Complex Stochastic Gradient Descent and Directional Bias in Reproducing Kernel Hilbert Spaces

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Alpay, Natanael, Battaglia, Emeric
Formato: Preprint
Publicado: 2026
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866913160951234560
author Alpay, Natanael
Battaglia, Emeric
author_facet Alpay, Natanael
Battaglia, Emeric
contents Stochastic Gradient Descent (SGD) is a known stochastic iterative method popular for large-scale convex optimization problems due to its simple implementation and scalability. Some objectives, such as those found in complex-valued neural networks, benefit from updates like in SGD and Gradient Descent (GD) with a newly defined ``gradient'' that allows for complex parameters. This complex variant of the SGD/GD methods has already been proposed, but convergence guarantees without analyticity constraints have not yet been provided. We propose a variant of SGD (complex SGD) that allows for complex parameters, and we provide convergence guarantees under assumptions that parallel those from the real setting. Notably, these results extend to GD as well, and with the same set of assumptions, we confirm that some directional bias results extend from the real to the complex setting for kernel regression problems. We provide empirical results demonstrating the efficacy of the complex SGD in kernel regression problems utilizing complex reproducing kernel Hilbert spaces. In particular, we demonstrate we may recover superoscillation functions and Blaschke products from the Fock Space and Hardy Space, respectively, as the optimal functions for a particular choice of a loss function.
format Preprint
id arxiv_https___arxiv_org_abs_2604_23017
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Complex Stochastic Gradient Descent and Directional Bias in Reproducing Kernel Hilbert Spaces
Alpay, Natanael
Battaglia, Emeric
Machine Learning
Numerical Analysis
Complex Variables
65K10, 62L20, 46E22, 30H10, 65F10, 90C25
Stochastic Gradient Descent (SGD) is a known stochastic iterative method popular for large-scale convex optimization problems due to its simple implementation and scalability. Some objectives, such as those found in complex-valued neural networks, benefit from updates like in SGD and Gradient Descent (GD) with a newly defined ``gradient'' that allows for complex parameters. This complex variant of the SGD/GD methods has already been proposed, but convergence guarantees without analyticity constraints have not yet been provided. We propose a variant of SGD (complex SGD) that allows for complex parameters, and we provide convergence guarantees under assumptions that parallel those from the real setting. Notably, these results extend to GD as well, and with the same set of assumptions, we confirm that some directional bias results extend from the real to the complex setting for kernel regression problems. We provide empirical results demonstrating the efficacy of the complex SGD in kernel regression problems utilizing complex reproducing kernel Hilbert spaces. In particular, we demonstrate we may recover superoscillation functions and Blaschke products from the Fock Space and Hardy Space, respectively, as the optimal functions for a particular choice of a loss function.
title Complex Stochastic Gradient Descent and Directional Bias in Reproducing Kernel Hilbert Spaces
topic Machine Learning
Numerical Analysis
Complex Variables
65K10, 62L20, 46E22, 30H10, 65F10, 90C25
url https://arxiv.org/abs/2604.23017