For example, to do the "Some employees are qualified to do either role, but others can only be a cashier, or a restocker." constraint in the article, it would be written like this:
def required_skill(constraint_factory: ConstraintFactory):
return (constraint_factory.for_each(Shift)
.filter(lambda shift: shift.required_skill not in shift.employee.skills)
.penalize(HardSoftScore.ONE_HARD)
.as_constraint("Missing required skill")
)
- Employee scheduling (https://github.com/TimefoldAI/timefold-quickstarts/tree/stab...)
- Vehicle routing (https://github.com/TimefoldAI/timefold-quickstarts/tree/stab...)
- School timetabling (https://github.com/TimefoldAI/timefold-quickstarts/tree/stab...)
The Python examples seem to have a very strong Java smell. That might just be my prefer for functional styles over OOP styles though.
We aim to treat Python as a first-class citizen (while keeping it maintainable). For instance, many of the Java methods are mapped to properties on the Python classes with more Pythonic names (see `ScoreExplanation` for an example).
I suspect what gives the Java smell is probably the `SolverFactory`/`SolverConfig`, which is a lot of boilerplate code. A lot of the code can be generated, although we would need to design an API for that.
The fluent (method chaining) API might also be giving the Java smell; I don't see many fluent API being used in Python. In particular, needing to either end lines with `\` or surround the statement with brackets make long fluent chains annoying to use. This is harder to change, since there is no Pythonic alternative that I know of for method chaining.
Many problems in business and manufacturing fit this bill. Optimal product mix, optimal routing, choosing the best spot for a warehouse, scheduling employees, constructing an investment protfolio, coming up with a diet that fits certain criteria, etc.
I even remember a practice problem from uni where we had to optimally distribute songs on two sides of a tape album (it was an old professor), satisfying constraints such as “each side should have a ballad” and “each side has at most x minutes of running time”.
You can do this with regular coding too, but if you can easily construct a certain kind of mathematical model of your problem, you can easily solve it with linear programming.