Multi-Exécution setting in order to do DOE approach on Flux models

Yoann Q
Yoann Q Altair Community Member
edited March 2022 in Community Q&A

Hi everyone,

I m having troubles to set the good number of multi-execution task to do a DOE on flux models.

image

If I set the number of multi-tasks low, the calculation time is obviously high. But if I set the number of multiple execution tasks to a high level, the calculation is not performed because of a license error.

How to set this parameter according to the number of cores/memory of the computer or according to the number of Flux licenses?

 

Best regards

Yoann Q

 

 

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Answers

  • Stephan Koerner
    Stephan Koerner New Altair Community Member
    edited February 2022

    This does become a balancing act.  The help in the 'Solver Arguments' dialog offers example of some of the controls one can use on the commandline.  See if this would help.

     

  • Diana_38240
    Diana_38240
    Altair Employee
    edited February 2022

    Hello,

    Indeed, the maximum number of concurrent Flux instances (I think it is Flux3D in your case?) will depend on the licence available, the memory required for each Flux3D simulation, and the resources on your machine (RAM,number of cores).

    Concerning the memory, I would suggest to run Flux in dynamic memory mode. This will not manage automatically how many Flux you can launch in parallel, but it can make the memory usage more efficient, and maybe allow you to run more jobs (ex. in case you have specified unecessary high value of the numerical memory for each Flux, this can limit the number of concurrent jobs or slow down the solving because of the swap).

    Dynamic memory mode can be enabled in the Flux Supervisor prior to export the f2hst, or you can enable it in Hst through the solver input arguments (see example on the jpg above).

    Concerning the cores, if multi-execution is higher than 1, Flux is automatically launched in monocore mode. If you have 4 physical cores + enough tokens + enough memory, then I would suggest to run up to 4 concurrent Flux3D.

    Concerning the licence, do you know how many tokens you have available? Does it work with 2 Flux3D at a time?

    Regards,

    Diana

  • Yoann Q
    Yoann Q Altair Community Member
    edited March 2022

    Hello Diana and hello Stephan,

    Thank you for your helpful answers.

    I am now able to use all the physical cores and available memory to runs multi-execution calculation.

     

    Best Regards

    Yoann Q

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