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From Simon Willnauer <simon.willna...@googlemail.com>
Subject Re: Help understanding fieldNorm
Date Mon, 05 Oct 2009 09:15:22 GMT
Did you change any boost values for URL field or document while reindexing
the document by any chance? Or do you look at different documents - one is
internal id 0 and other is internal id 22 - this could be the updated one
just curious if that might be the cause?!

simon

On Mon, Oct 5, 2009 at 10:21 AM, Ole-Martin Mørk <olemartin@gmail.com>wrote:

> Hi. I am trying to understand Lucene's scoring algorithm. We're
> getting some strange results. First we search for a given page by it's
> url. We get this result:
>
> 0.0014793393 = fieldWeight(url:"our super secret url" in 22), product of:
>  1.0 = tf(phraseFreq=1.0)
>  32.31666 = idf(url: www=7327 host=321 com=7327 article=2456
> something=2 something=44 704290075=1)
>  4.5776367E-5 = fieldNorm(field=url, doc=22)
>
> When this is done, we use solrJ to read and write the document. The
> only change is the title of the document (appends the number 2)
>
> We search again and the fieldNorm is changed significantly:
>
> 9.874598 = fieldWeight(url:"our super secret url" in 0), product of:
>  1.0 = tf(phraseFreq=1.0)
>  31.598713 = idf(url: www=7328 host=322 com=7328 article=2457
> something=3 somthing=45 704290075=2)
>  0.3125 = fieldNorm(field=url, doc=0)
>
> Why does the value of fieldNorm change so much?
>
> Looking forward to your answers.
>
> --
> Ole-Martin Mørk
> http://twitter.com/olemartin
> http://flickr.com/olemartin
>

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