Help: How to allow task overlap in JobShop like problem?

[gustavo-barros]

Hi,

I have a set of machines that can do tasks on parallel, how can I allow these tasks to overlap?
I tried this:

Applying this way the NoOverlap constraint only to the normal machines and ignoring the parallel ones. At first it seemed to work. But because some unkown reason some taks simply dissappear. Any Ideas?

[lperron]

Use a Cumulative constraint. Laurent Perron | Operations Research | lperron@google.com | (33) 1 42 68 53 00 Le mar. 25 juin 2019 à 20:06, gustavo-barros <notifications@github.com> a écrit :

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Hi, I have a set of machines that can do tasks on parallel, how can I allow these tasks to overlap? I tried this: [image: image] <https://user-images.githubusercontent.com/36746102/60121925-87a37c80-975a-11e9-97e0-c6e45634dee5.png> Applying this way the NoOverlap constraint only to the normal machines and ignoring the parallel ones. At first it seemed to work. But because some unkown reason some taks simply dissappear. Any Ideas? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1379?email_source=notifications&email_token=ACUPL3O4SE5WHZM3KSMZHFLP4JNBRA5CNFSM4H3K4DJKYY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4G3TVMSA>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACUPL3K3TKG6J3S6FBCIU6DP4JNBRANCNFSM4H3K4DJA> .

[gustavo-barros]

How I use that, you have an example?
For example, what means demands? And capacity in this context? How I use it?

[lperron]

Can you start reading the doc ? Le mar. 25 juin 2019 à 20:16, gustavo-barros <notifications@github.com> a écrit :

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How I use that, you have an example? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#1379?email_source=notifications&email_token=ACUPL3LPUW7PWX33CI5NB3TP4JOGPA5CNFSM4H3K4DJKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODYRECHY#issuecomment-505561375>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACUPL3OUNCIZR2UDUNEJQYLP4JOGPANCNFSM4H3K4DJA> .

[lperron]

http://google.github.io/or-tools/python/ortools/sat/python/cp_model.html#cp_model.CpModel.AddCumulative

I have no documentation for C# currently.

[gustavo-barros]

Thank you for the link Laurent.

The problem is I don't understand how that will help me to make the tasks overlap with each other in the chosen machine. Maybe I don't have the knowledge required to understand what that function actually does, despite I understand the code it expresses.

I made some tests here, but I was not able to extract some sense of it.

[gustavo-barros]

All that I need is to tell the solver, "hey, in this machine the tasks can run free and wildly as they want to". My first idea was simply remove the NoOverlap constraint, but that seems not to work.

[lperron]

Here is another explanation on the cumulative constraint: http://www.emn.fr/x-info/sdemasse/gccat/Ccumulative.html Laurent Perron | Operations Research | lperron@google.com | (33) 1 42 68 53 00 Le jeu. 27 juin 2019 à 16:36, gustavo-barros <notifications@github.com> a écrit :

…

All that I need is to tell the solver, "hey, in this machine the tasks can run free and wildly as they want to". My first idea was simply remove the NoOverlap constraint, but that seems not to work. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#1379?email_source=notifications&email_token=ACUPL3JSBSCYVFSUNN2CUMDP4TF6TA5CNFSM4H3K4DJKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODYXKIFQ#issuecomment-506373142>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACUPL3KMQSMD7EVU635SL5DP4TF6TANCNFSM4H3K4DJA> .

[lperron]

I propose that for each interval 'i', you create an optional interval 'i_c' using the start, duration and end variable of the interval 'i', and an new Boolean variable 'p'.

Then you add all 'i_c' to the no_overlap.

Now to enforce the no_overlap, just set the 'p' variables to true.