When can the two-armed bandit algorithm be trusted?

We investigate the asymptotic behavior of one version of the so-called two-armed bandit algorithm. It is an example of stochastic approximation procedure whose associated ODE has both a repulsive and an attractive equilibrium, at which the procedure is noiseless. We show that if the gain parameter i...

Full description

Bibliographic Details
Main Authors: Lamberton, D, Pages, G, Tarres, P
Format: Journal article
Language:English
Published: 2004
_version_ 1826277617586667520
author Lamberton, D
Pages, G
Tarres, P
author_facet Lamberton, D
Pages, G
Tarres, P
author_sort Lamberton, D
collection OXFORD
description We investigate the asymptotic behavior of one version of the so-called two-armed bandit algorithm. It is an example of stochastic approximation procedure whose associated ODE has both a repulsive and an attractive equilibrium, at which the procedure is noiseless. We show that if the gain parameter is constant or goes to 0 not too fast, the algorithm does fall in the noiseless repulsive equilibrium with positive probability, whereas it always converges to its natural attractive target when the gain parameter goes to zero at some appropriate rates depending on the parameters of the model. We also elucidate the behavior of the constant step algorithm when the step goes to 0. Finally, we highlight the connection between the algorithm and the Polya urn. An application to asset allocation is briefly described. © Institute of Mathematical Statistics, 2004.
first_indexed 2024-03-06T23:31:37Z
format Journal article
id oxford-uuid:6c38dcc1-ceb6-48ba-a3af-ec6bb3d74de2
institution University of Oxford
language English
last_indexed 2024-03-06T23:31:37Z
publishDate 2004
record_format dspace
spelling oxford-uuid:6c38dcc1-ceb6-48ba-a3af-ec6bb3d74de22022-03-26T19:09:20ZWhen can the two-armed bandit algorithm be trusted?Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:6c38dcc1-ceb6-48ba-a3af-ec6bb3d74de2EnglishSymplectic Elements at Oxford2004Lamberton, DPages, GTarres, PWe investigate the asymptotic behavior of one version of the so-called two-armed bandit algorithm. It is an example of stochastic approximation procedure whose associated ODE has both a repulsive and an attractive equilibrium, at which the procedure is noiseless. We show that if the gain parameter is constant or goes to 0 not too fast, the algorithm does fall in the noiseless repulsive equilibrium with positive probability, whereas it always converges to its natural attractive target when the gain parameter goes to zero at some appropriate rates depending on the parameters of the model. We also elucidate the behavior of the constant step algorithm when the step goes to 0. Finally, we highlight the connection between the algorithm and the Polya urn. An application to asset allocation is briefly described. © Institute of Mathematical Statistics, 2004.
spellingShingle Lamberton, D
Pages, G
Tarres, P
When can the two-armed bandit algorithm be trusted?
title When can the two-armed bandit algorithm be trusted?
title_full When can the two-armed bandit algorithm be trusted?
title_fullStr When can the two-armed bandit algorithm be trusted?
title_full_unstemmed When can the two-armed bandit algorithm be trusted?
title_short When can the two-armed bandit algorithm be trusted?
title_sort when can the two armed bandit algorithm be trusted
work_keys_str_mv AT lambertond whencanthetwoarmedbanditalgorithmbetrusted
AT pagesg whencanthetwoarmedbanditalgorithmbetrusted
AT tarresp whencanthetwoarmedbanditalgorithmbetrusted