Encode declared constraints and print on demand the violated ones

[alxhotel]

Is there a way to check if a particular constraint has been added to the problem manager before calling nextSolution?

For example, check if the constraints var == 1 has been added.

[pothitos]

Good morning, Alex, and thank you for the question!

If we want to add a constraint, we use e.g. pm.add(var == 1). But, unfortunately, there isn't a similar pm.check_if_added(var == 1) call.

Right now, the only way to check this is some sort of workarounds. In your example you could just check if var.min() == 1 && var.max() == 1 for example.

I don't know if your case is more complicated.

[alxhotel]

Hi Nikolaos, thanks for the answer. I'm trying to add new constraints based on the currently added.

Right now, the only way to check this is some sort of workarounds. In your example you could just check if var.min() == 1 && var.max() == 1 for example.

But you can only do that after running nextSolution, right?

My current workaround is just using another structure to save the current constraints.

By the way, (totally unrelated) is there a way to get the constraints that are giving a conflict (when a solution is not found)? In my program I need to output why a solution was not found, so having the conflicting constraints could help.

[pothitos]

Buenos días, Alex!

The check about the bounds of var can be done even before calling nextSolutioon. Because, when you declare a contraint, a first naive consistency level is immediately applied to the domain of var. Anyway, your solution is much more better.

Regarding reporting the violated constraint, there's some significant work in the bibliography I'm not aware of. I guess that just printing the last inspected constraint (before a domain wipeout) isn't a complete solution.

Anyway, I'll keep this issue open in case somebody wants to implement it.

[alxhotel]

Thanks, Nikolaos.

Great, I'll keep an eye on this issue.