Hi everybody.

I have a problem with chained planning variables.

I'm using optaplanner 5.5.0.Final.

I have a planning entity like:

@PlanningEntity()
public class Case implements Chained {
    private Chained previous;
    @PlanningVariable(chained = true)
    @ValueRanges({
            @ValueRange(type = ValueRangeType.FROM_SOLUTION_PROPERTY, solutionProperty = "doctors"),
            @ValueRange(type = ValueRangeType.FROM_SOLUTION_PROPERTY, solutionProperty = "cases", excludeUninitializedPlanningEntity = true) })
    public Chained getPrevious() {
        return previous;
    }
}

A fact class:
public class Doctor implements Chained {
...
}

An a solution class:
public class Plan extends implements Solution<HardAndSoftScore> {
    private List<Doctor> doctors;
    private List<Case> cases;
    private HardAndSoftScore score;

    @PlanningEntityCollectionProperty
    public List<Case> getCases() {
        return cases;
    }

    public Collection<? extends Object> getProblemFacts() {
        return new ArrayList<Doctor>(doctors);
    }
}

The equals / hashCode / clone methods are inspired on the TravelingSalesmanTour example.

I want that Optaplanner generates chains like:

DoctorA <- Case1 <- Case2

DoctorB <- Case3

This model tries to represent a list of Cases assigned to each Doctor.

Suppose I build a solution like:

Plan plan = new Plan();

plan.setDoctors(DoctorA, DoctorB); //pseudo-code

plan.setCases(Case1, Case2); //pseudo-code

Then I build a solver:
Solver solver = getSolverFactory().buildSolver();
solver.setPlanningProblem(plan);
solver.solve();
Plan bestPlan = (Plan) solver.getBestSolution();

The problem is that, Optaplanner is not testing all the posible combinations of chains. I mean, suppose that we know that the better solution (based on the scoring rules) is:

DoctorA

DoctorB <- Case1 <- Case2

But Optaplanner seems to test only chains with DoctorA, so the result of calling getBestSolution() is:
DoctorA <- Case1 <- Case2

I guess that Optaplanner only test chains whit DoctorA, becouse it logs lines like:
...
DEBUG: org.drools.planner.core.localsearch.DefaultLocalSearchSolverPhase - Step index (1), time spend (20002), score (1hard/2soft), best score (1hard/2soft), accepted/selected move count (0/58187) for picked step (Case [id=2, previous=Doctor [id=1]] => Case [id=1, previous=Case [id=2, previous=Doctor [id=1]]]).
...

That is, no lines whith "DoctorB" are logged.
If the doctor list is inverted, the same problem happen (the DoctorA is no processed). That is:

Plan plan = new Plan();

plan.setDoctors(DoctorB, DoctorA); //pseudo-code

plan.setCases(Case1, Case2); //pseudo-code
Solver solver = getSolverFactory().buildSolver();
solver.setPlanningProblem(plan);
solver.solve(); // DoctorA is not part of chains

I guess the problem is on the solver configuration, specifically on the localSearch configuration:

<localSearch>
        <unionMoveSelector>
            <changeMoveSelector>
                <valueSelector/>
            </changeMoveSelector>
            <swapMoveSelector />
            <subChainChangeMoveSelector>
                <selectReversingMoveToo>true</selectReversingMoveToo>
            </subChainChangeMoveSelector>
            <subChainSwapMoveSelector>
                <selectReversingMoveToo>true</selectReversingMoveToo>
            </subChainSwapMoveSelector>
        </unionMoveSelector>
        <acceptor>
            <planningEntityTabuSize>9</planningEntityTabuSize>
        </acceptor>
        <forager>
            <minimalAcceptedSelection>2000</minimalAcceptedSelection>
        </forager>
    </localSearch>

I tried some alternatives to this configuration, but with no success.

Do you know what I am doing wrong?

Thanks a lot.

Regards