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Subject: Re: [OMPI users] open-mpi behaviour on Fedora, Ubuntu, Debian and CentOS
From: Sylvestre Ledru (sylvestre.ledru_at_[hidden])
Date: 2010-04-26 02:38:08


Hello,

Le lundi 26 avril 2010 à 14:33 +1200, Asad Ali a écrit :
> Hi Jodi,
>
> > I once got different results when running on a 64-Bit platform
> instead of
> > a 32 bit platform - if i remember correctly, the reason was that on
> the
> > 32-bit platform 80bit extended precision floats were used but on the
> 64bit
> > platform only 64bit floats.
>
> Could you please give me an idea as how to check this extended
> precision.
This code will set the precision to double:

#include <fpu_control.h>
fpu_control_t _cw;
_FPU_GETCW(_cw);
_cw = (_cw & ~_FPU_DOUBLE) | _FPU_EXTENDED;
_FPU_SETCW(_cw);

You should get the same result on 32 & 64 bits CPU then.

Sylvestre