Terrible FPU performance

David Cournapeau cournape at gmail.com
Wed Apr 27 21:03:11 CEST 2011


On Wed, Apr 27, 2011 at 10:04 PM, Mihai Badoiu <mbadoiu at gmail.com> wrote:
> I'm using intel xeon harpertown (E5450) and Python 2.6.4.
> In the cython code, when I use fpclassify, in the slow case I get 3
> (FP_SUBNORMAL)
> In the pure-C code, when I use fpclassify, in the case that's supposed to be
> slow but it's not, I get a 2 (FP_ZERO)

Ok, so this is indeed a denormal issue. Could you post the exact code
(and compilation steps) you used in both cases ?

cheers,

David



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