D2PO: Discriminator-Guided DPO with Response Evaluation Models

Fuente: arXiv
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Main Authors: Singhal, Prasann, Lambert, Nathan, Niekum, Scott, Goyal, Tanya, Durrett, Greg
Format: Preprint
Published: 2024
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author Singhal, Prasann
Lambert, Nathan
Niekum, Scott
Goyal, Tanya
Durrett, Greg
author_facet Singhal, Prasann
Lambert, Nathan
Niekum, Scott
Goyal, Tanya
Durrett, Greg
contents Varied approaches for aligning language models have been proposed, including supervised fine-tuning, RLHF, and direct optimization methods such as DPO. Although DPO has rapidly gained popularity due to its straightforward training process and competitive results, there is an open question of whether there remain practical advantages of using a discriminator, like a reward model, to evaluate responses. We propose D2PO, discriminator-guided DPO, an approach for the online setting where preferences are being collected throughout learning. As we collect gold preferences, we use these not only to train our policy, but to train a discriminative response evaluation model to silver-label even more synthetic data for policy training. We explore this approach across a set of diverse tasks, including a realistic chat setting, we find that our approach leads to higher-quality outputs compared to DPO with the same data budget, and greater efficiency in terms of preference data requirements. Furthermore, we show conditions under which silver labeling is most helpful: it is most effective when training the policy with DPO, outperforming traditional PPO, and benefits from maintaining a separate discriminator from the policy model.
format Preprint
id arxiv_https___arxiv_org_abs_2405_01511
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle D2PO: Discriminator-Guided DPO with Response Evaluation Models
Singhal, Prasann
Lambert, Nathan
Niekum, Scott
Goyal, Tanya
Durrett, Greg
Computation and Language
Varied approaches for aligning language models have been proposed, including supervised fine-tuning, RLHF, and direct optimization methods such as DPO. Although DPO has rapidly gained popularity due to its straightforward training process and competitive results, there is an open question of whether there remain practical advantages of using a discriminator, like a reward model, to evaluate responses. We propose D2PO, discriminator-guided DPO, an approach for the online setting where preferences are being collected throughout learning. As we collect gold preferences, we use these not only to train our policy, but to train a discriminative response evaluation model to silver-label even more synthetic data for policy training. We explore this approach across a set of diverse tasks, including a realistic chat setting, we find that our approach leads to higher-quality outputs compared to DPO with the same data budget, and greater efficiency in terms of preference data requirements. Furthermore, we show conditions under which silver labeling is most helpful: it is most effective when training the policy with DPO, outperforming traditional PPO, and benefits from maintaining a separate discriminator from the policy model.
title D2PO: Discriminator-Guided DPO with Response Evaluation Models
topic Computation and Language
url https://arxiv.org/abs/2405.01511