fieldNorm is lengthNorm * document boost. The lengthNorm formula is defined within Lucene's similarity class (which is a function of the number of terms within the document) and the document boost is calculated in IndexSegment.java .
Nutch assigns different boosts to each field so that you can tune your search results. For example, you can use explain to see if anchor matches are too strong, and adjust accordingly. Andy On Apr 11, 2005 12:17 AM, Kannan Sundaramoorthy <[EMAIL PROTECTED]> wrote: > > Hi, > I am trying to understand how Nutch computes score for each document. I > could figure out how tf, idf and queryNorm are computed but I do not > understand how fieldNorm (normalisation for each field) value is > computed. It seems to be a magic number for me and this is where Nutch > seems to differ from Lucene in computing score. > Also Nutch assigns different boosts for different fields (e.g, 4.0 for > url field) and uses this value while computing queryWeight. Can anyone > explain these please? > > Thanks, > Kannan > > This e-mail and any files transmitted with it are for the sole use of the > intended recipient(s) and may contain confidential and privileged information. > If you are not the intended recipient, please contact the sender by reply > e-mail and destroy all copies of the original message. > Any unauthorised review, use, disclosure, dissemination, forwarding, printing > or copying of this email or any action taken in reliance on this e-mail is > strictly > prohibited and may be unlawful. > > Visit us at http://www.cognizant.com >
