Digital Library[ Search Result ]
Parallel Implementation of the Order-Preserving Multiple Pattern Matching Algorithm using the Karp-Rabin Algorithm
Kyung Bin Park, Youngho Kim, Jeong Seop Sim
http://doi.org/10.5626/JOK.2021.48.3.249
When two strings of the same length have the same relative orders, they are called order-isomorphic. Given a text T(｜T｜=n)and a set of patterns P̃={P₁,P₂,...,Pk}, the order-preserving multiple pattern matching problem is to find all substrings of T that are order-isomorphic to any pattern in P̃ . Let m be the length of the shortest pattern, m̅ be the length of the longest pattern, and M be the sum of lengths of all the patterns in P̃. When M is polynomial with respect to m, an order-preserving multiple pattern matching algorithm using the Karp-Rabin algorithm was presented whose searching step runs in O(n) time on average. In this paper, we implemented an order-preserving multiple pattern matching algorithm using the Karp-Rabin algorithm in parallel. It runs in O(m̅) time on average using O(M) threads in the preprocessing step and runs in O(m) time on average using O(n) threads in the searching step. The experimental results for random strings as input showed that our parallel implementation performed approximately 201.5 times faster than the existing sequential algorithm when n=1,000,000, k=1,000, m=5.
Parallel Computation of Z-Function for Order-Preserving Pattern Matching and Order-Preserving Multiple Pattern Matching
Youkun Shin, Youngho Kim, Jeong Seop Sim
http://doi.org/10.5626/JOK.2018.45.8.778
Given a text T of length n and a pattern P of length m, the order-preserving pattern matching problem is to find all substrings in T which are order-isomorphic to P. Given a text T of length n and a set of patterns W={P₁, P₂,…, Pb}, the order-preserving multiple pattern matching problem is to find all substrings in T which are order-isomorphic to patterns of W. In this paper, we present two parallel algorithms based on the Z-function. The first algorithm for the order-preserving pattern matching problem runs in O(m) time using O(n+hm) threads and the second algorithm for the order-preserving multiple pattern matching problem runs in O(n+M) time using O(b(n+M)) threads, where h is the number of blocks and M is the length of the longest pattern in W. Experimental results show that our parallel algorithm for the order-preserving pattern matching problem is approximately 71.2 times faster than the sequential algorithm when m=10 and n=1,000,000, and that our parallel algorithm for the order-preserving multiple pattern matching problem is approximately 12.2 times faster than the sequential algorithm when b=1,000, m=10, and n=1,000.
A Hashing-Based Algorithm for Order-Preserving Multiple Pattern Matching
Munseong Kang, Sukhyeun Cho, Jeong Seop Sim
Given a text Tand a pattern P, the order-preserving pattern matching problem is to find all substrings in T which have the same relative orders as P. The order-preserving pattern matching problem has been studied in terms of finding some patterns affected by relative orders, not by their absolute values. Given a text T and a pattern set ℙ, the order-preserving multiple pattern matching problem is to find all substrings in T which have the same relative orders as any pattern in ℙ. In this paper, we present a hashing-based algorithm for the order-preserving multiple pattern matching problem.
Search
Journal of KIISE
- ISSN : 2383-630X(Print)
- ISSN : 2383-6296(Electronic)
- KCI Accredited Journal
Editorial Office
- Tel. +82-2-588-9240
- Fax. +82-2-521-1352
- E-mail. chwoo@kiise.or.kr