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Posted to java-user@lucene.apache.org by Marc Sturlese <ma...@gmail.com> on 2009/04/06 22:01:32 UTC
boost and score doubt
Hey there,
Does de function doc.setBoost(x.y) accept negative values or values minor
than 1?? I mean... it compile and doesn't give errors but the behabiour is
not exactly what I was expecting.
In my use case I have the field title... I want to give very very low
relevance to the documents witch title has less that 40 characters. I have
tried setting boost to negatives values or to 0.1
Wich is the best way to do that?
Is there any range of values for setting boost?
And another thing that confuses me... if I omit norms is the score
function... how does it affect to the boosting I am setting? does it loose
the effect?
Thanks in advance!
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Re: boost and score doubt
Posted by Marc Sturlese <ma...@gmail.com>.
That was my problem... I was ommiting norms, so the boost I gave at the
document at index time was not taking effect.
Since I stop omitting them results have changed completely.
Thanks!
Michael McCandless-2 wrote:
>
> Negative boosts are accepted, though rather "unusual". Also note that
> Lucene by default filters out any hits with scores <= 0.0.
>
> Normally you'd set boost to something > 0.0 (0.1 should work).
>
> What unexpected effect are you seeing?
>
> If you omit norms, then indeed your per-doc boost (and per-field
> boost, if used) are discarded (have no effect).
>
> Mike
>
> On Mon, Apr 6, 2009 at 4:01 PM, Marc Sturlese <ma...@gmail.com>
> wrote:
>>
>> Hey there,
>> Does de function doc.setBoost(x.y) accept negative values or values minor
>> than 1?? I mean... it compile and doesn't give errors but the behabiour
>> is
>> not exactly what I was expecting.
>> In my use case I have the field title... I want to give very very low
>> relevance to the documents witch title has less that 40 characters. I
>> have
>> tried setting boost to negatives values or to 0.1
>> Wich is the best way to do that?
>> Is there any range of values for setting boost?
>>
>> And another thing that confuses me... if I omit norms is the score
>> function... how does it affect to the boosting I am setting? does it
>> loose
>> the effect?
>>
>> Thanks in advance!
>> --
>> View this message in context:
>> http://www.nabble.com/boost-and-score-doubt-tp22916108p22916108.html
>> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>>
>>
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>> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
>> For additional commands, e-mail: java-user-help@lucene.apache.org
>>
>>
>
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Re: boost and score doubt
Posted by Michael McCandless <lu...@mikemccandless.com>.
Negative boosts are accepted, though rather "unusual". Also note that
Lucene by default filters out any hits with scores <= 0.0.
Normally you'd set boost to something > 0.0 (0.1 should work).
What unexpected effect are you seeing?
If you omit norms, then indeed your per-doc boost (and per-field
boost, if used) are discarded (have no effect).
Mike
On Mon, Apr 6, 2009 at 4:01 PM, Marc Sturlese <ma...@gmail.com> wrote:
>
> Hey there,
> Does de function doc.setBoost(x.y) accept negative values or values minor
> than 1?? I mean... it compile and doesn't give errors but the behabiour is
> not exactly what I was expecting.
> In my use case I have the field title... I want to give very very low
> relevance to the documents witch title has less that 40 characters. I have
> tried setting boost to negatives values or to 0.1
> Wich is the best way to do that?
> Is there any range of values for setting boost?
>
> And another thing that confuses me... if I omit norms is the score
> function... how does it affect to the boosting I am setting? does it loose
> the effect?
>
> Thanks in advance!
> --
> View this message in context: http://www.nabble.com/boost-and-score-doubt-tp22916108p22916108.html
> Sent from the Lucene - Java Users mailing list archive at Nabble.com.
>
>
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> To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
> For additional commands, e-mail: java-user-help@lucene.apache.org
>
>
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