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Re: Floating-point differences between ARM processors
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Re: Floating-point differences between ARM processors


  • Subject: Re: Floating-point differences between ARM processors
  • From: vincent habchi <email@hidden>
  • Date: Mon, 07 Jan 2013 21:50:38 +0100

On 7 janv. 2013, at 20:22, Greg Parker <email@hidden> wrote:

> IEEE 754 guarantees exact results for + - * / sqrt. Everything else is implementation-defined.

That’s why I suggested a mixed approach combining exact table lookup and a refinement via only multiplications and divisions. It should give, if not exact, at least consistent results whatever processor is involved.

> Note also that physics simulations will always need to be careful with the error inherent to finite precision floating-point arithmetic. IEEE specification of exact results for every operation wouldn't […]

I assumed the original poster had a knowledge of both rounding error and stability theory in algorithms, including use of ad-hoc band-aids like preconditioning. Writing a simulation code w/out such knowledge would anyhow be somewhat vain.

Cheers!
Vincent


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References: 
 >Floating-point differences between ARM processors (From: Rick Mann <email@hidden>)
 >Re: Floating-point differences between ARM processors (From: vincent habchi <email@hidden>)
 >Re: Floating-point differences between ARM processors (From: Rick Mann <email@hidden>)
 >Re: Floating-point differences between ARM processors (From: Greg Parker <email@hidden>)

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