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From Shi Hui Liu <shi...@nextbio.com>
Subject RE: Clarity: Is there a Query boosting 50-50 over 1000-1 ?
Date Thu, 28 Aug 2008 17:37:25 GMT
Hi Grant,

Thank you for your help. My query is A AND B. The problem is if I use BooleanQuery, I got
score 120 from TermQuery(A) and 0.5 from TermQuery(B) for the first article; for second article,
I got score 27 from TermQuery(A) and 36 from TermQuery(B). From my point of view, I think
the second article is better than the first one, however, the result is otherwise. I'm thinking
to create a Query to multiply the score of A and B instead of sum. But I want to know if there
is an existing query doing same thing since I'm still a new user to Lucene.

Thank you in advance,
Shi Hui

-----Original Message-----
From: Grant Ingersoll [mailto:gsingers@apache.org]
Sent: Thursday, August 28, 2008 5:57 AM
To: java-user@lucene.apache.org
Subject: Re: Clarity: Is there a Query boosting 50-50 over 1000-1 ?


On Aug 27, 2008, at 7:34 PM, Shi Hui Liu wrote:

> Hi,
>
> I think I should clarify my question a little bit. I'm using
> BooleanQuery to combine TermQuery(A) and TermQuery(B). But I'm not
> satisfied with its scoring algorigthm. Is there other queries can
> boost up the documents with 50 of A and 50 of B on top of documents
> with 1000 of A and 1 of B?

Is your query A + B meant to be A OR B or A AND B?  That is, are both
terms required?  You notation suggests they are, but the description
suggests you are getting documents that have only A in them, which
suggests "OR".

Have you looked at the explains?  What about the scoring aren't you
happy with?  It's not perfect (there is no such thing) but it works
pretty well in most cases, and works great if you spend a little time
figuring out the right length normalization factors.


> And I'm looking at the source code and found lots of classes are not
> public and some important methods are protected. What's the reason?
> Why make them public and let users to customize the Query easily?

Because there not meant to be overridden, but of course we are open to
specific suggestions on things that should be made public and often do
this when someone shows a valid reason.

Cheers,
Grant

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