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Continuous action reinforcement learning from a mixture of interpretable experts

Akrour, Riad ; Tateo, Davide LU orcid and Peters, Jan (2022) In IEEE Transactions on Pattern Analysis and Machine Intelligence 44(10). p.6795-6806
Abstract

Reinforcement learning (RL) has demonstrated its ability to solve high dimensional tasks by leveraging non-linear function approximators. However, these successes are mostly achieved by 'black-box' policies in simulated domains. When deploying RL to the real world, several concerns regarding the use of a 'black-box' policy might be raised. In order to make the learned policies more transparent, we propose in this paper a policy iteration scheme that retains a complex function approximator for its internal value predictions but constrains the policy to have a concise, hierarchical, and human-readable structure, based on a mixture of interpretable experts. Each expert selects a primitive action according to a distance to a prototypical... (More)

Reinforcement learning (RL) has demonstrated its ability to solve high dimensional tasks by leveraging non-linear function approximators. However, these successes are mostly achieved by 'black-box' policies in simulated domains. When deploying RL to the real world, several concerns regarding the use of a 'black-box' policy might be raised. In order to make the learned policies more transparent, we propose in this paper a policy iteration scheme that retains a complex function approximator for its internal value predictions but constrains the policy to have a concise, hierarchical, and human-readable structure, based on a mixture of interpretable experts. Each expert selects a primitive action according to a distance to a prototypical state. A key design decision to keep such experts interpretable is to select the prototypical states from trajectory data. The main technical contribution of the paper is to address the challenges introduced by this non-differentiable prototypical state selection procedure. Experimentally, we show that our proposed algorithm can learn compelling policies on continuous action deep RL benchmarks, matching the performance of neural network based policies, but returning policies that are more amenable to human inspection than neural network or linear-in-feature policies.

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author
; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Interpretability, Mixture of experts, Reinforcement learning, Robotics
in
IEEE Transactions on Pattern Analysis and Machine Intelligence
volume
44
issue
10
pages
12 pages
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • pmid:34375280
  • scopus:85138448448
ISSN
0162-8828
DOI
10.1109/TPAMI.2021.3103132
language
English
LU publication?
no
id
266e057d-a685-4a83-9298-9d0d26baf9eb
date added to LUP
2025-10-16 14:34:57
date last changed
2025-10-22 03:43:16
@article{266e057d-a685-4a83-9298-9d0d26baf9eb,
  abstract     = {{<p>Reinforcement learning (RL) has demonstrated its ability to solve high dimensional tasks by leveraging non-linear function approximators. However, these successes are mostly achieved by 'black-box' policies in simulated domains. When deploying RL to the real world, several concerns regarding the use of a 'black-box' policy might be raised. In order to make the learned policies more transparent, we propose in this paper a policy iteration scheme that retains a complex function approximator for its internal value predictions but constrains the policy to have a concise, hierarchical, and human-readable structure, based on a mixture of interpretable experts. Each expert selects a primitive action according to a distance to a prototypical state. A key design decision to keep such experts interpretable is to select the prototypical states from trajectory data. The main technical contribution of the paper is to address the challenges introduced by this non-differentiable prototypical state selection procedure. Experimentally, we show that our proposed algorithm can learn compelling policies on continuous action deep RL benchmarks, matching the performance of neural network based policies, but returning policies that are more amenable to human inspection than neural network or linear-in-feature policies.</p>}},
  author       = {{Akrour, Riad and Tateo, Davide and Peters, Jan}},
  issn         = {{0162-8828}},
  keywords     = {{Interpretability; Mixture of experts; Reinforcement learning; Robotics}},
  language     = {{eng}},
  month        = {{10}},
  number       = {{10}},
  pages        = {{6795--6806}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  series       = {{IEEE Transactions on Pattern Analysis and Machine Intelligence}},
  title        = {{Continuous action reinforcement learning from a mixture of interpretable experts}},
  url          = {{http://dx.doi.org/10.1109/TPAMI.2021.3103132}},
  doi          = {{10.1109/TPAMI.2021.3103132}},
  volume       = {{44}},
  year         = {{2022}},
}