dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Wed, May 20, 2009 at 11:30:43PM +0200, Johan Hake wrote:
> On Wednesday 20 May 2009 22:56:39 Anders Logg wrote:
> > The problem is that the edges in the mesh don't exist until they are
> > created (or you use a mesh iterator in which case they will be created
> > automatically).
> >
> > Just add the line
> >
> >   mesh.init(1)
> >
> > (before accessing the facets/edges) and then it should work.
> >
> > There should be a sensible error message instead of a bus error.
> 
> This has to be implemented in the c++ library as the calling graph for that 
> command was quite extensive. 
> 
> Should there be an error message or should there somewhere in the calling 
> sequence be a call to mesh.init(dim). Is this not done due to some 
> performance issues? Couldn't we just add an mesh.init call in the 
> MeshEntity.num_entities, and MeshEntity.entities functions?
> 
> Johan

I'm not sure. It was a design decision not to do any automatic
initialization when accessing the data structures directly as is done
with num_entities() and entities() for performance. As it is now,
those two functions are inlined all the way down to the underlying
arrays storing the mesh topology. Initialization is done automatically
for the higher level mesh iterator interface.

I think it should be enough to add the test to constructor of
MeshEntity. I'll try that shortly.

-- 
Anders

Attachment: signature.asc
Description: Digital signature