Principal component analysis by optimisation of symmetric functions has no spurious local optima

Principal component analysis (PCA) finds the best linear representation of data and is an indispensable tool in many learning and inference tasks. Classically, principal components of a dataset are interpreted as the directions that preserve most of its “energy,” an interpretation that is theoretica...

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Main Authors: Eftekhari, A, Hauser, R
Format: Journal article
Language:English
Published: Society for Industrial and Applied Mathematics 2020
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author Eftekhari, A
Hauser, R
author_facet Eftekhari, A
Hauser, R
author_sort Eftekhari, A
collection OXFORD
description Principal component analysis (PCA) finds the best linear representation of data and is an indispensable tool in many learning and inference tasks. Classically, principal components of a dataset are interpreted as the directions that preserve most of its “energy,” an interpretation that is theoretically underpinned by the celebrated Eckart--Young--Mirsky theorem. This paper introduces many other ways of performing PCA, with various geometric interpretations, and proves that the corresponding family of nonconvex programs has no spurious local optima, while possessing only strict saddle points. These programs therefore loosely behave like convex problems and can be efficiently solved to global optimality, for example, with certain variants of the stochastic gradient descent. Beyond providing new geometric interpretations and enhancing our theoretical understanding of PCA, our findings might pave the way for entirely new approaches to structured dimensionality reduction, such as sparse PCA and nonnegative matrix factorization. More specifically, we study an unconstrained formulation of PCA using determinant optimization that might provide an elegant alternative to the deflating scheme commonly used in sparse PCA. Read More: https://epubs.siam.org/doi/abs/10.1137/18M1188495
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spelling oxford-uuid:ea47944f-07e6-4fe6-9db6-9a763767a0c12022-03-27T11:00:51ZPrincipal component analysis by optimisation of symmetric functions has no spurious local optimaJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ea47944f-07e6-4fe6-9db6-9a763767a0c1EnglishSymplectic Elements at OxfordSociety for Industrial and Applied Mathematics2020Eftekhari, AHauser, RPrincipal component analysis (PCA) finds the best linear representation of data and is an indispensable tool in many learning and inference tasks. Classically, principal components of a dataset are interpreted as the directions that preserve most of its “energy,” an interpretation that is theoretically underpinned by the celebrated Eckart--Young--Mirsky theorem. This paper introduces many other ways of performing PCA, with various geometric interpretations, and proves that the corresponding family of nonconvex programs has no spurious local optima, while possessing only strict saddle points. These programs therefore loosely behave like convex problems and can be efficiently solved to global optimality, for example, with certain variants of the stochastic gradient descent. Beyond providing new geometric interpretations and enhancing our theoretical understanding of PCA, our findings might pave the way for entirely new approaches to structured dimensionality reduction, such as sparse PCA and nonnegative matrix factorization. More specifically, we study an unconstrained formulation of PCA using determinant optimization that might provide an elegant alternative to the deflating scheme commonly used in sparse PCA. Read More: https://epubs.siam.org/doi/abs/10.1137/18M1188495
spellingShingle Eftekhari, A
Hauser, R
Principal component analysis by optimisation of symmetric functions has no spurious local optima
title Principal component analysis by optimisation of symmetric functions has no spurious local optima
title_full Principal component analysis by optimisation of symmetric functions has no spurious local optima
title_fullStr Principal component analysis by optimisation of symmetric functions has no spurious local optima
title_full_unstemmed Principal component analysis by optimisation of symmetric functions has no spurious local optima
title_short Principal component analysis by optimisation of symmetric functions has no spurious local optima
title_sort principal component analysis by optimisation of symmetric functions has no spurious local optima
work_keys_str_mv AT eftekharia principalcomponentanalysisbyoptimisationofsymmetricfunctionshasnospuriouslocaloptima
AT hauserr principalcomponentanalysisbyoptimisationofsymmetricfunctionshasnospuriouslocaloptima