Re: score and frequency

[Phil brunet]

Hi to all.
Maybe the term frequency is not the only parameter you need to override to 
"customize" the score attributed by Lucene.

Maybe you should consider the normalisation factor, the idf and the coord 
factor ?

Philippe
From: "Niraj Alok" <[EMAIL PROTECTED]>
Reply-To: "Lucene Users List" <[EMAIL PROTECTED]>
To: "Lucene Users List" <[EMAIL PROTECTED]>
Subject: Re: score and frequency
Date: Fri, 4 Jun 2004 15:13:32 +0530
Hi Erik,
Thanks for the suggestion.
I tried this:
public class RelevanceSimilarity extends DefaultSimilarity
{
public float tf(float freq) {
System.out.println("discounting frequency");
return (float)1;
}
}

and in my query class, I used :
Similarity.setDefault(similarity);
Hits hits = is.search(query);
for(i = 0; i < hits.length(); i ++)
  result = result + hits.score(i);

However, this is still not giving me the expected result. Do I need to do
something else?
Regards,
Niraj
----- Original Message -----
From: "Erik Hatcher" <[EMAIL PROTECTED]>
To: "Lucene Users List" <[EMAIL PROTECTED]>
Sent: Friday, June 04, 2004 1:55 PM
Subject: Re: score and frequency
> On Jun 4, 2004, at 2:52 AM, Niraj Alok wrote:
> > Hi,
> >
> > I am having some problems with the score of lucene.
> > I am trying to get the results displayed according to hits.score and
> > it is giving the results correctly.
> > However I do not want the frequency factor to be used for the
> > computation of the score.
> >
> > Is it possible to get the score which does not have the frequency
> > factor in it ?
>
> Have a look at the javadocs for Similarity.  DefaultSimilarity is used
> unless otherwise specified.  You could subclass that and override this:
>
>    public float tf(float freq) {
>      return (float)Math.sqrt(freq);
>    }
>
> and return 1.0.  This might give you the effect you want.
>
> Erik
>
>
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