Mitigating Catastrophic Forgetting in Language Transfer via Model Merging

Fuente: arXiv
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Autori principali: Alexandrov, Anton, Raychev, Veselin, Müller, Mark Niklas, Zhang, Ce, Vechev, Martin, Toutanova, Kristina
Natura: Preprint
Pubblicazione: 2024
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author Alexandrov, Anton
Raychev, Veselin
Müller, Mark Niklas
Zhang, Ce
Vechev, Martin
Toutanova, Kristina
author_facet Alexandrov, Anton
Raychev, Veselin
Müller, Mark Niklas
Zhang, Ce
Vechev, Martin
Toutanova, Kristina
contents As open-weight large language models (LLMs) achieve ever more impressive performances across a wide range of tasks in English, practitioners aim to adapt these models to different languages. However, such language adaptation is often accompanied by catastrophic forgetting of the base model's capabilities, severely limiting the usefulness of the resulting model. We address this issue by proposing Branch-and-Merge (BaM), a new adaptation method based on iteratively merging multiple models, fine-tuned on a subset of the available training data. BaM is based on the insight that this yields lower magnitude but higher quality weight changes, reducing forgetting of the source domain while maintaining learning on the target domain. We demonstrate in an extensive empirical study on Bulgarian and German that BaM can significantly reduce forgetting while matching or even improving target domain performance compared to both standard continued pretraining and instruction finetuning across different model architectures.
format Preprint
id arxiv_https___arxiv_org_abs_2407_08699
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mitigating Catastrophic Forgetting in Language Transfer via Model Merging
Alexandrov, Anton
Raychev, Veselin
Müller, Mark Niklas
Zhang, Ce
Vechev, Martin
Toutanova, Kristina
Machine Learning
As open-weight large language models (LLMs) achieve ever more impressive performances across a wide range of tasks in English, practitioners aim to adapt these models to different languages. However, such language adaptation is often accompanied by catastrophic forgetting of the base model's capabilities, severely limiting the usefulness of the resulting model. We address this issue by proposing Branch-and-Merge (BaM), a new adaptation method based on iteratively merging multiple models, fine-tuned on a subset of the available training data. BaM is based on the insight that this yields lower magnitude but higher quality weight changes, reducing forgetting of the source domain while maintaining learning on the target domain. We demonstrate in an extensive empirical study on Bulgarian and German that BaM can significantly reduce forgetting while matching or even improving target domain performance compared to both standard continued pretraining and instruction finetuning across different model architectures.
title Mitigating Catastrophic Forgetting in Language Transfer via Model Merging
topic Machine Learning
url https://arxiv.org/abs/2407.08699