状態保存式パターン照合アルゴリズムの定性的コスト分析と最良アルゴリズム選択法

抄録

State saving is a powerful technique to improve the efficiency of pattern matching in production systems. The Rete and the Treat algorithms which both utilize this technique have been experimentally compared but the evaluation has not yet been settled. This paper gives a unifying view to the state saving methods by introducing the concept of "saving level". The change of pattern matching cost against the saving level is qualitatively analyzed and the following results are obtained. (l)The optimal saving level strongly depends upon problem domains. (2) Rete, Treat and no-saving methods have a suitable problem domain respectively. (3) The cost-balancing method is not always effective. Finally, we propose an approach to the saving-level optimization problem.