[Gmsh] Elements & Physical entities

Stephen Guzik sguzik at utias.utoronto.ca
Fri Aug 1 04:21:39 CEST 2008


Hi Bob,

In the nightly snapshots there is a routine MakeGraph for building a 
graph of the mesh in Mesh/Partition.h.  A vertex in the graph is an 
interior element and an edge in the graph is a face (or edge in 2D) 
between two elements.  So the graph describes the connectivity between 
all the interior elements.  The routine MakeGraph will also return a 
vector of all boundary elements and the graph vertex (interior element) 
that they connect to.

Hope that helps,
Stephen

Borek Patzak wrote:
> Hello,
>
> I have a question concerning the way how physical entities are exported.
> I would like to use the concept of physical entities to handle boundary 
> conditions.
>  From the documentation and my experiments it seems to me, that on 
> output the mesh contains the elements associated to individual physical 
> entities. My problem is following: if the physical entity is some part 
> of boundary (curve in 2D or surface in 3D) of the whole domain, I need 
> in some cases somehow to relate  this information to domain elements, 
> not to the "elements" discretized on the boundary. In the case of square 
> 2D domain, where boundary condition is applied to one side, I need to 
> pass this information to 2D elements, that have heir edge on this side.
> 1) Is there some way how to get this  information from mesher?
> 2) If not, one can reconstruct this information from a list of 
> edge-elements generated for this side. Does such a tool already exists?
>
> Thank you
> Bob
>
>
>
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