Papers › A Monte Carlo AIXI Approximation

A Monte Carlo AIXI Approximation

4 Sep 2009arXiv:0909.0801archive 2025-07-28

Joel Veness, Kee Siong Ng, Marcus Hutter, William Uther, David Silver

This paper introduces a principled approach for the design of a scalable general reinforcement learning agent. Our approach is based on a direct approximation of AIXI, a Bayesian optimality notion for general reinforcement learning agents. Previously, it has been unclear whether the theory of AIXI could motivate the design of practical algorithms. We answer this hitherto open question in the affirmative, by providing the first computationally feasible approximation to the AIXI agent. To develop our approximation, we introduce a new Monte-Carlo Tree Search algorithm along with an agent-specific extension to the Context Tree Weighting algorithm. Empirically, we present a set of encouraging results on a variety of stochastic and partially observable domains. We conclude by proposing a number of directions for future research.

PaperPDFCode

Code

gkassel/pyaixi mentioned on GitHub report
sgkasselau/pyaixi mentioned on GitHub report

Repository list and official/mentioned flags are the archive's, frozen 2025-07-28. Reachability, where shown, is from one Syntology probe window (2026-09-16 to 2026-09-18); repositories not probed show nothing. GitHub stars are not tracked.

Code Syntology ran Syntology

Not run by Syntology. Nothing on this page verifies that the listed code works.

Tasks

General Reinforcement LearningOpen-Ended Question AnsweringReinforcement LearningReinforcement Learning (RL)reinforcement-learning

Results from the paper archive 2025-07-28

No leaderboard rows for this paper in the archive.

Methods

Monte-Carlo Tree Search

Report a problem or propose a change · a person checks every report against the paper or source before anything changes; decisions are listed on /corrections