Search arXivSearch

arXiv · 1402.1807

Recurrence for Pandimensional Space-Filling Functions

Abstract

A space-filling function is a bijection from the unit line segment to the unit square, cube, or hypercube. The function from the unit line segment is continuous. The inverse function, while well-defined, is not continuous. Space-filling curves, the finite approximations to space-filling functions, have found application in global optimization, database indexing, and dimension reduction among others. For these applications the desired transforms are mapping a scalar to multidimensional coordinates and mapping multidimensional coordinates to a scalar. Presented are recurrences which produce space-filling functions and curves of any rank $d\ge2$ based on serpentine Hamiltonian paths on $({\bf Z}\bmod s)^d$ where $s\ge2$. The recurrences for inverse space-filling functions are also presented. Both Peano and Hilbert curves and functions and their generalizations to higher dimensions are produced by these recurrences. The computations of these space-filling functions and their inverse functions are absolutely convergent geometric series. The space-filling functions are constructed as limits of integer recurrences and equivalently as non-terminating real recurrences. Scaling relations are given which enable the space-filling functions and curves and their inverses to extend beyond the unit area or volume and even to all of $d$-space. This unification of pandimensional space-filling curves facilitates quantitative comparison of curves generated from different Hamiltonian paths. The isotropy and performance in dimension reduction of a variety of space-filling curves are analyzed. For dimension reduction it is found that Hilbert curves perform somewhat better than Peano curves and their isotropic variants.

Explore related subjects

Keep this discovery

BibTeXRIS

Aubrey Jaffer. 2014-02-08. Recurrence for Pandimensional Space-Filling Functions. https://arxiv.org/abs/1402.1807

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Almost Linear Universal Point Sets for Planar Graphs

A point set is universal for planar graphs on $n$ vertices if every such graph has a straight-line drawing without crossings whose vertices belong to the set. We construct universal point sets of size $n^{1+o(1)}$, improving the previous quadratic upper bound. Our construction uses the reduction of Bannister, Cheng, Devanny, and Eppstein from universal point sets to superpatterns for $213$-avoiding permutations. We represent these permutations by ordered rooted forests and construct a small family of intervals containing every such forest. The result follows from a straightforward bound on the size of the family of intervals. GPT-6 Astra assisted in developing the construction and proof.

cs.CG

Some results on Archdeacon's conjecture for rotation systems

A rotation system on $n$ elements assigns to each element a cyclic order of the other $n-1$ elements. A four-element subset is non-planar if its induced rotation system cannot be realized by a crossing-free drawing of $K_4$. As a combinatorial strengthening of Hill's conjecture on the crossing number of the complete graph, Archdeacon conjectured that every rotation system on $n$ elements has at least $H(n)=\frac{1}{4} \lfloor\frac {n}{2}\rfloor \lfloor\frac{n-1}{2}\rfloor \lfloor\frac{n-2}{2}\rfloor \lfloor\frac{n-3}{2}\rfloor$ non-planar four-element subsets. We computationally verify Archdeacon's conjecture for $n\leq 10$ and show that every extremal rotation system in these orders is realizable by a simple drawing. With computer assistance, we prove that every rotation system on $n$ elements has at least $(8/9 - o(1)) H(n)$ non-planar four-element subsets. We also present a proof by hand for a weaker lower bound of $(2/3-o(1)) H(n)$. Finally, extending recent work of Felsner on antipodal pairs in drawings, we show that Archdeacon's conjecture holds for antipodally shellable rotation systems.

cs.CG

The Hyperbolic Surface Distance, Diameter, and Dirichlet Problems

Despite the prominence of hyperbolic surfaces in mathematics, basic algorithmic questions about them, even computing the distance between two points, have remained open, leaving many features of these surfaces inaccessible. The classical machinery assumes a polyhedral structure absent on a smooth surface. We remove these obstacles. We begin with an efficient $O(g^2)$ algorithm for the distance between two points, where $g$ is the genus of the surface. Building on it, we obtain an $O(g^2 \log g)$ method for answering distance queries from a fixed source and, as a consequence, for recentering a Dirichlet domain around an arbitrary point. This understanding of distances on the surface then lets us approximate the diameter to within any $\eps$ in time $O(g^3 \log g / \eps^2)$. We further show that the diameter, a single real number encoding a great deal about the surface, is exactly computable. Its hyperbolic cosine is an algebraic number over the field encoding the coefficients of the hyperbolic isometries defining the surface.

cs.CG