Similarity search apparatus for searching unit string based on similarity

Abstract

Provided is a similarity search apparatus for searching data at a higher speed than that of the prior art without limiting the types of letter of a search key. A unit position correspondence memory stores therein a table that expresses the ordinal number among units at which each unit in a search key inputted by means of a keyboard has appeared within the search key. A search section refers to the table stored in the unit position correspondence memory and operates every time units are read out one by one from a database memory including a plurality of units to generate a plurality of status parameters each of which includes a similarity, a position of coincidence and a skip number, which express with what number of units from the top of the search key the units read out from the database have coincided at what degree of similarity, and express how many units in the database have been skipped over subsequently. Through the above process, the search section updates each status parameter stored in a status parameter memory and operates upon detecting a unit string coincident at a similarity equal to or lower than an inputted similarity, to output the detected unit string as a unit string of a similarity.