You are viewing a plain text version of this content. The canonical link for it is here.

Posted to java-user@lucene.apache.org by Grant Ingersoll <gs...@syr.edu> on 2004/02/05 16:22:29 UTC

Using Explain and fieldNorm

Hi,

Was wondering what the fieldNorm section means when using the Explain functionality?  How does this relate to the scoring algorithm given in the Similarity javadocs?

Thanks,
Grant


---------------------------------------------------------------------
To unsubscribe, e-mail: lucene-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: lucene-user-help@jakarta.apache.org

Re: Using Explain and fieldNorm

Posted by Doug Cutting <cu...@apache.org>.

Using the terminology in

 
http://jakarta.apache.org/lucene/docs/api/org/apache/lucene/search/Similarity.html

fieldNorm is defined as

   getBoost(t.field in d) * lengthNorm(t.field in d)

These two values are multipled into a single value at index time, and it 
is unfortunately impossible to separate them at search time, when 
explanations are produced.

If you never apply boosts, fieldNorm() is just lengthNorm().  If you 
apply boosts, then it is these two factors combined.

Doug

Grant Ingersoll wrote:
> Hi,
> 
> Was wondering what the fieldNorm section means when using the Explain functionality?  How does this relate to the scoring algorithm given in the Similarity javadocs?
> 
> Thanks,
> Grant
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: lucene-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: lucene-user-help@jakarta.apache.org
> 


---------------------------------------------------------------------
To unsubscribe, e-mail: lucene-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: lucene-user-help@jakarta.apache.org