Global AI and Data Science

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  • 1.  Pause CPLEX optimizer

    Posted Tue June 22, 2021 04:05 PM
    Hi everyone.

    Sorry for my ignorance. I'm trying to follow the instructions at

    https://www.ibm.com/support/pages/stop-cplex-optimization-run-and-resume-it-later-time

    I'm optimizing a problem in LP format using CPLEX_Studio128, where all variables are binary. CPLEX is running for a long time after the following standard shell commands:

    CPLEX> read filename.lp
    CPLEX> optimize

    I was told that in a day or two there will be a power interruption at my place of work. So before that happens I will need to stop CPLEX, apply some appropriate shell commands, and exit CPLEX. Once the power comes back on I would like to resume optimization from where it stopped.

    I've run some test examples to try and follow the instructions in the above link and got the following error:

    CPLEX> write filename.bas
    CPLEX Error 1262: No basis exists.

    I also tried:

    CPLEX> write filename.mst

    CPLEX Error  3020: No MIP start exists.
    No file written.

    Can someone please tell me the explicit commands I need to enter before exiting CPLEX so that I can resume where I was during the optimization procedure?

    Thank you,

    Marcus.





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    Marcus Garvie
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    #GlobalAIandDataScience
    #GlobalDataScience


  • 2.  RE: Pause CPLEX optimizer

    Posted Tue July 20, 2021 04:55 AM
    @Paul Rubin answered this in https://community.ibm.com/community/user/datascience/communities/community-home/digestviewer/viewthread?GroupId=5557&MessageKey=86bdb48d-e141-4f9c-a666-5f445e109990&CommunityKey=ab7de0fd-6f43-47a9-8261-33578a231bb7&tab=digestviewer&ReturnUrl=%2fcommunity%2fuser%2fdatascience%2fcommunities%2fcommunity-home%2fdigestviewer%3fcommunitykey%3dab7de0fd-6f43-47a9-8261-33578a231bb7%26tab%3ddigestviewer​

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    [Alex] [Fleischer]
    [EMEA CPLEX Optimization Technical Sales]
    [IBM]
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