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Re: Setting tolerances for multigrid

On 6/14/07, Knut Erik Teigen <knutert@xxxxxxxxxxxx> wrote: 
Hello,

How do I set the tolerances for the KSP solvers when using the
DMMG routines without using command line arguments? It seems that
I can use the argument -ksp_rtol on the command line, but in the code I
can't use KSPSetTolerances since I don't have access to the KSP solver
context?


You can use DMMGGetKSP() for the finest level, and dmmg[level]->ksp for
any others.

Also, I see there is a reference to the function DMMGSetUseGalerkin
in the source code, but I can't find the documentation for it.
Does this function not exist yet? Again I would like to use
-dmmg_galerkin, but setting it in the code instead of on the command
line.


I think you want this:

http://www-unix.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/DA/DMMGSetUseGalerkinCoarse.html

 Matt

Regards,
Knut Erik Teigen




--
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which
their experiments lead.
-- Norbert Wiener