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From "Christian Moen (Created) (JIRA)" <>
Subject [jira] [Created] (LUCENE-3935) Optimize Kuromoji inner loop - rewrite ConnectionCosts.get() method
Date Thu, 29 Mar 2012 10:04:28 GMT
Optimize Kuromoji inner loop - rewrite ConnectionCosts.get() method

                 Key: LUCENE-3935
             Project: Lucene - Java
          Issue Type: Improvement
          Components: modules/analysis
    Affects Versions: 3.6, 4.0
            Reporter: Christian Moen

I've been profiling Kuromoji, and not very surprisingly, method {{ConnectionCosts.get(int
forwardId, int backwardId)}} that looks up costs in the Viterbi is called many many times
and contributes to more processing time than I had expected.

This method is currently backed by a {{short[][]}}.  This data stored here structure is a
two dimensional array with both dimensions being fixed with 1316 elements in each dimension.
 (The data is {{matrix.def}} in MeCab-IPADIC.)

We can rewrite this to use a single one-dimensional array instead, and we will at least save
one bounds check, a pointer reference, and we should also get much better cache utilization
since this structure is likely to be in very local CPU cache.

I think this will be a nice optimization.  Working on it... 

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