Performance improvement of state space exploration by regular & differential hashing functions

Abstract

This paper presents regular hashing functions. Used in conjunction with differential computation process, regular hashing functions enable searching time of global state to be optimized. After a formal definition of the regular property for hashing functions, we propose a characterization of this property. Then the formal definition of differential hashing function is given. Next, we show the performance acceleration produced by the preeomputed differential computation process applied to three hashing functions commonly used. The observed accelerations can be significant because the complexity of proposed implementation is independent of key length or respectively of item difference contrary to the usual or respectively differential implementations. Last we study the performances of precomputed differential hashing computation process on reachability graph exploration of distributed systems specified by Petri net using the Bouster tool, and on state space exploration of protocols specified by Lotos using the Open/Caesar environment.