[petsc-dev] ML via --download-ml

[Matthew Knepley]

On Fri, Jun 12, 2015 at 6:24 AM, Garth N. Wells <gnw20 at cam.ac.uk> wrote:

> I've noticed very different performance with ML when I (a) link PETSc
> to a Trilinos installation; or (b) use --download-ml. I observe
>
> - Case (a): solver behaves exactly as I would expect. Iteration counts
> very close to GAMG iteration counts, minimal dependency on problem
> size.
>
> - Case (b): iteration counts higher and substantial increase in
> iteration count with problem size.
>
> I haven't debugged since I usually link to Trilinos, in which case
> performance is as I expect.


ML stopped being distributed independent of Trilinos a while ago, so we
might not
have upstream changes. This sounds like a difference of settings. The first
step I think
is to look at -ksp_view for both runs.

  Thanks,

     Matt


> Garth
>



-- 
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
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