Simultaneous off-the-grid learning of mixtures issued from a continuous dictionary

Fuente: arXiv
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Autores principales: Butucea, Cristina, Delmas, Jean-François, Dutfoy, Anne, Hardy, Clément
Formato: Preprint
Publicado: 2022
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author Butucea, Cristina
Delmas, Jean-François
Dutfoy, Anne
Hardy, Clément
author_facet Butucea, Cristina
Delmas, Jean-François
Dutfoy, Anne
Hardy, Clément
contents In this paper we observe a set, possibly a continuum, of signals corrupted by noise. Each signal is a finite mixture of an unknown number of features belonging to a continuous dictionary. The continuous dictionary is parametrized by a real non-linear parameter. We shall assume that the signals share an underlying structure by assuming that each signal has its active features included in a finite and sparse set. We formulate regularized optimization problem to estimate simultaneously the linear coefficients in the mixtures and the non-linear parameters of the features. The optimization problem is composed of a data fidelity term and a $(\ell_1,L^p)$-penalty. We call its solution the Group-Nonlinear-Lasso and provide high probability bounds on the prediction error using certificate functions. Following recent works on the geometry of off-the-grid methods, we show that such functions can be constructed provided the parameters of the active features are pairwise separated by a constant with respect to a Riemannian metric.When the number of signals is finite and the noise is assumed Gaussian, we give refinements of our results for $p=1$ and $p=2$ using tail bounds on suprema of Gaussian and $χ^2$ random processes. When $p=2$, our prediction error reaches the rates obtained by the Group-Lasso estimator in the multi-task linear regression model. Furthermore, for $p=2$ these prediction rates are faster than for $p=1$ when all signals share most of the non-linear parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2210_16311
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Simultaneous off-the-grid learning of mixtures issued from a continuous dictionary
Butucea, Cristina
Delmas, Jean-François
Dutfoy, Anne
Hardy, Clément
Machine Learning
Probability
Statistics Theory
In this paper we observe a set, possibly a continuum, of signals corrupted by noise. Each signal is a finite mixture of an unknown number of features belonging to a continuous dictionary. The continuous dictionary is parametrized by a real non-linear parameter. We shall assume that the signals share an underlying structure by assuming that each signal has its active features included in a finite and sparse set. We formulate regularized optimization problem to estimate simultaneously the linear coefficients in the mixtures and the non-linear parameters of the features. The optimization problem is composed of a data fidelity term and a $(\ell_1,L^p)$-penalty. We call its solution the Group-Nonlinear-Lasso and provide high probability bounds on the prediction error using certificate functions. Following recent works on the geometry of off-the-grid methods, we show that such functions can be constructed provided the parameters of the active features are pairwise separated by a constant with respect to a Riemannian metric.When the number of signals is finite and the noise is assumed Gaussian, we give refinements of our results for $p=1$ and $p=2$ using tail bounds on suprema of Gaussian and $χ^2$ random processes. When $p=2$, our prediction error reaches the rates obtained by the Group-Lasso estimator in the multi-task linear regression model. Furthermore, for $p=2$ these prediction rates are faster than for $p=1$ when all signals share most of the non-linear parameters.
title Simultaneous off-the-grid learning of mixtures issued from a continuous dictionary
topic Machine Learning
Probability
Statistics Theory
url https://arxiv.org/abs/2210.16311