(using MySQL) How do I efficiently limit resulting dictionary candidates to only those with DamLev distance <=2? about symspell

[wolfgarbe]

Generally, we have to calculate the Levenshtein distance ONLY for candidates that were found when deleting chars both on the input term, AND the dictionary term (deleting on both sides is required for replaces [kar->car] and adjacent transposes [acr->car] only).

Additionally, we can discard a candidate WITHOUT calculating the Levenshtein distance, if the delete positions in input term and dictionary term were on different sides of the resulting delete stem, and the number of deleted chars on both sides > maximum edit distance. But this requires that we store the delete positions together with the deletes.

Example:

[a]re
   re[do]

The sum of deleted chars is 3, the maximum edit distance is 2, the delete positions are on different sides of the stem, so we can discard the suggestion without calculating the Levenshtein distance.

SymSpell contains additional optimizations (discard candidates without Levenshtein calculation) for the case when we don't need all suggestions below a maximum edit distance (Verbosity.All), but only those candidates with the lowest edit distance (Verbosity.Top Verbosity.Closest).

[rockroland]

That makes sense. Thanks for the clear answer.. now I can proceed with confidence. Best Regards