[FLASH-USERS] Big Problem??

Seyit Hocuk seyit at astro.rug.nl
Wed Jul 30 08:18:47 EDT 2008


Tomek,

I tried using only " -c -r8 -i4 -I $(MPI_PATH)/include " optimizations 
on all with single proc, single refinement level. The differences are 
still there. Including  -I $(MPI_PATH)/include has no effect (though pc 
1 does not work without it). Is this still agressive optimization? I 
always need -c otherwise I get errors compiling. I need -r8 otherwise 
while running I get errors. I guess i4 in not so necessary, but I 
thought it wouldn't hurt. It also makes no difference by the way in my 
simulations.

Oh and the differences in calculations of k, kJ, c0, omega ... etc. is 
purely precision. Pc 1 and pc 3 have same values, but pc 2 has one more 
digit to them.


Tomasz Plewa wrote:
> Seyit -
>
> The "problem" is already present in a serial model.
>
> Also, I noticed that you are using very aggressive compiler 
> optimizations. This frequently affects floating point accuracy. Can 
> you produce a single processor, single patch models with no 
> optimizations?
>
> Tomek
> -- 




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