We are using the "auto delay until last" pattern from the docs, https://www.optaplanner.org/docs/optaplanner/latest/design-patterns/design-patterns.html
The loop detection computation is extremely expensive, and we would like to minimize the number of times it is called. Right now, it is being called in the @AfterVariableChanged method of the arrival time shadow variable listener.
The only information I have available in that method is the stop that got a new previous stop and the score director. A move may change several planning variables, so I will be doing the loop detection once for every planning variable that changed, when I should only have to do it once per move (and possibly undo move, unless I can be really clever and cache the loop detection result across moves).
Is there a way for me, from the score director, to figure out what move is being executed right now? I have no need to know exactly what move or what kind of move is being performed, only whether I am still in the same move as before.
I tried using scoreDirector.toString(), which has an incrementing number in it, but that number appears to be the same for a move and the corresponding undo move.
No, there is no access to a move from scoring code. That is by design - scoring needs to be independent of moves executed. Any solution has a score, and if two solutions represent the same state of the problem, their scores must equal - therefore the only thing that matters for the purposes of scoring is the state of the solution, not the state of the solver or any other external factor.