Comparison of the Rete an Matchers for Soar (A Summary)*

RETE and TREAT are two well known algorithms used for performing match in production systems (rule-based systems). In this paper, we compare the performance of these two algorithms in the context of Soar programs. Using the number of tokens processed by each algorithm as the performance metric, we show that the RETE algorithm performs better than the TREAT algorithm in most cases. Our results are different than the ones shown by Miranker for OPS5. The main reasons for this difference are related to the following: (i) fraction of times no joins need to be done; (ii) the long chain effect; (iii) matching of static structures; and (iv) handling of combinatorial joins. These reasons go beyond Soar in their applicability, and are relevant to other OPS5-based production systems that share some of Soar’s properties. We also discuss several implementation issues for the two algorithms.