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Hi Gregor,<br>
<br>
I can't provide a very detailed view on this, but a coarse roadmap
would be to use a P/Q1-P0 CompositeGridFunctionSpace, P0 for u_1 and
P/Q1 for u_2. I can't find any usage of CompositeGridFunctionSpace
in the current PDELab tutorial, but <br>
<a class="moz-txt-link-freetext" href="https://gitlab.dune-project.org/pdelab/dune-pdelab/blob/master/dune/pdelab/test/testutilities.cc">https://gitlab.dune-project.org/pdelab/dune-pdelab/blob/master/dune/pdelab/test/testutilities.cc</a><br>
should get you there.<br>
<br>
You should adapt and combine things from Tutorials 01 and 02 from<br>
<a class="moz-txt-link-freetext" href="https://gitlab.dune-project.org/pdelab/dune-pdelab-tutorials">https://gitlab.dune-project.org/pdelab/dune-pdelab-tutorials</a><br>
<br>
For the fluxes over cell-centered volumes, you would use the
"..._skeleton" functions as in Tutorial 02, while for the
vertex-centered volumes, you would use the "..._volume" parts as in
Tutorial 01. For the latter, you would divide each primal element
into a corresponding amount of subcontrol volumes. The total fluxes
would be assembled automatically from these contributions.<br>
<br>
Hope this helps. Kind regards<br>
Bernd<br>
<br>
<br>
<div class="moz-cite-prefix">On 01/23/2018 10:29 AM, Gregor Corbin
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:16ed5fc0-e641-afa9-6b5b-d996691464b4@mathematik.uni-kl.de">
<pre wrap="">Hello everyone,
I need to implement a method on staggered grids and would like to know
if it is possible in PDELab, and if so, how?
More specifically, I have a system of hyperbolic equations that will be
solved with a first-order finite volume method. It has the structure
d_t u_1 + dx F(u_2) = 0,
d_t u_2 + dx G(u_1,u_2) = 0.
The solution components u are split into two parts, u_1 and u_2.
u_1 is associated with some grid, let's say grid1, (a tensor product
grid, i.e. YASP grid, in my case) as usual. But u_2 should be defined on
the complement grid2, i.e. the grid that has the corners of grid1 as the
new cell centers, and the cell centers of grid1 as the new cell corners.
I don't think that the usual local operators can handle this situation,
so I'm currently inclined to iterate over the grid, evaluate the
solution from the GFS, and compute the updates manually, without the
help of grid operators.
I'd really appreciate your help.
Cheers,
Gregor
</pre>
<br>
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<br>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
_______________________________________________________________
Bernd Flemisch phone: +49 711 685 69162
IWS, Universität Stuttgart fax: +49 711 685 60430
Pfaffenwaldring 61 email: <a class="moz-txt-link-abbreviated" href="mailto:bernd@iws.uni-stuttgart.de">bernd@iws.uni-stuttgart.de</a>
D-70569 Stuttgart url: <a class="moz-txt-link-abbreviated" href="http://www.hydrosys.uni-stuttgart.de">www.hydrosys.uni-stuttgart.de</a>
_______________________________________________________________
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