Human Alignment of Large Language Models through Online Preference Optimisation

Fuente: arXiv
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Autori principali: Calandriello, Daniele, Guo, Daniel, Munos, Remi, Rowland, Mark, Tang, Yunhao, Pires, Bernardo Avila, Richemond, Pierre Harvey, Lan, Charline Le, Valko, Michal, Liu, Tianqi, Joshi, Rishabh, Zheng, Zeyu, Piot, Bilal
Natura: Preprint
Pubblicazione: 2024
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author Calandriello, Daniele
Guo, Daniel
Munos, Remi
Rowland, Mark
Tang, Yunhao
Pires, Bernardo Avila
Richemond, Pierre Harvey
Lan, Charline Le
Valko, Michal
Liu, Tianqi
Joshi, Rishabh
Zheng, Zeyu
Piot, Bilal
author_facet Calandriello, Daniele
Guo, Daniel
Munos, Remi
Rowland, Mark
Tang, Yunhao
Pires, Bernardo Avila
Richemond, Pierre Harvey
Lan, Charline Le
Valko, Michal
Liu, Tianqi
Joshi, Rishabh
Zheng, Zeyu
Piot, Bilal
contents Ensuring alignment of language models' outputs with human preferences is critical to guarantee a useful, safe, and pleasant user experience. Thus, human alignment has been extensively studied recently and several methods such as Reinforcement Learning from Human Feedback (RLHF), Direct Policy Optimisation (DPO) and Sequence Likelihood Calibration (SLiC) have emerged. In this paper, our contribution is two-fold. First, we show the equivalence between two recent alignment methods, namely Identity Policy Optimisation (IPO) and Nash Mirror Descent (Nash-MD). Second, we introduce a generalisation of IPO, named IPO-MD, that leverages the regularised sampling approach proposed by Nash-MD. This equivalence may seem surprising at first sight, since IPO is an offline method whereas Nash-MD is an online method using a preference model. However, this equivalence can be proven when we consider the online version of IPO, that is when both generations are sampled by the online policy and annotated by a trained preference model. Optimising the IPO loss with such a stream of data becomes then equivalent to finding the Nash equilibrium of the preference model through self-play. Building on this equivalence, we introduce the IPO-MD algorithm that generates data with a mixture policy (between the online and reference policy) similarly as the general Nash-MD algorithm. We compare online-IPO and IPO-MD to different online versions of existing losses on preference data such as DPO and SLiC on a summarisation task.
format Preprint
id arxiv_https___arxiv_org_abs_2403_08635
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Human Alignment of Large Language Models through Online Preference Optimisation
Calandriello, Daniele
Guo, Daniel
Munos, Remi
Rowland, Mark
Tang, Yunhao
Pires, Bernardo Avila
Richemond, Pierre Harvey
Lan, Charline Le
Valko, Michal
Liu, Tianqi
Joshi, Rishabh
Zheng, Zeyu
Piot, Bilal
Machine Learning
Artificial Intelligence
Ensuring alignment of language models' outputs with human preferences is critical to guarantee a useful, safe, and pleasant user experience. Thus, human alignment has been extensively studied recently and several methods such as Reinforcement Learning from Human Feedback (RLHF), Direct Policy Optimisation (DPO) and Sequence Likelihood Calibration (SLiC) have emerged. In this paper, our contribution is two-fold. First, we show the equivalence between two recent alignment methods, namely Identity Policy Optimisation (IPO) and Nash Mirror Descent (Nash-MD). Second, we introduce a generalisation of IPO, named IPO-MD, that leverages the regularised sampling approach proposed by Nash-MD. This equivalence may seem surprising at first sight, since IPO is an offline method whereas Nash-MD is an online method using a preference model. However, this equivalence can be proven when we consider the online version of IPO, that is when both generations are sampled by the online policy and annotated by a trained preference model. Optimising the IPO loss with such a stream of data becomes then equivalent to finding the Nash equilibrium of the preference model through self-play. Building on this equivalence, we introduce the IPO-MD algorithm that generates data with a mixture policy (between the online and reference policy) similarly as the general Nash-MD algorithm. We compare online-IPO and IPO-MD to different online versions of existing losses on preference data such as DPO and SLiC on a summarisation task.
title Human Alignment of Large Language Models through Online Preference Optimisation
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2403.08635