DISTRIBUTED SIMULATION OF HIGH-LEVEL ALGEBRAIC PETRI NETS WITH LIMITED CAPACITY PLACES

The aim of this paper is to search for techniques to accelerate simulations exploiting the parallelism available in current multicomputers, and to use these techniques to study a class of Petri nets called high-level algebraic nets. These nets exploit the rich theory of algebraic specifications for high-level Petri nets. They also gain a great deal of modelling power by representing dynamically changing items as structured tokens whereas algebraic specifications turned out to be an adequate and flexible instrument for handling structured items. We focus on ECATNets (Extended Concurrent Algebraic Term Nets), a kind of high-level algebraic Petri nets with limited capacity places Three distributed simulation techniques have been considered: asynchronous conservative, asynchronous optimistic and synchronous. These algorithms have been implemented in a network of workstations with MPI (Message Passing Interface). The influence that factors such as the characteristics of the simulated models, the organisation of the simulators and the characteristics of the target multicomputer have in the performance of the simulations have been measured and characterized It is concluded that distributed simulation of ECATNets on a multicomputer system can in fact gain speedup over the sequential simulation, and this can be achieved even for small scale simulation models.