dolfin team mailing list archive

[Bartosz Sawicki <sawickib@xxxxxxxxxxxxx>]

Jehanzeb Hameed wrote:
> I am still struggling with this....
>
> I am trying to store subdomain identifiers in meshdata object, so that
> they get updated when the mesh is refined. To do this, I have a file,
> mesh.xml. In that file, there is a tag named "data". The "data" tag
> has a child "array" with name = "material indicators". So, now when I
> create mesh, will my meshdata have this array?

Not really. Tag <data> can contain arrays, meshfunctions and mappings.
"material indicators" has to be stored in meshfunction.

I'll send you example of xml mesh file with material data directly on 
your email.


> And how do I create cell dependent functions. The example in Dolfin
> user manual seems outdated. I think I need to use UFCfunction, but
> what do I pass as Function arguement to its constructor (if
> UFCfunction is indeed the correct way to go).

Maybe you can use UFCFunction to initialize MeshFunction, but for me 
more natural is using MeshFunction constructors.
http://www.fenics.org/pub/documents/dolfin/dolfin-progr-reference/d0/d94/classdolfin_1_1MeshFunction.html

For example if want to have meshfunction defined over tetrahedral:
MeshFunction meshfunction(mesh, 3);

cheers,
BArtek



> -Jehanzeb
>
> On Thu, Jun 11, 2009 at 11:55 AM, Bartosz Sawicki<sawickib@xxxxxxxxxxxxx> wrote:
> > Jehanzeb Hameed wrote:
> > > Hello,
> > >
> > > I am new to Dolfin, and was wondering how subdomains are supported as
> > > regards to mesh reading and refinement. In my case, I will have a
> > > mesh, with 2 subdomains. Each cell has an identifier indicating which
> > > domain it belongs to. Looking at the examples, it seems I will need to
> > > store domain identifiers in a separate xml file. Is that correct?
> > Subdomain identifiers can be stored in different ways, as a separate
> > MeshFunction, or in the MeshData structure.
> > I prefer MeshData, because it is directly included in the Mesh object.
> > You can also store boundary indicators using MeshData structure, see
> > demo/pde/bcs.
> >
> > > With regard to mesh refinement, I assume I will be able to define
> > > subdomains for each domain based on cell identifiers. Now, when I
> > > refine the mesh, will the subdomains also be updated (i.e. will dolfin
> > > know what domain the new cells belong to) ?
> > If you name your MeshFunction "material indicators" it will be transformed
> > to follow refined mesh. Arrays which store boundary indicators will be
> > updated too.
> > See LocalMeshRefinement::transformMeshData()
> >
> > > Also, is there a way to read archives of this list?
> > Yes, there is http://www.fenics.org/pipermail/dolfin-dev/
> >
> > regrds.
> > BArtek
> >
> >
> > > Thanks,
> > > -Jehanzeb
> > > _______________________________________________
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