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Resolved Burst floating point determinism

Discussion in 'DOTS Dev Blitz Day 2023 - Q&A' started by TheOtherMonarch, Aug 23, 2023.

  1. TheOtherMonarch

    TheOtherMonarch

    Joined:
    Jul 28, 2012
    Posts:
    791
    Burst cross-architecture floating point determinism is on the roadmap. Can you talk about what the plans are for that?

    Also, what are the plans for supporting determinism on the same platform? In the future can we expect, for example, that all AVX2 CPUs will return the same results? Or will we need to enable cross-architecture floating points to guarantee determinism?
     
    TheOtherMonarch, Aug 23, 2023
    #1
    Samsle and saskenergy like this.

  2. elliotc-unity

    elliotc-unity

    Unity Technologies

    Joined:
    Nov 5, 2015
    Posts:
    228
    Nobody to my knowledge is working on it, because everybody who could is either fixing burst bugs or helping with the migration to coreclr (which is going to be great).

    So, the plans are basically "wouldn't that be cool at Some Point(tm)."
     
    elliotc-unity, Aug 24, 2023
    #2
    Occuros, saskenergy, DevDunk and 2 others like this.

  3. Pavlov_Oleg

    Pavlov_Oleg

    Joined:
    Dec 1, 2021
    Posts:
    1
    Although it's not guaranteed that CPU will have IEEE 754 standard, practically everyone implements it. And many game dev companies just assume it's gonna be on every platform and the result across devices gonna be the same if you use standard float precision. What you can't expect is that you can turn off certain float features for optimization on every platform. And be aware certain unity packages change float precision of your C# code, but it doesn't affect Burst
     
    Pavlov_Oleg, Aug 25, 2023
    #3