CudaCHPre2D: A straightforward preprocessing approach for accelerating 2D convex hull computations on the GPU

Summary An effective strategy for accelerating the calculation of convex hulls is to filter the input points by discarding interior points. In this paper, we present such a straightforward preprocessing approach by discarding the points locating in a convex polygon formed by 16 extreme points. Extreme points of a planar point set do not alter when all points are rotated with the same angle in the plane. Four groups of four extreme points with min or max x or y coordinates can be found for the original point set and three rotated point sets. These 16 extreme points are used to form a planar convex polygon. We discard those points locating in the convex polygon and calculate the desired convex hull of the remaining points. The proposed preprocessing algorithm is evaluated on two computational platforms. Experiments show that, when employing the proposed preprocessing algorithm on the computational platform 1, it achieves speedups of approximately 4 ×∼5× on average and 5 ×∼6× in the best cases over the cases where the proposed approach is not used, while on the computational platform 2, the speedups are approximately 6 ×∼9× on average and 9 ×∼14× in the best cases. Moreover, more than 99% input points can be discarded in most cases.