To follow up on this, I have run some tests on a smaller test case (same
model, coarser mesh). The options I tried are:
8 MPI processes with:
"-ksp_type gmres -pc_type gamg"
"-ksp_type fgmres -pc_type gamg"
"-ksp_type cg -pc_type gamg"
"-ksp_type cg -pc_type gamg -ksp_norm_type natural"
"-ksp_type
r<#secure method=pgpmime mode=sign>
Matthew Knepley writes:
> Yikes! I did not check that. Why do we have PRECONDITIONED as the default
> for CG?
So we can do an extra reduction on each iteration? I mean, who doesn't
want that? ;-)
On Fri, Nov 13, 2015 at 12:28 PM, Jed Brown wrote:
> Matthew Knepley writes:
> > Something very strange is happening here. CG should converge
> monotonically,
> > but above it does not. What could be happening?
>
> Are you use -ksp_norm_type natural? CG is not monotone in other norms.
>
Yikes!
Matthew Knepley writes:
> Something very strange is happening here. CG should converge monotonically,
> but above it does not. What could be happening?
Are you use -ksp_norm_type natural? CG is not monotone in other norms.
Also, if boundary conditions are enforced using a nonsymmetric
formulati
On Fri, Nov 13, 2015 at 9:45 AM, Matthew Knepley wrote:
> On Thu, Nov 12, 2015 at 10:02 PM, David Knezevic <
> david.kneze...@akselos.com> wrote:
>
>> On Thu, Nov 12, 2015 at 9:58 AM, David Knezevic <
>> david.kneze...@akselos.com> wrote:
>>
>>> On Thu, Nov 12, 2015 at 9:50 AM, Mark Adams wrote:
On Thu, Nov 12, 2015 at 10:02 PM, David Knezevic wrote:
> On Thu, Nov 12, 2015 at 9:58 AM, David Knezevic <
> david.kneze...@akselos.com> wrote:
>
>> On Thu, Nov 12, 2015 at 9:50 AM, Mark Adams wrote:
>>
>>> Note, I suspect the zero pivot is coming from a coarse grid. I don't
>>> know why no-in
