Grammatical tenses Stemming in SOLR

Question

I want to know which stemming filter factory can be used to fetch all the possible tenses of a stem word.

Example : If "run" is the search word -> it has to fetch results for all files involving

run , running , runs , ran. 

Also the vice-versa --> whichever tense of a word is searched , it has to retrieve all the results from the files.

I tried using POrterStemFilterFactory , snowball , kstem --> none of these seems to fetch the intended results.

Please help ! thanks in advance

Thanks, Aishwarya

Answer 1

For me i use this in schema.xml

<fieldType name="text" class="solr.TextField" positionIncrementGap="100">
      <analyzer type="index">
        <charFilter class="solr.MappingCharFilterFactory" mapping="mapping-ISOLatin1Accent.txt"/>
        <tokenizer class="solr.WhitespaceTokenizerFactory"/>
        <filter class="solr.StopFilterFactory"
                ignoreCase="true"
                words="stopwords.txt"
                />
        <filter class="solr.WordDelimiterFilterFactory"
                protected="protwords.txt"
                generateWordParts="1"
                generateNumberParts="1"
                catenateWords="1"
                catenateNumbers="1"
                catenateAll="0"
                splitOnCaseChange="0"
                preserveOriginal="1"/>
        <filter class="solr.LengthFilterFactory" min="2" max="100" />
        <filter class="solr.LowerCaseFilterFactory"/>
        <filter class="solr.SnowballPorterFilterFactory" language="English" protected="protwords.txt"/>
        <filter class="solr.EdgeNGramFilterFactory" minGramSize="3" maxGramSize="15" />
        <filter class="solr.RemoveDuplicatesTokenFilterFactory"/>
      </analyzer>
      <analyzer type="query">
        <charFilter class="solr.MappingCharFilterFactory" mapping="mapping-ISOLatin1Accent.txt"/>
        <tokenizer class="solr.WhitespaceTokenizerFactory"/>
        <filter class="solr.SynonymFilterFactory" synonyms="synonyms.txt" ignoreCase="true" expand="true"/>
        <filter class="solr.StopFilterFactory"
                ignoreCase="true"
                words="stopwords.txt"
                />
        <filter class="solr.WordDelimiterFilterFactory"
                protected="protwords.txt"
                generateWordParts="1"
                generateNumberParts="1"
                catenateWords="0"
                catenateNumbers="0"
                catenateAll="0"
                splitOnCaseChange="0"
                preserveOriginal="1"/>
        <filter class="solr.LengthFilterFactory" min="2" max="100" />
        <filter class="solr.LowerCaseFilterFactory"/>
        <filter class="solr.SnowballPorterFilterFactory" language="English" protected="protwords.txt"/>
        <filter class="solr.RemoveDuplicatesTokenFilterFactory"/>
      </analyzer>
      <analyzer type="multiterm">
<charFilter class="solr.MappingCharFilterFactory" mapping="mapping-ISOLatin1Accent.txt"/>
        <tokenizer class="solr.WhitespaceTokenizerFactory"/>
        <filter class="solr.SynonymFilterFactory" synonyms="synonyms.txt" ignoreCase="true" expand="true"/>
        <filter class="solr.StopFilterFactory"
                ignoreCase="true"
                words="stopwords.txt"
                />
        <filter class="solr.WordDelimiterFilterFactory"
                protected="protwords.txt"
                generateWordParts="1"
                generateNumberParts="1"
                catenateWords="0"
                catenateNumbers="0"
                catenateAll="0"
                splitOnCaseChange="1"
                preserveOriginal="1"/>
        <filter class="solr.LengthFilterFactory" min="2" max="100" />
        <filter class="solr.LowerCaseFilterFactory"/>
        <filter class="solr.SnowballPorterFilterFactory" language="English" protected="protwords.txt"/>
        <filter class="solr.EdgeNGramFilterFactory" minGramSize="3" maxGramSize="25" />
        <filter class="solr.RemoveDuplicatesTokenFilterFactory"/>
      </analyzer>
    </fieldType>

Answer 2

No, what you're asking for is not stemming, but Lemmatisation.

Lemmatisation (or lemmatization) in linguistics is the process of grouping together the inflected forms of a word so they can be analysed as a single item, identified by the word's lemma, or dictionary form.

In computational linguistics, lemmatisation is the algorithmic process of determining the lemma of a word based on its intended meaning. Unlike stemming, lemmatisation depends on correctly identifying the intended part of speech and meaning of a word in a sentence, as well as within the larger context surrounding that sentence, such as neighboring sentences or even an entire document. As a result, developing efficient lemmatisation algorithms is an open area of research.

Solr supports lemmatisation through multiple plugins, some are bundled and some are available as third party plugins.

The most complete one is probably the plugin for the OpenNLP lemmatizer.

<filter class="solr.OpenNLPLemmatizerFilterFactory"
      dictionary="lemmas.txt"
      lemmatizerModel="en-lemmatizer.bin"/>

dictionary

(optional) The path of a lemmatization dictionary file. This path may be an absolute path, or path relative to the Solr config directory. The dictionary file must be encoded as UTF-8, with one entry per line, in the form word[tab]lemma[tab]part-of-speech, e.g., wrote[tab]write[tab]VBD.

lemmatizerModel

(optional) The path of a language-specific OpenNLP lemmatizer model file. This path may be an absolute path, or path relative to the Solr config directory.

You can find a dictionary used for Elasticsearch's plugin at github.