[vtkusers] vtk3.2beta available

[Will Schroeder]

Hi John-

>I'm attaching a diff of vtkUnstructuredGrid.h, vtkUnstructuredGrid.cxx, and
>vtkGeometryFilter.cxx.  I believe that the other classes derived from
>vtkDataSet could also benefit from a GetFirstCellNeighbor() method, but
>since I'm only working with unstructured grids, I haven't really looked into
>it.  I'd be more than happy to write and test them if there's an interest
>in incorporating them into the VTK library.
>
>One more note: the only place GetCellNeighbors() is called outside of
>vtkGeometryFilter is in vtkPointSet.  Again, only the first neighbor is
>used.

Thanks for the feedback.

What you have done assumes that the mesh is manifold (i.e., each face of the
tetrahedron is used by at most by one other tetrahedron). Your fix is good, 
thanks.
Quite frankly, I am totally unhappy with the speed of this operation, even 
with your
improvements. (What version are you running, some changes were made in the last
several months. Also, would it be possible to get your data?) I'd like to 
find a better
way to do this...for example, it is possible to extend the unstructured 
grid structure
so that it can be optimized for this operation at the cost of additional 
memory, etc.

Will