Hard Constraint doesn't seem to be applying

[jie31best]

Hi @kneekill,

Regarding why this happens, a possible reason is the ruin process. See the following related discussions:

HardActivityConstraint behavior

Is it possible that a route (list of activities) which fails HardActivityConstraint be part of the final response? I’m currently am experiencing this issue and would like to know if it’s my dab or the library’s. I’ve made sure every time a route with an specific list of activities goes through a certain constraint it fails, even singled out the shape of it. But it continues to appear. The other case are routes which never pass by the constraints end up being part of the result.

Non-fulfilled routes appear as solution

I have a hard constraint which verifies that the load at any moment of the route does not go below zero. The constraint worked well most times but some edge cases started to appear where the solution would contain invalid routes which do contain only one activity with a negative load. I started to check the iterations that lead to such result and there was never a FULFILLED iteration with such route. That specific combination would always appear as NOT_FULFILLED or NOT_FULFILLED_BREAK. My que…

Regarding how to resolve this, an elegant way is to implement a custom ruin strategy to make sure that, when the ruin phase ends, you will not have two “delivery” activities in a row.

A workaround would be to implement a soft activity insertion constraint to encourage the insertion of a non-“delivery” activity between two “delivery” activities.

Best regards,
He