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Posted to java-user@lucene.apache.org by Jason Haruska <jh...@gmail.com> on 2004/10/28 19:23:07 UTC
Re: Negative boosting?
Hi Terry,
I know this is an old message on the list but it does not look like
anyone responded to your request. I had to do negative boosting for my
search functionality as well so I'd like to share the modification to
QueryParser.jj to make it work. Find your <Boost> TOKEN and change it
to:
<Boost> TOKEN : {
<NUMBER: (["-"])? (<_NUM_CHAR>)+ ( "." (<_NUM_CHAR>)+ )? > : DEFAULT
}
This simply allows an optional negative sign in front of a boost
value. After stepping through the program I've seen the
negative value carry through to the weight calculation.
Hope this helps.
------- Start Quote --------
I've often found the use of query-based boosting to be very
beneficial. This is particularly so when it's easy to identify the
term that I want to stand out as a primary selector.
However, I've come across quite a few other cases where it would be
easier (and more logical) to apply a negative boost - to de-emphasize
the match when the term is present.
Is it possible to apply a negative boost (It doesn't seem to work),
and if not, would it break anything significant [sic] if that were added?
Regards,
Terry
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Re: Negative boosting?
Posted by Jason Haruska <jh...@gmail.com>.
You'll have to run tests but it shouldn't. All it does is change the
NUMBER token to accept an optional "-" in front of a number. So,
existing queries with no negative numbers should not be impacted.
On Thu, 28 Oct 2004 13:50:47 -0400, Terry Steichen <te...@net-frame.com> wrote:
>
> Jason,
>
> Thanks for the info. I'll try it.
>
> Do you know if the change you describe has any impact on existing queries
> (other than to support negative boosting, if that's specified)? In other
> words, if I apply this change to existing queries, will I likely see any
> changes in results because of the change?
>
> Regards,
>
> Terry
>
>
>
> ----- Original Message -----
> From: Jason Haruska
> To: Lucene Users List
> Sent: Thursday, October 28, 2004 1:23 PM
> Subject: Re: Negative boosting?
>
> Hi Terry,
>
> I know this is an old message on the list but it does not look like
> anyone responded to your request. I had to do negative boosting for my
> search functionality as well so I'd like to share the modification to
> QueryParser.jj to make it work. Find your <Boost> TOKEN and change it
> to:
>
> <Boost> TOKEN : {
> <NUMBER: (["-"])? (<_NUM_CHAR>)+ ( "." (<_NUM_CHAR>)+ )? > : DEFAULT
> }
>
>
> This simply allows an optional negative sign in front of a boost
> value. After stepping through the program I've seen the
> negative value carry through to the weight calculation.
>
> Hope this helps.
>
> ------- Start Quote --------
> I've often found the use of query-based boosting to be very
> beneficial. This is particularly so when it's easy to identify the
> term that I want to stand out as a primary selector.
>
> However, I've come across quite a few other cases where it would be
> easier (and more logical) to apply a negative boost - to de-emphasize
> the match when the term is present.
>
> Is it possible to apply a negative boost (It doesn't seem to work),
> and if not, would it break anything significant [sic] if that were added?
>
> Regards,
>
> Terry
>
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