You are viewing a plain text version of this content. The canonical link for it is here.

Posted to issues@lucene.apache.org by "Bruno Roustant (Jira)" <ji...@apache.org> on 2021/11/17 10:54:00 UTC

[jira] [Resolved] (LUCENE-10225) Improve IntroSelector with 3-way partitioning

     [ https://issues.apache.org/jira/browse/LUCENE-10225?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Bruno Roustant resolved LUCENE-10225.
-------------------------------------
    Fix Version/s: 9.1
       Resolution: Fixed

Thanks Dawid and Adrien!

> Improve IntroSelector with 3-way partitioning
> ---------------------------------------------
>
>                 Key: LUCENE-10225
>                 URL: https://issues.apache.org/jira/browse/LUCENE-10225
>             Project: Lucene - Core
>          Issue Type: Improvement
>            Reporter: Bruno Roustant
>            Priority: Major
>             Fix For: 9.1
>
>          Time Spent: 3h 20m
>  Remaining Estimate: 0h
>
> The same way we improved IntroSorter, we can improve IntroSelector with Bentley-McIlroy 3-way partitioning. The gain in performance is roughly the same.
> With this new approach, we always use medians-of-medians (Tukey's Ninther), so there is no real gain to fallback to a slower medians-of-medians technique as an introspective protection (like the existing implementation does). Instead we can simply shuffle the sub-range if we exceed the recursive max depth (this does not change the speed as this intro-protective mechanism almost never happens - maybe only in adversarial cases).



--
This message was sent by Atlassian Jira
(v8.20.1#820001)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@lucene.apache.org
For additional commands, e-mail: issues-help@lucene.apache.org