In complicated scenarios with deep nesting of solvers it is sometimes not
possible to set the options for the deeply nested solvers directly from the
code with function calls. Thus we recommend using the options database for such
cases. Note that one can provide options on the command line,
On Wed, Aug 23, 2017 at 6:42 AM, Khai Pham wrote:
> Hi All,
>
> I searched for the information about Petsc with OpenMP support. I came
> cross Danyang Su question a couple of month ago at
> https://lists.mcs.anl.gov/pipermail/petsc-users/2017-June/032975.html
>
Hi All,
I searched for the information about Petsc with OpenMP support. I came cross
Danyang Su question a couple of month ago at
https://lists.mcs.anl.gov/pipermail/petsc-users/2017-June/032975.htmlhttps://lists.mcs.anl.gov/pipermail/petsc-users/2017-June/032975.html
. I tried to configure
On 23/08/17 07:51, Klaij, Christiaan wrote:
> Lawrence,
>
> Well, I was looking for something like SubPCFactorSetShiftType,
> or is it supposed to somehow "trickle down" to the sub pc's?
Ah, I see. No, the approach below is what you need. Imagine that you
used a sub_pc inside a multigrid
Lawrence,
Well, I was looking for something like SubPCFactorSetShiftType,
or is it supposed to somehow "trickle down" to the sub pc's?
Or should I setup the pc, get the sub-pc's and then apply
PCFactorSetShiftType on the sub pc's, something like
CALL KSPSetup(ksp)
CALL PCBJacobiGetSubKSP(ksp,
On Wed, Aug 23, 2017 at 2:30 AM, Barry Smith wrote:
>
>Some argue that the preconditioned residual is "closer to" the norm of
> the error than the unpreconditioned norm. I don't have a solid mathematical
> reason to prefer left preconditioning with the preconditioned
Some argue that the preconditioned residual is "closer to" the norm of the
error than the unpreconditioned norm. I don't have a solid mathematical reason
to prefer left preconditioning with the preconditioned norm.
Barry
> On Aug 22, 2017, at 11:27 PM, Klaij, Christiaan
Barry,
Thanks for the explanation.
We do have some rare cases that give false convergence, but
decided to use
CALL KSPSetNormType(ksp,KSP_NORM_UNPRECONDITIONED,ierr)
so that convergence is always based on the true residual. Our
results are much more consistent now. So that could have been