Sequencing constraint with a sliding window

[Scott Anderson]

Given a set of tasks with categories and varying lengths:

id, category, length in seconds
1, "cat1", 180
2, "cat1", 210
3, "cat2", 205
4, "cat3", 300
5, "cat2", 250
etc.

How feasible is implementing the following constraint:

Create a sequence of the tasks such that there are no more than 4 tasks of a particular category within a sliding 3 hour window.

And are there particular constructs I should be looking at using?

Pardon the newbie questions, I'm just starting to get my head around constraint programming.

Regards,
-scott

[Laurent Perron]

Hello,

The scheduling version to implement this, you need to create a set of interval variables, all of length 180 minutes,  whose start times are synchronized with your tasks. And add those in a cumulative of capacity 4.

There is a constructor of interval variables that takes integer variables as input. This can ease the model.

--Laurent

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--Laurent