Details

    • Type: New Feature
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 3.6, 4.0-ALPHA
    • Fix Version/s: 4.1, 6.0
    • Component/s: modules/spellchecker
    • Labels:
      None
    • Lucene Fields:
      New

      Description

      Since we added shortest-path wFSA search in LUCENE-3714, and generified the comparator in LUCENE-3801,
      I think we should look at implementing suggesters that have more capabilities than just basic prefix matching.

      In particular I think the most flexible approach is to integrate with Analyzer at both build and query time,
      such that we build a wFST with:
      input: analyzed text such as ghost0christmas0past <-- byte 0 here is an optional token separator
      output: surface form such as "the ghost of christmas past"
      weight: the weight of the suggestion

      we make an FST with PairOutputs<weight,output>, but only do the shortest path operation on the weight side (like
      the test in LUCENE-3801), at the same time accumulating the output (surface form), which will be the actual suggestion.

      This allows a lot of flexibility:

      • Using even standardanalyzer means you can offer suggestions that ignore stopwords, e.g. if you type in "ghost of chr...",
        it will suggest "the ghost of christmas past"
      • we can add support for synonyms/wdf/etc at both index and query time (there are tradeoffs here, and this is not implemented!)
      • this is a basis for more complicated suggesters such as Japanese suggesters, where the analyzed form is in fact the reading,
        so we would add a TokenFilter that copies ReadingAttribute into term text to support that...
      • other general things like offering suggestions that are more "fuzzy" like using a plural stemmer or ignoring accents or whatever.

      According to my benchmarks, suggestions are still very fast with the prototype (e.g. ~ 100,000 QPS), and the FST size does not
      explode (its short of twice that of a regular wFST, but this is still far smaller than TST or JaSpell, etc).

        Attachments

        1. LUCENE-3842.patch
          118 kB
          Michael McCandless
        2. LUCENE-3842.patch
          117 kB
          Michael McCandless
        3. LUCENE-3842.patch
          116 kB
          Michael McCandless
        4. LUCENE-3842.patch
          46 kB
          Michael McCandless
        5. LUCENE-3842.patch
          22 kB
          Michael McCandless
        6. LUCENE-3842.patch
          25 kB
          Michael McCandless
        7. LUCENE-3842.patch
          17 kB
          Michael McCandless
        8. LUCENE-3842.patch
          20 kB
          Michael McCandless
        9. LUCENE-3842.patch
          72 kB
          Michael McCandless
        10. LUCENE-3842.patch
          74 kB
          Sudarshan Gaikaiwari
        11. LUCENE-3842.patch
          65 kB
          Robert Muir
        12. LUCENE-3842.patch
          64 kB
          Michael McCandless
        13. LUCENE-3842.patch
          58 kB
          Michael McCandless
        14. LUCENE-3842.patch
          53 kB
          Michael McCandless
        15. LUCENE-3842.patch
          34 kB
          Robert Muir
        16. LUCENE-3842.patch
          34 kB
          Robert Muir
        17. LUCENE-3842.patch
          44 kB
          Robert Muir
        18. LUCENE-3842-TokenStream_to_Automaton.patch
          17 kB
          Michael McCandless
        19. LUCENE-3842.patch
          26 kB
          Robert Muir

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              • Assignee:
                mikemccand Michael McCandless
                Reporter:
                rcmuir Robert Muir
              • Votes:
                2 Vote for this issue
                Watchers:
                6 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: