WIAS Preprint No. 2744, (2020)

An enumerative formula for the spherical cap discrepancy



Authors

  • Heitsch, Holger
  • Henrion, René

2010 Mathematics Subject Classification

  • 11K38 90C15

Keywords

  • Spherical cap discrepancy, uniform distribution on sphere, optimality conditions

DOI

10.20347/WIAS.PREPRINT.2744

Abstract

The spherical cap discrepancy is a widely used measure for how uniformly a sample of points on the sphere is distributed. Being hard to compute, this discrepancy measure is typically replaced by some lower or upper estimates when designing optimal sampling schemes for the uniform distribution on the sphere. In this paper, we provide a fully explicit, easy to implement enumerative formula for the spherical cap discrepancy. Not surprisingly, this formula is of combinatorial nature and, thus, its application is limited to spheres of small dimension and moderate sample sizes. Nonetheless, it may serve as a useful calibrating tool for testing the efficiency of sampling schemes and its explicit character might be useful also to establish necessary optimality conditions when minimizing the discrepancy with respect to a sample of given size.

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