Computing the geodesic diameter of a 3-polytope
Joseph O’Rourke, Catherine A. Schevon · 1989
We present an Ο(n14 log n) algorithm for computing the geodesic diameter of a 3-polytope of n vertices. The geodesic diameter is the greatest separation between two points on the surface, where distance is determined by the shortest (geodesic) path between two points. We assume a model of computation that permits finding roots of a one-variable polynomial of fixed degree in constant time. The key geometric result underlying the algorithm is that, although it may be that neither endpoint of the diameter is a vertex of the polytope, when this occurs, there must be at least five distinct equal-length paths between the diameter endpoints.