# Interior nodes of a closed graph?

Does anybody know if any graph partitioner library such as Metis, Scotch, or Zoltan can (besides splitting a domain), differentiate between internal (i) and boundary (b) nodes?

• If you only have the graph, there is no difference between the "interior" and "boundary nodes": you can draw the same graph taking any triangle as the boundary (then there will be an internal "face" with 8 vertices - the previous border). You need the facets to make the difference (and metis does not "see" them...) Dec 16, 2015 at 15:39
• Very enlightening, thank you. I actually have the facets as I'm dealing with an unstructured grid (made out of triangles) from a Finite Elements discretization. Now recognizing that I have the faces, my question remains the same, will METIS allow me to differentiate between faces in the bounday, and internal facets?
– Mark
Jan 13, 2016 at 13:33
• Then it depends on what you mean by "differentiate". METIS can take into account different "weights" for the points, then depending on what you want to achieve, maybe you can give a different weight to interior points and boundary points... Jan 13, 2016 at 20:34