Comments on: Xapian Search Architecture

By: yoa

yoa — Mon, 20 Apr 2009 19:53:53 +0000

Thanks for answering, I appreciate it, I’m working on my thesis for engineer and I work with xapian but is new for me.

thank you again,
Yoa

By: Richard Boulton

Richard Boulton — Mon, 20 Apr 2009 19:35:29 +0000

yoa – if you want to discuss the weighting model used by Xapian, the Xapian mailing list, or the Xapian IRC channel, would probably be better places: see http://xapian.org/lists and #xapian on irc.freenode.net But briefly, BM25 uses the frequency of terms in both documents and across the database as a whole, as well as information on the document length and the frequency of terms in the query. ie – it uses a superset of the statistics used by tf-idf, and combines them differently. The formula has performed a lot better in many retrieval experiments, and has some sound theoretical basis justifying its derivation.

By: yoa

yoa — Mon, 20 Apr 2009 18:27:15 +0000

Thanks for answering, but the inverse frequency is used to calculate the weight BM25?. I studied the BM25 and I think only works with the importance of frequency of occurrence.
I hope you answer

Yoa

By: Tom

Tom — Mon, 20 Apr 2009 18:06:38 +0000

Yoa, Xapian uses BM25, as documented on the Xapian website.

http://xapian.org/docs/bm25.html

Tom

By: yoa

yoa — Mon, 20 Apr 2009 17:58:44 +0000

I need know if the calculated weight for each term (word) is the multiplication of
tf * idf. So if the multiplication of the importance of frequency of occurrence of each word in the text per the inverse frequency of each word in the collection.
Please I need help with this, expect quick responses

Yoa

By: Xapian terms, values and data explained « Searching with Xapian

Xapian terms, values and data explained « Searching with Xapian — Thu, 02 Apr 2009 16:45:28 +0000

[...] a comment » My colleague Tom Mortimer has made a useful post on the Flax blog to clear up a common set of confusions regarding Xapian; covering the difference between, and the [...]