[dune-pdelab] Hanging Nodes

[Felix Heimann]

Hi Volker,

revision 1438 fixes the problem. I apologize for not investigating the
problem earlier, but the pdelab review week caused a lot of additional
workload and I just could not look into it before today.

Best Regards, Felix



Am Freitag, den 25.03.2011, 17:30 +0100 schrieb schauer:
> Hi Felix,
> 
> thanks for your answer. I tried to have an insight into the way the
> constraints are upset and treated in the grid operator space, but
> honestly, like so many source code parts in pdelab, when it comes to the
> details, it seems quite confusing to me.
> 
> Regards
> 
> Volker 
> 
> 
> 
> Am Mittwoch, den 23.03.2011, 17:02 +0100 schrieb Felix Heimann:
> > Hi Volker,  
> > actually i think you are correct with all your assumptions. About one
> > week ago i noticed that the hanging node howto example does not work
> > anymore. However i was not yet able to look into it. I'll try to
> > tackle it next week. However, if you find the problem before me, feel
> > free to send a patch. 
> > 
> > Best Regards, Felix
> > 
> > Durch MOTOBLUR™ verbunden
> > 
> > 
> > -----Ursprüngliche Nachricht-----
> >         Von: schauer <schauer at mechbau.uni-stuttgart.de>
> >         An: dune-pdelab <dune-pdelab at dune-project.org>
> >         Gesendet: Mi, 23 Mrz 2011, 16:30:04 MEZ
> >         Betreff: [dune-pdelab] Hanging Nodes
> >         
> >         
> >         Dear PDELabers,
> >         
> >         I try to implement hanging nodes together with Dirichlet
> >         constraints. I 
> >         acted as in the poisson example of the pdelab howto. 
> >         
> >         But now some things appear strange to me:
> >         
> >         - The transformation of a vector with 
> >         gos.backtransform 
> >         
> >         as well as
> >         
> >         gos.forwardtransform
> >         
> >         only seem to multiply the hanging node entry of the
> >         input-vector 
> >         with a value from the constraints container without any kind
> >         of
> >         interpolation with the neighbouring nodes - so the
> >         transformation
> >         matrix is diagonal and in my case the backward transformation
> >         after a
> >         forward transformation do not give the original vector but in
> >         my case 
> >         these transformations even seem to be identical. 
> >         
> >         I then looked at the constraints container with the verbosity
> >         flag in
> >         the constraints call, and also saw that all the hanging nodes
> >         had just
> >         one entry with the same line as row index, e.g. like:
> >         
> >         266: (266,0.25) 
> >         267: (267,0.25) 
> >         268: (268,0.25) 
> >         275: (275,0.5) 
> >         276: (276,0.5) 
> >         278: (278,0.5) 
> >         
> >         which also consists of only one value in every row (somehow I
> >         supposed
> >         the neighbouring, non-constrained nodes should show up here). 
> >         
> >         The row entries of the resulting matrix at a hanging node
> >         position were
> >         trivial, which seems to be fine to me, but I don't think that
> >         the other
> >         rows were changed correctly (though I didn't verify).
> >         
> >         I suppose these things can also be verified on the hanging
> >         nodes example
> >         poisson.cc of the pdelab-howto.
> >         
> >         
> >         So is the way the constraints container gets filled for the
> >         hanging
> >         nodes wrong - or am I not correct with some of my
> >         assumptions ? 
> >         
> >         Thanks
> >         
> >         Volker
> >         
> >         
> >         
> >         
> >         
> >         -- 
> >         
> >         _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> >         
> >         Volker Schauer (Dipl.Phys)
> >         
> >         Institute of Applied Mechanics (Civil Engineering), Chair 1
> >         University of Stuttgart
> >         Pfaffenwaldring 7
> >         D-70569 Stuttgart
> >         GERMANY
> >         
> >         Phone ++49 (0)711-68560044
> >         email: schauer at mechbau.uni-stuttgart.de
> >         
> >         
> >         _______________________________________________
> >         dune-pdelab mailing list
> >         dune-pdelab at dune-project.org
> >         http://lists.dune-project.org/mailman/listinfo/dune-pdelab
> 
> -- 
> 
> _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
> 
> Volker Schauer (Dipl.Phys)
> 
> Institute of Applied Mechanics (Civil Engineering), Chair 1
> University of Stuttgart
> Pfaffenwaldring 7
> D-70569 Stuttgart
> GERMANY
> 
> Phone ++49 (0)711-68560044
> email: schauer at mechbau.uni-stuttgart.de
> 

-- 
Felix Heimann
Universität Heidelberg
Interdisziplinäres Zentrum für Wissenschaftliches Rechnen
Arbeitsgruppe Paralleles Rechnen
IWR 368, Raum 422
Tel: 06221 / 54 8881