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-   -   GAMG vs. PCG in fvSolution (http://www.cfd-online.com/Forums/openfoam-solving/90806-gamg-vs-pcg-fvsolution.html)

grandgo July 21, 2011 04:39

GAMG vs. PCG in fvSolution
 
hi foamers,

i'm working with two domains of exactly same geometry and case configurations. one domain has 150000 cells, the other about 6*10^6 cells.

in the coarse domain case the GAMG solver needs about 30 iterations for one timestep (nCellsInCoarsestLevel = 1000). on the other hand, if i choose PCG the calculation needs 230 iterations.

in the fine domain case it's the opposite: PCG needs about 1000 iterations but GAMG does need more (maxIter limitation at 1500, various nCellsInCoarsestLevel).

what's your experience with GAMG? any tips what i could try?

best regards
grandgo


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