[Xapian-discuss] Relevance wdf

[Richard Boulton]

On Fri, 2005-03-18 at 13:50 +0000, James Aylett wrote:
> > Is it possible that get desired result with Xapian?
> 
> If you add a dummy term you never search over with a wdf such that all
> document lengths are the same, that might do it. However it will stop
> the normal relevance mechanism from working, and will probably cause
> you other problems further down the line.

Or, you could perform your match using different parameters for the BM25
weighting function, such that document length is ignored.  Try using a
BM25Weight object with the k2 and b parameters to the constructor set to
0.

(See the documentation of Enquire::set_weighting_scheme() at
http://www.xapian.org/docs/apidoc/html/classXapian_1_1Enquire.html#a4

and the documentation of the BM25weight class at
http://www.xapian.org/docs/apidoc/html/classXapian_1_1BM25Weight.html#a0
)

-- 
Richard Boulton <richard at tartarus.org>