A Constant-Factor Approximation for Continuous Dynamic Time Warping in 2D

Fuente: arXiv
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Main Authors: Buchin, Kevin, Buchin, Maike, Swiadek, Jan Erik, Wong, Sampson
Format: Preprint
Published: 2026
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author Buchin, Kevin
Buchin, Maike
Swiadek, Jan Erik
Wong, Sampson
author_facet Buchin, Kevin
Buchin, Maike
Swiadek, Jan Erik
Wong, Sampson
contents Continuous Dynamic Time Warping (CDTW) is a robust similarity measure for polygonal curves that has recently found a variety of applications. Despite its practical use, not much is known about the algorithmic complexity of computing it in 2D, especially when one requires either an exact solution or strong approximation guarantees. We fill this gap by introducing a $5$-approximation algorithm with running time $O(n^5)$ under the 1-norm. This is the first constant-factor approximation for 2D CDTW with polynomial running time. We extend our algorithm to all polygonal norms on $\mathbb{R}^2$, which we subsequently use in order to achieve a $(5+\varepsilon)$-approximation with time complexity $O(n^5 / \varepsilon^{1/2})$ for CDTW in 2D under any fixed norm. The latter result in particular includes the usual Euclidean 2-norm.
format Preprint
id arxiv_https___arxiv_org_abs_2605_05917
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Constant-Factor Approximation for Continuous Dynamic Time Warping in 2D
Buchin, Kevin
Buchin, Maike
Swiadek, Jan Erik
Wong, Sampson
Computational Geometry
Continuous Dynamic Time Warping (CDTW) is a robust similarity measure for polygonal curves that has recently found a variety of applications. Despite its practical use, not much is known about the algorithmic complexity of computing it in 2D, especially when one requires either an exact solution or strong approximation guarantees. We fill this gap by introducing a $5$-approximation algorithm with running time $O(n^5)$ under the 1-norm. This is the first constant-factor approximation for 2D CDTW with polynomial running time. We extend our algorithm to all polygonal norms on $\mathbb{R}^2$, which we subsequently use in order to achieve a $(5+\varepsilon)$-approximation with time complexity $O(n^5 / \varepsilon^{1/2})$ for CDTW in 2D under any fixed norm. The latter result in particular includes the usual Euclidean 2-norm.
title A Constant-Factor Approximation for Continuous Dynamic Time Warping in 2D
topic Computational Geometry
url https://arxiv.org/abs/2605.05917