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From Em <mailformailingli...@yahoo.de>
Subject Re: custom scoring
Date Thu, 16 Feb 2012 15:02:32 GMT
Hello carlos,

could you show us how your Solr-call looks like?

Regards,
Em

Am 16.02.2012 14:34, schrieb Carlos Gonzalez-Cadenas:
> Hello all:
> 
> We'd like to score the matching documents using a combination of SOLR's IR
> score with another application-specific score that we store within the
> documents themselves (i.e. a float field containing the app-specific
> score). In particular, we'd like to calculate the final score doing some
> operations with both numbers (i.e product, sqrt, ...)
> 
> According to what we know, there are two ways to do this in SOLR:
> 
> A) Sort by function [1]: We've tested an expression like
> "sort=product(score, query_score)" in the SOLR query, where score is the
> common SOLR IR score and query_score is our own precalculated score, but it
> seems that SOLR can only do this with stored/indexed fields (and obviously
> "score" is not stored/indexed).
> 
> B) Function queries: We've used _val_ and function queries like max, sqrt
> and query, and we've obtained the desired results from a functional point
> of view. However, our index is quite large (400M documents) and the
> performance degrades heavily, given that function queries are AFAIK
> matching all the documents.
> 
> I have two questions:
> 
> 1) Apart from the two options I mentioned, is there any other (simple) way
> to achieve this that we're not aware of?
> 
> 2) If we have to choose the function queries path, would it be very
> difficult to modify the actual implementation so that it doesn't match all
> the documents, that is, to pass a query so that it only operates over the
> documents matching the query?. Looking at the FunctionQuery.java source
> code, there's a comment that says "// instead of matching all docs, we
> could also embed a query. the score could either ignore the subscore, or
> boost it", which is giving us some hope that maybe it's possible and even
> desirable to go in this direction. If you can give us some directions about
> how to go about this, we may be able to do the actual implementation.
> 
> BTW, we're using Lucene/SOLR trunk.
> 
> Thanks a lot for your help.
> Carlos
> 
> [1]: http://wiki.apache.org/solr/FunctionQuery#Sort_By_Function
> 

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