[rules-users] Best model for planning? technicians, airplanes and shifts => insertLogical problems

[Geoffrey De Smet]

Op 03-09-12 10:21, Michiel Vermandel schreef:
> Hi Geoffrey,
>
> Thanks for the support so far.
> I understand that you do not provide full support on this level.
> Though I have the feeling that this is really
> - a very basic solution setup
> - a beginners-mistake and since I'm looking into it now for about 3 days
> (since I started with planner) it seems to be not obvious to find for a
> beginner.
> So I was trying my luck in offering the code.
> It could be an opportunity to enrich the documentation ;-) ;-)

Good point, the score corruption problem is often a beginner problem and 
it's a PITA. I 'll write some more docs about.

Do note that your 3 day implementation should be able to scale out to 
10000 planes pretty easily, so hang in there :)
I fear you might have started copying from the wrong example nqueens (if 
you did that) :/ Nurse rostering is a far more similar to this kind of 
problem. I am not sure which example to promote in the docs: the nqueens 
is simple enough to explain things on, but it's too simple to copy from 
for real world stuff :/ Feedback welcome.

>
>
> Ok,
>
> 1) adding the $t2 results in the same sort of exception, only
> planningEntity seems different:
>
> with insertLogical(new
> UnweightedConstraintOccurrence("tasksInSameJobMustBeInSamePeriod", $t1,
> $t2));
>
> Exception in thread "main" java.lang.IllegalStateException: Score
> corruption: the workingScore (-2) is not the uncorruptedScore (0):
>    The workingMemory has 2 ConstraintOccurrence(s) in excess:
>      tasksInSameJobMustBeInSamePeriod/NEGATIVE_HARD:[Maintenance of
> Boeing 737 - PJ23.I#1 73111693, Maintenance of Boeing 737 - PJ23.I#2
> 427578167]
>      tasksInSameJobMustBeInSamePeriod/NEGATIVE_HARD:[Maintenance of
> Boeing 737 - PJ23.I#2 427578167, Maintenance of Boeing 737 - PJ23.I#1
> 73111693]
>    Check the score rules who created those ConstraintOccurrences. Verify
> that each ConstraintOccurrence's causes and weight is correct.
>      at
> org.drools.planner.core.score.director.AbstractScoreDirector.assertWorkingScore(AbstractScoreDirector.java:101)
>      at
> org.drools.planner.core.constructionheuristic.greedyFit.decider.DefaultGreedyDecider.doMove(DefaultGreedyDecider.java:110)
>      at
> org.drools.planner.core.constructionheuristic.greedyFit.decider.DefaultGreedyDecider.decideNextStep(DefaultGreedyDecider.java:78)
>      at
> org.drools.planner.core.constructionheuristic.greedyFit.DefaultGreedyFitSolverPhase.solve(DefaultGreedyFitSolverPhase.java:63)
>      at
> org.drools.planner.core.solver.DefaultSolver.runSolverPhases(DefaultSolver.java:183)
>      at
> org.drools.planner.core.solver.DefaultSolver.solve(DefaultSolver.java:151)
>      at
> be.axi.planner.domain.MaintenancePlanning.main(MaintenancePlanning.java:27)
>
> with insertLogical(new
> UnweightedConstraintOccurrence("tasksInSameJobMustBeInSamePeriod", $t1));
>
> Exception in thread "main" java.lang.IllegalStateException: Score
> corruption: the workingScore (-2) is not the uncorruptedScore (0):
>    The workingMemory has 2 ConstraintOccurrence(s) in excess:
>      tasksInSameJobMustBeInSamePeriod/NEGATIVE_HARD:[Maintenance of
> Airbus A350 - XJ34.I#2 778813475]
>      tasksInSameJobMustBeInSamePeriod/NEGATIVE_HARD:[Maintenance of
> Airbus A350 - XJ34.I#0 225744121]
>    Check the score rules who created those ConstraintOccurrences. Verify
> that each ConstraintOccurrence's causes and weight is correct.
>      at
> org.drools.planner.core.score.director.AbstractScoreDirector.assertWorkingScore(AbstractScoreDirector.java:101)
>      at
> org.drools.planner.core.constructionheuristic.greedyFit.decider.DefaultGreedyDecider.doMove(DefaultGreedyDecider.java:110)
>      at
> org.drools.planner.core.constructionheuristic.greedyFit.decider.DefaultGreedyDecider.decideNextStep(DefaultGreedyDecider.java:78)
>      at
> org.drools.planner.core.constructionheuristic.greedyFit.DefaultGreedyFitSolverPhase.solve(DefaultGreedyFitSolverPhase.java:63)
>      at
> org.drools.planner.core.solver.DefaultSolver.runSolverPhases(DefaultSolver.java:183)
>      at
> org.drools.planner.core.solver.DefaultSolver.solve(DefaultSolver.java:151)
>      at
> be.axi.planner.domain.MaintenancePlanning.main(MaintenancePlanning.java:27)
>
>
> 2) You suggested to replace UnweightedConstraintOccurrence with
> IntConstraintOccurrence. I will.
> UnweightedConstraintOccurrence is used in the very basic Queens example
> though...

Yep, my mistake.

>
> 3) Where is the best place to read about what insertLogical and
> IntConstraintOccurrence really do?
> What is the purpose of the Cause -objects, which should be passed?
> => where is the best place to find explanation about this?
> (http://docs.jboss.org/drools/release/5.4.0.Final/drools-planner-docs/html_single/
> doesn't really enlighten me on that part)

Look for "insertLogical" in the Drools Expert guide:
 
http://docs.jboss.org/drools/release/5.4.0.Final/drools-expert-docs/html_single/index.html

When rules do an insertLogical of an object A, it's discarded if another 
object B in the WorkingMemory equals object A (through equals() and 
through hashcode()). Because the ConstraintOccurrences need to be unique 
so they aren't discarded, they ruleId, constraintType and causes are 
used for equals()/hashcode().

Future work: "compensation action"
Recently, drools introduced something called "compensation action",
which can probably replace the use insertLogical(ConstraintOccurrence) 
and make the causes parameter obsolete.
It's also faster.
My first experiments look very promising, but I haven't got time yet to 
experiment with it on all examples and make it easy for users to use.

It would allow us to do something like this in the then part of a rule:
   hardAndSoftScoreHelper.addHardScore(-5);
or
   hardAndSoftScoreHelper.addSoftScore(- $sum);
or
   simpleScoreHelper.addScore(-7);

No need for causes, insertLogicals, no equals/hashcode() worries, much 
more flexible, ...


4) Does your MaintenanceTask implement equals()/hashcode() other than 
Object's original implementation?


>
> Thanks in advance.
>

yw