Hi W and Jean-Paul,
Thanks again for your suggestions.
I realized that the bubble functions that I prefer are actually the shape
functions from other standard elements. Thus I only need to define two sets
of FE (i.g. FE_1 and FE_b). Then I use the iterator from triangulation as
for (const auto &cell : triangulation.active_cell_iterators())
{
fe_values_1.reinit(cell); // standard Lagrange elements
fe_values_b.reinit(cell); // bubble functions
This way I can freely use bubble functions and only construct local K and F
of FE_1. However, one issue is that, apparently, triangulation.cell does
not support cell->get_dof_indices(local_dof_indices). Is there any way to
call the DOFhandler by the cell in triangulation and then access the
local_dof_indices?
Regards,
Lixing
On Friday, January 8, 2021 at 12:40:54 PM UTC+8 Wolfgang Bangerth wrote:
> On 1/7/21 6:58 PM, Lixing Zhu wrote:
> >
> > I implemented the local elimination as you suggested and it works.
> However,
> > this ends up with many extra "redundant" DOFs in the global system. For
> > example, if I am using N*N linear elements for a scalar 2D problem with
> > structured mesh, instead of (N+1)^2 global DOFs, I end up with (N+1)^2 +
> N^2
> > global DOFs. The extra DOFs are coming from the bubble supports. Of
> course,
> > they won't affect the solution at vertices due to the nature of bubble
> > functions, but such an increase of DOFs may require more memory in the
> > solution process. How should I also reduce the size of the global system?
>
> Do you need to? Is memory consumption an issue for you? Unless you have a
> concrete problem, it's probably not worth optimizing for.
>
> Best
> W.
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth email: [email protected]
> www: http://www.math.colostate.edu/~bangerth/
>
>
--
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 [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/dealii/ab5ea038-d7f1-4dc5-8e17-ae82bf0ab3f7n%40googlegroups.com.
