KSP/PC choice

[Lisandro Dalcin]

On 7/24/07, Ben Tay <zonexo at gmail.com> wrote:
> I am also trying to solve the NS eqns in 2d, finite volume mtd, using
> fractional step formulation.
>
> I am currently using KSPBCGS and PCILU to solve the momentum eqn matrix
> and HYPRE's AMG and the default ksptype to solve the poisson eqn. Do you
> ppl think this is a good choice? Or is there a better recommendation?
>

This seems a godd starting point, but I would try to make sure using
KSPCG for the poisson problem (of course, this if your poisson matrix
is SPD, as it usually is in a fractional step methods). Additionally,
if your poisson matrix is exactly the same for every time step, I
believe HYPRE AMG is the best option for PC if your problem is rather
large.

Of course, as Barry said, all this is strongly problem dependent. You
should try for the best combination. It's easy, just use command line
options (of course, you have to set a different 'prefix' for your
velocity and pressure solvers).

Regards,

-- 
Lisandro Dalcín
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