ULLME: A Unified Framework for Large Language Model Embeddings with Generation-Augmented Learning

Hieu Man, Nghia Trung Ngo, Franck Dernoncourt, Thien Huu Nguyen


Abstract
Large Language Models (LLMs) excel in various natural language processing tasks, but leveraging them for dense passage embedding remains challenging. This is due to their causal attention mechanism and the misalignment between their pre-training objectives and the text ranking tasks. Despite some recent efforts to address these issues, existing frameworks for LLM-based text embeddings have been limited by their support for only a limited range of LLM architectures and fine-tuning strategies, limiting their practical application and versatility. In this work, we introduce the Unified framework for Large Language Model Embedding (ULLME), a flexible, plug-and-play implementation that enables bidirectional attention across various LLMs and supports a range of fine-tuning strategies. We also propose Generation-augmented Representation Learning (GRL), a novel fine-tuning method to boost LLMs for text embedding tasks. GRL enforces consistency between representation-based and generation-based relevance scores, leveraging LLMs’ powerful generative abilities for learning passage embeddings. To showcase our framework’s flexibility and effectiveness, we release three pre-trained models from ULLME with different backbone architectures, ranging from 1.5B to 8B parameters, all of which demonstrate strong performance on the Massive Text Embedding Benchmark. Our framework is publicly available at: https://github.com/nlp-uoregon/ullme. A demo video for ULLME can also be found at https://rb.gy/ws1ile.
Anthology ID:
2024.emnlp-demo.24
Volume:
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Delia Irazu Hernandez Farias, Tom Hope, Manling Li
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
230–239
Language:
URL:
https://aclanthology.org/2024.emnlp-demo.24
DOI:
Bibkey:
Cite (ACL):
Hieu Man, Nghia Trung Ngo, Franck Dernoncourt, and Thien Huu Nguyen. 2024. ULLME: A Unified Framework for Large Language Model Embeddings with Generation-Augmented Learning. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing: System Demonstrations, pages 230–239, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
ULLME: A Unified Framework for Large Language Model Embeddings with Generation-Augmented Learning (Man et al., EMNLP 2024)
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PDF:
https://aclanthology.org/2024.emnlp-demo.24.pdf