2:35 p.m.
it seems odd - I want to use POSITIVE but I am using it to reduce the
soft constraints broken?
You got a good point.
I already tried fixing that situation when refactoring from a double to
the Score interface.
I wanted to remove the ScoreCalculator and just do:
global Score score;
with a single rule that has 2 accumulates: one for the hard and one for
the soft constraints. It then updates the score field.
But because I ran into these issues:
https://jira.jboss.org/jira/browse/JBRULES-2238
https://jira.jboss.org/jira/browse/JBRULES-2239
the performance was divided by 3.
So I had to keep using a ScoreCalculator (where I didn't fix that
oddness yet), for now.
Mark's true modify work will probably resolve those issues (especially
in the Drools Planner use cases) and allow me to do the global Score
score the way it needs to be done without loosing huge performance. So
go Mark, go :)
Actually, the rule you wrote:
when
$softTotal : Number() from accumulate(
IntConstraintOccurrence(constraintType ==
ConstraintType.NEGATIVE_SOFT, $weight : weight),
sum($weight) // Vote for
http://jira.jboss.com/jira/browse/JBRULES-1075
);
$positiveTotal: Number() from accumulate(
IntConstraintOccurrence(constraintType ==
ConstraintType.POSITIVE, $weight : weight),
sum($weight) // Vote for
http://jira.jboss.com/jira/browse/JBRULES-1075
);
will get killed in performance because of those issues.
For now, just hack it by only making POSITIVE IntConstraintOccurrence's
and use negative weights for NEGATIVE_SOFT's.
Currently, the ConstraintOccurrence aren't used outside the DRL (nothing
specific in the drools planner core) but that might change once I
implement the option to do conflict based statistics (or guided local
search).
With kind regards,
Geoffrey De Smet
Greg Barton schreef:
So, basically what you're saying is, "The impact of a given
negative soft constraint is reduced by the occurrence of another positive
constraint."
If that's the case, the rule makes sense to me: total up the occurrences of the
negative constraint, total up the occurrences of the positive constraint, and then combine
them in a way that describes their relationship.
In this case, what the positive constraint "favors" is the reduction or
elimination of the negative constraint, so subtracting the positive constraint makes
sense. (A classic "interference pattern" situation.)
--- On Thu, 1/7/10, Michael Neale <michael.neale(a)gmail.com> wrote:
> From: Michael Neale <michael.neale(a)gmail.com>
> Subject: [rules-users] Planner/solver - POSITIVE scoring...
> To: "Rules Users List" <rules-users(a)lists.jboss.org>,
"Geoffrey" <ge0ffrey.spam(a)gmail.com>
> Date: Thursday, January 7, 2010, 12:23 AM
> Hi All - FYI I have been conversing
> with Geoffrey on basic
> solver/planner usage questions, but we are bring the
> discussion here
> in case others can benefit.
>
> So I am looking at using IntConstraintOccurrence, for
> scoring with
> weights, and HardAndSoftConstraintScoreCalculator. So I can
> see how
> NEGATIVE_HARD and NEGATIVE_SOFT scores would work, with
> appropriate
> accumulator rules doing that etc.
>
> What I am not sure about is ConstraintType.POSITIVE - so I
> want to use
> that to "favour" certain aspects of a solution. So would
> the correct
> way to use that to be to have rules that use a positive
> IntConstrainOccurrence, and then do something like:
>
> when
> $softTotal : Number() from
> accumulate(
>
> IntConstraintOccurrence(constraintType ==
> ConstraintType.NEGATIVE_SOFT, $weight : weight),
> sum($weight) //
> Vote for
> http://jira.jboss.com/jira/browse/JBRULES-1075
> );
> $positiveTotal: Number()
> from accumulate(
>
> IntConstraintOccurrence(constraintType ==
> ConstraintType.POSITIVE, $weight : weight),
> sum($weight) //
> Vote for
> http://jira.jboss.com/jira/browse/JBRULES-1075
> );
>
> then
>
> scoreCalculator.setSoftConstraintsBroken($softTotal.intValue()
> - $positiveTotal.intValue());
>
>
>
> ?? it seems odd - I want to use POSITIVE but I am using it
> to reduce
> the soft constraints broken? The the higher the positive
> score, the
> less softConstraintsBroken property of the score calculator
> is set -
> that seems odd... or should I not use HardAndSoft if I am
> using
> POSITIVE and NEGATIVE scoring?
>
>
> --
> Michael D Neale
> home: www.michaelneale.net
> blog: michaelneale.blogspot.com
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users