dolfin team mailing list archive

[Johan Hake <johan.hake@xxxxxxxxx>]

On Wednesday February 9 2011 15:03:28 Garth N. Wells wrote:
> On 09/02/11 22:43, Anders Logg wrote:
> > 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 really don't get the approach to hierarchies. Mesh refinement was
> simple, and now something simple has become complex (with bugs that are
> hard to track down because of the introduced complexity).

I tend to agree, allthough I think we have nailed most of the errors.

> This hierarchy business looks viral - now I get Swig warnings for
> DirichleBC.

That is because Anders did not declare DirichletBC as stored using shared_ptr.

Johan

> I would much rather keep basic classes simple, and have hierarchical
> containers that can keep track of parent/child relationships. The
> present approach seems to take a narrow/immediate view on the issue.
> 
> Garth
> 
> > 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
> > 
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