removing a field from the relevance calculation

Hi,

I'm having trouble getting a field of type
SortableFloatField to not
weigh into to the relevancy score returned for a document.

<fieldtype name="sfloat"
class="solr.SortableFloatField"
sortMissingLast="true"
omitNorms="true"/>

So far I've tried boosting the field to 0.0 at index time
using this
field type - and also implemented a custom Similarity
implementation
that overrode lengthNorm(String fieldname, int numTerms)
after
converting the field to a text field.

Nothing I do seems to affect the behavior that when the
value of the
field in question changes, the score of the document changes
along with
it.  The field does need to be both indexed and stored. 
There is a
requirement to be able to sort by that field, and it must be
returned in
the document when searching.

Am I going about this the wrong way?

Regards,

Bart Smyth

 


IMPORTANT: This e-mail, including any attachments, may
contain private or confidential information.
If you think you may not be the intended recipient, or if
you have received this e-mail in error, please contact the
sender immediately and delete all copies of this e-mail. 
If you are not the intended recipient, you must not
reproduce any part of this e-mail or disclose its contents
to any other party. 
This email represents the views of the individual sender,
which do not necessarily reflect those of education.au
limited except where the sender expressly states otherwise.

It is your responsibility to scan this email and any files
transmitted with it for viruses or any other defects.
education.au limited will not be liable for any loss, damage
or consequence caused directly or indirectly by this email.

On 9/6/07, Bart Smyth <bsmytheducationau.edu.au>
wrote:
> I'm having trouble getting a field of type
SortableFloatField to not
> weigh into to the relevancy score returned for a
document.
>
> <fieldtype name="sfloat"
class="solr.SortableFloatField"
> sortMissingLast="true"
omitNorms="true"/>
>
> So far I've tried boosting the field to 0.0 at index
time using this
> field type - and also implemented a custom Similarity
implementation
> that overrode lengthNorm(String fieldname, int
numTerms) after
> converting the field to a text field.
>
> Nothing I do seems to affect the behavior that when the
value of the
> field in question changes, the score of the document
changes along with
> it.

Perhaps it's a coincidence that when you change the value of
that
field (presumably by re-indexing the document) that the
relevancy
score changes.  The relevancy score can change somewhat
because lucene
deleted documents are only marked for deletion until a
segment merge
removes them, and the terms in that document still count in
the idf
factor (inverse document frequency).   To test this theory,
optimize
the index after you change the value each time.

-Yonik

: I'm having trouble getting a field of type
SortableFloatField to not
: weigh into to the relevancy score returned for a
document.

unless you actually use the field in your query in some way
it will not 
factor into the score at all -- no matter what options you
set on it or 
the fieldtype.

you use add the debugQuery=true param to your queries and
look at the 
score explanation output for each doc that gets added to the
very bottom 
of your results, you'll see a lot of stuff that may not make
much sense -- 
but unless your field name appears in there somewhere your
field isn't 
part of the score calculation.




-Hoss