Hybrid algorithm for deletion of a point in regular and Delaunay triangulation

  • Authors:
  • Michal Zemek;Ivana Kolingerová

  • Affiliations:
  • University of West Bohemia, Pilsen, Czech Republic;University of West Bohemia, Pilsen, Czech Republic

  • Venue:
  • Proceedings of the 25th Spring Conference on Computer Graphics
  • Year:
  • 2009

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Abstract

In this paper, we propose a randomized algorithm that allows to delete a point in three--dimensional regular or Delaunay triangulation by a sequence of flips. All the previous algorithms check regularity of each new tetrahedron globally, i.e. with respect to all vertices of tetrahedra incident to the point, which is being deleted. In contrast, the proposed hybrid algorithm uses a combination of local and global regularity tests. First, the proposed algorithm tries to delete a point by a randomized sequence of flips of faces satisfying a certain local condition. This simple approach will always delete the point successfully, but theoretically in an unbounded time in the worst case. Therefore we combine it with the global regularity tests -- if the point is not deleted after a certain number of flips, the proposed algorithm replaces the local regularity test by the global regularity test. In practice, the local regularity tests are sufficient in most cases and the global regularity tests are used only rarely. In consequence, the proposed algorithm needs less tests of regularity in average than the previous algorithms.