Dear Andrew, Markus and Wolfgang,
I have already implemented the idea of Markus of having not connected
domains. The problem is, as you pointed out, that we lose in this way the
connectivity of the grid through the discontinuities, i.e. an element at
the border of two different domains doesn't know its neighbour on the
other side.
I have created the connectivity manually and solved the problem, but in
this way you lose the refining and coarsening mechanisms already
implemented in deal.ii.
To avoid this problem we had the idea to use a hp_collector as I've shown
in the last mail.
To come to the question of Wolfgang.
Can you say where exactly this exception is produced?
It happens when I call "distribute_dofs", because fe_system calls the
following function:
template <int dim>
FiniteElementDomination::Domination
FE_Nothing<dim> ::
compare_for_face_domination (const FiniteElement<dim> & fe_other) const
{
if(dynamic_cast<const FE_Nothing<dim>*>(&fe_other) != 0)
return FiniteElementDomination::either_element_can_dominate;
else
return FiniteElementDomination::this_element_dominates;
}
How should be the behavior of this function in the FE_Nothing case?
We have a problem because the pair is symmetric
fe_1 ( FE_Q<dim>(1), 1, FE_Nothing<dim>(), 1 ),
fe_2 ( FE_Nothing<dim>(), 1, FE_Q<dim>(1), 1 ),
and fe_system ends up with neither_element_dominates.
So actually fe_system should not use "compare_for_face_domination" when we
use FE_Nothing, but how can you a priori control this, if you still want
the hp features?
Here the error message in deal.ii:
--------------------------------------------------------
An error occurred in line <2547> of file
<deal.II/source/fe/fe_system.cc> in
function
dealii::FiniteElementDomination::Domination dealii::FESystem<dim,
spacedim>::compare_for_face_domination(const dealii::FiniteElement<dim,
spacedim>&) const [with int dim = 2, int spacedim = 2]
The violated condition was:
domination != FiniteElementDomination::neither_element_dominates
The name and call sequence of the exception was:
ExcInternalError()
Additional Information:
(none)
Stacktrace:
-----------
#0
lib/libdeal_II_2d.g.so.6.3.1:
dealii::FESystem<2,
2>::compare_for_face_domination(dealii::FiniteElement<2, 2> const&) const
#1
lib/libdeal_II_2d.g.so.6.3.1:
unsigned int dealii::internal::hp::get_most_dominating_fe_index<2, 2,
dealii::TriaIterator<dealii::DoFAccessor<1, dealii::hp::DoFHandler<2, 2> >
>(dealii::TriaIterator<dealii::DoFAccessor<1, dealii::hp::DoFHandler<2,
2> > > const&)
#2
lib/libdeal_II_2d.g.so.6.3.1:
dealii::hp::DoFHandler<2,
2>::compute_line_dof_identities(std::vector<unsigned int,
std::allocator<unsigned int> >&) const
#3
lib/libdeal_II_2d.g.so.6.3.1:
dealii::hp::DoFHandler<2, 2>::distribute_dofs(dealii::hp::FECollection<2,
2> const&)
#4 ./step-3: LaplaceProblem::make_grid_and_dofs()
#5 ./step-3: LaplaceProblem::run()
#6 ./step-3: main
--------------------------------------------------------
Best
Thomas
_______________________________________________
dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
