Hi, me once more.

I guess you figured out by now that I am quite a newbie to Drools (planning).
Problem is I need to write a POC in max 3 to 4 days...
I'm drifting, so please help...

I have written a basic solution for planning plane-maintenance.
I stripped it to it's very basics and it works... if I keep the number of planes, periods and technicians to a very minimum.
I removed all additional constraints like skill matching and availability during a period...

Planning maintenance for 3 planes with each 2 required technicians, 4 available periods and a list of 10 available technicians delivers a solution in about 3 seconds.
Simply increasing the number of technicians per plane from 2 to 3 results in an indefinite solving time (I did not wait longer than a few minutes).
Decreasing the numbers obviously works, at an elapsed time slightly under 3 seconds.

I finally need to plan about 500 plane maintenance jobs (3 to 4 technicians per maintenance job) over 12 available periods with about 400 available technicians..
So there must be something wrong/incomplete in my solution.

What I did:

I have created a planningEntity MaintenanceTask with two planning variables (technician and period) and a simple rule file.
(See all below)
Running this solution thus results in such poor solving time.

Can you please advice me in what I am doing wrong?

Many thanks!!

PlanningEntity (MaintenanceTask .java):

@PlanningEntity(difficultyWeightFactoryClass = TaskDifficultyWeightFactory.class)
public class MaintenanceTask {

    private Period period;
    private Project project;
    private Technician technician;

    public MaintenanceTask (Project aProject) {
        this.project = aProject;
    }

    public String getId(){
        return project.getId()+"-"+hashCode();
    }

    @PlanningVariable
    @ValueRange(type = ValueRangeType.FROM_SOLUTION_PROPERTY, solutionProperty = "technicians")
    public Technician getTechnician() {
        return technician;
    }

    public void setTechnician(Technician aTechnician) {
        this.technican= aTechnician;
    }

    @PlanningVariable
    @ValueRange(type = ValueRangeType.FROM_SOLUTION_PROPERTY, solutionProperty = "periods")
    public Period getPeriod() {
        return period;
    }

    public void setPeriod(Period aPeriod) {
        this.period = aPeriod;
    }

    public String getPeriodId(){
        return period == null ? null : period.getId();
    }

    public String getProjectId(){
        return project == null ? null : project.getId();
    }

   public MaintenanceTask clone() {
        MaintenanceTask clone = new MaintenanceTask (project);
        clone.period = this.period;
        clone.technician= this.technician;
        return clone;
    }

}

Project.java

public class Project {
    private Plane plane;

    public Project(Plane aPlane) {
        this.plane = aPlane;
    }

    public Plane getPlane() {
        return plane;
    }

    public String getId() {
        return getPlane().getName();
    }

    public int getTechnicianLoad(){
        return getPlane().getTechnicianLoad();
    }

    public List<MaintenanceTask> getTasks() {
        List<MaintenanceTask> tasks = new ArrayList<MaintenanceTask>();
        for (int i = 0; i < getTechnicianLoad(); i++) {
            tasks.add(new MaintenanceTask(this));
        }
        return tasks;
    }
}

Technician.java and Period.java are at this moment basically just classes having an getId and getName method, nothing more.

Plane.java has a method getTechnicianLoad that returns the number of required technicians for the maintenance.

This is the config file (basically copy from one of the examples)

<?xml version="1.0" encoding="UTF-8"?>
<solver>

<solutionClass>be.axi.planner.domain.MaintenanceSchedule</solutionClass>
<planningEntityClass>be.axi.planner.domain.MaintenanceTask</planningEntityClass>


<scoreDirectorFactory>
    <scoreDefinitionType>SIMPLE</scoreDefinitionType>
    <scoreDrl>/maintenancePlannerRules.drl</scoreDrl>
</scoreDirectorFactory>

<termination>
    <maximumSecondsSpend>700</maximumSecondsSpend>
</termination>

<constructionHeuristic>
    <constructionHeuristicType>FIRST_FIT_DECREASING</constructionHeuristicType>
    <constructionHeuristicPickEarlyType>FIRST_LAST_STEP_SCORE_EQUAL_OR_IMPROVING</constructionHeuristicPickEarlyType>
</constructionHeuristic>
<localSearch>
    <selector>
      <moveFactoryClass>org.drools.planner.core.move.generic.GenericChangeMoveFactory</moveFactoryClass>
      
      
    </selector>
    <acceptor>
      <solutionTabuSize>1000</solutionTabuSize>
      <planningEntityTabuSize>7</planningEntityTabuSize>
    </acceptor>
    <forager>
      <minimalAcceptedSelection>800</minimalAcceptedSelection>
    </forager>
</localSearch>
</solver>

this is the rules file:

package org.drools.planner.examples.pas.solver;
    dialect "java"

import org.drools.planner.core.score.buildin.simple.SimpleScoreHolder;
import org.drools.planner.core.score.constraint.IntConstraintOccurrence;
import org.drools.planner.core.score.constraint.UnweightedConstraintOccurrence
import org.drools.planner.core.score.constraint.ConstraintType;

import be.axi.planner.domain.MaintenanceTask;

global SimpleScoreHolder scoreHolder;

// ############################################################################
// Hard constraints
// ############################################################################

rule "noMultipleAssignmentsInOnePeriod"
    when
        $t1 : MaintenanceTask($id : id, $periodId : periodId, $technician : technician )
        $t2 : MaintenanceTask(id != $id, periodId == $periodId, technician == $technician)
    then
        insertLogical(new UnweightedConstraintOccurrence("noMultipleAssignmentsInOnePeriod", $t1, $t2));
end

rule "tasksInSameProjectMustBeInSamePeriod"
    when
        $t1 : MaintenanceTask($id : id, $periodId : periodId, $projectId : projectId )
        $t2 : MaintenanceTask(id != $id, periodId != $periodId, projectId == $projectId)
    then
        insertLogical(new UnweightedConstraintOccurrence("tasksInSameProjectMustBeInSamePeriod", $t1, $t2));
end

// ############################################################################
// Calculate score
// ############################################################################

rule "hardConstraintsBroken"
    when
        $occurrenceCount : Number() from accumulate(
            $unweightedConstraintOccurrence : UnweightedConstraintOccurrence(),
            count($unweightedConstraintOccurrence)
        )
    then
        scoreHolder.setScore(- $occurrenceCount.intValue());
end

Solution file:

package be.axi.planner.domain;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.drools.planner.api.domain.solution.PlanningEntityCollectionProperty;
import org.drools.planner.core.score.buildin.simple.SimpleScore;
import org.drools.planner.core.solution.Solution;

public class MaintenanceSchedule implements Solution<SimpleScore>{

    private SimpleScore score;
    private List<MaintenanceTask> maintenanceTasks;
    private List<Period> periods;
    private List<Technician> technicians;

    public MaintenanceSchedule cloneSolution() {
        MaintenanceSchedule clone = new MaintenanceSchedule();
        clone.periods = this.periods;
        clone.technicians = this.technicians;
        List<MaintenanceTask> clonedTasks = new ArrayList<MaintenanceTask>(
                maintenanceTasks.size());
        for (MaintenanceTask task : maintenanceTasks) {
            MaintenanceTask clonedTask = task.clone();
            clonedTasks.add(clonedTask);
        }
        clone.maintenanceTasks = clonedTasks;
        clone.score = this.score;

        return clone;
    }

    public Collection<? extends Object> getProblemFacts() {
        System.out.println(">>getting problemfacts");
        List<Object> facts = new ArrayList<Object>();
        facts.addAll(periods);
        facts.addAll(technicians);
        // Do not add the planning entity's (maintenaceTasks) because that will be done automatically
        return facts;
    }

    public SimpleScore getScore() {
        return this.score;
    }

    public void setScore(SimpleScore aScore) {
        this.score = aScore;
        if (aScore != null){
        System.out.println("Score set to " + aScore.getScore());
        }
    }

    @PlanningEntityCollectionProperty
    public List<MaintenanceTask> getMaintenanceTasks() {
        System.out.println("getting tasks: #" +maintenanceTasks.size());
        return maintenanceTasks;
    }

    public void setMaintenanceTasks(List<MaintenanceTask> aMaintenanceTasks) {
        System.out.println("setting tasks");
        this.maintenanceTasks = aMaintenanceTasks;
    }

    public void setTechnicians(List<Technician> aTechnicians) {
        System.out.println("setting Technicians");
        this.technicians = aTechnicians;
    }

    public List<Technician> getTechnicians() {
        System.out.println("Getting Technicians: #"+technicians.size());
        return technicians;
    }

    public List<Period> getPeriods() {
        System.out.println("getting periods");
        return periods;
    }

    public void setPeriods(List<Period> periods) {
        this.periods = periods;
    }

}

-----------------
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From: Geoffrey De Smet <ge0ffrey.spam@gmail.com>
To: rules-users@lists.jboss.org
Sent: Friday, August 31, 2012 10:54 AM
Subject: Re: [rules-users] Best model for planning? technicians, airplanes and shifts

Op 31-08-12 09:46, Michiel Vermandel schreef:
> Thank you for the response.
> I think I forgot one level of complexity (?):
>
> The moment of maintenance of a plane is not fixed.
>
> We have 12 "periods" per year for maintenance.
> One period every month.
>
> We need to make the planning in such way that the list of planes is
> planned somewhere in these 12 periods.
> But it is not important that a specific plane is maintained at a
> specific period.
> It has though a calendar of unavailability.
>
> So the job (==Shift) of the Task (==ShiftAssignment) has no hard
> constraint on period.
>
> We need to find that combination with the best match between required
> skills for the job and available technicians.
> It's better to plan the job on a later period if at that time a more
> skilled technician is available.
>
> I hope this is a bit clear.
>
> So, given this addition, should I take as planning variables:
>
> 1) Period (List of 12 periods)
> 2) Technician

Good idea

>
> Then use period to check availability on both plane and technician
> (hard-constraint)
I see 3:
- plane availability
- technician conflicts (2 tasks at the same time)
- technician availability
> Then give a better weight on skill-match (soft-constrain)?

yes (and possible others, such as work load, technician desires, ...)

>
> Thank you.
>
> Michiel
>
> -----------------
> http://www.codessentials.com - Your essential software, for free!
> Follow us at http://twitter.com/#!/Codessentials
> ------------------------------------------------------------------------
> *From:* Geoffrey De Smet <ge0ffrey.spam@gmail.com>
> *To:* rules-users@lists.jboss.org
> *Sent:* Friday, August 31, 2012 9:08 AM
> *Subject:* Re: [rules-users] Best model for planning? technicians,
> airplanes and shifts
>
> Op 30-08-12 18:02, mvermand schreef:
> > Hi,
> >
> > I'd like some advice on how to make my model.
> >
> > I need to plan maintenance-schedules for - let's say - airplanes.
> > Constraints are:
> > - planes are only at given moments available for maintenance (when not in
> > the air ;-)
> > - maintenance of a planes requires a number of techniciens (with specific
> > skills).
> > - techniciens have skills and also shifts and vacation.
> >
>
> Sounds like the nurse rostering example in Planner :)
> In nurse rostering, such a Shift has a ShiftDate and a ShiftType.
> The difference is, you need to assign jobs instead of shifts.
>
> > Now, first I tought to make the maintenance of a plane the
> planningEntity.
> > But I did not know how to populate and match the techniciens.
>
> I wouldn't make plane the planningEntity either, it's on the one side of
> the manyToOne relation.
>
> >
> > So, second I tought to make a new Task-class the planningEntity.
> > A Task is a job that needs to be done by a technicien with specific
> skills.
> > Maintaining a plane requires then a number of tasks.
>
> Good idea. In nurse rostering, a Task is called a ShiftAssignment.
> You can generate all Tasks in advance based on the Planes and their jobs
> and the number of technicians needed by each job.
>
> I recommend to make separate Task instances for multiple technicians
> that perform the same job together on the same plane. In nurse rostering
> there are also multiple ShiftAssignments (=tasks) per Shift (=job).
>
> >
> > If I choose this model, I think I'll have to pass two Plannings
> variables to
> > the Task planningEntity:
> > 1) a Maintenance-fact (Plane + Period + list of required tasks) and
>
> I don't think this is a planner variable on the planning entity Task.
> It really defines the Task: what job on what plane (and some of sort of
> requiredTechnicanCountIndex)
>
> > 2) a Technicien-fact (?)
> This is a planning variable.
> You're assigning task to techinicians.
> Each task has exactly 1 technician (because a job has multiple tasks,
> one per required technician).
> Each technician can work on multiple tasks, but the hard/soft
> constraints make sure that it's not at the same time.
>
> >
> > Then I'll need to check if availabity of plane and availability of
> > technicien match and also skill-requirement of task and skills of
> > technicien.
>
> Yep, with constraints
>
> >
> > Do you think this second model is the right one?
> >
> > Will it perform well?
> > => ? matching all combinations of plane availabilty and
> > techniciens-availability and -skills.
>
> It should, see the nurse rostering problem.
> In Planner 5.5.0.Beta1, I would add a filter on the swap move selector
> to prevent it from swapping 2 technicians assigned to different tasks on
> the same job.
>
> https://github.com/droolsjbpm/drools-planner/blob/master/drools-planner-examples/src/main/java/org/drools/planner/examples/curriculumcourse/solver/move/DifferentCourseSwapMoveFilter.javatd
>
> >
> > Thanks in advance
> >
> >
> >
> > --
> > View this message in context:
> http://drools.46999.n3.nabble.com/Best-model-for-planning-tp4019464.html
> > Sent from the Drools: User forum mailing list archive at Nabble.com
> <http://nabble.com/>.
> > _______________________________________________
> > rules-users mailing list
> > rules-users@lists.jboss.org <mailto:rules-users@lists.jboss.org>
> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
>
>
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