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arXiv 1807.07527cs.DS
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$\ell_p$中的最优Las Vegas近似近邻

Optimal Las Vegas Approximate Near Neighbors in $\ell_p$

Alexander Wei

摘要:

我们表明,在高维近似近邻搜索可以解决拉斯维加斯的方式(即,没有假阴性),同时匹配最佳位置敏感散列的性能。具体来说,我们构建了一个数据独立的拉斯维加斯数据结构与查询时间$O(dn^ρ)$和空间使用$O(dn^{1+ρ})$的$(r, c r)$ -近似近邻$\mathbb{R}^{d}$下的$\ell_p$规范,其中$ρ= 1/c^p + o(1)$。此外,我们给出了单位球的Las Vegas局部敏感滤波器构造,该构造可与Andoni等人的数据依赖数据结构(SODA 2017)一起使用,以在数据依赖设置中实现最佳时空权衡。对于对称的情况下,这给了我们一个数据相关的拉斯维加斯数据结构与查询时间$O(dn^ρ)$和空间使用$(r, c r)$ $O(dn^{1+ρ})$-近似近邻$\mathbb{R}^{d}$下的$\ell_p$规范,其中$ρ= 1/(2c^p - 1) + o(1)$。我们的数据独立构造改进了最近的拉斯维加斯数据结构的Ahle(FOCS 2017)$\ell_p$时,$1 < p\le 2$。我们的数据相关的建设甚至更好的$\ell_p$为所有$p\in [1, 2]$,是第一个拉斯维加斯近似近邻数据结构,利用数据相关的方法。我们还回答了Indyk(SODA 2000),Pagh(SODA 2016)和Ahle的公开问题,表明对于近似近邻,Las Vegas数据结构可以在数据独立和数据相关设置以及时空权衡的性能方面与最先进的Monte Carlo数据结构相匹配。

英文摘要:

We show that approximate near neighbor search in high dimensions can be solved in a Las Vegas fashion (i.e., without false negatives) for $\ell_p$ ($1\le p\le 2$) while matching the performance of optimal locality-sensitive hashing. Specifically, we construct a data-independent Las Vegas data structure with query time $O(dn^ρ)$ and space usage $O(dn^{1+ρ})$ for $(r, c r)$-approximate near neighbors in $\mathbb{R}^{d}$ under the $\ell_p$ norm, where $ρ= 1/c^p + o(1)$. Furthermore, we give a Las Vegas locality-sensitive filter construction for the unit sphere that can be used with the data-dependent data structure of Andoni et al. (SODA 2017) to achieve optimal space-time tradeoffs in the data-dependent setting. For the symmetric case, this gives us a data-dependent Las Vegas data structure with query time $O(dn^ρ)$ and space usage $O(dn^{1+ρ})$ for $(r, c r)$-approximate near neighbors in $\mathbb{R}^{d}$ under the $\ell_p$ norm, where $ρ= 1/(2c^p - 1) + o(1)$. Our data-independent construction improves on the recent Las Vegas data structure of Ahle (FOCS 2017) for $\ell_p$ when $1 < p\le 2$. Our data-dependent construction does even better for $\ell_p$ for all $p\in [1, 2]$ and is the first Las Vegas approximate near neighbors data structure to make use of data-dependent approaches. We also answer open questions of Indyk (SODA 2000), Pagh (SODA 2016), and Ahle by showing that for approximate near neighbors, Las Vegas data structures can match state-of-the-art Monte Carlo data structures in performance for both the data-independent and data-dependent settings and across space-time tradeoffs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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