Hi Wolfgang,
I've been looking at a few sources regarding FE_Enriched:
(A) https://www.dealii.org/current/doxygen/deal.II/classFE__Enriched.html
(B)
https://github.com/dealii/dealii/blob/master/tests/fe/fe_enriched_step-36b.cc
I've been trying to get my problem class to work with a placeholder
enrichment function from example (B), but I'm getting tripped up.
I looked at the formatting on Line 146 of fe_enriched.cc:
FE_Enriched<dim, spacedim>::FE_Enriched(
const FiniteElement<dim, spacedim> &fe_base,
const FiniteElement<dim, spacedim> &fe_enriched,
const Function<spacedim> * enrichment_function)
I have tried to implement this format in the constructor for my problem
class. I am trying to set fe_base as FE_Q, and then fe_enriched as another
FE_Q multiplied
by the enrichment function.
template <int dim, int spacedim>
shElast<dim, spacedim>::shElast(
const std::string & initial_mesh_filename,
const std::string & output_filename)
:
*fe( FE_Q<dim>(1) , FE_Q<dim>(1) , enrichment)*
, dof_handler(triangulation)
, quadrature_formula(fe.degree + 1)
, initial_mesh_filename(initial_mesh_filename)
, output_filename(output_filename)
, mapping( FE_Q<dim>(1))
{}
where I've previously declared:
Triangulation<dim> triangulation;
* const FE_Enriched<dim> fe;*
DoFHandler<dim> dof_handler;
const QGauss<dim> quadrature_formula;
const MappingFE<dim> mapping;
* EnrichmentFunction<dim> enrichment;*
*When I try to compile my program, I get this error:*
dealii/examples/enrich/enrich9.cc:324:25: error: no matching function for
call to ‘dealii::FE_Enriched<3, 3>::FE_Enriched(dealii::FE_Q<3, 3>,
dealii::FE_Q<3, 3>, problem_namespace::EnrichmentFunction<3>&)’
324 | , mapping( FE_Q<dim>(1))
*Then I get the following notes about my arguments and failure to find
conversions:*
In file included from dealii/examples/enrich/enrich9.cc:53:
fe/fe_enriched.h:263:3: note: candidate: ‘dealii::FE_Enriched<dim,
spacedim>::FE_Enriched(const std::vector<const
dealii::FiniteElement<dimension_, space_dimension_>*>&, const
std::vector<unsigned int>&, const
std::vector<std::vector<std::function<const
dealii::Function<spacedim>*(const typename dealii::Triangulation<dim,
spacedim>::cell_iterator&)> > >&) [with int dim = 3; int spacedim = 3;
typename dealii::Triangulation<dim, spacedim>::cell_iterator =
dealii::TriaIterator<dealii::CellAccessor<3, 3> >]’
263 | FE_Enriched(
| ^~~~~~~~~~~
deal.II/fe/fe_enriched.h:264:62: note: no known conversion for argument 1
from ‘dealii::FE_Q<3, 3>’ to ‘const std::vector<const
dealii::FiniteElement<3, 3>*, std::allocator<const dealii::FiniteElement<3,
3>*> >&’
264 | const std::vector<const FiniteElement<dim, spacedim> *> &fes,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
deal.II/fe/fe_enriched.h:249:3: note: candidate: ‘dealii::FE_Enriched<dim,
spacedim>::FE_Enriched(const dealii::FiniteElement<dimension_,
space_dimension_>*, const std::vector<const
dealii::FiniteElement<dimension_, space_dimension_>*>&, const
std::vector<std::vector<std::function<const
dealii::Function<spacedim>*(const typename dealii::Triangulation<dim,
spacedim>::cell_iterator&)> > >&) [with int dim = 3; int spacedim = 3;
typename dealii::Triangulation<dim, spacedim>::cell_iterator =
dealii::TriaIterator<dealii::CellAccessor<3, 3> >]’
249 | FE_Enriched(
| ^~~~~~~~~~~
deal.II/fe/fe_enriched.h:250:62: note: no known conversion for argument 1
from ‘dealii::FE_Q<3, 3>’ to ‘const dealii::FiniteElement<3, 3>*’
250 | const FiniteElement<dim, spacedim> *
fe_base,
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
deal.II/fe/fe_enriched.h:200:3: note: candidate: ‘dealii::FE_Enriched<dim,
spacedim>::FE_Enriched(const dealii::FiniteElement<dimension_,
space_dimension_>&) [with int dim = 3; int spacedim = 3]’
200 | FE_Enriched(const FiniteElement<dim, spacedim> &fe_base);
| ^~~~~~~~~~~
deal.II/fe/fe_enriched.h:200:3: note: candidate expects 1 argument, 3
provided
deal.II/fe/fe_enriched.h:186:3: note: candidate: ‘dealii::FE_Enriched<dim,
spacedim>::FE_Enriched(const dealii::FiniteElement<dimension_,
space_dimension_>&, const dealii::FiniteElement<dimension_,
space_dimension_>&, const dealii::Function<spacedim>*) [with int dim = 3;
int spacedim = 3]’
186 | FE_Enriched(const FiniteElement<dim, spacedim> &fe_base,
| ^~~~~~~~~~~
deal.II/fe/fe_enriched.h:188:51: note: no known conversion for argument 3
from ‘shell::EnrichmentFunction<3>’ to ‘const dealii::Function<3, double>*’
188 | const Function<spacedim> *
enrichment_function);
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
It seems that I'm misunderstanding a few things about how FE_Enriched
works. Can you see what I'm doing wrong in constructing the FE_Enriched?
It looks like there's issues with forms I am using for FE_Q and the
enrichment function. Do you have any tips or suggested resources?
Many thanks,
Alex
On Friday, June 9, 2023 at 8:27:37 AM UTC-4 Alex Quinlan wrote:
> Thanks, Wolfgang. I'll dig into FE_Enriched!
>
> On Thursday, June 8, 2023 at 6:57:44 PM UTC-4 Wolfgang Bangerth wrote:
>
>> On 6/8/23 09:40, Alex Quinlan wrote:
>> >
>> > I am looking to modify the FE_Q element to have non-polynomial shape
>> > functions. It looks like FE_Q_Base takes an argument of type
>> > ScalarPolynomialBase<dim> (fe_q_base.cc: line 418).
>> >
>> > I am looking at a 2D element and instead of 2D polynomial shape
>> functions like
>> > this:
>> >
>> > N = (1 - ξ)(1 - η)
>> >
>> > I would like to add some additional terms like this:
>> >
>> > N = (1 - ξ)(1 - η) + ζ
>> >
>> > where ζ changes at different quadrature points.
>> >
>> > It seems that I would need to access the values of ζ before computing
>> > fe_values, since the shape functions and their derivatives would be
>> dependent
>> > on ζ.
>> >
>> > Any thoughts on how feasible this would be to implement?
>>
>> Alex:
>> if your shape functions are not polynomial, then this is the wrong
>> approach --
>> FE_Q_Base is derived from FE_Poly, which is specifically built to create
>> polynomial bases.
>>
>> I'm not sure we have a particularly good starting point for a completely
>> general choice of ζ(ξ,η), but you might want to take a look at what
>> FE_Enriched is doing.
>>
>> Best
>> W.
>>
>> --
>> ------------------------------------------------------------------------
>> Wolfgang Bangerth email: [email protected]
>> www: http://www.math.colostate.edu/~bangerth/
>>
>>
>>
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