Re: Explanation of Scoring

[Erik Hatcher]

My guess is that you've used the IndexSearcher.explain method 
incorrectly.  What are you passing to it?  Along with the query, the 
document id should be passed.  If you are iterating over Hits, be sure 
not to pass the hit iteration number.

	Erik

On May 10, 2004, at 9:38 AM, Matthew W. Bilotti wrote:

Hello,

I'm using Lucene 1.4 RC2, and I'm having trouble understanding how the
scoring relates to document rank.  The work I am doing is going to 
depend
very much on knowing exactly how the scoring algorithm works and 
printing
out the the score components so that I can analyze contributions of
individual terms by hand.  If anyone can help me do this, I would be 
truly
grateful.

Particularly, I would like help understanding the following strange
phenomenon:
I executed a query and the first document returned had a score of 
0.592.
The explanation string read "0.0 = match required".  Can anyone tell me
what this means?

The next 39 documents retrieved had steadily decreasing score with the
same explanation string.
The 40th document retrieved, though had a score of 1.0 and the 
explanation
string:

0.0 = fieldWeight(contents:invented in 0), product of:
  0.0 = tf(termFreq(contents:invented)=0)
  6.507968 = idf(docFreq=4189)
  0.0390625 = fieldNorm(field=contents, doc=0)
If anyone can help me decipher the explanation strings, or help me to
understand why a document with score 1.0 is ranked lower than a 
document
with score 0.592, or show me how to print out the individual 
components of
the score as I am retrieving the documents, please reply.  My work very
much depends on your help.

Regards,

Matthew Bilotti

---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]


---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]