Re: [deal.II] Re: anisotropic polynomial degree

2023-03-12 Thread Martin Kronbichler 

Dear Greg,

Just to extend on what Peter said: It should be possible to define 
anisotropic degrees in a completely discontinuous finite element, say 
FE_DGP or FE_DGQ. In that case, you would derive from `FE_Poly` and 
insert an anisotropic polynomial space, doing whatever you think is 
appropriate. For elements imposing some continuity, include 
FE_FaceP/FE_FaceQ or the regular H1 functions (FE_Q), you can't do that 
as Peter said. However, one could work around this by constructing 
constraints that constrain the polynomial space of uniform high order in 
one of the directions to the lower polynomial degree. It would be a bit 
of work to realize this (say 200-400 lines of code to set up the 
constraints), but the easiest solution I could come up.


Best,
Martin


On 11.03.23 17:26, Greg Wang wrote:

Hi Peter,

Thanks a lot for the info!

We have recently implemented in deal.II a space-time HDG method for 
the advection-diffusion problem on deforming domains. Our analysis 
allows the spatial polynomial order p_s to differ from the temporal 
one p_t. When p_t = p_s, we just call FE_DGP, FE_FaceP constructors 
with nothing extra to do and the rates come out nicely matching the a 
priori rates of convergence. And now we are trying to have a p_t = p_s 
+1 test case to further validate our analysis, which led to this post.


Best regards,
Greg

On Saturday, March 11, 2023 at 2:20:37 PM UTC peterr...@gmail.com wrote:

Hi Greg,

unfortunately we do not support anisotropic polynomials: we make
the assumption that all faces (of the same type) and lines have
the same number of DoFs. For what do you need such polynomial spaces?

Best,
Peter

On Saturday, 11 March 2023 at 15:05:25 UTC+1 ygre...@gmail.com wrote:

Hi there,

I was wondering if finite elements with anisotropic polynomial
degrees are possible in deal.II. As an example, for a 3D
element, can we construct a tensor product polynomial space of
{1,x,y,z,xy,xz,yz, z^2,xz^2,yz^2}, i.e., order 1 in x- and
y-directions and 2 in z-direction?

I was looking at, for example, constructors of FE_DGQ() class
[1]. The second constructor [2] takes an arbitrary vector of
polynomials to build the tensor product polynomial space. This
is close to what I want but it seems the argument can only be
one-dimensional polynomials, which means equal order on all
dimensions.

Would really appreciate any insights and/or tips!

Best,
Greg

--
[1] https://dealii.org/current/doxygen/deal.II/classFE__DGQ.html
[1]

https://dealii.org/current/doxygen/deal.II/fe__dgq_8cc_source.html#l00100

--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en

---
You received this message because you are subscribed to the Google 
Groups "deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send 
an email to dealii+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/dealii/3dcc5829-7218-4c51-9c86-ae8fccb4ba82n%40googlegroups.com 
.


--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups "deal.II User Group" group.

To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/dealii/edd06b31-9646-10f5-c6a1-8130e7bd93f9%40gmail.com.

[deal.II] Using affine constraints object to apply boundary condition at a vertex

2023-03-12 Thread Wasim Niyaz Munshi ce21d400 
I am solving an elasticity problem wherein I have a pin support at one 
vertex. Earlier, I was using std::map object to apply BCs. Now, I am trying 
to solve the same problem using an affine constraint object to apply BCs. 
But, I am facing issues filling my affine constraint object with the 
information corresponding to the vertex with pin support.

I was doing the following for my std::map boundary_values object:

for (const auto &cell : dof_handler.active_cell_iterators())
{
for (const auto &face : cell->face_iterators())

for (const auto vertex_number : cell->vertex_indices())
{
const auto vert = cell->vertex(vertex_number);
if (vertices satisfy the condition)
{

   types::global_dof_index x=
cell->vertex_dof_index(vertex_number, 0);
boundary_values[x] = 0;
types::global_dof_index 
y=
cell->vertex_dof_index(vertex_number, 1);
boundary_values[y] = 0; 
}
}

}

What changes should I do to fill my constraint object with the same 
information?
Thanks and regards
Wasim Niyaz

-- 
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/dealii/932c962f-e382-4c73-9ab3-a1486b2624b4n%40googlegroups.com.

Re: [deal.II] Using affine constraints object to apply boundary condition at a vertex

2023-03-12 Thread Daniel Arndt 
Wasim,

Have a look at step-11 (
https://www.dealii.org/current/doxygen/deal.II/step_11.html).

Best,
Daniel

On Sun, Mar 12, 2023 at 9:17 AM Wasim Niyaz Munshi ce21d400 <
ce21d...@smail.iitm.ac.in> wrote:

> I am solving an elasticity problem wherein I have a pin support at one
> vertex. Earlier, I was using std::map object to apply BCs. Now, I am trying
> to solve the same problem using an affine constraint object to apply BCs.
> But, I am facing issues filling my affine constraint object with the
> information corresponding to the vertex with pin support.
>
> I was doing the following for my std::map boundary_values object:
>
> for (const auto &cell : dof_handler.active_cell_iterators())
> {
> for (const auto &face : cell->face_iterators())
>
> for (const auto vertex_number : cell->vertex_indices())
> {
> const auto vert = cell->vertex(vertex_number);
> if (vertices satisfy the condition)
> {
>
>types::global_dof_index x=
> cell->vertex_dof_index(vertex_number, 0);
> boundary_values[x] = 0;
>
> types::global_dof_index y=
> cell->vertex_dof_index(vertex_number, 1);
> boundary_values[y] = 0;
> }
> }
>
> }
>
> What changes should I do to fill my constraint object with the same
> information?
> Thanks and regards
> Wasim Niyaz
>
> --
> The deal.II project is located at http://www.dealii.org/
> For mailing list/forum options, see
> https://groups.google.com/d/forum/dealii?hl=en
> ---
> You received this message because you are subscribed to the Google Groups
> "deal.II User Group" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to dealii+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/dealii/932c962f-e382-4c73-9ab3-a1486b2624b4n%40googlegroups.com
> 
> .
>

-- 
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/dealii/CAOYDWbKxTZ4raz%2BShKajZKXVbknaq-b8uLYmGz%2BVJ0pyyf4VRg%40mail.gmail.com.

Re: [deal.II] Using affine constraints object to apply boundary condition at a vertex

2023-03-12 Thread Timo Heister 
It should be as simple as doing

constraints.add_line(y);

Unless you are writing an MPI parallel program. Then you would need to
check if this line can be stored first.

-- https://www.math.clemson.edu/~heister/

On Sun, Mar 12, 2023, 09:17 Wasim Niyaz Munshi ce21d400 <
ce21d...@smail.iitm.ac.in> wrote:

> I am solving an elasticity problem wherein I have a pin support at one
> vertex. Earlier, I was using std: : map object to apply BCs. Now, I am
> trying to solve the same problem using an affine constraint object to apply
> BCs. But, I am facing issues
> ZjQcmQRYFpfptBannerStart
> This Message Is From an External Sender
> Use caution when opening links or attachments if you do not recognize the
> sender.
>
> ZjQcmQRYFpfptBannerEnd
> I am solving an elasticity problem wherein I have a pin support at one
> vertex. Earlier, I was using std::map object to apply BCs. Now, I am trying
> to solve the same problem using an affine constraint object to apply BCs.
> But, I am facing issues filling my affine constraint object with the
> information corresponding to the vertex with pin support.
>
> I was doing the following for my std::map boundary_values object:
>
> for (const auto &cell : dof_handler.active_cell_iterators())
> {
> for (const auto &face : cell->face_iterators())
>
> for (const auto vertex_number : cell->vertex_indices())
> {
> const auto vert = cell->vertex(vertex_number);
> if (vertices satisfy the condition)
> {
>
>types::global_dof_index x=
> cell->vertex_dof_index(vertex_number, 0);
> boundary_values[x] = 0;
>
> types::global_dof_index y=
> cell->vertex_dof_index(vertex_number, 1);
> boundary_values[y] = 0;
> }
> }
>
> }
>
> What changes should I do to fill my constraint object with the same
> information?
> Thanks and regards
> Wasim Niyaz
>
> --
> The deal.II project is located at http://www.dealii.org/
> 
> For mailing list/forum options, see
> https://groups.google.com/d/forum/dealii?hl=en
> 
> ---
> You received this message because you are subscribed to the Google Groups
> "deal.II User Group" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to dealii+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/dealii/932c962f-e382-4c73-9ab3-a1486b2624b4n%40googlegroups.com
> 
> .
>

-- 
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see 
https://groups.google.com/d/forum/dealii?hl=en
--- 
You received this message because you are subscribed to the Google Groups 
"deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to dealii+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/dealii/CAMRj59GcYMsiSphMe76wGfNZcTcYVQ46HKe%2BV%2BWxtbU92YMMag%40mail.gmail.com.

Re: [deal.II] Re: anisotropic polynomial degree

2023-03-12 Thread Greg Wang 
Hi Martin,

Thanks a lot for the elucidation! I found out after your answer that there 
is already an AnisotropicPolynomials class. It was remiss of me not even 
doing a quick search...

I noticed that FE_DGQ class is derived from FE_Poly with a polynomial space 
argument:
*TensorProductPolynomials 
(Polynomials
 
::generate_complete_Lagrange_basis(internal
 
::FE_DGQ 
::get_QGaussLobatto_points(degree))*
It seems that if we write a FE_DGQAnistropic class, we'd probably want to 
replace this argument with a counterpart of the AnisotropicPolynomials 
class. Do you think this replacement alone would cut it? We are not looking 
for any more features out of the fe space than what FE_DGQ is already doing.

FE_DGQ involves implementing quite a bunch of virtual functions 
. 
Apart from, as far as I can parse, FE_DGQ::rotate_indices 
,
 
they seem to be coordinate direction agnostic.

Would really appreciate if you can shed more light on this!

Best,
Greg
On Sunday, March 12, 2023 at 8:33:02 AM UTC Martin Kronbichler wrote:

> Dear Greg,
>
> Just to extend on what Peter said: It should be possible to define 
> anisotropic degrees in a completely discontinuous finite element, say 
> FE_DGP or FE_DGQ. In that case, you would derive from `FE_Poly` and insert 
> an anisotropic polynomial space, doing whatever you think is appropriate. 
> For elements imposing some continuity, include FE_FaceP/FE_FaceQ or the 
> regular H1 functions (FE_Q), you can't do that as Peter said. However, one 
> could work around this by constructing constraints that constrain the 
> polynomial space of uniform high order in one of the directions to the 
> lower polynomial degree. It would be a bit of work to realize this (say 
> 200-400 lines of code to set up the constraints), but the easiest solution 
> I could come up.
>
> Best,
> Martin
>
>
> On 11.03.23 17:26, Greg Wang wrote:
>
> Hi Peter,
>
> Thanks a lot for the info! 
>
> We have recently implemented in deal.II a space-time HDG method for the 
> advection-diffusion problem on deforming domains. Our analysis allows the 
> spatial polynomial order p_s to differ from the temporal one p_t. When p_t 
> = p_s, we just call FE_DGP, FE_FaceP constructors with nothing extra to do 
> and the rates come out nicely matching the a priori rates of convergence. 
> And now we are trying to have a p_t = p_s +1 test case to further validate 
> our analysis, which led to this post.
>
> Best regards,
> Greg
>
> On Saturday, March 11, 2023 at 2:20:37 PM UTC peterr...@gmail.com wrote:
>
>> Hi Greg, 
>>
>> unfortunately we do not support anisotropic polynomials: we make the 
>> assumption that all faces (of the same type) and lines have the same number 
>> of DoFs. For what do you need such polynomial spaces?
>>
>> Best,
>> Peter 
>>
>> On Saturday, 11 March 2023 at 15:05:25 UTC+1 ygre...@gmail.com wrote:
>>
>>> Hi there,
>>>
>>> I was wondering if finite elements with anisotropic polynomial degrees 
>>> are possible in deal.II. As an example, for a 3D element, can we construct 
>>> a tensor product polynomial space of {1,x,y,z,xy,xz,yz, z^2,xz^2,yz^2}, 
>>> i.e., order 1 in x- and y-directions and 2 in z-direction?
>>>
>>> I was looking at, for example, constructors of FE_DGQ() class [1]. The 
>>> second constructor [2] takes an arbitrary vector of polynomials to build 
>>> the tensor product polynomial space. This is close to what I want but it 
>>> seems the argument can only be one-dimensional polynomials, which means 
>>> equal order on all dimensions.
>>>
>>> Would really appreciate any insights and/or tips!
>>>
>>> Best,
>>> Greg
>>>
>>> --
>>> [1] https://dealii.org/current/doxygen/deal.II/classFE__DGQ.html
>>> [1] 
>>> https://dealii.org/current/doxygen/deal.II/fe__dgq_8cc_source.html#l00100
>>>
>> -- 
> The deal.II project is located at http://www.dealii.org/
> For mailing list/forum options, see 
> https://groups.google.com/d/forum/dealii?hl=en
> --- 
> You received this message because you are subscribed to the Google Groups 
> "deal.II User Group" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to dealii+un...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/dealii/3dcc5829-7218-4c51-9c86-ae8fccb4ba82n%40googlegroups.com
>  
> 
> .
>
>

-- 
The deal.II project is located at http://www.dealii