知识工程高级模式匹配.pptxVIP

Chapter 10:Advanced Pattern MatchingExpert Systems: Principles and Programming, Fourth EditionObjectivesLearn about field constraintsLearn how to use functions and expressionsLearn how to perform summing values using rulesLearn how to use the bind functionLearn how to use I/O functionsExpert Systems: Principles and Programming, Fourth EditionObjectivesExamine the two-player game called SticksLearn how to use the test conditional elementLearn how to use the predicate field constraint and the return value constraintExamine the or, and, not, exists, forall logical elements.Expert Systems: Principles and Programming, Fourth EditionField Constraints 字段约束In addition to pattern matching capabilities and variable bindings, CLIPS has more powerful pattern matching operators.Consider writing a rule for all people who do not have brown hair:We could write a rule for every type of hair color that is not brown.This involves testing the condition in a roundabout manner 迂回方式– tedious冗长乏味, but effective.Expert Systems: Principles and Programming, Fourth EditionField ConstraintsThe technique for writing a rule for all non-brown hair colors implies that we have the ability to supply all hair colors – virtually impossible.An alternative is to use a field constraint to restrict the values a field may have on the LHS – the THEN part of the rule.解决这一问题方法是使用字段约束来限制一个字段可能在LHS中的值。Expert Systems: Principles and Programming, Fourth EditionConnective ConstraintsConnective constraints are used to connect variables and other constraints.Not connective – the ~ acts on the one constraint or variable that immediately follows it.Expert Systems: Principles and Programming, Fourth EditionConnective ConstraintsOr constraint – the symbol | is used to allow one or more possible values to match a field or a pattern.Expert Systems: Principles and Programming, Fourth EditionConnective ConstraintsAnd constraint – the symbol is useful with binding instances of variables and on conjunction with the not constr