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It has been quite a journey for me to go from 0 to understanding the job shop (js) and the flexible job shop (fjs) examples given by Google's ORTOOLS team.

Now the time has come for me to start modeling my reality which I believe is a variant of the FJS example above.

In my case :

  • Instead of having 1 resource per alternatives I need to have several resources per alternatives. For example, to perform task A I need to have Machine 1 and employee number 412 (alternative 1) or Machine 1 and employee number 516 (alternative 2) or machine 2 and machine 3 (alternative 3).

So, my take on this for now is :

  • Instead of having an alternative task described as [(3, 0), (1, 1), (5, 2)] I'm thinking of having something like [(3, List1), (1, List2), (5, List3)] where List1, List2 and List3 are sets of resources with different combinations.
  • Then having a NewBoolVar for each set of resources I have and implement it just as I saw in the example above.
  • But the enigma for me is how to force resources to be available at the same Interval ?

Before spending too much coding time in the wrong direction I wanted to ask some questions to the public :

  • Is it in your opinion the right approach to the problem (having a set of resources, a bool to toggle between the sets, and a way to have resources available in the same interval)?
  • Do you see another way of solving this?
  • Is there references/examples on this subject that I have missed (I didn't find any example with an alternative more than 1 machine/resource)?

As I said I'm in a learning process so don't hesitate to suggest learning paths.

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  • $\begingroup$ Is it possible to share your mathematical model which you have tried to do? $\endgroup$
    – A.Omidi
    Sep 25, 2020 at 18:35

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The sum(bool_vars) tells you each job has only one way to be executed. It does not tell you what is 'a' way.

You can reuse the bool_var from each alternative in multiple resources.

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