Neural collapse under cross-entropy loss

We consider the variational problem of cross-entropy loss with n feature vectors on a unit hypersphere in Rd. We prove that when d≥n−1, the global minimum is given by the simplex equiangular tight frame, which justifies the neural collapse behavior. We also prove that, as n→∞ with fixed d, the minim...

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Bibliographic Details
Published in:Applied and computational harmonic analysis Vol. 59; pp. 224 - 241
Main Authors: Lu, Jianfeng, Steinerberger, Stefan
Format: Journal Article
Language:English
Published: Elsevier Inc 01.07.2022
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ISSN:1063-5203
Online Access:Get full text
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Summary:We consider the variational problem of cross-entropy loss with n feature vectors on a unit hypersphere in Rd. We prove that when d≥n−1, the global minimum is given by the simplex equiangular tight frame, which justifies the neural collapse behavior. We also prove that, as n→∞ with fixed d, the minimizing points will distribute uniformly on the hypersphere and show a connection with the frame potential of Benedetto & Fickus.
ISSN:1063-5203
DOI:10.1016/j.acha.2021.12.011