On Softmax Direct Preference Optimization for Recommendation

Fuente: arXiv
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Autores principales: Chen, Yuxin, Tan, Junfei, Zhang, An, Yang, Zhengyi, Sheng, Leheng, Zhang, Enzhi, Wang, Xiang, Chua, Tat-Seng
Formato: Preprint
Publicado: 2024
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author Chen, Yuxin
Tan, Junfei
Zhang, An
Yang, Zhengyi
Sheng, Leheng
Zhang, Enzhi
Wang, Xiang
Chua, Tat-Seng
author_facet Chen, Yuxin
Tan, Junfei
Zhang, An
Yang, Zhengyi
Sheng, Leheng
Zhang, Enzhi
Wang, Xiang
Chua, Tat-Seng
contents Recommender systems aim to predict personalized rankings based on user preference data. With the rise of Language Models (LMs), LM-based recommenders have been widely explored due to their extensive world knowledge and powerful reasoning abilities. Most of the LM-based recommenders convert historical interactions into language prompts, pairing with a positive item as the target response and fine-tuning LM with a language modeling loss. However, the current objective fails to fully leverage preference data and is not optimized for personalized ranking tasks, which hinders the performance of LM-based recommenders. Inspired by the current advancement of Direct Preference Optimization (DPO) in human preference alignment and the success of softmax loss in recommendations, we propose Softmax-DPO (S-DPO) to instill ranking information into the LM to help LM-based recommenders distinguish preferred items from negatives, rather than solely focusing on positives. Specifically, we incorporate multiple negatives in user preference data and devise an alternative version of DPO loss tailored for LM-based recommenders, which is extended from the traditional full-ranking Plackett-Luce (PL) model to partial rankings and connected to softmax sampling strategies. Theoretically, we bridge S-DPO with the softmax loss over negative sampling and find that it has an inherent benefit of mining hard negatives, which assures its exceptional capabilities in recommendation tasks. Empirically, extensive experiments conducted on three real-world datasets demonstrate the superiority of S-DPO to effectively model user preference and further boost recommendation performance while providing better rewards for preferred items. Our codes are available at https://github.com/chenyuxin1999/S-DPO.
format Preprint
id arxiv_https___arxiv_org_abs_2406_09215
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On Softmax Direct Preference Optimization for Recommendation
Chen, Yuxin
Tan, Junfei
Zhang, An
Yang, Zhengyi
Sheng, Leheng
Zhang, Enzhi
Wang, Xiang
Chua, Tat-Seng
Information Retrieval
Artificial Intelligence
Recommender systems aim to predict personalized rankings based on user preference data. With the rise of Language Models (LMs), LM-based recommenders have been widely explored due to their extensive world knowledge and powerful reasoning abilities. Most of the LM-based recommenders convert historical interactions into language prompts, pairing with a positive item as the target response and fine-tuning LM with a language modeling loss. However, the current objective fails to fully leverage preference data and is not optimized for personalized ranking tasks, which hinders the performance of LM-based recommenders. Inspired by the current advancement of Direct Preference Optimization (DPO) in human preference alignment and the success of softmax loss in recommendations, we propose Softmax-DPO (S-DPO) to instill ranking information into the LM to help LM-based recommenders distinguish preferred items from negatives, rather than solely focusing on positives. Specifically, we incorporate multiple negatives in user preference data and devise an alternative version of DPO loss tailored for LM-based recommenders, which is extended from the traditional full-ranking Plackett-Luce (PL) model to partial rankings and connected to softmax sampling strategies. Theoretically, we bridge S-DPO with the softmax loss over negative sampling and find that it has an inherent benefit of mining hard negatives, which assures its exceptional capabilities in recommendation tasks. Empirically, extensive experiments conducted on three real-world datasets demonstrate the superiority of S-DPO to effectively model user preference and further boost recommendation performance while providing better rewards for preferred items. Our codes are available at https://github.com/chenyuxin1999/S-DPO.
title On Softmax Direct Preference Optimization for Recommendation
topic Information Retrieval
Artificial Intelligence
url https://arxiv.org/abs/2406.09215