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From Doug Cutting <cutt...@lucene.com>
Subject Re: Lucene Scoring Behavior
Date Wed, 17 Sep 2003 21:51:05 GMT
Terry Steichen wrote:
>   0.03125 = fieldNorm(field=pub_date, doc=90992)
>   1.0 = fieldNorm(field=pub_date, doc=90970)

It looks like the fieldNorm's are what differ, not the IDFs.  These are 
the product of the document and/or field boost, and 1/sqrt(numTerms) 
where numTerms is the number of terms in the "pub_date" field of the 
document.  Thus if each document is only assigned one date, and you 
didn't boost the field or the document when you indexed it, this should 
be 1.0.  But if the document has two dates, then this would be 
1/sqrt(2).  Or if you boosted this document pub_date field, then this 
will have whatever boost you provided.

So, did you boost anything when indexing?  Or could a single document 
have two or more different values for pub_date?  Either would explain this.

Doug


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