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https://issues.apache.org/jira/browse/RNG-168?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alex Herbert resolved RNG-168.
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Fix Version/s: 1.5
Resolution: Implemented
Added in commit:
d5e653c43ec68d55e23ad8ad5a3cc755567ffdb9
> LXM family of random number generators
> --------------------------------------
>
> Key: RNG-168
> URL: https://issues.apache.org/jira/browse/RNG-168
> Project: Commons RNG
> Issue Type: New Feature
> Components: core, simple
> Affects Versions: 1.4
> Reporter: Alex Herbert
> Priority: Major
> Fix For: 1.5
>
> Attachments: lcg128carry.jpg
>
> Time Spent: 1h
> Remaining Estimate: 0h
>
> JDK 17 updates the random number support and adds a LXM family of random
> number generators. The generators are described in the following paper:
> {noformat}
> Steele and Vigna (2021)
> LXM: better splittable pseudorandom number generators (and almost as fast).
> Proceedings of the ACM on Programming Languages, Volume 5, Article 148, pp
> 1–31
> {noformat}
> [https://doi.org/10.1145/3485525]
> The generators mix the output of a linear conguential generator (LCG; L) and
> a Xor-based generator (XBG; X). The paper provides code examples for
> L64X128MixRandom and L128X256MixRandom from JDK 17.
> Details of the combinations of the linear conguential generator (LCG; L) and
> Xor-based generators (XBG; X) used in JDK 17 are provided in the package
> javadoc:
> [JDK 17
> java.util.random|https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/random/package-summary.html]
> The current commons RNG library implements all the XBG generators. Adding
> support for these generators should add a LCG to combine with the output of
> the XBG via the specified mix function.
> All constants are supplied in the JDK 17 package javadoc to allow
> implementation with the exception of the mixing functions lea32 and lea64.
> The lea64 function is provided in the paper above but the reference origin is
> personal communication with Doug Lea (2013). Thus the lea32 mix function for
> 32-bit generators is not published. Obtaining from the JDK source code is
> possible but would be subject to the Java licence.
> The generators support jump functionality and are suitable for streaming in
> large numbers for parallel applications (the paper tests up to 2^24
> generators) by using a different additive constant for the LCG for each
> generator to ensure no sequence overlap. Creating a new additive constant is
> significantly faster than performing a jump operation.
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