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Conformal Symplectic Optimization for Stable Reinforcement Learning

delete2024-01-01
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OA
AI
Y
Yao Lyu
X
Xiangteng Zhang
S
Shengbo Eben Li *
J
Jingliang Duan
L
Letian Tao
许庆 (Qing Xu)
L
Lei He
K
Keqiang Li
DOI:10.1109/TNNLS.2024.3511670delete
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Abstract

Abstract

En 中文
Training deep reinforcement learning (RL) agents necessitates overcoming the highly unstable nonconvex stochastic optimization inherent in the trial-and-error mechanism. To tackle this challenge, we propose a physics-inspired optimization algorithm called relativistic adaptive gradient descent (RAD), which enhances long-term training stability. By conceptualizing neural network (NN) training as the evolution of a conformal Hamiltonian system, we present a universal framework for transferring long-term stability from conformal symplectic integrators to iterative NN updating rules, where the choice of kinetic energy governs the dynamical properties of resulting optimization algorithms. By utilizing relativistic kinetic energy, RAD incorporates principles from special relativity and limits parameter updates below a finite speed, effectively mitigating abnormal gradient influences. In addition, RAD models NN optimization as the evolution of a multiparticle system where each trainable parameter acts as an independent particle with an individual adaptive learning rate. We prove RAD's sublinear convergence under general nonconvex settings, where smaller gradient variance and larger batch sizes contribute to tighter convergence. Notably, RAD degrades to the well-known adaptive moment estimation (ADAM) algorithm when its speed coefficient is chosen as one and symplectic factor as a small positive value. Experimental results show RAD outperforming nine baseline optimizers with five RL algorithms across twelve environments, including standard benchmarks and challenging scenarios. Notably, RAD achieves up to a 155.1% performance improvement over ADAM in Atari games, showcasing its efficacy in stabilizing and accelerating RL training.
Keywords:
Training
Optimization
Convergence
Artificial neural networks
Kinetic energy
Heuristic algorithms
Stochastic processes
Thermal stability
Dynamical systems
Stability criteria
Conformal Hamiltonian
nonconvex stochastic optimization
reinforcement learning (RL)
symplectic preservation
training stability

Journal

IEEE Transactions on Neural Networks and Learning Systems cover
IEEE Transactions on Neural Networks and Learning Systems
IF:
8.9
Papers:
7.5K
Citations:
7.2W

Organization

T
tsinghua university
Scholars:
11.8W
Papers: 10.0W
Citations: 137