Connectivity Shapes Implicit Regularization in Matrix Factorization Models for Matrix Completion

Fuente: arXiv
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Main Authors: Bai, Zhiwei, Zhao, Jiajie, Zhang, Yaoyu
Format: Preprint
Published: 2024
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_version_ 1866913869053558784
author Bai, Zhiwei
Zhao, Jiajie
Zhang, Yaoyu
author_facet Bai, Zhiwei
Zhao, Jiajie
Zhang, Yaoyu
contents Matrix factorization models have been extensively studied as a valuable test-bed for understanding the implicit biases of overparameterized models. Although both low nuclear norm and low rank regularization have been studied for these models, a unified understanding of when, how, and why they achieve different implicit regularization effects remains elusive. In this work, we systematically investigate the implicit regularization of matrix factorization for solving matrix completion problems. We empirically discover that the connectivity of observed data plays a crucial role in the implicit bias, with a transition from low nuclear norm to low rank as data shifts from disconnected to connected with increased observations. We identify a hierarchy of intrinsic invariant manifolds in the loss landscape that guide the training trajectory to evolve from low-rank to higher-rank solutions. Based on this finding, we theoretically characterize the training trajectory as following the hierarchical invariant manifold traversal process, generalizing the characterization of Li et al. (2020) to include the disconnected case. Furthermore, we establish conditions that guarantee minimum nuclear norm, closely aligning with our experimental findings, and we provide a dynamics characterization condition for ensuring minimum rank. Our work reveals the intricate interplay between data connectivity, training dynamics, and implicit regularization in matrix factorization models.
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id arxiv_https___arxiv_org_abs_2405_13721
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publishDate 2024
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spellingShingle Connectivity Shapes Implicit Regularization in Matrix Factorization Models for Matrix Completion
Bai, Zhiwei
Zhao, Jiajie
Zhang, Yaoyu
Machine Learning
Matrix factorization models have been extensively studied as a valuable test-bed for understanding the implicit biases of overparameterized models. Although both low nuclear norm and low rank regularization have been studied for these models, a unified understanding of when, how, and why they achieve different implicit regularization effects remains elusive. In this work, we systematically investigate the implicit regularization of matrix factorization for solving matrix completion problems. We empirically discover that the connectivity of observed data plays a crucial role in the implicit bias, with a transition from low nuclear norm to low rank as data shifts from disconnected to connected with increased observations. We identify a hierarchy of intrinsic invariant manifolds in the loss landscape that guide the training trajectory to evolve from low-rank to higher-rank solutions. Based on this finding, we theoretically characterize the training trajectory as following the hierarchical invariant manifold traversal process, generalizing the characterization of Li et al. (2020) to include the disconnected case. Furthermore, we establish conditions that guarantee minimum nuclear norm, closely aligning with our experimental findings, and we provide a dynamics characterization condition for ensuring minimum rank. Our work reveals the intricate interplay between data connectivity, training dynamics, and implicit regularization in matrix factorization models.
title Connectivity Shapes Implicit Regularization in Matrix Factorization Models for Matrix Completion
topic Machine Learning
url https://arxiv.org/abs/2405.13721