arXiv Machine Learning
Oct 3

Reusing Past Samples in Proximal Policy Optimization: When and How Does It Help?

The paper investigates how reusing past samples can improve the sample efficiency of Proximal Policy Optimization (PPO). Two variants, wPPO-U and wPPO-BH, are introduced within a multiple importance weighting framework, each reusing data from recent iterations while preserving core PPO mechanics. The authors derive theoretical policy improvement bounds for both variants and empirically evaluate their impact on continuous control tasks.

By Alessandro Montenegro, Riccardo Venturelli, Marco Mussi, Matteo Papini, Alberto Maria Metelli
OpenAI Blog
Jul 20, 2017

Proximal Policy Optimization

We’re releasing a new class of reinforcement learning algorithms, Proximal Policy Optimization (PPO), which perform comparably or better than state-of-the-art approaches while being much simpler to implement and tune. PPO has become the default reinforcement learning algorithm at OpenAI because of its ease of use and good performance.

arXiv AI
Oct 12

Beyond State-Wise Mirror Descent: Offline Policy Optimization with Parametric Policies

The paper extends theoretical guarantees for offline reinforcement learning to parameterized policy classes over large or continuous action spaces, overcoming limitations of prior algorithms that required finite action sets and state‑wise mirror descent. By addressing contextual coupling and linking mirror descent to natural policy gradients, the authors provide new analyses, algorithmic insights, and a surprising connection between offline RL and imitation learning.

By Xiang Li, Yuheng Zhang, Nan Jiang