Leftover Lunch: Advantage-based Offline Reinforcement Learning for Language Models

Fuente: arXiv
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Autores principales: Baheti, Ashutosh, Lu, Ximing, Brahman, Faeze, Bras, Ronan Le, Sap, Maarten, Riedl, Mark
Formato: Preprint
Publicado: 2023
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author Baheti, Ashutosh
Lu, Ximing
Brahman, Faeze
Bras, Ronan Le
Sap, Maarten
Riedl, Mark
author_facet Baheti, Ashutosh
Lu, Ximing
Brahman, Faeze
Bras, Ronan Le
Sap, Maarten
Riedl, Mark
contents Reinforcement Learning with Human Feedback (RLHF) is the most prominent method for Language Model (LM) alignment. However, RLHF is an unstable and data-hungry process that continually requires new high-quality LM-generated data for finetuning. We introduce Advantage-Leftover Lunch RL (A-LoL), a new class of offline policy gradient algorithms that enable RL training on any pre-existing data. By assuming the entire LM output sequence as a single action, A-LoL allows incorporating sequence-level classifiers or human-designed scoring functions as rewards. Subsequently, by using LM's value estimate, A-LoL only trains on positive advantage (leftover) data points, making it resilient to noise. Overall, A-LoL is an easy-to-implement, sample-efficient, and stable LM training recipe. We demonstrate the effectiveness of A-LoL and its variants with a set of four different language generation tasks. We compare against both online RL (PPO) and recent preference-based (DPO, PRO) and reward-based (GOLD) offline RL baselines. On the commonly-used RLHF benchmark, Helpful and Harmless Assistant (HHA), LMs trained with A-LoL methods achieve the highest diversity while also being rated more safe and helpful than the baselines according to humans. Additionally, in the remaining three tasks, A-LoL could optimize multiple distinct reward functions even when using noisy or suboptimal training data. We also release our experimental code. https://github.com/abaheti95/LoL-RL
format Preprint
id arxiv_https___arxiv_org_abs_2305_14718
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Leftover Lunch: Advantage-based Offline Reinforcement Learning for Language Models
Baheti, Ashutosh
Lu, Ximing
Brahman, Faeze
Bras, Ronan Le
Sap, Maarten
Riedl, Mark
Computation and Language
Reinforcement Learning with Human Feedback (RLHF) is the most prominent method for Language Model (LM) alignment. However, RLHF is an unstable and data-hungry process that continually requires new high-quality LM-generated data for finetuning. We introduce Advantage-Leftover Lunch RL (A-LoL), a new class of offline policy gradient algorithms that enable RL training on any pre-existing data. By assuming the entire LM output sequence as a single action, A-LoL allows incorporating sequence-level classifiers or human-designed scoring functions as rewards. Subsequently, by using LM's value estimate, A-LoL only trains on positive advantage (leftover) data points, making it resilient to noise. Overall, A-LoL is an easy-to-implement, sample-efficient, and stable LM training recipe. We demonstrate the effectiveness of A-LoL and its variants with a set of four different language generation tasks. We compare against both online RL (PPO) and recent preference-based (DPO, PRO) and reward-based (GOLD) offline RL baselines. On the commonly-used RLHF benchmark, Helpful and Harmless Assistant (HHA), LMs trained with A-LoL methods achieve the highest diversity while also being rated more safe and helpful than the baselines according to humans. Additionally, in the remaining three tasks, A-LoL could optimize multiple distinct reward functions even when using noisy or suboptimal training data. We also release our experimental code. https://github.com/abaheti95/LoL-RL
title Leftover Lunch: Advantage-based Offline Reinforcement Learning for Language Models
topic Computation and Language
url https://arxiv.org/abs/2305.14718