如何将这两个规则与CLIPS结合起来?

时间:2013-04-12 04:41:54

标签: expert-system clips knowledge-capture

我在CLIPS中有两个规则,如果它们都是真的我想要合并......但不确定如何做到这一点。我有一个名为grant-eligible的属性....我在想是否将其设置为TRUE然后我可以阅读下一条规则,然后将'grant-eligible'设置为{{1 ....但是,当我这样做时,似乎我的代码进入了无限循环...

所以这是我的规则:

FALSE

这是我现在尝试实施的那些

    (defrule complete "rule for app completeness"
  ?f <- (application (transcript-received Yes) (app-complete FALSE)
    (gpa
                ?v_gpa&:(
                    > ?v_gpa 0)))

  =>
  (modify ?f (app-complete TRUE)))


    (defrule denied "rule for admission - DENIED"
  ?f <- (application (app-complete TRUE) (app-decision FALSE)
    (gpa
                ?v_gpa&:(
                    < ?v_gpa 3.0))

    (ssat
                ?v_ssat&:(
                    >= ?v_ssat 0.0))



        )


  =>
  (modify ?f (app-decision DENIED))

  )

(defrule accepted "rule for admission - ACCEPTED"
  ?f <- (application (app-complete TRUE) (app-decision FALSE)
    (gpa
                ?v_gpa&:(
                    >= ?v_gpa 3.5))

    (ssat
                ?v_ssat&:(
                    >= ?v_ssat 1500))


        )

  =>
  (modify ?f (app-decision ACCEPTED))

  )

如果这两条规则都属实,则授予的奖励应为9500,或者可能为5000或者可能为4500 ......任何想法?

解决方案:(其中(defrule female-finaid "rule for finaid applications for female students" ?f <- (application (app-decision ACCEPTED) (gender F) (grade-entry Freshman) (country USA) (grant-eligible TRUE) (grant ?v_grant) ) => (modify ?f (grant (+ ?v_grant 5000)) (grant-eligible TRUE) ) ) (defrule great-students-finaid "rule for finaid applications for female students" ?f <- (application (app-decision ACCEPTED) (country USA) (grant-eligible TRUE) (grant ?v_grant) (gpa ?v_gpa&:( >= ?v_gpa 4.0)) ) => (modify ?f (grant (+ ?v_grant 4500)) (grant-eligible FALSE) ) ) ff-grant-eligible是我的控制事实......他们代表ff =女性finaid,es =优秀学生)

es-grant-eligible

1 个答案:

答案 0 :(得分:2)

您可以通过多种方式控制程序的执行(例如,控制事实,突出性,模块)。这个答案将使用控制事实(有突出性)来处理应用程序的各个阶段。我还假设您有一个与每个应用程序关联的唯一id插槽。

考虑以下事实和规则:

(deffacts application-stages "ordered sequence of stages for an application"
  (stages app-received app-accept-reject app-evaluate-grants
          app-apply-grants app-complete))

(defrule go-to-next-stage "Advances to the next application stage"
  ?stage <- (app-stage ?id ?current-stage)
  (stages $? ?current-stage ?next-stage $?)
  =>
  (retract ?stage)
  (assert (app-stage ?id ?next-stage))
  (printout t "Application " ?id " moved from stage " ?current-stage
              " to " ?next-stage "." crlf))

application-stages deffact定义应用程序的阶段序列,go-to-next-stage规则推进应用程序阶段。由于规则的显着性低于默认值(0),因此只有在没有与当前阶段对应的其他规则时才会执行该规则。因此,如果您的计划中没有其他规则,您将获得以下内容:

CLIPS> (reset)
CLIPS> (assert (app-stage app-001 app-received))
<Fact-2>
CLIPS> (run)
Application app-001 moved from stage app-received to app-accept-reject.
Application app-001 moved from stage app-accept-reject to app-evaluate-grants.
Application app-001 moved from stage app-evaluate-grants to app-apply-grants.
Application app-001 moved from stage app-apply-grants to app-complete.
CLIPS> 

但是如果您有与特定阶段相关的任何规则,它们将首先执行。因此,您可以将规则添加到app-evaluate-grants阶段,如下所示:

(defrule female-finaid "rule for finaid applications for female students"
  (app-stage ?id app-evaluate-grants)
  (application (app-decision ACCEPTED) (id ?id)
    (gender F) (grade-entry Freshman) (country USA)
  =>
  (assert (grant ?id female 5000)))

您同样会添加great-student-finaid规则。然后,app-apply-grants阶段有一条规则:

(defrule apply-grant "Adds the amount of a grant to an application"
  (app-stage ?id app-apply-grants)
  ?grant <- (grant ?id ? ?amount)
  ?app <- (application (id ?id) (grant ?v_grant))
  =>
  (retract ?grant)
  (modify (?app (grant (+ ?v_grant ?amount))))

以这种方式对其进行建模的一个好处是,您不必在应用程序的数据中包含控制事实(例如grant-eligible)。也就是说,您的控制逻辑与数据模型是分开的。请注意,通过使用CLIPS模块(通过defmodule),您可以获得与我在此处所做的相同的效果,这通常是可取的,但它需要更长的答案(并且这个已经相当长)。 / p>