Lookahead Pathology in Monte-Carlo Tree Search

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Nguyen, Khoi P. N., Ramanujan, Raghuram
Format: Preprint
Published: 2022
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914829664518144
author Nguyen, Khoi P. N.
Ramanujan, Raghuram
author_facet Nguyen, Khoi P. N.
Ramanujan, Raghuram
contents Monte-Carlo Tree Search (MCTS) is a search paradigm that first found prominence with its success in the domain of computer Go. Early theoretical work established the soundness and convergence bounds for Upper Confidence bounds applied to Trees (UCT), the most popular instantiation of MCTS; however, there remain notable gaps in our understanding of how UCT behaves in practice. In this work, we address one such gap by considering the question of whether UCT can exhibit lookahead pathology in adversarial settings -- a paradoxical phenomenon first observed in Minimax search where greater search effort leads to worse decision-making. We introduce a novel family of synthetic games that offer rich modeling possibilities while remaining amenable to mathematical analysis. Our theoretical and experimental results suggest that UCT is indeed susceptible to pathological behavior in a range of games drawn from this family.
format Preprint
id arxiv_https___arxiv_org_abs_2212_05208
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Lookahead Pathology in Monte-Carlo Tree Search
Nguyen, Khoi P. N.
Ramanujan, Raghuram
Artificial Intelligence
Multiagent Systems
Monte-Carlo Tree Search (MCTS) is a search paradigm that first found prominence with its success in the domain of computer Go. Early theoretical work established the soundness and convergence bounds for Upper Confidence bounds applied to Trees (UCT), the most popular instantiation of MCTS; however, there remain notable gaps in our understanding of how UCT behaves in practice. In this work, we address one such gap by considering the question of whether UCT can exhibit lookahead pathology in adversarial settings -- a paradoxical phenomenon first observed in Minimax search where greater search effort leads to worse decision-making. We introduce a novel family of synthetic games that offer rich modeling possibilities while remaining amenable to mathematical analysis. Our theoretical and experimental results suggest that UCT is indeed susceptible to pathological behavior in a range of games drawn from this family.
title Lookahead Pathology in Monte-Carlo Tree Search
topic Artificial Intelligence
Multiagent Systems
url https://arxiv.org/abs/2212.05208