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plaans / aries

Toolbox for automated planning and combinatorial solving.
MIT License
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Schedule does not respect epsilon #127

Closed IreneBrugnara closed 5 months ago

IreneBrugnara commented 5 months ago

The attached scheduling problem modeled in unified-planning and solved by Aries produces a schedule which is unexpected since it does not respect the problem's parameter epsilon equal to 1.

scheduling_problem.txt

arbimo commented 5 months ago

Under the discrete time semantics, the epsilon gives the time elapsed between two epochs and is here respected.

What may be surprising to you is that two increase/decrease effects are allowed to overlap (not mutex) as long as the modified resource stays within its bounds after the effects. This is not perfectly compliant with the no-moving-target rule (at least is some of its interpretations) but is necessary to accurately represent many scheduling problems.

Note that you have always the ability to release the resource one time step later if that is what you want your model to do.

PS: the deadline is constraint is irrelevant to the discussion. If you were to minimize the makespan, you would get the same behavior.

IreneBrugnara commented 5 months ago

I understand, thank you for the clarification.