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-   -   Memory requirement for lattice boltzmann methods (simple BGK) (http://www.cfd-online.com/Forums/hardware/84026-memory-requirement-lattice-boltzmann-methods-simple-bgk.html)

amaal January 18, 2011 12:14

Memory requirement for lattice boltzmann methods (simple BGK)
 
Hi every1,

I wondered if anyone can give an assumption on the memory requirement for a LBM - simulation with simple BGK dynamics.

So far I used only a 128x128x256 lattice, and my quad-core Desktop could run the simulations within 1-3 days.

Now we are increasing the lattice size, possible to even 1000x1000x1000 (or 750^3 is ok too).

The forumla Ive come up with looks like:

M = N^3 * 19 * 8 * x (in byte)

19 since im using D3Q19, 8 bytes for a double datatype (could scale down to 4 for float), and N^3 for the 3 dimensions.
The big question now is the x, which should basically be 3 if Im correct (2 velocity and 1 density matrix yes?). I do not use my own code, but use the package http://www.lbmethod.org/palabos/index.html
From the simulations Ive done so far, it seems <x> is around 1.5 for palabos, so maybe they store the data in a more efficient way. Also, for multiple cores the required memory increases, but with 4 cores on my desktop, this can be estimated too.

Im new to the subject, so if any1 has more experience a good estimate would help a lot, since it affects the new hardware we will buy.

thanks in advance


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