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Re: [PATCH] Optimized generic expf and exp2f
Arjan van de Ven wrote:
>
> I'm seeing a 16% throughput increase (not 1.5x) but still impressive.
Was that using the expf trace input or something else? And with wrapper?
> I do see different numerical answers between the two (I had to disable
> the code in my bench that detects differences) and sampling a few
> it seems that the C code is a little bit less accurate in places,
> likely a simpler polynomal.
> (for example for 20.636783599853515625 as input)
It's still way more accurate than necessary. The only reason is to
minimize ULP error for non-nearest rounding modes. If you don't
care about worst-case ULP for non-standard rounding modes, the
polynomial can be further simplified within 1ULP max error in round
to nearest.
Wilco