextLong(). It can provide up to 232 non-overlapping subsequences of length 296; each subsequence can provide up to 232 non-overlapping subsequences of length 264 using the JumpableUniformRandomProvider.jump() method.

      Specified by:
      longJump in interface LongJumpableUniformRandomProvider
      Returns:
      A copy of the current state.