use of a PC with two processors

edodo

Hi everybody,

Please help me in the following issue. I'm using Femlab 3.0a for fuel cell modeling and currently I work with heat transfer and fluid dynamics models. The problem is that even for a small model the program takes too much resource from my computer and solution time is too long. My PC's configuration is Pentium(R) 4, CPU 2.66GHz, 512MB of RAM, OS is WinXP SP2.  
Will use of a PC with two processors help me to solve these problems more efficiently?

Arman Danelyan
Research Engineer

edodo

Arman,

Hello. Unfortunately, I don't believe that using 2 processors will be of any help. COMSOL/FEMLAB does not support multi-threading which is what you would need to be able to use 2 different processors simultaneously. This is more of a problem inherent to the Finite Element Method more than it is to COMSOL. This is why a lot of persons will opt for Finite Difference Time Domain (FDTD) based simulation approaches. Having a good processor with a high clock rate will help but in the end adding memory is the best way to enhance a computer that you are going to run COMSOL on. Also, there are tricks that can help you in building more "efficient" models. If there is any type of symmetry condition that you can introduce into the model, that will help you by effectively cutting your model size in half. Also, proper choice of the type of mesh elements you and the solver are critical. Iterative methods take longer but they run on much less memory so you can run even bigger models than using a direct solver. Also, I have found that the multigrid solver is amazing and makes COMSOL/FEMLAB run much more efficiently. I hope this helps. Please feel free to email me if you have any more questions.

Regards,
Jason Deibel

edodo

When put simply, more memory you have, the larger are the geometries you would be able to solve. The solution time will probably scale with processor speed which should be pretty good for your processor. Two processors will not help you in the sense that FEMLAB can not do multi-tasking (as of yet). It will help you in the sense that you could have FEMLAB occupy one of your processors and do outher routine jobs with the other processor. The operating system will take care of assigning processors to different processes and for most cases FEMLAB should get 100% usage on one processor.

I do not think you will see any speed improvement in your case unless you have to use swap memory right now, in which case, more RAM would definitely make things much faster.

More experienced people could correct me!

-Sushil

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