Rethinking the Trust Region in LLM Reinforcement Learning (Feb 2026) скачать в хорошем качестве

Rethinking the Trust Region in LLM Reinforcement Learning (Feb 2026)

Title: Rethinking the Trust Region in LLM Reinforcement Learning (Feb 2026) Link: http://arxiv.org/abs/2602.04879v1 Date: February 2026 Summary: This paper introduces Divergence Proximal Policy Optimization (DPPO), an improved reinforcement learning algorithm specifically designed for fine-tuning Large Language Models (LLMs). The authors argue that standard PPO's ratio clipping is ill-suited for the long-tailed vocabulary distributions of LLMs, as it over-penalizes low-probability tokens and under-constrains high-probability ones. DPPO addresses this by replacing heuristic clipping with a more principled constraint based on direct estimates of policy divergence (like Total Variation or KL), using efficient Binary and Top-K approximations. Empirical results show that DPPO achieves superior training stability and efficiency across various reasoning tasks. Key Topics: Reinforcement Learning (RL) Large Language Models (LLMs) Proximal Policy Optimization (PPO) Trust Region Methods Policy Divergence Total Variation (TV) KL Divergence Training Stability Training Efficiency Chapters: 00:00 - Intro: Rethinking PPO 01:50 - Why PPO Fails LLMs 02:47 - Rare Token Trap 04:26 - Common Token Collapse 06:03 - Defining DPPO Mechanism 07:43 - Binary Approximation Trick 09:43 - Analyzing Clipped Tokens 11:22 - Preventing Catastrophic Forgetting 13:06 - Anchor Point Efficiency 15:04 - Mixture Of Experts Results 16:15 - Preserving Model Creativity Stock video credits: Claudiu Ciobanu - https://www.pexels.com/@claudiuciobanu Google DeepMind - https://www.pexels.com/@googledeepmind Kindel Media - https://www.pexels.com/@kindelmedia Pavel Danilyuk - https://www.pexels.com/@pavel-danilyuk José Alfredo Munguía Lira - https://www.pexels.com/@rectorretro StefWithAnF - https://www.pexels.com/@stefwithanf-1... Colin Jones - https://www.pexels.com/@larchmedia Pressmaster - https://www.pexels.com/@pressmaster Anete Lusina - https://www.pexels.com/@anete-lusina Yaroslav Shuraev - https://www.pexels.com/@yaroslav-shuraev Cyriac von Czapiewski - https://www.pexels.com/@cyriac-von-cz... Max Fischer - https://www.pexels.com/@max-fischer cottonbro studio - https://www.pexels.com/@cottonbro Anthony 🙂 - https://www.pexels.com/@inspiredimages Pachon in Motion - https://www.pexels.com/@pachon-in-mot... Bedrijfsfilmspecialist.nl - https://www.pexels.com/@bedrijfsfilms... crazy motions - https://www.pexels.com/@crazy-motions... Colors Motion Graphics - https://www.pexels.com/@colors-motion... Soumya - https://www.pexels.com/@soumya-1446957 tunnel motions - https://www.pexels.com/@tunnelmotions Trippy Lagoon - https://www.pexels.com/@trippy-lagoon... Dan Cristian Pădureț - https://www.pexels.com/@paduret Tima Miroshnichenko - https://www.pexels.com/@tima-miroshni... Ketut Subiyanto - https://www.pexels.com/@ketut-subiyanto Ron Lach - https://www.pexels.com/@ron-lach Adis Resic - https://www.pexels.com/@adis-resic-29... MART PRODUCTION - https://www.pexels.com/@mart-production Oleg Gamulinskii - https://www.pexels.com/@oleg-gamulins... Silviu Din - https://www.pexels.com/@silviu-din-16... Caleb Oquendo - https://www.pexels.com/@caleboquendo Charlie Mounsey - https://www.pexels.com/@charlie-mouns... Engin Akyurt - https://www.pexels.com/@enginakyurt Kelly - https://www.pexels.com/@kelly Tom Fisk - https://www.pexels.com/@tomfisk Pixabay - https://www.pexels.com/@pixabay @svetjekolem - https://www.pexels.com/@svetjekolem KATRIN BOLOVTSOVA - https://www.pexels.com/@ekaterina-bol... Mikhail Nilov - https://www.pexels.com/@mikhail-nilov Nino Souza - https://www.pexels.com/@ninosouza olia danilevich - https://www.pexels.com/@olia-danilevich