Xapian discuss - Jun 2011 - Relevance, weighting and searching by specifically weighted text

Hi guys

In our implementation of Xapian for one of our sites, we index the
title, subtitle, summary and table of contents of around 200,000
products on ReportBuyer.com. When we create each Xapian doc to index
this information, we apply a weighting to each of these 'fields' and add
these to the doc using index_text with the second parameter passing in a
weighting.

I've been asked if it's possible to narrow queries to just a particular
field (translating into fields with a specific weight) within the index.
I've had a look at the reference for the
Xapian_Enquire::set_weighting_scheme method and cannot see a way where
altering the parameters of the BM25 weighting scheme can achieve this. 

Is there a way this can be done?

Thanks,

Justin

-- 
Redwire Design Limited
 
54 Maltings Place
169 Tower Bridge Road
London SE1 3LJ
www.redwiredesign.com
 
[ 020 7403 1444 ] - voice
[ 020 7378 8711 ] - fax

On 1 June 2011 11:06, Justin Finkelstein
> I've been asked if it's possible to narrow queries to just a
particular
> field (translating into fields with a specific weight) within the index.
> I've had a look at the reference for the
> Xapian_Enquire::set_weighting_scheme method and cannot see a way where
> altering the parameters of the BM25 weighting scheme can achieve this.
>
> Is there a way this can be done?
Yes, there is.  You need to index each field you want to be able to
search (or weight) individually, with a unique prefix.  Then, see
http://trac.xapian.org/wiki/FAQ/ExtraWeight

-- 
Richard