On Detection of Bounded Global Predicates

I.-C. Wu
1998 Computer journal  
Distributed programs often follow some bounded global predicates, for example, the total number of certain tokens is always the same or bounded in a range. In order to detect bounded global predicates, we can first derive the minimum and maximum global snapshots and then check if the minimum and maximum are out of the range. Recently, Chase and Garg proposed an efficient method to derive the minimum global snapshot by reducing this problem to a maximum network flow problem. A restriction of
more » ... method is that all message values (e.g., the token number in messages) must be zero and all process state values (e.g., the token number in processes) must be non-negative. In this paper, we propose an elegant technique, called normalization. By using this technique, we can remove the above restriction and also derive the minimum and maximum global snapshots at the same time. Groselj [7] proposed an interesting method to derive the global state with minimum cost, called the minimum global snapshot [7] , by reducing the problem to a maximum network flow (or minimum cut) problem. However, Groselj only considered message costs and assumed that all messages had cost one. Later, Chase and Garg [4] also used the maximum flow algorithm to derive the global state with minimum THE
doi:10.1093/comjnl/41.4.231 fatcat:wpsdoykccfhl7iapqlszv3hy7u