$μ$pscaling small models: Principled warm starts and hyperparameter transfer

Fuente: arXiv
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Main Authors: Ma, Yuxin, Chen, Nan, Díaz, Mateo, Hayou, Soufiane, Kunisky, Dmitriy, Villar, Soledad
Format: Preprint
Published: 2026
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author Ma, Yuxin
Chen, Nan
Díaz, Mateo
Hayou, Soufiane
Kunisky, Dmitriy
Villar, Soledad
author_facet Ma, Yuxin
Chen, Nan
Díaz, Mateo
Hayou, Soufiane
Kunisky, Dmitriy
Villar, Soledad
contents Modern large-scale neural networks are often trained and released in multiple sizes to accommodate diverse inference budgets. To improve efficiency, recent work has explored model upscaling: initializing larger models from trained smaller ones in order to transfer knowledge and accelerate convergence. However, this method can be sensitive to hyperparameters that need to be tuned at the target upscaled model size, which is prohibitively costly to do directly. It remains unclear whether the most common workaround -- tuning on smaller models and extrapolating via hyperparameter scaling laws -- is still sound when using upscaling. We address this with principled approaches to upscaling with respect to model widths and efficiently tuning hyperparameters in this setting. First, motivated by $μ$P and any-dimensional architectures, we introduce a general upscaling method applicable to a broad range of architectures and optimizers, backed by theory guaranteeing that models are equivalent to their widened versions and allowing for rigorous analysis of infinite-width limits. Second, we extend the theory of $μ$Transfer to a hyperparameter transfer technique for models upscaled using our method and empirically demonstrate that this method is effective on realistic datasets and architectures.
format Preprint
id arxiv_https___arxiv_org_abs_2602_10545
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle $μ$pscaling small models: Principled warm starts and hyperparameter transfer
Ma, Yuxin
Chen, Nan
Díaz, Mateo
Hayou, Soufiane
Kunisky, Dmitriy
Villar, Soledad
Machine Learning
Artificial Intelligence
Modern large-scale neural networks are often trained and released in multiple sizes to accommodate diverse inference budgets. To improve efficiency, recent work has explored model upscaling: initializing larger models from trained smaller ones in order to transfer knowledge and accelerate convergence. However, this method can be sensitive to hyperparameters that need to be tuned at the target upscaled model size, which is prohibitively costly to do directly. It remains unclear whether the most common workaround -- tuning on smaller models and extrapolating via hyperparameter scaling laws -- is still sound when using upscaling. We address this with principled approaches to upscaling with respect to model widths and efficiently tuning hyperparameters in this setting. First, motivated by $μ$P and any-dimensional architectures, we introduce a general upscaling method applicable to a broad range of architectures and optimizers, backed by theory guaranteeing that models are equivalent to their widened versions and allowing for rigorous analysis of infinite-width limits. Second, we extend the theory of $μ$Transfer to a hyperparameter transfer technique for models upscaled using our method and empirically demonstrate that this method is effective on realistic datasets and architectures.
title $μ$pscaling small models: Principled warm starts and hyperparameter transfer
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2602.10545