Added a comment to LevensteinDistance class

1 files changed, 10 insertions, 0 deletions

diff --git a/vespalib/src/vespa/vespalib/fuzzy/levenstein_distance.h b/vespalib/src/vespa/vespalib/fuzzy/levenstein_distance.h
index e109db3178c..bce7599fc23 100644
--- a/vespalib/src/vespa/vespalib/fuzzy/levenstein_distance.h
+++ b/vespalib/src/vespa/vespalib/fuzzy/levenstein_distance.h
@@ -7,6 +7,16 @@
 
 namespace vespalib {
 
+/**
+ * LevensteinDistance::calculate implements basic Levenstein distance algorithm
+ * with early stopping if the distance is already too high.
+ * If the distance is above threshold method would return empty optional,
+ * if the distance is below or equal to it, the distance will be wrapped in optional.
+ * The types it's built upon are uint32 and it used to compare codepoints from terms,
+ * but in future code can be generalized.
+ *
+ * Algorithm is based off Java implementation from commons-text library
+ */
 class LevensteinDistance {
 public:
     static std::optional<uint32_t> calculate(const std::vector<uint32_t>& left, const std::vector<uint32_t>& right, uint32_t threshold);