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From Rads2029 <>
Subject Re: Modifying score based on tf and slop
Date Tue, 30 Jun 2009 10:52:50 GMT

Restarting this thread. 
I did try out the soln mentioned by Simon below, however that did not work.
As changing the tf implementation to return 1, adversely affected by span
scoring . ie, the slop distance does not affect score if i make tf as 1. 

I had found a work around in some other way, but that has a hole. I really
have no way other than to find a solution for this. :(

To summarize, how to make sure tf does not affect the scoring but the span
should still affect the scoring? 

Simon Willnauer wrote:
> Hey,
> If I get you right you wanna make tf not affecting the score at all.
> if so why don't you just return 1.0f by overriding similarity?
> If you just wanna do that for the query you are using you could
> override Query#getSimilarity and return a delegate to the actual
> similarity.
> Hope that helps.
> simon
> On Wed, May 6, 2009 at 7:44 PM, Radha Sreedharan <>
> wrote:
>> Hi all,
>> All I have is a query running on a document with a single field which
>> has some search value. This is all which will be present.
>> No more documents / fields.
>> I have the following specific requirements
>> 1) Length of document should not affect score - Implemented as per
>> lucene documentation using concept of Fair Similairty by making
>> lengthnorm as 1
>> 2) The no of times a term in the query  occurs in the search field
>> should not affect the score
>> 3) I am using the spannearquery. Hence the slop should affect the score.
>> I implemented 2) by changing the tf to return 1 if freq >0 .
>> But this adversely affects  3) as the slop value is factored into the
>> tf ( as per what I can see in the span scorer)
>> How can I ensure the frequency of a certain term does not affect the
>> score while at the same ensuring that the slop does affect it ?
>> Thanks,
>> Radha

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