A Tight Lower Bound for Computing the Diameter of a 3D Convex Polytope

  • Authors:
  • Hervé Fournier;Antoine Vigneron

  • Affiliations:
  • Université de Versailles Saint-Quentin-en-Yvelines, Laboratoire PRiSM, 45 avenue des États-Unis, 78035, Versailles cedex, France;UR341 Mathématiques et Informatique Appliquées, INRA, Domaine de Vilvert, 78352, Jouy-en-Josas cedex, France

  • Venue:
  • Algorithmica
  • Year:
  • 2007

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Abstract

The diameter of a set P of n points in ℝ d is the maximum Euclidean distance between any two points in P. If P is the vertex set of a 3-dimensional convex polytope, and if the combinatorial structure of this polytope is given, we prove that, in the worst case, deciding whether the diameter of P is smaller than 1 requires Ω(nlog n) time in the algebraic computation tree model. It shows that the O(nlog n) time algorithm of Ramos for computing the diameter of a point set in ℝ3 is optimal for computing the diameter of a 3-polytope. We also give a linear time reduction from Hopcroft’s problem of finding an incidence between points and lines in ℝ2 to the diameter problem for a point set in ℝ7.