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https://issues.apache.org/jira/browse/LUCENE-5236?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13930217#comment-13930217
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Sebastiano Vigna commented on LUCENE-5236:
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Sorry guys—just happened to read at this thread. My 2€¢:
- Rank9/Select9 and full ranking structures, not rank/select-in-a-word
algorithms.
- I'm using Long.bitCount(), Long.numberOfTralilingZeros() etc. everywhere
since Jan 2013. Intrinsification is a bet, but it pays, and using them will
convince them IBM and others to intrinsify. If only Oracle would add
Long.clearLowestBitSet() ...
- The alternative algorithm for sideways addition (a.k.a. popcount) should be
called "broadword" or Wilkes–Wheeler–Gill.
- Selection gets better and better every day.
http://vigna.di.unimi.it/select.php tries to keep track of the improvement. The
current code in it.unimi.dsi.bits.Fast is the best I'm aware of.
Ciao!
> Use broadword bit selection in EliasFanoDecoder
> -----------------------------------------------
>
> Key: LUCENE-5236
> URL: https://issues.apache.org/jira/browse/LUCENE-5236
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Paul Elschot
> Assignee: Adrien Grand
> Priority: Minor
> Fix For: 4.6
>
> Attachments: LUCENE-5236.patch, LUCENE-5236.patch, LUCENE-5236.patch,
> LUCENE-5236.patch, TestDocIdSetBenchmark.java
>
>
> Try and speed up decoding
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