[dune-pdelab] some problems in dune

[Christian Engwer]

Dear Robert,

the PDELab solver classes are convinience class which help you setup
the ISTL solvers. Some options are not exported... in this case you
have to setup your ISTL solvers by hand.

Ciao
Christian

On Tue, Oct 14, 2014 at 03:07:30PM +0200, Robert Jendrny wrote:
> Dear all,
> 
> I visited the DUNE COURSE this march.
> 
> And no I have some problems with my AMG settings
> 
> My Code is based on "pdelab-exercise2" "example02"
> 
> I have some questions:
> Do you know how I can change some AMG settings in this code
> -----------------------------------------------------------
>   // <<<5>>> Select a linear solver backend
>    typedef Dune::PDELab::ISTLBackend_SEQ_LS_AMG_SOR<GO> LS;
>    LS ls(5000,-1,false,false);
> 
>   // <<<6>>> assemble and solve linear problem
>   typedef Dune::PDELab::StationaryLinearProblemSolver<GO,LS,U> SLP;
>   SLP slp(go,ls,1e-6,1e-99,-1);
>   slp.apply(u);
> -----------------------------------------------------------
> 
> - I want to change the cycle ... the default case is V cycle, but I
> want or have to use W cycle
> I found it in amg.hh in the variable gamma = 2 ==> W cycle, but I do
> not know how I can change or call this one in my code
> 
> - I want to control the coarse grid
> I found in hierarchy.hh the variable coarsenTarget
> But I have the same problem as below: How can I change this in my code
> 
> It would be very nice if you can help me
> 
> Thank you for your help
> Robert Jendrny
> 
> -- 
> Robert Jendrny
> B.Sc. Technomathematik
> 
> TU Dortmund, Fakultät für Mathematik
> LS III: Angewandte Mathematik und Numerik
> M 1020, Vogelpothsweg 87, 44227 Dortmund
> robert.jendrny at math.tu-dortmund.de
> 
> 
> 
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-- 
Prof. Dr. Christian Engwer 
Institut für Numerische und Angewandte Mathematik
Fachbereich Mathematik und Informatik der Universität Münster
Einsteinstrasse 62
48149 Münster

E-Mail	christian.engwer at uni-muenster.de
Telefon	+49 251 83-35067
FAX		+49 251 83-32729