[dune-pdelab] Fwd: solver fails to reset correctly after FMatrixError (singular matrix)

[Markus Blatt]

Hi,

I am probably missing a lot here, but have you tried the poor-man's solution, below?

On Wed, Jul 10, 2019 at 11:55:45AM +0200, Shubhangi Gupta wrote:

> *// code layout*
> 
>     ...UG grid, generated using gmsh, GV, ...
> 
>     typedef Dune::PDELab::QkDGLocalFiniteElementMap<GV::Grid::ctype, double,
> 0, dim, Dune::PDELab::QkDGBasisPolynomial::lagrange> FEMP0;
>     FEMP0 femp0;
>     typedef Dune::PDELab::GridFunctionSpace<GV,FEMP0,Dune::PDELab::P0ParallelConstraints,Dune::PDELab::ISTL::VectorBackend<>>
> GFS0;
>     GFS0 gfs0(gv,femp0);
>     typedef Dune::PDELab::PowerGridFunctionSpace< GFS0,num_of_vars,
> Dune::PDELab::ISTL::VectorBackend<Dune::PDELab::ISTL::Blocking::fixed>,
> Dune::PDELab::EntityBlockedOrderingTag> GFS_TCH;
> 
>     ... LocalOperator LOP lop, TimeLocalOperator TOP top, GridOperator GO
> go, InstationaryGridOperator IGO igo, ...
> 
>     typedef Dune::PDELab::ISTLBackend_BCGS_AMG_SSOR<IGO> LS;
>     LS ls(gfs,50,1,false,true);
>     typedef Dune::PDELab::Newton< IGO, LS, U > PDESOLVER;
>     PDESOLVER pdesolver( igo, ls );
> Dune::PDELab::ImplicitEulerParameter<double> method;
> 
>     Dune::PDELab::OneStepMethod< double, IGO, PDESOLVER, U, U > osm( method,
> igo, pdesolver );
> 
>     //TIME-LOOP
>     while( time < t_END - 1e-8){
              int applyWorked=0;
>             try{
>                 //PDE-SOLVE
>                 osm.apply( time, dt, uold, unew );
>                 applyWorked=1
>             }catch ( Dune::Exception &e ) {
>                 //RESET
>                 exceptionCaught = true;
>                 std::cout << "Catched Error, Dune reported error: " << e <<
> std::endl;
              }
	      applyWorked = grid.comm().min(applyWorked);
	      if(applyWorked)
	      {
>                 unew = uold;
>                 dt *= 0.5;
> osm.getPDESolver().discardMatrix();
>                 continue;
>             }
>             uold = unew;
>             time += dt;
>     }
> 
-- 
Dr. Markus Blatt - HPC-Simulation-Software & Services http://www.dr-blatt.de
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