lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Grant Ingersoll <>
Subject Re: concise definition of Lucene score?
Date Wed, 03 Sep 2008 14:36:53 GMT
What's not concise about a complex math formula?  :-)

The basic Term Vector approach to IR, that Lucene more or less  
implements, says that the score for a document given a query is the  
cosine of the angle formed between the query vector and the document  

I like to draw a standard x-y axis graph and then draw two vectors,  
one being the query and the other the document and then draw in the  
angle between them (w/ their tails at the same point).  The score is  
the cosine of that angle (more or less).  That is usually sufficient  
for "most people".  People who like math can read the formula.


On Sep 3, 2008, at 6:17 AM, Jon Loken wrote:

> Hi all,
> I have attempted to find a concise definition of how the Lucene  
> score is
> calculated, something that can be understood by most people.
> The information I found is accurate, but not particularly concise.
> he/lucene/search/Similarity.html
> If there is no boosting or sorting involved, how is a default sort
> calculated?
> Many thanks,
> Jon
> BiP Solutions Limited is a company registered in Scotland with  
> Company Number SC086146 and VAT number 383030966 and having its  
> registered office at Park House, 300 Glasgow Road, Shawfield,  
> Glasgow, G73 1SQ  
> ****************************************************************************
> This e-mail (and any attachment) is intended only for the attention  
> of the addressee(s). Its unauthorised use, disclosure, storage or  
> copying is not permitted. If you are not the intended recipient,  
> please destroyall copies and inform the sender by return e-mail.
> This e-mail (whether you are the sender or the recipient) may be  
> monitored, recorded and retained by BiP Solutions Ltd.
> E-mail monitoring/ blocking software may be used, and e-mail content  
> may be read at any time. You have a responsibility to ensure laws  
> are not broken when composing or forwarding e-mails and their  
> contents.
> ****************************************************************************
> ---------------------------------------------------------------------
> To unsubscribe, e-mail:
> For additional commands, e-mail:

Grant Ingersoll

Lucene Helpful Hints:

To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message