Apache Solr Reference Guide Covering Apache Solr 6.0

carrot.produceSummary When true the clustering component will run a highlighter pass on the
content of logical fields pointed to by carrot.title and carrot.snippet.
Otherwise full content of those fields will be clustered.
carrot.fragSize
carrot.summarySnippets
The size, in characters, of the snippets (aka fragments) created by the
highlighter. If not specified, the default highlighting fragsize ( hl.fragsize)
will be used.
The number of summary snippets to generate for clustering. If not specified,
the default highlighting snippet count ( hl.snippets) will be used.
Logical to Document Field Mapping
As already mentioned in Preliminary Concepts, the clustering component clusters "documents" consisting of
logical parts that need to be mapped onto physical schema of data stored in Solr. The field mapping attributes
provide a connection between fields and logical document parts. Note that the content of title and snippet fields
must be stored so that it can be retrieved at search time.
Parameter
carrot.title
carrot.snippet
carrot.url
Description
The field (alternatively comma- or space-separated list of fields) that should be mapped
to the logical document's title. The clustering algorithms typically give more weight to the
content of the title field compared to the content (snippet). For best results, the field
should contain concise, noise-free content. If there is no clear title in your data, you can
leave this parameter blank.
The field (alternatively comma- or space-separated list of fields) that should be mapped
to the logical document's main content. If this mapping points to very large content fields
the performance of clustering may drop significantly. An alternative then is to use
query-context snippets for clustering instead of full field content. See the description of
the carrot.produceSummary parameter for details.
The field that should be mapped to the logical document's content URL. Leave blank if
not required.
Clustering Multilingual Content
The field mapping specification can include a carrot.lang parameter, which defines the field that stores ISO
639-1 code of the language in which the title and content of the document are written. This information can be
stored in the index based on apriori knowledge of the documents' source or a language detection filter applied at
indexing time. All algorithms inside the Carrot2 framework will accept ISO codes of languages defined in Langua
geCode enum.
The language hint makes it easier for clustering algorithms to separate documents from different languages on
input and to pick the right language resources for clustering. If you do have multi-lingual query results (or query
results in a language different than English), it is strongly advised to map the language field appropriately.
Parameter
carrot.lang
Description
The field that stores ISO 639-1 code of the language of the document's text fields.
carrot.lcmap A mapping of arbitrary strings into ISO 639 two-letter codes used by carrot.lang. The
syntax of this parameter is the same as langid.map.lcmap, for example: langid.map.
lcmap=japanese:ja polish:pl english:en
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