dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Wed, Feb 09, 2011 at 10:11:40AM -0800, Johan Hake wrote:
> Hello!
>
> I am pretty sure the reason the Macbot still complains (mesh unit test) is
> that refine is broken for SWIG 2.0.
>
> I think it is some premature destruction of a refined mesh. I would suggest we
> implement a full shared_ptr version of the interface to get around this
> problem. I have no clue of why it works for SWIG 1.3.40. Probably because a
> faulty implementation.
>
> I also suggest more developers upgrade to SWIG 2.0.1 and maybe one of the
> linux build bots two? If it is only the Macbot that uses SWIG 2.0 it is easily
> to think it is some Mac specific error.
>
> Johan

I plan to merge with main tomorrow if my buildbot is green. Then Marie
also needs to merge (we have both touched refine.h/cpp). Then we can
sort out the shared_ptrs.

I've been working on a new (old) refinement algorithm which instead of
bisection divides marked triangles into 4 triangles, then fixes the
neighbors. It's sometimes a better option since fewer refinements are
needed and it guarantees that all edges of marked triangles will be
split during refinement.

We had this a while back but it was removed since it relied heavily on
parent-child relationships between the individual cells and vertices
of the mesh. We don't have that anymore (only between the meshes).

It's currently only implemented in 2D and can be enabled with the
global option "refinement_algoritm" set to "regular_cut". The default
value is "recursive_bisection". There are some other options that I
plan to remove since they don't work and are presumably not as good as
"recursive_bisection". In the near future, we will need to
remove/reimplement both algorithms to work in parallel, or (ideally)
wrap an external library that provides parallel mesh refinement (like
MAdLib). Niclas has some parallel mesh refinement but I don't know if
there are any plans to merge it into DOLFIN.

--
Anders