[MITgcm-devel] [MITgcm-cvs] MITgcm/tools/build_options CVS Commit

[Jean-Michel Campin]

Hi Dimitris,

On Mon, Apr 26, 2010 at 09:10:19AM -0700, Menemenlis, Dimitris (3248) wrote:
> Has anyone actually tested that "-fp-model precise -ftz" breaks the restart?
I thought you would have tried before checking in the changes ?
Cheers,
Jean-Michel

> I thought that "-mp" implies "-ftz" and that is why EVP code runs fine with "-mp".
> If noone has tested restarts with "-fp-model precise -ftz", I can put it on my todo list.
> Dimitris
> 
> On Apr 26, 2010, at 8:41 AM, Constantinos Evangelinos wrote:
> 
> > On Saturday 24 April 2010 07:42:55 pm Jean-Michel Campin wrote:
> >> Hi Dimitris,
> >> 
> >> I think that if your modified optfile degrade the results of
> >> the 2+2 test, it's better to go back and leave the new option
> >> commented: the reason is that it's quiet nice to be able
> >> to restart exactly, and if it's no longer the case, it could
> >> disturb other users. I personally don't run the 2+2 test very
> >> often (apart from the standard verification tests), and it might
> >> take them some time to realize that they lost this capability.
> > 
> > So essentially we have an option (-mp) that works but is not going to be there 
> > in the Intel 12.0 compilers while its suggested equivalent option (-fp-model 
> > precise) is producing underflows in the EVP solver slowing it down immensely 
> > and at the same time a modification to -fp-model precise to avoid the 
> > underflows (-ftz) breaks the restart... What a mess. 
> > 
> > Constantinos
> 
> 
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