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tom April 15, 2008 11:20

parallel CCM+
 
Hi,

I am using a quad core processor and would like to use its max processing power. If I do a serial simulation I can only use 25% of total CPU. However, if I make the simulation parallel and increase the number compute processes to, say, 2 I then for a few minutes I get full throttle until I get a "memory access exception".

Does this mean multi-core can only run serial simulations, or is the fact that I am running 32 bit XP hinder progress.

Thanks for any help

Jim April 15, 2008 12:48

Re: parallel CCM+
 
Have you got parallel licenses?

tom April 15, 2008 13:44

Re: parallel CCM+
 
I have been told that we do. But as this is my first time doing this I will let the support guys guide me.

Quad-core seems to be of little benefit for speeding up simulations in serial. Its a shame tom

Jim April 15, 2008 13:46

Re: parallel CCM+
 
Serial is Serial whatever chip you use, I wouldn't recommend running on all four cores anyway, you will actually run slower than on 3 due to the memory bus becoming overloaded


Thomas April 17, 2008 05:46

Re: parallel CCM+
 
Hi, I have similar problem running STAR-CD V3.26 on DualCore cpu. I got very often a memory access error and simulation stops on 2nd cpu. I could solve most of these problems when disabling the AMG solver. But some cases still do not want to run in parallel. Info: 32 bit windows Xp prof. 4GB RAM ( I know, I cannot adress the full 4GB, but above describes problem occur even on relativly small cases which definitly fit into 2GB!!)

So my only advice: try to run the case with CG-solver. maybe it works ;-) Thomas

Dan May 8, 2008 19:54

Re: parallel CCM+
 
I run a parallel system with quad core, 64 bit linux and 10Gb Ram, never have had any memory access errors unless StarCCM corrupts my simulation file (does happen frequently, I've never had problems exporting my mesh, re-setting up analysis if I get in a bind). Without knowing any more about your system, I would guess there's a conflict in your setup, I'd advise against 32 bit Windows for CFD work.


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