What data is saved in Single (Double) precision in Hybrid precision setting?

Shinichiro_Oshiro
Shinichiro_Oshiro Altair Community Member
edited May 27 in 質問と回答 (Q&A)

Hello.

I would like to know the specifications of Hybrid precision setting in order to appropriately select the precision of the CUDA solver.

What data is saved in Single (or Double) Precision in Hybrid Precision setting?

Best regards,
Oshiro

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Answers

  • Stephen Cole
    Stephen Cole
    Altair Employee
    edited May 23

    Hi,

     

    The precision modes save the same data, it's the accuracy of the calculation which is changed.

    This is outlined further here:

    EDEM Particle Simulation: CUDA GPU and Precision Modes

    Which also gives links to our e-learning lesson on the GPU.


    Regards

    Stephen

  • Shinichiro_Oshiro
    Shinichiro_Oshiro Altair Community Member
    edited May 23

    Hello, Stephen.

    Thank you for your response.

    What I would like to know is which physical quantities are stored in single precision or double precision in the context of hybrid precision.

    I apologize for the lack of clarity in my question, which may have caused confusion.

     

    Best regards,

    Oshiro

  • Stephen Cole
    Stephen Cole
    Altair Employee
    edited May 23
    Shinichiro Oshiro said:

    Hello, Stephen.

    Thank you for your response.

    What I would like to know is which physical quantities are stored in single precision or double precision in the context of hybrid precision.

    I apologize for the lack of clarity in my question, which may have caused confusion.

     

    Best regards,

    Oshiro

    Hi Oshiro,

    To clarify by stored were you looking for the size in Mb of data stored, or the calculation accuracy?

    In terms of the calculation we don't have a set list however it should follow what we see in the API.

    Absolute values like Positions are typically calculated/stored as Double precision when using the Mixed precision solver.  All other variables would be Single Precision.  Positions include Center of Mass, particle position, geometry node position, Field Data position, Contact Point. Other variables calculated as doubles include the current Simulation Time.


    Regards

    Stephen

  • Shinichiro_Oshiro
    Shinichiro_Oshiro Altair Community Member
    edited May 27
    Stephen Cole_21117 said:

    Hi Oshiro,

    To clarify by stored were you looking for the size in Mb of data stored, or the calculation accuracy?

    In terms of the calculation we don't have a set list however it should follow what we see in the API.

    Absolute values like Positions are typically calculated/stored as Double precision when using the Mixed precision solver.  All other variables would be Single Precision.  Positions include Center of Mass, particle position, geometry node position, Field Data position, Contact Point. Other variables calculated as doubles include the current Simulation Time.


    Regards

    Stephen

    Hello, Stephen.


    What I wanted to know was about the calculation accuracy.
    The information you provided is the answer I was looking for.
    Thank you very much.

     

    Best Regards,

    Oshiro

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