Topic
4 replies Latest Post - ‏2013-08-26T03:21:45Z by jonsonleou
jonsonleou
jonsonleou
3 Posts
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Pinned topic Job flow for parallel machines problem

‏2013-08-16T13:42:35Z |

Hello,


My name is Jonson from Taiwan, I am studying the flow job scheduling problem from Cplex existing examples.

As the model is a gap with the real production environment, I tried to extend this optimization model to parallel machines for multi stage/station problem, unfortunately it didn't work, as the attached file. I am not sure it can be solved by Cplex, or here is a similar example for reference? ask you help here!
 

Thanks,
 

Jonson

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  • GGR
    GGR
    34 Posts
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    Re: Job flow for parallel machines problem

    ‏2013-08-21T15:57:45Z  in response to jonsonleou

    Hi Jonson

    Is your question about modeling a flow shop scheduling problem with CPlex?

     

    If yes you are not posting your question on the right forum (you should used on of the Mathematical Programming category.

     

    If you wish to use the capabilities of CP Optimizer in scheduling, you will file example of shop scheduling and sequence scheduling in the distribution.

     

    Hope that helps

     

     

    • jonsonleou
      jonsonleou
      3 Posts
      ACCEPTED ANSWER

      Re: Job flow for parallel machines problem

      ‏2013-08-23T01:52:28Z  in response to GGR

      HI Rogerie:

       

      Thanks for your kindly reply,

       

      Yes, I am studying the shopfloor scheduling problem solved by Constrain Programming, and have checked several similar examples bundled inside ILOG Cplex IDE, such as open-shop problem, flexible job-shop problem, shop scheduling with trolley, and even house building problems.

       

      I find these examples constructed only one resource by one step problem, it's too simple to meet the real requirement, hence tried extending flow-shop problem for multi-resources assignment, the result is failed.....

       

      My purpose is to find a parallel machine dispatching problem example, therefore post my request in here to search for someone support.

       

      Yours sincerely,

      • GGR
        GGR
        34 Posts
        ACCEPTED ANSWER

        Re: Job flow for parallel machines problem

        ‏2013-08-23T12:14:43Z  in response to jonsonleou

        Hi Jonson

        If I understand well your problem, I suppose you work with the OPL Ide application. Let's admit a job is made of a set of tasks linked by precedence constraint  and a task can be executed by a subset of the machines. Let's call an operation , the execution of a task by a machine.

        You describe the breakdown structure of a job as a span of task and the tasks as an alternative of operation. That is you create interval variables for each job, task and operations (those being optional) and use a sequence variable of operation for each machine that you constraint with a non-overlap. Examples in the distribution is sched_joshopflex and, for more sophisticated examples sched_rcpspmm. As a start, that is wihtout choice of machine, have a look to sched_joshop, shed_flowshop, sched_openshop and sched_rcpsp samples.

         

        Hope that helps

         

         

        • jonsonleou
          jonsonleou
          3 Posts
          ACCEPTED ANSWER

          Re: Job flow for parallel machines problem

          ‏2013-08-26T03:21:45Z  in response to GGR

          Hi Rogerie:

          Sure, I found them and it did really work.

          Thank you again in here to show my sincere appreciation for the answer,

           

          Ps. If anyone requires the similar problem model, let me know to post my modified solution for reference.

           

          Cheers,