10. A method of similarity search initialization, the method comprising: selecting a leaf of a suffix tree generated from a target string representing a target sequence stored in a memory, the selected leaf being associated with a prefix in the suffix tree having a longest match to a suffix of a query string representing a query; and executing a distance operator using a processor, the distance operator to determine a distance between the query and a subsequence of the target sequence represented by a candidate substring of the target string, the candidate substring comprising the prefix associated with the selected leaf as a suffix, wherein the determined distance is an initial upper bound in a similarity search of the target sequence using the query.
10. A method of similarity search initialization, the method comprising: selecting a leaf of a suffix tree generated from a target string representing a target sequence stored in a memory, the selected leaf being associated with a prefix in the suffix tree having a longest match to a suffix of a query string representing a query; and executing a distance operator using a processor, the distance operator to determine a distance between the query and a subsequence of the target sequence represented by a candidate substring of the target string, the candidate substring comprising the prefix associated with the selected leaf as a suffix, wherein the determined distance is an initial upper bound in a similarity search of the target sequence using the query. 12. The method of similarity search initialization of claim 10 , wherein execution of the distance operator determines the distance between the query and each subsequence of a plurality of subsequences of the target sequence corresponding to respective ones of a plurality of candidate substrings, each candidate substring comprising a different prefix of a plurality of prefixes associated with a corresponding plurality of different query string suffixes, and wherein the determined distance used as the initial upper bound is a minimum of the determined distances.