[petsc-users] non-convergence for SNES ex5 and ex20

[Jed Brown]

On Wed, Jun 22, 2011 at 16:58, Qian Zhu <qzhu at mcs.anl.gov> wrote:

> For ex5, par=xxx,  using "-ksp_type gmres -pc_type ilu" will make the
> solution converge while using "-ksp_type cg -pc_type jacobi" cannot (all
> ksp's and pc's are just randomly picked...they may not make sense).


boundary conditions are not symmetric in this example


> What would this "xxx" value be? Or is there any input parameters I am
> missing out for these applications?


look at snes ex19 and use  -lidvelocity 100 -grashof 1e5 if you are looking
for something that doesn't converge. Or try a Stokes problem.
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