Decision Optimization

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  • 1.  Check the feasibility/ reduce the run time

    Posted Wed December 08, 2021 09:41 AM
    Hi

    I have a model which takes huge amount of time to run and then tell it is infeasible. Is there any way though which I can find the model is infeasible in less than 10 minutes. Additionally, what settings can help me to find any feasible solution (not global solution) for my model in less than 10 minutes.

    Please let me know your valuable suggestions.

    Thank you

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    sandeep singh chauhan
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    #DecisionOptimization


  • 2.  RE: Check the feasibility/ reduce the run time

    IBM Champion
    Posted Wed December 08, 2021 11:50 AM
    You could try setting the feasibility pump switch to 1. If the model is feasible, that might help find an initial solution. If the model is infeasible, I don't think it will get you to a proof of infeasibility any sooner (and might in fact slow down the proof of infeasibility).

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    Paul Rubin
    Professor Emeritus
    Michigan State University
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    Original Message


  • 3.  RE: Check the feasibility/ reduce the run time

    Posted Wed December 08, 2021 12:31 PM
    Hi

    Thanks for your response. Are you referring to 'MIP Emphasis switch' in the opl settings? and 1 denotes - emphasis integer feasibility over optimality. I am using 12.10.0.0 version

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    sandeep singh chauhan
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    Original Message


  • 4.  RE: Check the feasibility/ reduce the run time

    IBM Champion
    Posted Wed December 08, 2021 01:54 PM
    No, the emphasis switch is something else. I saw in your log that you already had that set. The OPL name for the feasibility pump switch is "fpheur".

    ------------------------------
    Paul Rubin
    Professor Emeritus
    Michigan State University
    ------------------------------

    Original Message