- Customizes the ranking (relevance) algorithm.
- Attribute 'cluster' is a boolean
- that controls whether Pazpar2 should boost ranking for merged
- records. Is 'yes' by default. A value of 'no' will make
- Pazpar2 avergage ranking of each record in a cluster.
+ Customizes the ranking (relevance) algorithm. Also known as
+ rank tweaks. The rank element
+ accepts the following attributes - all being optional:
+ </para>
+ <variablelist>
+ <varlistentry>
+ <term>cluster</term>
+ <listitem>
+ <para>
+ Attribute 'cluster' is a boolean
+ that controls whether Pazpar2 should boost ranking for merged
+ records. Is 'yes' by default. A value of 'no' will make
+ Pazpar2 average ranking of each record in a cluster.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>debug</term>
+ <listitem>
+ <para>
+ Attribute 'debug' is a boolean
+ that controls whether Pazpar2 should include details
+ about ranking for each document in the show command's
+ response. Enable by using value "yes", disable by using
+ value "no" (default).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>follow</term>
+ <listitem>
+ <para>
+ Attribute 'follow' is a a floating point number greater than
+ or equal to 0. A positive number will boost weight for terms
+ that occur close to each other (proximity, distance).
+ A value of 1, will double the weight if two terms are in
+ proximity distance of 1 (next to each other). The default
+ value of 'follow' is 0 (order will not affect weight).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>lead</term>
+ <listitem>
+ <para>
+ Attribute 'lead' is a floating point number.
+ It controls if term weight should be reduced by position
+ from start in a metadata field. A positive value of 'lead'
+ will reduce weight as it apperas further away from the lead
+ of the field. Default value is 0 (no reduction of weight by
+ position).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>length</term>
+ <listitem>
+ <para>
+ Attribute 'length' determines how/if term weight should be
+ divided by lenght of metadata field. A value of "linear"
+ divide by length. A value of "log" will divide by log2(length).
+ A value of "none" will leave term weight as is (no division).
+ Default value is "linear".
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ <para>
+ Refer to <xref linkend="relevance_ranking"/> to see how
+ these tweaks are used in computation of score.