The
--spl_sthresh
and
--dym_sthresh
flags are used to set the threshold
spelling correction score for words used by the auto-correct or DYM engines,
respectively. This is the threshold at which the engine will consider the
suggestion. Words that qualify have a score below a given threshold. The higher
the edit distance for a term, the higher the score. The default for
--spl_sthresh
is 125, and the default for
--dym_sthresh
is 175.
Based on these default values, if a particular suggestion has a score of 100, it can be used for either DYM or auto-correct, and if it has a score of 200, it is not used by either. If the suggested word has a score better (that is, lower) than the default DYM threshold of 175, but not good enough (that is, higher) than the default auto-correct threshold of 125, it qualifies only for DYM.
A higher value for either of these settings generally results in more
suggestions being generated for a misspelled word. In an example query against
the sample wine data, changing the
--dym_sthresh
value from 175 to 225 increased the
number of terms considered for DYM from one to ten. However, raising scores too
high could result in a lot of noise. That is to say, it is generally a good
thing if nonsense strings used as search terms receive neither auto-correct nor
DYM suggestions.