Hello Ernest,
thanks for your really good explanation, now I realize that I have a
problem
desinng because I have placed on the LHS some responsibilities which
weren't
its... That's due to I have to keep reference between facts and I do that
using a 'id' slot... That would be better done from Java... but I think
that
it's too late becase my piece of software is almost finished... except
for
this "little" lapse :). So I'd like to fix the problem in other manner so
that I wouldn't need to break up all my code...
Anyhow, if I add all my facts in one batch there are no exceptions. I
find
problems problems just when running the engine (Rete#RunUntilHalt()) in
order to check constraints, then I wait the engine to stop and afterwards
adding/modifing/retracting facts. Is there any reason to think that I'm
re-running the engine when I call 'modify','retrarct' or 'assert' from
Java?
If I can keep stopped the engine while processing the facts (because they
are inconsistent until the last one has been processed, for that reason I
get a nonexistent fact's id in fact-slot-value), I think that all will
work
fine.
Thank for your help,
Filix.
PS. I'm sorry if my explanitions are too confused, it might be my
english's
fault, although I'm not sure if they would be better in spanish...
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <jess-users@sandia.gov>
Sent: Saturday, August 27, 2005 9:42 PM
Subject: Re: JESS: How to stop firing rules (again)
> Felix,
>
> The error is happening during pattern-matching, which is driven by
> working memory changes (i.e., all matching involving a given fact
> happens whenever that fact is asserted, retracted, or modified.)
>
> The problems are happening during calls to fact-slot-value. It's easy
> enough to fix this: don't do that, ever. There is never a reason to
> call fact-slot-value on the left hand side of a rule -- you've already
> got ahold of a fact (or if you don't, you can get it) and so you can
> match the slots directly. Your problem is that you're calling fact-id
> to get ahold of some nonexistent fact, then passing that nonexistent
> fact's id (-1) to fact-slot-value, which is reporting that, indeed,
> there's no such fact.
>
> As an aside, the fact-id function is virtually never needed: it turns
> a real integer into a Fact by doing a slow lookup. It's useful when
> debugging from the command line, but there's never a need to use it
> during normal Jess coding (although you might use it to restore links
> when loading interconnected facts in from a flat file of some kind.)
> If you're actually got a number and need a jess.Fact object, then use
> it. But if you're got a fact binding, then it's already a jess.Fact
> object.
>
> I untangled your code extract into this, which *really* doesn't belong
> on the LHS of a rule. Apparently this is part of a deffunction that
> you're calling from a test CE -- i.e., from the LHS of a rule.
>
> (if (or (eq (fact-slot-value (fact-id ?fact) template) imple-method)
> (eq (fact-slot-value (fact-id ?fact) template) global-method))
> then
> (return ?fact)
> else
> (if (eq (fact-slot-value (fact-id ?fact) template) class)
> then (return "-1")
> else
> (bind ?p-id (fact-slot-value (fact-id ?fact) parent-id))
> (get-method-id ?p-id)))
>
> Now, you *could* simply add some "guard clauses." Just as in Java
> code, you'd check things for null before using them, here you need to
> check that ?fact isn't "-1" before continuing with this routine. But
> the right thing to do is to break this all up and do it as pattern
> matching instead. It would not only be vastly simpler, but it'd
> probably be vastly more efficient, too.
>
> I can't tell you exactly what to do, because you really need to
> rethink the fundamental design. You've got this whole system designed
> in a procedural way. Instead of using if-then logic on the LHS of a
> rule, you instead what to write multiple rules, one for each case you
> need to handle.
>
> Something like
>
> (if (or (eq (fact-slot-value (fact-id ?fact) template) imple-method)
> (eq (fact-slot-value (fact-id ?fact) template) global-method))
>
> could instead be written as something like
>
> (call-method (template imple-method | global-method))
>
> if you followed my advice.
>
> I think =?iso-8859-1?Q?F=E9lix_G=F3mez_Cordero?= wrote:
> [Charset iso-8859-1 unsupported, filtering to ASCII...]
>> Hi Jason,
>>
>> thanks for your answer, one of errors I get is throwed when I try to
>> assert the next fact: (MAIN::call-method (id "13") (template
>> call-method)
>> (parent-method-id "9") (parent-id "12") (params "10")).
>>
>> Error Message is:
>> Jess reported an error in routine factid
>>
>> while executing (fact-id ?fact)
>>
>> while executing deffunction fact-slot-value
>>
>> while executing (fact-slot-value (fact-id ?fact) template)
>>
>> while executing (eq (fact-slot-value (fact-id ?fact) template)
>> imple-method)
>>
>> while executing (or (eq (fact-slot-value (fact-id ?fact) template)
>> imple-method) (eq (fact-slot-value (fact-id ?fact) template)
>> global-method))
>>
>> while executing (if (or (eq (fact-slot-value (fact-id ?fact) template)
>> imple-method) (eq (fact-slot-value (fact-id ?fact) template)
>> global-method)) then (return ?fact) else (if (eq (fact-slot-value
>> (fact-id ?fact) template) class) then (return "-1") else (bind ?p-id
>> (fact-slot-value (fact-id ?fact) parent-id)) (get-method-id ?p-id)))
>>
>> while executing deffunction get-method-id
>>
>> while executing (get-method-id ?p-id)
>>
>> while executing (if (eq (fact-slot-value (fact-id ?fact) template)
>> class)
>> then (return "-1") else (bind ?p-id (fact-slot-value (fact-id ?fact)
>> parent-id)) (get-method-id ?p-id))
>>
>> while executing (if (or (eq (fact-slot-value (fact-id ?fact) template)
>> imple-method) (eq (fact-slot-value (fact-id ?fact) template)
>> global-method)) then (return ?fact) else (if (eq (fact-slot-value
>> (fact-id ?fact) template) class) then (return "-1") else (bind ?p-id
>> (fact-slot-value (fact-id ?fact) parent-id)) (get-method-id ?p-id)))
>>
>> while executing deffunction get-method-id
>>
>> while executing (get-method-id ?parent-id)
>>
>> while executing (str-compare (get-method-id ?parent-id) (get-method-id
>> ?param-id))
>>
>> while executing (= (str-compare (get-method-id ?parent-id)
>> (get-method-id
>> ?param-id)) 0)
>>
>> while executing 'test' CE
>>
>> // The above functions are part of my rules, but the engine should not
>> be
>> running....
>>
>> while executing rule LHS (Node2)
>>
>> while executing rule LHS (MTELN)
>>
>> while executing rule LHS (TECT).
>>
>> Message: No such fact-id: -1.
>>
>> at jess.MakeFactID.call(MiscFunctions.java:817)
>>
>> at jess.FunctionHolder.call(FunctionHolder.java:30)
>>
>> at jess.Funcall.execute(Funcall.java:266)
>>
>> at jess.FuncallValue.resolveValue(FuncallValue.java:33)
>>
>> at jess.Deffunction.call(Deffunction.java:164)
>>
>> at jess.FunctionHolder.call(FunctionHolder.java:30)
>>
>> at jess.Funcall.execute(Funcall.java:266)
>>
>> at jess.FuncallValue.resolveValue(FuncallValue.java:33)
>>
>> at jess.Eq.call(Funcall.java:1072)
>>
>> .........
>>
>> on the follow engine status:
>>
>> ID: 0 (MAIN::initial-fact)
>>
>> ID: 1 (MAIN::default-type (id "1") (template default-type) (parent-id
>> "-2") (name "E"))
>>
>> ID: 2 (MAIN::default-type (id "2") (template default-type) (parent-id
>> "-2") (name "R"))
>>
>> ID: 3 (MAIN::default-type (id "3") (template default-type) (parent-id
>> "-2") (name "N"))
>>
>> ID: 4 (MAIN::default-type (id "4") (template default-type) (parent-id
>> "-2") (name "Cadena"))
>>
>> ID: 5 (MAIN::default-type (id "5") (template default-type) (parent-id
>> "-2") (name "Objeto"))
>>
>> ID: 6 (MAIN::global-method (id "6") (parent-id "-1") (template
>> global-method) (name "imprimir") (returned-type "-1") (params "7"))
>>
>> ID: 7 (MAIN::parameter (id "7") (template parameter) (parent-id "6")
>> (name "cadena") (type "4") (value nil))
>>
>> ID: 8 (MAIN::class (id "8") (template class) (name "Clase")
>> (implementation-method "9") (field "11"))
>>
>> ID: 9 (MAIN::imple-method (id "9") (template imple-method) (method
>> "-1")
>> (name "metodo") (parent-id "8") (returned-type "1") (params "10")
>> (body ))
>>
>> ID: 10 (MAIN::parameter (id "10") (template parameter) (parent-id "9")
>> (name "param") (type "1") (value nil))
>>
>> ID: 11 (MAIN::imple-field (id "11") (template imple-field) (name
>> "field")
>> (parent-id "8") (type "1") (value nil))
>>
>>
>> I get similar errors messages sometimes (these errors are not shown
>> always) when I modify facts. I modify and add facs from the next java
>> methods:
>>
>> // To assert facts
>> public static void assertFact(Fact f){
>> try {
>>
>> // This call is not outstanding
>> f.setSlotValue("id",new
>> Value(FactIdProvider.INSTANCE.getNewFactId(),RU.STRING));
>>
>>
>> engine.assertFact(f);
>>
>> facts.addFact(f);
>>
>> } catch (JessException e) {
>>
>> System.err.println(
>> "Se produjo un error afirmando el hecho: "
>> + f.toString());
>> e.printStackTrace();
>> }
>> }
>>
>> // To modify slot values
>> public static void setSlotValue(
>> int factId,
>> String slotName,
>> String slotValue) {
>> try {
>> // Si esta vacio se establece a 'espacio en blanco'
>> if (slotValue.equals("")){
>> slotValue = " ";
>>
>> }
>>
>> // Se ejecuta la sentencia
>> engine.executeCommand(
>> "(modify " + factId + " (" + slotName + " " + slotValue +
>> "))");
>>
>>
>> } catch (JessException e) {
>> System.err.println(
>> "FactID como int: Se ha producido un error estableciendo el valor
>> del
>> slot "
>> + slotName
>> + " del hecho con id "
>> + factId
>> + " al valor "
>> + slotValue);
>> e.printStackTrace();
>> }
>> }
>>
>>
>> I hope this source code to help you to understand what I'm trying to
>> do,
>> thanks againg,
>>
>>
>> Felix.
>>
>>
>>
>> ----- Original Message -----
>> From: Jason Morris
>> To: jess-users@sandia.gov
>> Sent: Saturday, August 27, 2005 8:21 AM
>> Subject: Re: JESS: How to stop firing rules (again)
>>
>>
>>
>>
>>
>> On 8/26/05, F_lix G_mez Cordero <[EMAIL PROTECTED]> wrote:
>> Hi all,
>>
>> I posted the same question some weeks ago. I thought at that time
>> that my problem was fixed... but it seems now that I was wrong! So I
>> will
>> explain it again...
>>
>>
>> Hi Flelix,
>>
>> An ounce of source code is worth a pound of explanation. :-D
>> Please post your actual code, and I bet the group can help you much
>> faster.
>>
>> Cheers,
>> Jason Morris
>> Co-Moderator Jess Listserver
>>
>>
>> -----------------------------------------------------
>> Morris Technical Solutions LLC
>> www.morristechnicalsolutions.com
>> [EMAIL PROTECTED]
>> phone/fax: 503.692.1088
>
>
>
> ---------------------------------------------------------
> Ernest Friedman-Hill
> Advanced Software Research Phone: (925) 294-2154
> Sandia National Labs FAX: (925) 294-2234
> PO Box 969, MS 9012 [EMAIL PROTECTED]
> Livermore, CA 94550 http://herzberg.ca.sandia.gov
>
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