Michael, thank you.
Query filter only solves half of my problem. Unfortunately I do need
to have a proper score for some fields.
I ended up extending Term class (I removed sealed attribute which is a
bad thing). The new myTerm class has one boolean member, omitIdf.
Then, when I compile my queries, I use myTerm with omitIdf set to
true, for some fields. Then I extended Similarity cladd and I cast
Term passes into Idf method to myTerm and only calculate Idf if
omitIdf is true. Seems to work.
I don't like the solution but that's the best I could do today.
Any thoughts?
Regards,
Artem
On 10/12/2009, at 15:51, Michael Garski <mgar...@myspace-inc.com> wrote:
Artem,
Do you need any scoring information at all on that field? How about
using a QueryFilter for those fields?
Michael
-----Original Message-----
From: Artem Chereisky [mailto:a.cherei...@gmail.com]
Sent: Wed 12/9/2009 4:53 PM
To: lucene-net-user@incubator.apache.org;
lucene-net-develo...@incubator.apache.org
Subject: idf on per-field basis
Hi,
I came across a situation when my scores are adversely affected by
the IDF
component. Let me explain.
My index documents contain a number of fields, for some, TF and IDF
are
important and need to be taken into account, for others niether TF
nor IDF
should apply. I dealt with TF by omiting norms during indexing but I
can't
find a way to calculate IDF for certain fields only.
The formula for IDF is defined in Similarity. I have my own
implementation
of Similarity where I can set it to 1 or use the default
implementation.
mySearcher.SetSimilarity is where I tell Lucene which similarity
instance to
use, but that's global, so it applies to all fields in the index.
So, here's my question. Is there a way to calculate IDF on per-field
basis?
Regards,
Art
