[Numpy-discussion] numpy and roundoff(?)

Lisandro Dalcin dalcinl@gmail....
Tue Mar 4 09:26:50 CST 2008


Damian Eads wrote:
> One used -mfpmath=sse, and the other, -mfpmath=387.
> Keeping them both
> the same cleared the discrepancy.

Oh yes! I think you  got it...

On 3/3/08, Christopher Barker <Chris.Barker@noaa.gov> wrote:
>
> Was it really a "significant" difference, or just noticeable? I hope
>  not, that would be pretty scary!
>

I now believe that this is possible causing the trouble. And yes, in
my case the cummulative differences leaded to different iteration
counts in a matrix-free Newton-Krylov method. Of course, the final
answer was as as accurate as the tolerances for the nonlinear solver.


-- 
Lisandro Dalcín
---------------
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
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