On Mar 30, 2006, at 11:28 AM, Schwenker, Stephen wrote:
Maybe I'm not being quite clear enough. I'm not simply looking to
boost a field by a fixed amount and it's not likely that the field
is going to match a word in the query because we won't be searching
for dates. So that means that that fields boost will not be taken
into consideration because there is no match.
At indexing time, you can boost a document and/or any of its fields.
Those factors are all multiplied together to form a single document-
level boost factor. So a field boosted at indexing time would not
need to be part of the query itself to boost found documents.
For example, All my documents have a publication date. And I want
newer documents to be ranked slightly higher than older documents.
Say I am searching for the word "Lucene" and it returns a list of
10 documents. The third one was written today and the first and
second documents were written 2 months ago but get ranked slightly
higher because of their score. Each of these documents have a date
field("pubdate") which has the following values.
20060130
20060210
20060329
Now, I want to turn these dates into numbers, multiply them by a
factor and add them to the total weight. e.g.
Date -> (Numerical value(mil.) / (Convert to days) * (daily
multiply factor) = (Boost Result)
20060130 -> 1138597200000 / (1000 * 60 * 60 * 24 ) * 0.00002 =
0.26356416...
20060210 -> 1139547600000 / (1000 * 60 * 60 * 24 ) * 0.00002 =
0.26378416...
20060329 -> 1143608400000 / (1000 * 60 * 60 * 24 ) * 0.00002 =
0.26472416...
This is the current equation I'm hoping to use but I haven't quite
worked it out. If I can add the boost result to the final score
then I'm hoping more recent articles will get a slightly higher
ranking.
I hope you understand what I'm trying to accomplish and maybe you
can help me figure out where I should look.
Since you need to factor in some type of factor based on the
difference of *today* and the publication date, I think FunctionQuery
is perhaps what you're after. It is part of Solr currently:
<http://incubator.apache.org/solr/docs/api/org/apache/solr/search/
function/FunctionQuery.html>
Erik
Thank you,
Steve.
-----Original Message-----
From: Erik Hatcher [mailto:[EMAIL PROTECTED]
Sent: Thursday, March 30, 2006 9:51 AM
To: [email protected]
Subject: Re: Date Boosting
On Mar 30, 2006, at 8:50 AM, Schwenker, Stephen wrote:
I'm new to Lucene and I want to make a query to dynamically boost a
document slightly based on a date field. I'm not sure which
classes are used to calculate the boost, so I wanted to ask which
classes I should extend to accomplish this? I'm just asking so I
can get to the job faster. I don't want to waste my time looking
in places I don't need to.
Extending classes is not necessary. To boost a date field you can
simply call Field.setBoost(). Use IndexSearcher.explain() to see
how your boosts affect scoring.
Since you might need dynamic data boosting, perhaps the new
FunctionQuery would be more what you're after though?
Erik
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