How to limit the range of planning values for another entity based on the value of one entity?

[kentbill]

Hi, Teams and all.

I need to plan the jobs of products in a factory. Each job can be assigned to a particular machine. There are two workshops, A and B, which contain some machines. Now there is a rule: all jobs from the same product can only be assigned to machines that are in the same workshop.
For instance:

• There are 2 workshops, WS-A and WS-B. WS-A has 2 Machines, M-A1 and M-A2, and another Workshop WS-B has 2 Machines M-B1 and M-B2.
• There is a product that contains 2 jobs, Job1 and Job2. Job1 can be assigned to either M-A1 or M-B1, and Job2 can be assigned to either M-A2 or M-B2
• If Job1 is assigned to M-A1, Job2 must be assigned to M-A2 and not to M-B2, as it belongs to workshop WS-B rather than workshop WS-A. If Job2 is assigned to M-B2, Job1 must be assigned to M-B1.

I can easily achieve this requirement by using a hard constraint, but it depends on the optimization. When a dataset is huge and a product has more jobs, it is difficult to ensure that this constraint can be fully satisfied. Is there a more direct way to achieve this requirement without using constraints?

Thanks in advance!

[TomCools]

We don't currently support re-loading of @ValueRangeProvider to do what you are suggesting here.

The 2 main ways to tackle this right now is either to:

• Segregate the dataset. Change your problem so Jobs within the same Product only can be assigned to a single Workshop. This of course misses a large amount of optimization possibilities.
• Keep the constraints, but add a custom move which moves these jobs together. This will avoid a bunch of moves that lead to nowhere.

Maybe the rest of the Solver team has other ideas on how to resolve this.

[triceo]

You're spot on, Tom.

[kentbill]

got it, thanks @TomCools and @triceo
I think using constraints with a custom move seems more appropriate here.

[kentbill]

I am implementing the custom move, but the model uses PlanningListVariable. How can I implement a custom SwapMove with PlanningListVariable? I couldn't find any methods in the documentation, quick start, or even in the OptaPlanner examples. Do you have any ideas?

[triceo]

There is a generic implementation of ListSwapMove in the codebase.

[kentbill]

Thank you! @triceo.
I tried to refer to ListSwapMove. java to implement it.