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From "Cedric Ho" <cedric...@gmail.com>
Subject Re: Can I do boosting based on term postions?
Date Fri, 03 Aug 2007 03:38:50 GMT
Hi Paul,

Isn't SpanFirstQuery only match those with position less than a
certain end position?

I am rather looking for a query that would score a document higher for
terms appear near the start but not totally discard those with terms
appear near the end.

Regards,
Cedric

On 8/2/07, Paul Elschot <paul.elschot@xs4all.nl> wrote:
> Cedric,
>
> SpanFirstQuery could be a solution without payloads.
> You may want to give it your own Similarity.sloppyFreq() .
>
> Regards,
> Paul Elschot
>
> On Thursday 02 August 2007 04:07, Cedric Ho wrote:
> > Thanks for the quick response =)
> >
> > On 8/1/07, Shailendra Sharma <shailendra.sharma@gmail.com> wrote:
> > > Yes, it is easily doable through "Payload" facility. During indexing
> process
> > > (mainly tokenization), you need to push this extra information in each
> > > token. And then you can use BoostingTermQuery for using Payload value to
> > > include Payload in the score. You also need to implement Similarity for
> this
> > > (mainly scorePayload method).
> >
> > If I store, say a custom boost factor as Payload, does it means that I
> > will store one more byte per term per document in the index file? So
> > the index file would be much larger?
> >
> > >
> > > Other way can be to extend SpanTermQuery, this already calculates the
> > > position of match. You just need to do something to use this position
> value
> > > in the score calculation.
> >
> > I see that SpanTermQuery takes a TermPositions from the indexReader
> > and I can get the term position from there. However I am not sure how
> > to incorporate it into the score calculation. Would you mind give a
> > little more detail on this?
> >
> > >
> > > One possible advantage of SpanTermQuery approach is that you can play
> > > around, without re-creating indices everytime.
> > >
> > > Thanks,
> > > Shailendra Sharma,
> > > CTO, Ver se' Innovation Pvt. Ltd.
> > > Bangalore, India
> > >
> > > On 8/1/07, Cedric Ho <cedric.ho@gmail.com> wrote:
> > > >
> > > > Hi all,
> > > >
> > > > I was wondering if it is possible to do boosting by search terms'
> > > > position in the document.
> > > >
> > > > for example:
> > > > search terms appear in the first 100 words, or first 10% words, or in
> > > > first two paragraphs would be given higher score.
> > > >
> > > > Is it achievable through using the new Payload function in lucene 2.2?
> > > > Or are there any easier ways to achieve these ?
> > > >
> > > >
> > > > Regards,
> > > > Cedric
> > > >
> > > > ---------------------------------------------------------------------
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> > > > For additional commands, e-mail: java-user-help@lucene.apache.org
> > > >
> > > >
> > >
> >
> > Thanks,
> > Cedric
> >
> > ---------------------------------------------------------------------
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> >
> >
> >
>
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