6.2.2.2 Optimization of the Strategy

A conflict resolution strategy may be optimized by combining the constituent tactics in a more effective manner. There are three different types of conflict resolution tactic:

• Rule-defined (meaning the tactic relies only on the rule of the instantiation and on nothing else), including priority , -priority , order , -order , specificity and -specificity
• Static (meaning the tactic does not look into the slots of the matched objects which make up the instantiation), including recency and -recency , and
• Dynamic (meaning the tactic may look into the objects making up the instantiation), including mea , -mea , lex and -lex .

KnowledgeWorks is best able to optimize rule-defined tactics and least able to optimize dynamic tactics. The optimizations for a particular type of tactic can only be applied if it is preceded only by tactics which can be optimized to the same degree (or better). For example, in the strategy (recency priority) , the tactic priority would only be optimized as a static tactic. In the strategy (priority mea recency) , priority can be optimized as a rule-defined tactic but recency will be treated as a dynamic tactic.

Some final points to bear in mind:

• Tactics which tend to prefer existing instantiations over newer ones (for example -mea , -lex and -recency ) will degrade performance
• recency and lex have similar functionality but recency is more efficient.

KnowledgeWorks and Prolog User Guide (Unix version) - 6 Dec 2011