OptaPlanner | OptaPlanner applications | Computer Vision library

I want to use Simulated Annealing in OptaPlanner, but I am a little baffled by the fact that there is only a setting for the initial temperature and not one for the decay rate. What is the reason for this choice?

How can I initialize a ConstraintVerifier in Kotlin without using Drools and Quarkus? I already added the optaplanner-test JAR and the Maven Dependency for Optaplanner 8.6.0.Final and tried it the following way:

I have a question about OptaPlanner constraint stream API. Are the constraint matches only used to calculate the total score and are meant to help the user see how the score results, or is this information used to find a better solution?

With "used to find a better solution" I mean the information is used to get the next move(s) in the local search phase.

So does it matter which planning entity I penalize?

Currently, I am working on an examination scheduler. One requirement is to distribute the exams of a single student optimally. The number of exams per student varies. Therefore, I wrote a cost function that gives a normalized value, indicating how well the student's exams are distributed.

Let's say the examination schedule in the picture has costs of 80. Now, I need to break down this value to the individual exams. There are two different ways to do this:

• Option A: Penalize each of the exams with 10 (10*8 = 80).
• Option B: Penalize each exam according to its actual impact.=> Only the exams in the last week are penalized as the distribution of exams in week one and week two is fine.

Obviously, option B is semantically correct. But does the choice of the option affect the solving process?

I'm looking at profiling the score calculation in my Optaplanner project to find out if there are any hotspots that would benefit from being optimised. However, visualvm shows most of the time to be taken in the self time of org.drools.modelcompiler.constraints.ConstraintEvaluator$InnerEvaluator$_2.evaluate. I therefore assume that this method is what actually runs a lot of the constraint's code. What is the best way to find out what specific pieces of code are taking the most time?

I am trying to use Optaplanner to optimally assign production units to a group of contractors. The goal is to assign the production units so that the real inventory is as close as possible to the optimal inventory. For this, I am using a soft constraint which, in simple terms, follows this basic equation:

This is the basis for my soft constraint score. The purpose of Optaplanner is to minimize this difference. However, I do have a hard constraint that specifies the minimum production units that can be assigned. Whenever this constraint is introduced to the problem, Optaplanner produces less than optimal solutions. It basically assigns all the available production units to one single contractor so as to not break the minimum production quantity constraint.

This ensures that no contractor is assigned a small amount of production units (assigning 0 is ok), but it has the unintended consequence that the soft constraint is not optimized at all. Extending the run time basically just moves the entirety of the production units around between different contractors.

It is not a matter of not having enough production units since I have around 10000 available units while the minimum production quantity is 120. This should be enough to assign it to several contractors and optimize the inventory instead of assigning the 10000 units to one single contractor.

Is there a way to include this hard constraint without Optaplanner completely ignoring the soft constraint?

EDIT: To clarify, the hard constraint is only punishing when the production units are bellow 120. It is not rewarding production units above 120. The max possible hard score is 0.

(For simplicity I said "assign units to contractors" when in reality Optaplanner is "assigning contractors to the units")

I created a new file known as "solverConfig.xml" under resources. I changed in application.properties, to write the following: quarkus.optaplanner.solver-config-xml=src/main/resources/solverConfig.xml. However, Quarkus does not recognize the classpath. It says: Invalid quarkus.optap lanner.solverConfigXML property (src/main/resources/solverConfig.xml): that classpath resource does not exist. I followed the response of Optaplanner and Quarkus solver config update. But, it does not work.

The solverConfig.xml is configured as:

We are trying to solve a VRP with Optaplanner. The score calculation runs via constraint streams.

Now I have two vehicles (A and B) and want to schedule two jobs (J1 and J2). The construction heuristic (FIRST_FIT_DECREASING) schedules J1 to A and J2 to B, what is correct so far.

Now the two jobs also have an attribute "customer", and I want to assign a penalty if the customer of the two jobs is the same but the vehicles are different.

For this purpose, I have created a constraint in the ConstraintProvider that filters all jobs via groupBy that have the same customer but different vehicles.

If I now switch on the FULL_ASSERT_MODE, an IllegalStateException occurs after scheduling J2, because the score that is calculated incrementally is different from the score for the complete calculation. I suspect this is because the VariableListener, which recalculates the times of the jobs, only tells the ScoreDirector about a change to Job J2 for my shadowvariables and therefore only changes the score part that is related to it.

How can I tell Optaplanner that the score for J1 must also be recalculated? I can't get to job J1 via the VariableListener to tell the ScoreDirector that the score has to be changed here.

Or does this problem require a different approach?

Need some ideas on how to build a rule in my task assignment project. Assign workers to tasks, each task has a happen location, want a soft constraint to make a worker's next task be as close as possible to the fulfilled task. But in DRL how can I know which task is the worker's previous task? the information is in the Solution class. An example is greatly appreciated. Is there any OptaPlanner example that I can refer to? for me to know how to get values from Solution.

New to OptaPlanner and want to debug the example Task Assigning in Eclipse to learn. Found that the breakpoints are hit only when the code are called by the UI related code, such as