DivMerge: A divergence-based model merging method for multi-tasking

Brahim Touayouch, Loïc Fosse, Géraldine Damnati, Gwénolé Lecorvé


Abstract
Merging fine-tuned models is a promising alternative to costly multi-task training, but task interference remains a challenge, especially as the number of tasks grows. We present DivMerge, a reference-free method that merges models trained on different tasks by minimizing Jensen-Shannon divergence between their outputs and those of the merged model, automatically balancing task importance. While the method exhibits strong theoretical properties, experiments on classification and generative tasks with autoregressive models show that DivMerge consistently outperforms prior work, and remains robust when scaling to more tasks.
Anthology ID:
2026.eacl-long.337
Volume:
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
7157–7180
Language:
URL:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-long.337/
DOI:
Bibkey:
Cite (ACL):
Brahim Touayouch, Loïc Fosse, Géraldine Damnati, and Gwénolé Lecorvé. 2026. DivMerge: A divergence-based model merging method for multi-tasking. In Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 7157–7180, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
DivMerge: A divergence-based model merging method for multi-tasking (Touayouch et al., EACL 2026)
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PDF:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-long.337.pdf