问题
I am working on a planning problem involving:
- a collection of planning entities each containing the planning variable A
- a global planning variable B (contained in the planning solution)
Since I am a beginner with Optaplanner and planning optimization in general, I started on a simpler version problem, focusing on optimizing A with B modeled as a planning fact.
Now that I have a program successfully optimizing A given B. I want to implement a new solver optimizing both A and B. It turns out that the best optimization search strategy is to first select a B value, and then optimize A given that B value. This process should be repeated until an optimum is found (the problem at hand is hierarchical)
I am looking for advice on how to implement this with Optaplanner. I initially thought I would implement this as two phases (optimize B -> optimize A) but I now understand Optaplanner phases are not meant to do that. For example, the solver cannot loop over this ordered sequence of two phases.
Instead, I think I should implement a custom MoveSelector which starts with a move on B, and then an infinite list of A move..
What do you think ? Am I on the right track ?
Kind regards,
回答1:
A and B are different stages, not different phases (in OptaPlanner terminology).
In multi-stage planning (see short entry in docs), it's basically 2 different solvers, with one feeding into the other. This is very common when A and B occur at different times (think strategic vs tactical vs operation planning) or due to Conway's law (the organization structure of the users). This is the easy solution and often also by far the most practical during change management for the business. It's the least risk. However, it's suboptimal (in theory at least).
The alternative is indeed to have multiple planning entities, which makes it one big planning problem. That is the perfect solution. That is challenging. Perfect can be the enemy of good. OptaPlanner's architecture supports it, but custom moves are indeed required (today in OptaPlanner 7.35), as the default move selectors won't escape local optima often enough.
来源：https://stackoverflow.com/questions/61489888/implementing-a-planning-optimization-algorithm-on-hierarchical-problem