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  1. Lucene - Core
  2. LUCENE-2286

enable DefaultSimilarity.setDiscountOverlaps by default

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Details

    • Improvement
    • Status: Closed
    • Major
    • Resolution: Fixed
    • None
    • 3.1, 4.0-ALPHA
    • core/query/scoring
    • None
    • New

    Description

      I think we should enable setDiscountOverlaps in DefaultSimilarity by default.

      If you are using synonyms or commongrams or a number of other 0-posInc-term-injecting methods, these currently screw up your length normalization.
      These terms have a position increment of zero, so they shouldnt count towards the length of the document.

      I've done relevance tests with persian showing the difference is significant, and i think its a big trap to anyone using synonyms, etc: your relevance can actually get worse if you don't flip this boolean flag.

      Attachments

        1. LUCENE-2286.patch
          1 kB
          Robert Muir

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            rcmuir Robert Muir
            rcmuir Robert Muir
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            Dates

              Created:
              Updated:
              Resolved: