Re: [Libmesh-users] question on nedelec elements

[Povolotskyi, M. <mpo...@pu...>]

Thank you, Paul.
If I want to have periodic boundary conditions for my application on a regular grid, can I do the following:

  1.  Find corresponding edges on the periodic sides
  2.  Get DOF numbers that correspond to those edges
  3.  Define DOF map constraints.

What do you think? Can it work?
(I have done something similar in 2004 with Lagrange elements because at that time periodic boundary conditions were not implemented in libmesh.)

Thank you,
Michael.

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From: Paul T. Bauman<mailto:ptb...@gm...>
Sent: Thursday, March 14, 2019 9:07 PM
To: Povolotskyi, Mykhailo<mailto:mpo...@pu...>
Cc: Stogner, Roy H<mailto:roy...@ic...>; lib...@li...<mailto:lib...@li...>
Subject: Re: [Libmesh-users] question on nedelec elements

No I'm sorry they're not. The reason BCs/projection/periodic BCs wasn't immediately trivial is, mathematically, we can only enforce continuity of the tangential components of the solution and IIRC the was a pain to do consistently between 2D and 3D (at least enough that it wasn't something I could do in an afternoon or two, which is all I had once the elements were deployed and we could solve the problems of interest on that project).

I know there's some interest from some others as well, but I'm happy to give pointers to the places where the implementation of all these pieces are needed if someone has the time.

On Thu, Mar 14, 2019 at 4:32 PM Michael Povolotskyi <mpo...@pu...<mailto:mpo...@pu...>> wrote:

Hello Paul,

One more question, please. Are periodic boundary conditions supported for Nedelec?

Michael.
On 03/14/2019 03:28 PM, Paul T. Bauman wrote:


On Thu, Mar 14, 2019 at 3:14 PM Stogner, Roy H <roy...@ic...<mailto:roy...@ic...>> wrote:

On Thu, 14 Mar 2019, Michael Povolotskyi wrote:

> Thank you,

No, thank Paul; reading further down the code it appears that I'm
wrong, and Paul *did* add some kind of vector-valued variable field
support to the Dirichlet code.

vector_fe_ex2/laplace_system.C seems to be our only example of it's
use.

Unfortunately, though, it's not there for Nedelec. What's needed is the constraint enforcement for HCurl which I never got time to implement. :( So for Nedelec, penalty is the only way for Dirichlet boundary conditions right now. (It's also why refinement/coarsening won't work for Nedelec because I never got time to implement projection for those elements either. :( )

---
Roy


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