Reinforcement learning

Policy optimisation, reward modelling and RLHF — how models are trained by feedback rather than by labels.

6,688 stories · RSS feed

arXiv AI
Oct 7

Personal-Agent Mediated Recommendation with Cross-Platform User History

The paper introduces Personal-Agent Mediated Recommendation, a new paradigm where a personal LLM agent uses cross‑platform user history to adjust a platform’s recommendation ranking. It presents MediateRec, a benchmark for evaluating this mediation, and proposes Personal Attribution Mediation Optimization (PAMO) to balance beneficial rescues against harmful overrides. Experiments show that PAMO improves over outcome‑only reinforcement learning, achieving a better rescue‑harm trade‑off on both synthetic and real cross‑platform tests.

By Yu Xia, Jiangfan Zhang, Jun Xiao, Julian McAuley, Xiangjun Fan
arXiv AI
Oct 7

LSC-DPO: Learning-Signal-Controlled Direct Preference Optimization

The paper introduces LSC-DPO, a variant of Direct Preference Optimization that dynamically controls the learning signal to maintain sensitivity during training. By analyzing the logistic DPO loss geometrically, the authors identify the sigmoid factor as a key learning signal and propose a log‑space framework for stable target‑regime tracking. Experiments on AlpacaEval 2, MT‑Bench, and Anthropic‑HH demonstrate that LSC‑DPO outperforms standard DPO and other preference‑optimization baselines, and a signal‑budget compensation rule further reduces variability across different coefficient initializations.

By Yang Qu, Yusheng Han, Chengjia Feng, Handan Liu
arXiv AI
Oct 7

Learning Explainable Representations of Complex Game-playing Strategies

The paper proposes a method that mimics human cognition to train reinforcement learning agents to generate explainable strategies and policies as executable procedures derived from sequences of gameplay actions. It demonstrates automatic learning of such programs for chess and a grid‑based environment, showing that the resulting strategies produce effective actions and can be learned from gameplay data.

By Abhijeet Krishnan, Colin M. Potts, Arnav Jhala, Harshad Khadilkar, Shirish Karande, Chris Martens
arXiv AI
Oct 7

Towards the Automatic Synthesis of Interpretable Chess Tactics

The paper presents a symbolic sub‑policy model for chess that incorporates domain knowledge to improve interpretability. By adapting patterns learned through inductive logic programming (PAL), the authors evaluate the model using a divergence metric against a random baseline and show that it can suggest moves comparable to a human beginner. They also propose a computational evaluation scheme that augments an existing engine with their model.

By Abhijeet Krishnan, Chris Martens
arXiv AI
Oct 7

DHCG: Dynamic Construction of Hierarchical Collaboration Graphs for LLM-Based Multi-Agent Reasoning

The paper introduces DHCG, a framework that dynamically constructs hierarchical collaboration graphs for large language model–based multi‑agent systems. DHCG coordinates Planner, Worker, and Generator modules to adaptively determine the composition and scale of agents during execution, guided by feedback and action‑aware preference optimization. Experiments on code generation, mathematical reasoning, and domain‑specific tasks show DHCG surpasses static and dynamic baselines, improving performance by 2.77–8.02 points and achieving a 13.06‑point gain over single‑agent baselines.

By Jie Ren, Jiakang Yuan, Chenyu Huang, Hezeer Ma, Jiayuan Fan, Tao Chen
arXiv AI
Oct 7

NeMo-DCR: Bit-Exact Delta-Compressed Refit for Scalable Agentic RL at Trillion-Parameter Scale

NeMo-DCR is a delta‑compressed refit method that sends only the changes in a trillion‑parameter policy model, achieving bit‑exact synchronization across AWS regions. By using fixed affine mappings, XOR masks, and a relay‑tree object storage, it avoids full checkpoint transfers and cross‑cluster collectives, reducing refit times from 87.5 min to 150 s for a 1 T model at 3% change rate. The approach scales to 30 B–1 T models, delivering 12–40× speedups over traditional full‑checkpoint refits.

By Songlin Jiang, Zhiyu Li, Terry Kong, Yu Yao, Youngeun Kwon, Bernard Nguyen, Ashwath Aithal, Mario Di Francesco