Bartosz Sawicki wrote:
Hi all,
Have any of you, some experience with posteriori error estimation in
Dolfin? I'm playing with adaptive refinement techniques, where proper
error estimation is essential.
I try to use form language with discontinous Lagrange elements to
describe error, but the results are somehow strange.
I found that in Unicorn there are some error estimation code, but I
can't find any application of it or any example? Is this code working?
regrd.
BArtek
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Hi!
Yes, the Unicorn error estimation code is working. I assume you're
looking at the Unicorn release, which is almost 1 year old now. There
you can find the dual and residual forms, but the demo problems only
computed residuals, not any error estimates with dual solutions.
Why not check out the development version of Unicorn from the repository
at:
hg clone http://www.nada.kth.se/cgi-bin/jjan/hgwebdir.cgi/unicorn-kth
(look at for example revision 103)
The ucsolver/icns/cube example has a "run.py" Python script which runs
the full adaptive algorithm with primal and dual solvers and adaptivity
based on the error estimate for drag output. You can use the mesh from
here to test:
| wget -O mesh.xml http://www.csc.kth.se/~jjan/transfer/cube-mesh11.xml
<http://www.csc.kth.se/%7Ejjan/transfer/cube-mesh11.xml>
|The residual is computed by multiplication of a DG test functihn as
Anders mentioned. The dual forms are generated by hand, it would be nice
to be able to automate that part as well.
