[pylucene-dev] Cutomizing Similarities

[Andi Vajda]

On Fri, 23 Feb 2007, Pranshu Sharma wrote:

> I have been trying to customize the similarity function in Lucene (the
> primary objective was to shut off the lengthNorm factor in Similarity
> Class). I was unsuccessful in it, then i got a couple of archived mails on
> this mailing lists. I got a fair idea, but I am still not so sure how to
> proceed in the PyLucene-2.0 version.

Similarity can be implemented in Python by creating a Python class that 
implements the Similarity methods (the native methods declared in [1]).
You can pass instances of this class to any Lucene API expecting a Similarity 
instance. PyLucene will wrap this instance with a Java instance of 
PythonSimilarity [1], the actual Similarity Java subclass visible to Lucene, 
but which calls into your Python implementation class.

For examples see:
   - test/test_Similarity.py
   - samples/LuceneInAction/lia/searching/ScoreTest.py

Andi..

[1] http://svn.osafoundation.org/pylucene/trunk/java/org/osafoundation/search/PythonSimilarity.java