Re: [Getfem-users] B = curl A : how to impose a jauge?

[Yves Renard]

On Monday 03 March 2008 07:55, Riccardo Scorretti wrote:
> Hi. I'm interested in modeling in quasi-static electromagnetism, and I
> want to represent a flux density through a vector potential (i.e. B =
> curl A). To this aim, a jauge condition has to be imposed on A. One
> convenient way to impose such a jauge is to impose A=0 over a subset of
> the edges, which is a tree (that is, all nodes of the geometry are
> "touched" without forming a closed loop).
>
> The question is: how to obtain the list of all the edges of a geometry,
> so as to build a tree?


I don't completely understand what you exactly mean by a tree in this context. 
I suppose you treat a 3D problem. The edges are not stored in the mesh, so 
there is no natural numbering of edges. In fact, for a mesh whose base 
element is a tetrahedron, the edges are caracterised by the pairs of mesh 
nodes lying on the same tetrahedron. The indices of the nodes of an element 
can be obtained with the method
mesh.ind_points_of_convex(ic)
Of course, with this method, edges will be meet more than once.

Yves.

-- 

  Yves Renard (address@hidden)       tel : (33) 04.72.43.87.08
  Pole de Mathematiques, INSA de Lyon          fax : (33) 04.72.43.85.29
  20, rue Albert Einstein
  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

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