Re: [Libmesh-users] Fwd: Problems with write_serialized_blocked_dof_objects() and subactive elements

[Roy S. <ro...@st...>]

On Thu, 3 Apr 2008, Lorenzo Botti wrote:

>> We know you have not done any coarsening, but have you done any
>>  refinement in this Mesh?  How was the Mesh initially created?  It
>>  would be helpful if you could provide a short sample code that
>>  demonstrates the problem(s).
>
> Exact, I haven't done any coarsening but I have a lot of h refinement levels.
> The problem arise after some refinement steps.
> I'm running an INS solver on the lid-driven cavity problem, the mesh
> is generetad
> using MeshTools::Generation::build_square ().
> Unfortunately my application isn't a short sample code...

It's not possible that you've refined to the point where the mesh has
torn, is it?  It used to be the case that around edge lengths of
10^-6, floating point tolerances would make it impossible for us to
keep the refined mesh correctly connected; AFAIK it's still the case
that that can happen around edge lengths of 10^-15.  That sounds
ridiculous, but on the lid-driven cavity it's not impossible to pick
an error estimator and refinement scheme that decide to refine only
in the corners over and over and over again.
---
Roy