blog update #2

[c.]

Marco,

Thanks for your blog posts on meshing formats.
I think your example on boundaries needs to be made more clear.

It is not usually sufficient to know whether a specific cell or node
is on the boundary, one needs to know which part of the boundary it belongs to.

For example in this BIM tutorial:
http://wiki.octave.org/Bim_package#2D_Diffusion_Advection_Reaction_example

Boundary regions marked as 1 and 2 in the mesh structure are given a Dirichlet
boundary condition while regions marked 3 and 4 are given a Neumann boundary 
condition.

In dolfin how does one apply a different boundary condition to a different 
region in the boundary?

could you add an example of this in your blog?

c.