On Thu, Nov 8, 2018 at 9:18 AM Ham, David A <david.ham@imperial.ac.uk> wrote:

 

 

From: Matthew Knepley <knepley@gmail.com>
Date: Thursday, 8 November 2018 at 14:13
To: "Ham, David A" <david.ham@imperial.ac.uk>
Cc: "mmfg@leeds.ac.uk" <mmfg@leeds.ac.uk>, Lawrence Mitchell <wencel@gmail.com>, firedrake <firedrake@imperial.ac.uk>
Subject: Re: [firedrake] Periodic domain with imported mesh

 

On Thu, Nov 8, 2018 at 9:08 AM Ham, David A <david.ham@imperial.ac.uk> wrote:

Dear Floriane,

 

Importing from FEniCS definitely won’t work as we have a completely different concept of periodicity from them.

 

It might be possible to load the existing gmsh file, map the boundary vertices to each other and produce the corresponding DG coordinate field, but that will be quite a fiddly process.

 

Gmsh supports periodicity to some extent. We can read periodic GMsh files and do the right thing in Plex. Is this a periodic Gmsh?

 

  Thanks,

 

     Matt

 

I think it can be a periodic GMSH if required. The problem occurs that Firedrake’s concept of periodic isn’t quite dmplex’s and so someone needs to sit down and do the renumbering legwork to get from one to the other. I believe Lawrence had a go once and gave up in a mess of renumberings.

 

I.e. I believe this is a Firedrake inadequacy rather than a Plex one.


I think we can just lie to Firedrake and not tell it the mesh is periodic. The coordinate field is automatically DG, and so will give believable numbers for all integrals. Of course output will probably not work completely right, but the solution will be understandable.

  Thanks,

     Matt
 

Regards,

 

David

 

 

Regards,

 

David

 

From: <firedrake-bounces@imperial.ac.uk> on behalf of "Floriane Gidel [RPG]" <mmfg@leeds.ac.uk>
Date: Wednesday, 7 November 2018 at 15:16
To: Lawrence Mitchell <wencel@gmail.com>
Cc: firedrake <firedrake@imperial.ac.uk>
Subject: Re: [firedrake] Periodic domain with imported mesh

 

Ok so there's no other way to do it with Firedrake?

 

Could I do it with FeniCs and import my mesh and corresponding function space to firedrake ?

 

De : Lawrence Mitchell <wencel@gmail.com>
Envoyé : mercredi 7 novembre 2018 14:24
À : Floriane Gidel [RPG]
Cc : firedrake
Objet : Re: [firedrake] Periodic domain with imported mesh

 



> On 7 Nov 2018, at 14:23, Floriane Gidel [RPG] <mmfg@leeds.ac.uk> wrote:
>
> Hi Lawrence,
>
> I need a way to distinguish the two subdomains, that are 1) the disk, 2) the square with a hole instead of the disk (see black and blue meshes in the attached figure).
> Can I make the equivalent to the blue mesh (i.e., a square with a hole) using PeriodicUnitSquareMesh ? And if so, can I make sure that the nodes at the boundary of my disk mesh (black) match those of the plane mesh (blue) at the hole boundary?

Ah, that's the bit I was missing. With periodic unit square mesh it is not possible. One could hack something that moved the mesh nodes around to capture the circle appropriately. But that's going to be fiddly too.

Cheers,
Lawrence

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--

What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener

 



--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener