[dunepdelab] Off maindiagonal Dirchlet conditions
Andreas Lauser
andreas.lauser at iws.unistuttgart.de
Thu Nov 26 18:03:00 CET 2009
Hi pdelabers,
Now I am able to use mixed boundary conditions with PowerGridFunctionSpace
which is great! The next thing which would be nice to have is a way to specify
which equation determines which dirichlet condition. If I my understanding of
the constraints framework in PDELab is correct I do not see a way to do this.
Example:
For twodimensional P1Elements, the LocalPowerGridFunctionSpace for two
equations looks like this:
(root)

 (local finite element for equation 0)
 > coefficient index for vertex 0
 > coefficient index for vertex 1
 \> coefficient index for vertex 2
\ (local finite element for equation 1)
> coefficient index for vertex 0
> coefficient index for vertex 1
\> coefficient index for vertex 2
If I understood everything correctly, constraints are defined by inserting the
weights of number of DOFs to the constraints tranformation. Also the weights
of the DOFs are specified by their index in the local finite element if I'm
not mistaken.
What I would like to have is a way to define constraints depending on the
solution of a different finite element, for example using equation 1 to
specify the dirichlet value for primary variable 0 on the the first vertex. I
guess this would require to store some global DOF indices in the constraints
transformation. How can I do this? Quite likely I'm just too stupid to see
some obvious solution...
Regards
Andreas

Andreas Lauser
Lehrstuhl für Hydromechanik und Hydrosystemmodellierung
Universität Stuttgart  Institut für Wasserbau
Pfaffenwaldring 61
D70569 Stuttgart
Tel: (+49) 0711/ 68564719
Fax: (+49) 0711/ 68560430
email: andreas.lauser at iws.unistuttgart.de
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