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From: Apache Wiki <wikidiffs@apache.org>
To: Apache Wiki <wikidiffs@apache.org>
Date: Sun, 18 Oct 2009 22:30:12 -0000
Message-ID: <20091018223012.4716.36097@eos.apache.org>
Subject: 
 =?utf-8?q?=5BSolr_Wiki=5D_Update_of_=22SolrRelevancyFAQ=22_by_YonikSeeley?=

Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Solr Wiki" for chan=
ge notification.

The "SolrRelevancyFAQ" page has been changed by YonikSeeley.
The comment on this change is: add full examples of date boosting.
http://wiki.apache.org/solr/SolrRelevancyFAQ?action=3Ddiff&rev1=3D13&rev2=
=3D14

--------------------------------------------------

    * Do an explicit sort by date (relevancy scores are ignored)
    * Use an index-time boost that is larger for newer documents
    * Use a FunctionQuery to influence the score based on a date field.
-     Use something of the form recip(rord(myfield),1,1000,1000)
+     * In Solr 1.3, use something of the form recip(rord(myfield),1,1000,1=
000)
+     * In Solr 1.4, use something of the form recip(ms(NOW,mydatefield),3.=
16e-11,1,1)
-     http://lucene.apache.org/solr/api/org/apache/solr/search/function/Rec=
iprocalFloatFunction.html
+   http://lucene.apache.org/solr/api/org/apache/solr/search/function/Recip=
rocalFloatFunction.html
+ =

+   http://lucene.apache.org/solr/api/org/apache/solr/search/BoostQParserPl=
ugin.html
+ =

+ A full example of a query for "ipod" with the score boosted higher the ne=
wer the product is:
+ {{{
+ http://localhost:8983/solr/select?q=3D{!boost b=3Drecip(ms(NOW,manufactur=
edate_dt),3.16e-11,1,1)}ipod
+ }}}
+ =

+ One can simplify the implementation by decomposing the query into multipl=
e arguments:
+ {{{
+ http://localhost:8983/solr/select?q=3D{!boost b=3D$dateboost v=3D$qq}&dat=
eboost=3Drecip(ms(NOW,manufacturedate_dt),3.16e-11,1,1)&qq=3Dipod
+ }}}
+ =

+ Now the main "q" argument as well as the "dateboost" argument may be spec=
ified as defaults in a search handler in solrconfig.xml, and clients would =
only need to pass "qq", the user query.
+ =

  =

  =3D=3D How do I give a very low boost to documents that match my query =
=3D=3D
  In general the problem is that a "low" boost is still a boost, it can onl=
y improve the score of documents that match. One way to fake a "negative bo=
ost" is to give a high boost to everything that does *not* match. For examp=
le: