Variable severity penalty on same constraint

[mikepictor]

Is it possible, in one constraint, to produce variable severities? What I want is a date comparison, where exact date match is ideal, but if date 1 is before date 2, that is a soft penalty, but if date 2 is before date 1 that is a hard penalty

So something along these lines

if (dateDifferenceMinutes < 0) {
                ofHard(1)
            } else {
                ofSoft(dateDifferenceMinutes)
            }

I can obviously do this in 2 different constraints, but I am checking the exact same entities and properties in both cases, so I am hoping to avoid the performance overhead of evaluating 2 different constraints

[triceo]

Hello @mikepictor - I see your point. Unfortunately, this is currently not possible - your workaround with multiple constraints is the only way how I could see it done.

To that end, we've actually implemented (and will soon release) a feature for our Enterprise customers that can actually merge these constraints, doing the work only once. The feature is called "automatic node sharing" if you want to look it up later. And it is actually useful for more situations than this, as it can reuse even parts of the work done by multiple constraints.

There are possible ways how I could see the Constraint Streams API changing to allow for your use case, but in the interest of openness, I don't think we'll be working on it in the foreseeable future.

[mikepictor]

dang it. Ok, thank you for the quick response

[triceo]

Before you go any further, I'd first measure if your score calc speeds suffer for this, and if you really need to be that much faster. For small and medium-sized problems, typically you won't. If you do, there are ways how to get manual node sharing done, if you're willing to accept significant compromises to your code quality.

The way to avoid those compromises is to use the Enterprise Edition and here, we are very clear - Timefold Solver Enterprise Edition exists to allow you to scale out to the biggest possible datasets.