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https://issues.apache.org/jira/browse/RNG-89?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alex Herbert closed RNG-89.
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> Configurable SplitMix generator
> -------------------------------
>
> Key: RNG-89
> URL: https://issues.apache.org/jira/browse/RNG-89
> Project: Commons RNG
> Issue Type: New Feature
> Components: core
> Affects Versions: 1.3
> Reporter: Alex Herbert
> Assignee: Alex Herbert
> Priority: Minor
>
> The {{SplitMix64}} algorithm is based on a [Weyl
> sequence|[https://en.wikipedia.org/wiki/Weyl_sequence]]. The increment for
> the sequence is denoted K.
> The current implementation uses a fixed increment for the Weyl sequence based
> on the Golden ratio ((sqrt(5)-1) / 2). However any odd number in the range [0
> - 2^64] can be used to ensure a full period.
> The JDK SplittableRandom exploits this fact in the split() method which
> creates a new generator that has a different increment for the Weyl sequence.
> The javadoc states that the two outputs are very unlikely to overlap and have
> the same statistical properties.
> Note that the SplittableRandom adds a further condition that the bit sequence
> of the increment K is a random mix of 0s and 1s. If the number of transitions
> between 0 and 1 or vice versa is too low then the number of transitions is
> increased. This ensures the state of the Weyl sequence is updated across all
> the bits at each iteration.
> Create a new SplitMix64K implementation that uses an additional {{long}} to
> seed the increment for the Weyl sequence and test if this viable.
> Such a generator would expand the usefulness of the vary fast SplitMix64
> generator as the low likelihood of sequence overlap would make it applicable
> for use in parallel computations.
>
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