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Date: Sun, 16 Aug 2015 19:58:32 +0200
From: magnum <>
Subject: Re: relbench over/underflow when calculating geometric

On 2015-08-16 17:44, Solar Designer wrote:
> The attached patch allows relbench to calculate the geometric mean even
> when there's a large number of significantly different benchmark
> results.  Without this patch, I was getting "inf" for $mr and (luckily)
> a crash on log() on line 266 when comparing OpenMP benchmarks for all of
> jumbo's formats on super for 1 vs. 15 threads.  This is currently 403
> total benchmarks and each may be sped up by ~15x (ideally), resulting in
> the naive implementation's intermediate value exceeding the maximum
> value for "double".  (And comparing these benchmarks the other way, we'd
> similarly have an underflow.)
> I think we should commit this into jumbo for now, even though the code
> comes from core.  There are by far not enough formats in core to trigger
> the problem in there.



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