How Does Overparameterization Affect Features?

Fuente: arXiv
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Hauptverfasser: Duzgun, Ahmet Cagri, Jelassi, Samy, Li, Yuanzhi
Format: Preprint
Veröffentlicht: 2024
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author Duzgun, Ahmet Cagri
Jelassi, Samy
Li, Yuanzhi
author_facet Duzgun, Ahmet Cagri
Jelassi, Samy
Li, Yuanzhi
contents Overparameterization, the condition where models have more parameters than necessary to fit their training loss, is a crucial factor for the success of deep learning. However, the characteristics of the features learned by overparameterized networks are not well understood. In this work, we explore this question by comparing models with the same architecture but different widths. We first examine the expressivity of the features of these models, and show that the feature space of overparameterized networks cannot be spanned by concatenating many underparameterized features, and vice versa. This reveals that both overparameterized and underparameterized networks acquire some distinctive features. We then evaluate the performance of these models, and find that overparameterized networks outperform underparameterized networks, even when many of the latter are concatenated. We corroborate these findings using a VGG-16 and ResNet18 on CIFAR-10 and a Transformer on the MNLI classification dataset. Finally, we propose a toy setting to explain how overparameterized networks can learn some important features that the underparamaterized networks cannot learn.
format Preprint
id arxiv_https___arxiv_org_abs_2407_00968
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle How Does Overparameterization Affect Features?
Duzgun, Ahmet Cagri
Jelassi, Samy
Li, Yuanzhi
Machine Learning
Overparameterization, the condition where models have more parameters than necessary to fit their training loss, is a crucial factor for the success of deep learning. However, the characteristics of the features learned by overparameterized networks are not well understood. In this work, we explore this question by comparing models with the same architecture but different widths. We first examine the expressivity of the features of these models, and show that the feature space of overparameterized networks cannot be spanned by concatenating many underparameterized features, and vice versa. This reveals that both overparameterized and underparameterized networks acquire some distinctive features. We then evaluate the performance of these models, and find that overparameterized networks outperform underparameterized networks, even when many of the latter are concatenated. We corroborate these findings using a VGG-16 and ResNet18 on CIFAR-10 and a Transformer on the MNLI classification dataset. Finally, we propose a toy setting to explain how overparameterized networks can learn some important features that the underparamaterized networks cannot learn.
title How Does Overparameterization Affect Features?
topic Machine Learning
url https://arxiv.org/abs/2407.00968