Self-Play with Adversarial Critic: Provable and Scalable Offline Alignment for Language Models

Fuente: arXiv
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Autores principales: Ji, Xiang, Kulkarni, Sanjeev, Wang, Mengdi, Xie, Tengyang
Formato: Preprint
Publicado: 2024
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author Ji, Xiang
Kulkarni, Sanjeev
Wang, Mengdi
Xie, Tengyang
author_facet Ji, Xiang
Kulkarni, Sanjeev
Wang, Mengdi
Xie, Tengyang
contents This work studies the challenge of aligning large language models (LLMs) with offline preference data. We focus on alignment by Reinforcement Learning from Human Feedback (RLHF) in particular. While popular preference optimization methods exhibit good empirical performance in practice, they are not theoretically guaranteed to converge to the optimal policy and can provably fail when the data coverage is sparse by classical offline reinforcement learning (RL) results. On the other hand, a recent line of work has focused on theoretically motivated preference optimization methods with provable guarantees, but these are not computationally efficient for large-scale applications like LLM alignment. To bridge this gap, we propose SPAC, a new offline preference optimization method with self-play, inspired by the on-average pessimism technique from the offline RL literature, to be the first provable and scalable approach to LLM alignment. We both provide theoretical analysis for its convergence under single-policy concentrability for the general function approximation setting and demonstrate its competitive empirical performance for LLM alignment on a 7B Mistral model with Open LLM Leaderboard evaluations.
format Preprint
id arxiv_https___arxiv_org_abs_2406_04274
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Self-Play with Adversarial Critic: Provable and Scalable Offline Alignment for Language Models
Ji, Xiang
Kulkarni, Sanjeev
Wang, Mengdi
Xie, Tengyang
Machine Learning
Artificial Intelligence
Computation and Language
This work studies the challenge of aligning large language models (LLMs) with offline preference data. We focus on alignment by Reinforcement Learning from Human Feedback (RLHF) in particular. While popular preference optimization methods exhibit good empirical performance in practice, they are not theoretically guaranteed to converge to the optimal policy and can provably fail when the data coverage is sparse by classical offline reinforcement learning (RL) results. On the other hand, a recent line of work has focused on theoretically motivated preference optimization methods with provable guarantees, but these are not computationally efficient for large-scale applications like LLM alignment. To bridge this gap, we propose SPAC, a new offline preference optimization method with self-play, inspired by the on-average pessimism technique from the offline RL literature, to be the first provable and scalable approach to LLM alignment. We both provide theoretical analysis for its convergence under single-policy concentrability for the general function approximation setting and demonstrate its competitive empirical performance for LLM alignment on a 7B Mistral model with Open LLM Leaderboard evaluations.
title Self-Play with Adversarial Critic: Provable and Scalable Offline Alignment for Language Models
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2406.04274