[petsc-users] Extra Variable in DMCircuit

[Matthew Knepley]

On Fri, Mar 14, 2014 at 4:13 AM, Florian Meier <florian.meier at koalo.de>wrote:

> Hi,
> I got quite far with my project, although I still have not managed (or
> better "have not tried...") to get the parallelization running (Shri:
> Any news about that?).
>
> Now I would like to add a single global variable (and a single equation)
> to the equation system. Is there an elegant way to do this with DMCircuit?
>
> A hackish solution might be to add an additional imaginary vertex that
> is excluded from all other calculations, but that does not seem to be
> the right way to do it.
>

The graph expresses the influence of variables on each other, so if you have
a globally coupled variable, then a node linked to all other nodes is the
appropriate structure.

 The problem is that this is not scalable since it will result in a dense
row. I
would do this for now. And when your problem is large enough for this to
be a drag on scalability (thousands of processes), switch to specialized
code.

   Matt


> Greetings,
> Florian
>



-- 
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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