1998 年 13 巻 4 号 p. 644-651
One of the important topics in production systems is how to deal with expensive productions. Expensive productions are rules which would be required the extraordinary time and space to match (compare the left-hand side of rule against the current working memory). In this paper, we propose a match algorithm which improved the direct match algorithm for managing the working memory elements (WMEs) compressed by their attribute values. By compression of WMEs, the number of WMEs which must be examined whether the condition of rule matches or not decreases. Therefore, the frequency of match decreases, and the time for matching will be improved. We also compare the proposed algorithm to Rete algorithm and direct match algorithm, and show that the proposed algorithm is effective to deal with some class of expensive productions.