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20232026
most citedSample Complexity of Neural Policy Mirror Descent for Policy Optimization on Low-Dimensional Manifolds

1 citations · 1 across the 7 of their papers we have counts for

collaborators

10 papers

cs.CL2026

Training LLM Judges from Language Feedback via Position-Selective Self-Distillation

Ilgee Hong, Changlong Yu, Zhenghao Xu +5

We study training LLM judges from natural language feedback, especially for subjective tasks where the verdict depends strongly on which evaluation criteria the judge invokes and h…

cs.LG2026

Approximation of Log-Partition Function in Policy Mirror Descent Induces Implicit Regularization for LLM Post-Training

Zhenghao Xu, Qin Lu, Changlong Yu +1

Policy mirror descent (PMD) provides a principled framework for reinforcement learning (RL) by iteratively solving KL-regularized policy improvement subproblems. While this approac…

cs.CL2025

Self-Rewarding PPO: Aligning Large Language Models with Demonstrations Only

Qingru Zhang, Liang Qiu, Ilgee Hong +11

Supervised fine-tuning (SFT) has emerged as a crucial method for aligning large language models (LLMs) with human-annotated demonstrations. However, SFT, being an off-policy approa…

cs.LG2025

Ask a Strong LLM Judge when Your Reward Model is Uncertain

Zhenghao Xu, Qin Lu, Qingru Zhang +9

Reward model (RM) plays a pivotal role in reinforcement learning with human feedback (RLHF) for aligning large language models (LLMs). However, classical RMs trained on human prefe…

cs.LG2025

Think-RM: Enabling Long-Horizon Reasoning in Generative Reward Models

Ilgee Hong, Changlong Yu, Liang Qiu +8

Reinforcement learning from human feedback (RLHF) has become a powerful post-training paradigm for aligning large language models with human preferences. A core challenge in RLHF i…

cs.LG2025

COSMOS: A Hybrid Adaptive Optimizer for Memory-Efficient Training of LLMs

Liming Liu, Zhenghao Xu, Zixuan Zhang +5

Large Language Models (LLMs) have demonstrated remarkable success across various domains, yet their optimization remains a significant challenge due to the complex and high-dimensi…

cs.LG2024

Provable Acceleration of Nesterov's Accelerated Gradient for Rectangular Matrix Factorization and Linear Neural Networks

Zhenghao Xu, Yuqing Wang, Tuo Zhao +2

We study the convergence rate of first-order methods for rectangular matrix factorization, which is a canonical nonconvex optimization problem. Specifically, given a rank- matri…

cs.LG2023

Score Matching-based Pseudolikelihood Estimation of Neural Marked Spatio-Temporal Point Process with Uncertainty Quantification

Zichong Li, Qunzhi Xu, Zhenghao Xu +3

Spatio-temporal point processes (STPPs) are potent mathematical tools for modeling and predicting events with both temporal and spatial features. Despite their versatility, most ex…

cs.LG2023

Good regularity creates large learning rate implicit biases: edge of stability, balancing, and catapult

Yuqing Wang, Zhenghao Xu, Tuo Zhao +1

Large learning rates, when applied to gradient descent for nonconvex optimization, yield various implicit biases including the edge of stability (Cohen et al., 2021), balancing (Wa…

cs.LG2023★ 1 cited

Sample Complexity of Neural Policy Mirror Descent for Policy Optimization on Low-Dimensional Manifolds

Zhenghao Xu, Xiang Ji, Minshuo Chen +2

Policy gradient methods equipped with deep neural networks have achieved great success in solving high-dimensional reinforcement learning (RL) problems. However, current analyses c…