dolfin team mailing list archive

[Jehanzeb Hameed <jhameed2@xxxxxxxxxxxx>]

I want to do evaluate a form like this, arising from poisson equation
with variable coefficient:

k * dot(grad(v),grad(u))*dx


To do this, I define k as

cellElement = FiniteElement("Discontinuous Lagrange", "triangle", 0)

k = Function(cellElement)

Now I want to define values of k dependent on material type of cell.
This is the link I cant figure out how to do.

-Jehanzeb

On Sun, Jun 14, 2009 at 5:50 PM, Jehanzeb Hameed<jhameed2@xxxxxxxxxxxx> 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?
>
> 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 user manual seems outdated.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).
>
> -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
>>> _______________________________________________
>>> DOLFIN-dev mailing list
>>> DOLFIN-dev@xxxxxxxxxx
>>> http://www.fenics.org/mailman/listinfo/dolfin-dev
>>
>>
>