Decision Optimization

Decision Optimization

Delivers prescriptive analytics capabilities and decision intelligence to improve decision-making.

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  • 1.  Emphasis MIP

    Posted Mon June 01, 2020 03:50 AM
    Edited by System Admin Fri January 20, 2023 04:25 PM
    Hello,

    I tried to solve an MIP model with mip gap setting as 0%. The problem is same as the article I posted several days ago ( Decision Optimization ). I solved .sav model written from my C# via Interactive.

    This time, I found that my best bound kept the same for a long time from the node log, so I refer to the parameter tuning in the slides (page9 & 10: Mining the CPLEX Node Log for Faster MIP Performance ) and set emphasis mip to 3 (Emphasize moving best bound). Then, it only took me 225 seconds to find an optimal.

    I did the experiment for all "emphasis mip" setting. The results were 3(225s) < 2(270s) < 4(284s) < 1(301s) < 0(more than 1hr).

    I would like to know the emphasis mip setting more clearly and understand the magic effects on solving time. I can't perfectly understand the description from IBM Knowledge Center ( https://www.ibm.com/support/knowledgecenter/SSSA5P_12.9.0/ilog.odms.cplex.help/CPLEX/Parameters/topics/MIPEmphasis.html ). Is there anyone who can give me more details and examples related to "Emphasis MIP Setting(0~4)"? Or tell me why "set emphasis mip 3" works on my model?

    Thanks!

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    Chia-Yuan Wu
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    #DecisionOptimization


  • 2.  RE: Emphasis MIP

    Posted Mon June 01, 2020 11:37 AM
    Hi

    some more at https://www.ibm.com/support/knowledgecenter/SSSA5P_12.10.0/ilog.odms.cplex.help/CPLEX/UsrMan/topics/discr_optim/mip/usage/10_emph_feas.html

    regards

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    ALEX FLEISCHER
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    Original Message