Planar Minimum-Weight Triangulations

Jesper Jansson
November, 1995
Master's Thesis in Computer Science



Abstract

The classic problem of finding a minimum-weight triangulation for a given planar straight-line graph is considered in this paper. A brief overview of known methods is given in addition to some new results. A parallel greedy triangulation algorithm is presented along with experimental data that suggest a logarithmic relationship between the number of input vertices and its running time in the average case. Next, some new graph-based algorithms for parallel dynamic programming for simple polygons are described and analyzed. They are combined into a general algorithm that can be employed when the number of available processors is anywhere between O(n2 / log(n)) and O(n6 / log(n)) to reach running times that vary from O(n log(n)) to O(log(n)2), where n denotes the number of vertices that the polygons contain. As a side effect, a method for constructing the greedy triangulation of simple polygons with O(n4.75 / log(n)2) processors in O(n0.75 log(n)) time is obtained. Finally, an upper-case Omega(n) lower bound for the nonoptimality of the MST-triangulation heuristic and an upper-case Omega(n0.5) lower bound for the nonoptimality of the GST-triangulation heuristic are proved.



PostScript version (756501 bytes).


A printed version of the thesis can be obtained from:
Technical Reports Librarian
Department of Computer Science
Lund University
Box 118
SE-221 00 Lund
Sweden
E-mail: Anne-Marie.Westerberg@cs.lth.se


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