Re: [rules-users] Re: drools 5.0.0-SNAPSHOT Maven repository broken?
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 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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