Relax and penalize: a new bilevel approach to mixed-binary hyperparameter optimization

Fuente: arXiv
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Main Authors: Venturini, Sara, de Santis, Marianna, Patracone, Jordan, Rinaldi, Francesco, Salzo, Saverio, Schmidt, Martin
Format: Preprint
Published: 2023
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author Venturini, Sara
de Santis, Marianna
Patracone, Jordan
Rinaldi, Francesco
Salzo, Saverio
Schmidt, Martin
author_facet Venturini, Sara
de Santis, Marianna
Patracone, Jordan
Rinaldi, Francesco
Salzo, Saverio
Schmidt, Martin
contents In recent years, bilevel approaches have become very popular to efficiently estimate high-dimensional hyperparameters of machine learning models. However, to date, binary parameters are handled by continuous relaxation and rounding strategies, which could lead to inconsistent solutions. In this context, we tackle the challenging optimization of mixed-binary hyperparameters by resorting to an equivalent continuous bilevel reformulation based on an appropriate penalty term. We propose an algorithmic framework that, under suitable assumptions, is guaranteed to provide mixed-binary solutions. Moreover, the generality of the method allows to safely use existing continuous bilevel solvers within the proposed framework. We evaluate the performance of our approach for two specific machine learning problems, i.e., the estimation of the group-sparsity structure in regression problems and the data distillation problem. The reported results show that our method is competitive with state-of-the-art approaches based on relaxation and rounding
format Preprint
id arxiv_https___arxiv_org_abs_2308_10711
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Relax and penalize: a new bilevel approach to mixed-binary hyperparameter optimization
Venturini, Sara
de Santis, Marianna
Patracone, Jordan
Rinaldi, Francesco
Salzo, Saverio
Schmidt, Martin
Machine Learning
In recent years, bilevel approaches have become very popular to efficiently estimate high-dimensional hyperparameters of machine learning models. However, to date, binary parameters are handled by continuous relaxation and rounding strategies, which could lead to inconsistent solutions. In this context, we tackle the challenging optimization of mixed-binary hyperparameters by resorting to an equivalent continuous bilevel reformulation based on an appropriate penalty term. We propose an algorithmic framework that, under suitable assumptions, is guaranteed to provide mixed-binary solutions. Moreover, the generality of the method allows to safely use existing continuous bilevel solvers within the proposed framework. We evaluate the performance of our approach for two specific machine learning problems, i.e., the estimation of the group-sparsity structure in regression problems and the data distillation problem. The reported results show that our method is competitive with state-of-the-art approaches based on relaxation and rounding
title Relax and penalize: a new bilevel approach to mixed-binary hyperparameter optimization
topic Machine Learning
url https://arxiv.org/abs/2308.10711