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.
On Sun, Apr 25, 2010 at 3:39 AM, Fabian Hänsel <fabta...@gmx.de> wrote: > Hi Asad, > >> I found that running the same source code on these OS, with the same >> versions of of gcc and open-mpi installed on them, gives different results >> than Fedora and Ubuntu after a few hundred iterations. The first >> few hundered iterations are exactly similar to that of Fedora and Ubuntu >> but then it starts giving different results. > > Are you also using the same hardware? Different hardware platforms may > exhibit different rounding behaviour. After some dependent interations such > effects might indeed sum up and yield different results. The issue is called > numeric (in)stability and is not specifically related to openmpi. > > Best regards > Fabian > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
