[rules-users] Re: drools 5.0.0-SNAPSHOT Maven repository broken? -> Lingering logically inserted facts problem

[Geoffrey De Smet]

Hi Tim

 >> I am convinced that:
 >>  2) Penalty's equals/hashcode uses both "cause" and "weight"?
 >>  then 3) happens: Keep Penalty(10), add Penalty(5)
 >> is an issue in drools core and instead 2) should happen:
 >>  Remove Penalty(10), add Penalty(5)
 >> because Penalty(10) is no longer true
 >
 > exactly!
 > that is the behavior i was expecting. it took me quite some time
 > to find out why my program did not find a solution.

I made a testcase and Edson might look into it :)
Watch this issue
   https://jira.jboss.org/jira/browse/JBRULES-1804
Once it's resolved, I 'll made the necessary adjustments in the 
equals/hashcode of the ConstraintOccurrence implementations.

With kind regards,
Geoffrey De Smet


tim tim schreef:

> 
>> I am going to make a testcase to isolate the problem and make it more
>> transparent that it is indeed an issue. And then try to convince Mark and
>> Edson that it's an issue :)
> 
> maybe there could be a switch, to tell drools which mode
> is prefered? then they could keep the strange behavior in the engine ;-)
> 
> 
>> which the HACK indeed that you quothed below:
>>  the hack causes the rule to no longer apply (retracting the
>> ConstraintOccurrence), after which it then refires.
> 
> argh, you are right! i didnt see that it gets retracted. i still have
> to get used
> to the drools way..
> 
> 
> best, tim
> 
>>> i solved the problem of improving constraints for the same causes that
>>> differ in hashCode by retracting the old fact before inserting the new
>>> one.
>>> but it takes quite some overhead to be able to do so. i could post my
>>> code if anyone is interested.
>>>
>>> unfortunately i could not find in your samples how you handle such a
>>> scenario.
>>>
>>> does the "HACK" part of this rule have something to do with it?
>>>
>>> from curriculumCourseScoreRules.drl
>>>
>>> // MinimumWorkingDays: The lectures of each course must be spread into
>>> a minimum number of days.
>>> // Each day below the minimum counts as 5 points of penalty.
>>> rule "minimumWorkingDays"
>>>    when
>>>        $course : Course($minWorkingDaySize : minWorkingDaySize);
>>>        $dayCount : Number(intValue < $minWorkingDaySize) from accumulate(
>>>            $day : Day()
>>>            and exists Lecture(course == $course, day == $day),
>>>            count($day)
>>>        );
>>>        // HACK to fix wierd truth maintance behavior in drools
>>>        // because making weight part of the equals/hashcode doesn't cut it
>>>        not IntConstraintOccurrence(
>>>            ruleId == "minimumWorkingDays",
>>>            constraintType == ConstraintType.NEGATIVE_SOFT,
>>>            causes contains $course,
>>>            eval(weight != (($minWorkingDaySize - $dayCount.intValue()) *
>>> 5))
>>>        );
>>>        // An uninitialized schedule should have no constraints broken
>>>        exists Lecture(course == $course);
>>>    then
>>>        insertLogical(new
>>> IntConstraintOccurrence("minimumWorkingDays",
>>> ConstraintType.NEGATIVE_SOFT,
>>>                (($minWorkingDaySize - $dayCount.intValue()) * 5),
>>>                $course));
>>> end
>>>
>>> but the hack makes the rule not fire at all, when it had fired before.
>>> even if the error has improved by now.
>>>
>> Feed back is always welcome :)
>>
>> With kind regards,
>> Geoffrey De Smet
>>
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