Abstract
In this paper we study the performance of Lawson’s Oriented Walk, a 25-year old randomized point location algorithm without any preprocessing and extra storage, in 2-dimensional Delaunay triangulations. Given n pseudo-random points drawn from a convex set C with unit area and their Delaunay triangulation \(\mathcal{D}\), we prove that the algorithm locates a query point q in \(\mathcal{D}\) in expected \(O(\sqrt{n {\rm log }n})\) time. We also present an improved version of this algorithm, Lawson’s Oriented Walk with Sampling, which takes expected O(n 1/3) time. Our technique is elementary and the proof is in fact to relate Lawson’s Oriented Walk with Walkthrough, another well-known point location algorithm without preprocessing. Finally, we present empirical results to compare these two algorithms with their siblings, Walkthrough and Jump&Walk.
The research is partially supported by NSF CARGO grant DMS-0138065 and a MONTS grant.
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Zhu, B. (2003). On Lawson’s Oriented Walk in Random Delaunay Triangulations. In: Lingas, A., Nilsson, B.J. (eds) Fundamentals of Computation Theory. FCT 2003. Lecture Notes in Computer Science, vol 2751. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-45077-1_21
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DOI: https://doi.org/10.1007/978-3-540-45077-1_21
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