Load-Balancing for Parallel Delaunay Triangulations

Abstract

Computing the Delaunay triangulation (DT) of a given point set in is one of the fundamental operations in computational geometry. Recently, Funke and Sanders [11] presented a divide-and-conquer DT algorithm that merges two partial triangulations by re-triangulating a small subset of their vertices – the border vertices – and combining the three triangulations efficiently via parallel hash table lookups. The input point division should therefore yield roughly equal-sized partitions for good load-balancing and also result in a small number of border vertices for fast merging. In this paper, we present a novel divide-step based on partitioning the triangulation of a small sample of the input points. In experiments on synthetic and real-world data sets, we achieve nearly perfectly balanced partitions and small border triangulations. This almost cuts running time in half compared to non-data-sensitive division schemes on inputs exhibiting an exploitable underlying structure.