lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Peter Keegan <peterlkee...@gmail.com>
Subject Re: queryNorm affect on score
Date Mon, 02 Mar 2009 01:57:26 GMT
As suggested, I added a query-time boost of 0.0f to the 'literals' field
(with index-time boost still there) and I did get the same scores for both
queries :)  (there is a subtlety between index-time and query-time boosting
that I missed.)

I also tried disabling the coord factor, but that had no affect on the
score, when combined with the above. This seems ok in this example since the
the matching terms had boost = 0.

Thanks Yonik,
Peter



On Sat, Feb 28, 2009 at 6:02 PM, Yonik Seeley <yonik@lucidimagination.com>wrote:

> On Sat, Feb 28, 2009 at 3:02 PM, Peter Keegan <peterlkeegan@gmail.com>
> wrote:
> >> in situations where you  deal with simple query types, and matching
> query
> > structures, the queryNorm
> >> *can* be used to make scores semi-comparable.
> >
> > Hmm. My example used matching query structures. The only difference was a
> > single term in a field with zero weight that didn't exist in the matching
> > document. But one score was 3X the other.
>
> But the zero boost was an index-time boost, and the queryNorm takes
> into account query-time boosts and idfs.  You might get closer to what
> you expect with a query time boost of 0.0f
>
> The other thing affecting the score is the coord factor - the fact
> that fewer of the optional terms matched (1/2) lowers the score.  The
> coordination factor can be disabled on any BooleanQuery.
>
> If you do both of the above, I *think* you would get the same scores
> for this specific example.
>
> -Yonik
> http://www.lucidimagination.com
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> For additional commands, e-mail: java-user-help@lucene.apache.org
>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message