[Libmesh-devel] Side vs. build_side for infinite elements

[John P. <pet...@cf...>]

Hi All,

As far as I understand, the side() method of the Elem
class is meant to return the *minimum* element necessary
to uniquely define the side, whereas the build_side()
method returns a special proxy for Elem, which is called
Side<X,Y> and which is meant to be more efficient than
building the full Elem.

Concerning the infinite elements, the build_side() function has
evidently been implemented in terms of side(), see
e.g. face_inf_quad4.h

  AutoPtr<Elem> build_side (const unsigned int i) const
  { AutoPtr<Elem> ap(this->side(i)); return ap;}

In our work on the 1D functionality, we found it useful to generalize
the side() method to return AutoPtr<DofObject> instead of AutoPtr<Elem>
so that for 1D you can return an auto-pointer to a Node in e.g.
find_neighbors() and maintain the same interface.

My first question is whether it is possible to correctly implement build_side()
for each of the infinite elements to return the proper Side<X,Y> object?
It seems do-able, but I'd rather not waste time trying to figure out something
someone else has already tried...


-- 
John W. Peterson