JESS: [EXTERNAL] nested foreach to return from the inner loop
Hi Jess users, I have the following function: (deffunction similarity-score (?base ?other) (bind ?score 0) (bind ?totalDistance 0) (bind ?counter 0) (foreach ?x ?base (bind ?counter (+ ?counter 1)) (printout t counter is: ?counter) (bind ?partialDistance 0) (printout t partialDist is: ?partialDistance) (foreach ?y ?other (bind ?partialDistance (+ ?partialDistance 1)) (printout t foreach partialDist is: ?partialDistance) (if (eq ?x ?y) then (bind ?score (+ ?score 1)) (printout t score is: ?score) (return) ) ) (bind ?totalDistance (/ ?counter ?partialDistance)) ) (return (- (/ ?score (length$ ?base)) (* (- 1 (/ (length$ ?base) ?totalDistance)) 0.1) )) ) As you can see, the above function has a nested foreach loop, which upon finding equal values in both list should skip to the next iteration of the outer loop. In java, instead of (return) one would normally put a break statement. As far as the documentation of the (foreach) construct reads, it says: The return function can be used to break the iteration. However, what I am finding is that the (return) function terminates the outer loop too - unless I seriously messed up the code - but this is the result of my observation of the (printout t) function. Moreover, when I remove the (return) function, the function iterates over the outer and inner loops just fine. Any advice on how can I break the inner's loop iteration? I know I can use a variable to flag that the match has been found and add it to the if statement, but I am hoping that there is an equivalent of break in Jess. Cheers, Pete
Re: JESS: [EXTERNAL] nested foreach to return from the inner loop
Did you try the (break)http://www.jessrules.com/jess/docs/71/functions.html#breakfunction? Arguments:NoneReturns:N/ADescription: Immediately exit any enclosing loop or control scope. Can be used inside of forhttp://www.jessrules.com/jess/docs/71/functions.html#for, while http://www.jessrules.com/jess/docs/71/functions.html#while, and foreach http://www.jessrules.com/jess/docs/71/functions.html#foreachloops, as well as within the body of a deffunctionhttp://www.jessrules.com/jess/docs/71/constructs.html#deffunctionor the right hand side of a defrule http://www.jessrules.com/jess/docs/71/constructs.html#defrule. If called anywhere else, will throw an exception. *Jason C. Morris* President, Principal Consultant Morris Technical Solutions LLC President, Rules Fest Association Chairman, IntelliFest 2012: International Conference on Reasoning Technologies phone: +01.517.376.8314 skype: jcmorris-mts email: consult...@morris-technical-solutions.com mybio: http://www.linkedin.com/in/jcmorris www.intellifest.org Invent * Innovate * Implement at IntelliFest! On Thu, May 23, 2013 at 12:43 PM, Przemyslaw Woznowski p.r.woznow...@cs.cf.ac.uk wrote: Hi Jess users, I have the following function: (deffunction similarity-score (?base ?other) (bind ?score 0) (bind ?totalDistance 0) (bind ?counter 0) (foreach ?x ?base (bind ?counter (+ ?counter 1)) (printout t counter is: ?counter) (bind ?partialDistance 0) (printout t partialDist is: ?partialDistance) (foreach ?y ?other (bind ?partialDistance (+ ?partialDistance 1)) (printout t foreach partialDist is: ?partialDistance) (if (eq ?x ?y) then (bind ?score (+ ?score 1)) (printout t score is: ?score) (return) ) ) (bind ?totalDistance (/ ?counter ?partialDistance)) ) (return (- (/ ?score (length$ ?base)) (* (- 1 (/ (length$ ?base) ?totalDistance)) 0.1) )) ) As you can see, the above function has a nested foreach loop, which upon finding equal values in both list should skip to the next iteration of the outer loop. In java, instead of (return) one would normally put a break statement. As far as the documentation of the (foreach) construct reads, it says: The return function can be used to break the iteration. However, what I am finding is that the (return) function terminates the outer loop too - unless I seriously messed up the code - but this is the result of my observation of the (printout t) function. Moreover, when I remove the (return) function, the function iterates over the outer and inner loops just fine. Any advice on how can I break the inner's loop iteration? I know I can use a variable to flag that the match has been found and add it to the if statement, but I am hoping that there is an equivalent of break in Jess. Cheers, Pete
JESS: [EXTERNAL] Nested not/and syntax question
Hello everyone and best wishes for the new year could someone please give me an explanation why the following two rules behave in a different way, although they express the same logical formula (i.e., not (Object ^ Pred) )? In fact, only the second rule reaches correct conclusions, as I note below. (defrule Rule1 (not (and ?o - (Object (name B)) (Pred (obj ?o)) )) = (printout t OK1 crlf) ) (defrule Rule2 (or (not (Object (name B))) (and ?o - (Object (name B)) (not (Pred (obj ?o))) )) = (printout t OK2 crlf) ) The definition of facts could be like: (deftemplate Object (slot name)) (assert (Object (name A))) (assert (Object (name B))) (deftemplate Pred (slot obj)) where obj is the id of some Object fact, eg. (defrule Rule (declare (salience 10)) ?o - (Object (name A)) = (assert (Pred (obj ?o))) ) What I notice is that Rule1 behaves erroneously when the Object fact exists in the KB, but not the Pred fact: although it is supposed to be triggered, it is not! Rule2, on the other hand, behaves correctly all the times. When both Object and Pred facts exist or when the Object does not exist, both rules behave fine. So, what is wrong with the syntax of the first rule? No variable definition is used outside the not pattern.. Thanks Theodore To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' in the BODY of a message to majord...@sandia.gov, NOT to the list (use your own address!) List problems? Notify owner-jess-us...@sandia.gov.
Re: JESS: [EXTERNAL] nested or-and-not
Hi, Maybe this helps you in understanding: http://www.jessrules.com/jess/docs/71/rules.html#not_ce Note that a not pattern cannot define any variables that are used in subsequent patterns (since a not pattern does not match any facts, it cannot be used to define the values of any variables!) You can introduce variables in a not pattern, so long as they are used only within that pattern i.e. you cannot (read: should not) use ?t3 outside of the not expression. Please correct me if I'm wrong.. 2011/12/12 Al C trapatk...@hotmail.com: Hello all, First, I apologize for the length of this post. I have an issue with the syntax of a rule of mine that is puzzling me. The rule is as follows (i copy it exactly as it appears in its program, all parentheses are as shown): (defrule ColorChange (Time (timepoint ?t2)) ?e0 - (event (name StartPressing) (arg B1)) (EC (predicate Happens) (event ?e0 ) (time ?t1)) (test (= (+ ?t1 5) ?t2)) (or (not (event (name StopPressing) (arg B1))) (and ?e2 - (event (name StopPressing) (arg B1)) (not (EC (predicate Happens) (event ?e2 ) (time ?t3 ) (test (= ?t3 ?t1)) (test ( ?t3 ?t2)) ?event - (event (name ChangeColor) (arg B1)) = (assert (EC (predicate Happens) (epistemic no) (event ?event) (time ?t2 The idea is that ?t1= ?t3 ?t2, where ?t2 = ?t1 + 5. That is, if event StartPressing(B1) occurs at ?t1 a ChangeColor event will occur after 5 timepoints, given that no StopPressing(B1) event happened in the meantime (events may or may not appear in the KB, yet their occurences are what we are interested in). The rule at first seems to work fine, but then I noticed that ?t3 is declared outside the scope of its declaration. In fact, although it is correctly instantiated somehow, i cannot print its value using (printout t ?t3 crlf) in the head of the rule (Message: No such variable t3) On the other hand, if I omit the first disjunct and write (defrule ColorChange (Time (timepoint ?t2)) ?e0 - (event (name StartPressing) (arg B1)) (EC (predicate Happens) (event ?e0 ) (time ?t1)) (test (= (+ ?t1 5) ?t2)) ?e2 - (event (name StopPressing) (arg B1)) (not (EC (predicate Happens) (event ?e2 ) (time ?t3))) (test (= ?t3 ?t1)) (test ( ?t3 ?t2)) ?event - (event (name ChangeColor) (arg B1)) = (assert (EC (predicate Happens) (epistemic no) (event ?event) (time ?t2 i get Message: Variable used before definition: t3 during parsing, as expected. The fact that ?t3 is instantiated correctly has been tested by running different cases, where all events exists in the KB and StopPressing(B1) happens before and after StartPressing(B1) (in the former the rule fires, in the latter it does not). In addition, trying to figure out whether the tests for ?t3 are actually considered or not, I added a trivial test condition (test ( 1 0)) just after the last test. When this condition is true and the rule should not fire (StopPressing(B2) has happened), indeed it does not fire. Surprisingly, when the condition is false (test (eq 1 0)) and the rule should not fire.. it fires. Even without the existence of the ?t3 tests in the body of the rule. I cannot ascribe this behavior (or even why ?t3 is instantiated in the first place) to anything. I could use some ideas to understand where to focus the syntactical reshaping. Thank you Alex To unsubscribe, send the words 'unsubscribe jess-users y...@address.com' in the BODY of a message to majord...@sandia.gov, NOT to the list (use your own address!) List problems? Notify owner-jess-us...@sandia.gov.
JESS: [EXTERNAL] nested or-and-not
Hello all, First, I apologize for the length of this post. I have an issue with the syntax of a rule of mine that is puzzling me. The rule is as follows (i copy it exactly as it appears in its program, all parentheses are as shown): (defrule ColorChange (Time (timepoint ?t2)) ?e0 - (event (name StartPressing) (arg B1)) (EC (predicate Happens) (event ?e0 ) (time ?t1)) (test (= (+ ?t1 5) ?t2)) (or (not (event (name StopPressing) (arg B1))) (and ?e2 - (event (name StopPressing) (arg B1)) (not (EC (predicate Happens) (event ?e2 ) (time ?t3 ) (test (= ?t3 ?t1)) (test ( ?t3 ?t2)) ?event - (event (name ChangeColor) (arg B1)) = (assert (EC (predicate Happens) (epistemic no) (event ?event) (time ?t2 The idea is that ?t1= ?t3 ?t2, where ?t2 = ?t1 + 5. That is, if event StartPressing(B1) occurs at ?t1 a ChangeColor event will occur after 5 timepoints, given that no StopPressing(B1) event happened in the meantime (events may or may not appear in the KB, yet their occurences are what we are interested in). The rule at first seems to work fine, but then I noticed that ?t3 is declared outside the scope of its declaration. In fact, although it is correctly instantiated somehow, i cannot print its value using (printout t ?t3 crlf) in the head of the rule (Message: No such variable t3) On the other hand, if I omit the first disjunct and write (defrule ColorChange (Time (timepoint ?t2)) ?e0 - (event (name StartPressing) (arg B1)) (EC (predicate Happens) (event ?e0 ) (time ?t1)) (test (= (+ ?t1 5) ?t2)) ?e2 - (event (name StopPressing) (arg B1)) (not (EC (predicate Happens) (event ?e2 ) (time ?t3))) (test (= ?t3 ?t1)) (test ( ?t3 ?t2)) ?event - (event (name ChangeColor) (arg B1)) = (assert (EC (predicate Happens) (epistemic no) (event ?event) (time ?t2 i get Message: Variable used before definition: t3 during parsing, as expected. The fact that ?t3 is instantiated correctly has been tested by running different cases, where all events exists in the KB and StopPressing(B1) happens before and after StartPressing(B1) (in the former the rule fires, in the latter it does not). In addition, trying to figure out whether the tests for ?t3 are actually considered or not, I added a trivial test condition (test ( 1 0)) just after the last test. When this condition is true and the rule should not fire (StopPressing(B2) has happened), indeed it does not fire. Surprisingly, when the condition is false (test (eq 1 0)) and the rule should not fire.. it fires. Even without the existence of the ?t3 tests in the body of the rule. I cannot ascribe this behavior (or even why ?t3 is instantiated in the first place) to anything. I could use some ideas to understand where to focus the syntactical reshaping. Thank you Alex
