MixLoRA-DSI: Dynamically Expandable Mixture-of-LoRA Experts for Rehearsal-Free Generative Retrieval over Dynamic Corpora

Fuente: arXiv
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Main Authors: Huynh, Tuan-Luc, Vu, Thuy-Trang, Wang, Weiqing, Le, Trung, Gašević, Dragan, Li, Yuan-Fang, Do, Thanh-Toan
Format: Preprint
Published: 2025
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author Huynh, Tuan-Luc
Vu, Thuy-Trang
Wang, Weiqing
Le, Trung
Gašević, Dragan
Li, Yuan-Fang
Do, Thanh-Toan
author_facet Huynh, Tuan-Luc
Vu, Thuy-Trang
Wang, Weiqing
Le, Trung
Gašević, Dragan
Li, Yuan-Fang
Do, Thanh-Toan
contents Continually updating model-based indexes in generative retrieval with new documents remains challenging, as full retraining is computationally expensive and impractical under resource constraints. We propose MixLoRA-DSI, a novel framework that combines an expandable mixture of Low-Rank Adaptation experts with a layer-wise out-of-distribution (OOD)-driven expansion strategy. Instead of allocating new experts for each new corpus, our proposed expansion strategy enables sublinear parameter growth by selectively introducing new experts only when significant number of OOD documents are detected. Experiments on NQ320k and MS MARCO Passage demonstrate that MixLoRA-DSI outperforms full-model update baselines, with minimal parameter overhead and substantially lower training costs.
format Preprint
id arxiv_https___arxiv_org_abs_2507_09924
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle MixLoRA-DSI: Dynamically Expandable Mixture-of-LoRA Experts for Rehearsal-Free Generative Retrieval over Dynamic Corpora
Huynh, Tuan-Luc
Vu, Thuy-Trang
Wang, Weiqing
Le, Trung
Gašević, Dragan
Li, Yuan-Fang
Do, Thanh-Toan
Information Retrieval
Artificial Intelligence
Computation and Language
Machine Learning
Continually updating model-based indexes in generative retrieval with new documents remains challenging, as full retraining is computationally expensive and impractical under resource constraints. We propose MixLoRA-DSI, a novel framework that combines an expandable mixture of Low-Rank Adaptation experts with a layer-wise out-of-distribution (OOD)-driven expansion strategy. Instead of allocating new experts for each new corpus, our proposed expansion strategy enables sublinear parameter growth by selectively introducing new experts only when significant number of OOD documents are detected. Experiments on NQ320k and MS MARCO Passage demonstrate that MixLoRA-DSI outperforms full-model update baselines, with minimal parameter overhead and substantially lower training costs.
title MixLoRA-DSI: Dynamically Expandable Mixture-of-LoRA Experts for Rehearsal-Free Generative Retrieval over Dynamic Corpora
topic Information Retrieval
Artificial Intelligence
Computation and Language
Machine Learning
url https://arxiv.org/abs/2507.09924