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Subject: Re: Checking Optimal Values for BM25
To: solr-user@lucene.apache.org
References: <CAHsXEHXQ7Lz_RcTfHo7mvZXA4p8Ed=r-mia+4s4ZY-p4_1TO+w@mail.gmail.com>
From: Sascha Szott <szott@zib.de>
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archived-at: Thu, 15 Dec 2016 21:18:10 -0000

Hi Furkan,

in order to change the BM25 parameter values k1 and b, the following XML 
snippet needs to be added in your schema.xml configuration file:

<similarity class="solr.BM25SimilarityFactory">
   <float name="k1">1.3</float>
   <float name="b">0.7</float>
</similarity>

It is even possible to specify the SimilarityFactory on individual index 
fields. See [1] for more details.

Best
Sascha

[1] https://wiki.apache.org/solr/SchemaXml#Similarity


Am 15.12.2016 um 14:58 schrieb Furkan KAMACI:
> Hi,
>
> Sole's default similarity is BM25 anymore. Its parameters are defined as
>
> k1=1.2, b=0.75
>
> as default. However is there any way that to check the effect of using
> different coefficients to calculate BM25 to find the optimal values?
>
> Kind Regards,
> Furkan KAMACI
>