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From David Philip <davidphilipshe...@gmail.com>
Subject Re: debugQuery, explain tag - What does the fieldWeight value refer to?,
Date Mon, 04 Mar 2013 10:38:11 GMT
Hi Chris,

   Thank you for the reply. okay understood about *fieldWeight*.

I am actually curious to know how are the documents sequenced in this case
when the  product of tf idf and fieldnorm is same for both the documents?

Afaik, at the first step, documents are sequenced based on
fieldWeight(product of tf idf and fieldnorm) order by desc[correct?]. But
if both are same  then what is the next factor taken in  consideration to
sequence?

 In the below case , why doc 1 is come first and then doc2 when both scores
are same.

:  1.0469098 =,
: *(MATCH) fieldWeight(title:updated in 7), *
: product of: 1.0 = tf(termFreq(title:updated)=1), 2.7917595 =
idf(docFreq=2,
: maxDocs=18), 0.375 = fieldNorm(field=title, doc=7)
:
:  1.0469098 =,
: *(MATCH) fieldWeight(title:updated in 9), *
: product of: 1.0 = tf(termFreq(title:updated)=1), 2.7917595 =
idf(docFreq=2,
: maxDocs=18), 0.375 = fieldNorm(field=title, doc=7)




Thanks  - David









On Sat, Mar 2, 2013 at 12:23 PM, Chris Hostetter
<hossman_lucene@fucit.org>wrote:

>
> :  In the explain tag  (debugQuery=true)
> : what does the *fieldWeight* value refer to?,
>
> fieldWeight is just a label being put on the the product of the tf, idf,
> and fieldNorm for that term.  (I don't remember why it's refered to as the
> "fieldWeight" ... i think it may just be historical, since these are all
> factors of the "field query" (ie: "term query", as opposed to a "boolean
> query" across multiple fields)
>
>
> : *1.0469098* is the product of tf, idf and fieldNorm,  for both the
> records.
> : But field weight is different. I would like to know what is the field
>
> what do you mean "field weight is different" ? ... in both of the examples
> you posted, the fieldWeight is 1.0469098 ?
>
> Are you perhaps refering to the numbers "7" and "9" that appear inside the
> fieldWeight(...) label?  Those are just refering to the (internal)
> docids (just like in the "fieldNorm(...)")
>
> :  1.0469098 =,
> : *(MATCH) fieldWeight(title:updated in 7), *
> : product of: 1.0 = tf(termFreq(title:updated)=1), 2.7917595 =
> idf(docFreq=2,
> : maxDocs=18), 0.375 = fieldNorm(field=title, doc=7)
> :
> :  1.0469098 =,
> : *(MATCH) fieldWeight(title:updated in 9), *
> : product of: 1.0 = tf(termFreq(title:updated)=1), 2.7917595 =
> idf(docFreq=2,
> : maxDocs=18), 0.375 = fieldNorm(field=title, doc=7)
>
>
> -Hoss
>

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