Barely Random Algorithms and Collective Metrical Task Systems

Fuente: arXiv
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Main Authors: Cosson, Romain, Massoulié, Laurent
Format: Preprint
Published: 2024
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author Cosson, Romain
Massoulié, Laurent
author_facet Cosson, Romain
Massoulié, Laurent
contents We consider metrical task systems on general metric spaces with $n$ points, and show that any fully randomized algorithm can be turned into a randomized algorithm that uses only $2\log n$ random bits, and achieves the same competitive ratio up to a factor $2$. This provides the first order-optimal barely random algorithms for metrical task systems, i.e., which use a number of random bits that does not depend on the number of requests addressed to the system. We discuss implications on various aspects of online decision-making such as: distributed systems, advice complexity, and transaction costs, suggesting broad applicability. We put forward an equivalent view that we call collective metrical task systems where $k$ agents in a metrical task system team up, and suffer the average cost paid by each agent. Our results imply that such a team can be $O(\log^2 n)$-competitive as soon as $k\geq n^2$. In comparison, a single agent is always $Ω(n)$-competitive.
format Preprint
id arxiv_https___arxiv_org_abs_2403_11267
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Barely Random Algorithms and Collective Metrical Task Systems
Cosson, Romain
Massoulié, Laurent
Data Structures and Algorithms
Computer Science and Game Theory
Optimization and Control
We consider metrical task systems on general metric spaces with $n$ points, and show that any fully randomized algorithm can be turned into a randomized algorithm that uses only $2\log n$ random bits, and achieves the same competitive ratio up to a factor $2$. This provides the first order-optimal barely random algorithms for metrical task systems, i.e., which use a number of random bits that does not depend on the number of requests addressed to the system. We discuss implications on various aspects of online decision-making such as: distributed systems, advice complexity, and transaction costs, suggesting broad applicability. We put forward an equivalent view that we call collective metrical task systems where $k$ agents in a metrical task system team up, and suffer the average cost paid by each agent. Our results imply that such a team can be $O(\log^2 n)$-competitive as soon as $k\geq n^2$. In comparison, a single agent is always $Ω(n)$-competitive.
title Barely Random Algorithms and Collective Metrical Task Systems
topic Data Structures and Algorithms
Computer Science and Game Theory
Optimization and Control
url https://arxiv.org/abs/2403.11267