Best way to connect domain data from xml file with mesh

On 12/14/2012 12:50 PM, Claas Abert wrote:
> New question #216788 on DOLFIN:
> https://answers.launchpad.net/dolfin/+question/216788
>
> I'm using the Python interface of dolfin-dev. I created a mesh with several subdomains with Gmsh and converted it with dolfin-convert which gives me two file: mesh.xml and mesh_physical_region.xml.
>
> How can I create a mesh object, where the subdomain data is included, so I can use dx(0),dx(1),... in my forms?
> I tried something like
>
> mesh = Mesh("mesh.xml")
> domains = MeshFunction("uint", mesh, "mesh_physical_region.xml")
> domain_collection = MeshValueCollection("uint", domains)
> mesh.domains().init(3)
> mesh.domains().markers(3).assign(collection)

Try:

 mesh = Mesh("mesh.xml")
 domains = MeshFunction("uint", mesh, "mesh_physical_region.xml")
 mesh.domains().init(3)
 mesh.domains().markers(3).assign(domains)

> But this does not work and seams to be pretty complicated.

Yes, working with mesh.domains() is fairly recently added and the syntax
is still not really worked out.

In stead of attaching the domain to the mesh you can also create a new
integral measure:

  dxx = dx[domains]

then use:

  dxx(0),dxx(1)

in your forms.

Johan