[petsc-users] -pc_asm_type none

[Fande Kong]

On Sat, Nov 5, 2016 at 10:10 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> > On Nov 5, 2016, at 9:35 PM, Fande Kong <fdkong.jd at gmail.com> wrote:
> >
> > Hi All,
> >
> > I know what "basic", "restrict" and "interpolate" represent, but have no
> idea about "none". Anybody knows what does mean when using "-pc_asm_type
> none"?
>
>  PC_ASM_NONE         - Residuals from ghost points are not used, computed
> ghost values are
> $                        discarded.
> $                        Not very good.
>
>   In the P (A_subdomain)^-1 R  both the R and the P skip values in the
> overlap region. Sort of the worst of restrict and interpolate.
>

Thanks, Barry.

Did some experiments, and I observed that "none" works better than "basic"
for an incompressible Navier-Stokes defined on a complex domain. Is it
normal?

I think for PC_ASM_BASIC, we could average the values on the overlap
region. Right now, we are just simply adding all values from different
processors together for the overlap region.

There are some literatures that shows the averaged version works similarly
as the restrict/interpolate version.

Fande,




>
>
> >
> > Regards,
> >
> > Fande Kong,
>
>
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