Both rules will be "activated," or placed on the agenda, ready for
firing.  Then one of them will fire first. It's hard to predict which
one, since their LHS are identical. Jess doesn't "pick one randomly,"
but one will naturally be placed first on the agenda. When that rule
fires, it retracts the two facts that activated it. This will result
in the second rule be deactivated and removed from the agenda.


I think Francisco Dario wrote:
> Hello,
> I have the following question:
> Supose I have the following rules
> 
> (defrule r1
>    ?f1 <- (a ?n1)
>    ?f2 <- (b ?n2)
> =>
>   (assert (c (+ ?n1 ?n2)))
>   (retract ?f1)
>   (retract ?f2))
> 
> 
> and another rule
> 
> (defrule r2
>    ?f1 <- (a ?n1)
>    ?f2 <- (b ?n2)
> =>
>   (assert (c (- ?n1 ?n2)))
>   (retract ?f1)
>   (retract ?f2))
> 
> 
> What should be the behavior of JESS when I assert the facts
> (a 4) and (a 6) for instance?
> These two facts satisfy the antecedents of the two rules, but when the first 
> one is fired it retracts the facts which would be used for the second rule, 
> isn't it? Thus, is the second rule fired? Jess chooses randomly the first 
> rule to fire?
> 
> Thanx.
> Dario
> 
> _________________________________________________________________
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> 



---------------------------------------------------------
Ernest Friedman-Hill  
Distributed Systems Research        Phone: (925) 294-2154
Sandia National Labs                FAX:   (925) 294-2234
Org. 8920, MS 9012                  [EMAIL PROTECTED]
PO Box 969                  http://herzberg.ca.sandia.gov
Livermore, CA 94550

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