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From Chris Hostetter <hossman_luc...@fucit.org>
Subject Re: Calculate Theoretical Max
Date Wed, 26 Aug 2009 01:18:18 GMT

: Is there a way to calculate a theoretical max score for the current query?

there's been some discussion on this on the java-user list over the years 
... the short answer is "yes it's possible, but only in very controlled 
situations" ... as i recall it depended on limiting the set of possible 
Query classs (because it's possible to write a Query object with an 
unpredictable max score) and having a Similarity implementation that 
returns bounded values.

: This would be the same score you'd get if a document matched the query
: exactly. For example:

but the concept of an "exact" match is very missleading ... even for a 
simple term query, a document contain exactly the term specified and 
nothing more isn't neccessarily the highest scoring doc for that query -- 
it depends on how the Similarity class defines lengthNorm and what the tf 
function look like -- a doc that has the term repeated multiple times 
along with lots of other "crap" terms might score higher in some cases 
(ie: constant lengthNorm, or expotential tf function)

there is no generic solution that will work for this ... just solutions 
that work in specific cases.



-Hoss


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