Efficient Estimation of the Central Mean Subspace via Smoothed Gradient Outer Products

Fuente: arXiv
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Autori principali: Yuan, Gan, Xu, Mingyue, Kpotufe, Samory, Hsu, Daniel
Natura: Preprint
Pubblicazione: 2023
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author Yuan, Gan
Xu, Mingyue
Kpotufe, Samory
Hsu, Daniel
author_facet Yuan, Gan
Xu, Mingyue
Kpotufe, Samory
Hsu, Daniel
contents We consider the problem of sufficient dimension reduction (SDR) for multi-index models. The estimators of the central mean subspace in prior works either have slow (non-parametric) convergence rates, or rely on stringent distributional conditions (e.g., the covariate distribution $P_{\mathbf{X}}$ being elliptical symmetric). In this paper, we show that a fast parametric convergence rate of form $C_d \cdot n^{-1/2}$ is achievable via estimating the \emph{expected smoothed gradient outer product}, for a general class of distribution $P_{\mathbf{X}}$ admitting Gaussian or heavier distributions. When the link function is a polynomial with a degree of at most $r$ and $P_{\mathbf{X}}$ is the standard Gaussian, we show that the prefactor depends on the ambient dimension $d$ as $C_d \propto d^r$.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15469
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Efficient Estimation of the Central Mean Subspace via Smoothed Gradient Outer Products
Yuan, Gan
Xu, Mingyue
Kpotufe, Samory
Hsu, Daniel
Machine Learning
Methodology
62B05, 62G08
We consider the problem of sufficient dimension reduction (SDR) for multi-index models. The estimators of the central mean subspace in prior works either have slow (non-parametric) convergence rates, or rely on stringent distributional conditions (e.g., the covariate distribution $P_{\mathbf{X}}$ being elliptical symmetric). In this paper, we show that a fast parametric convergence rate of form $C_d \cdot n^{-1/2}$ is achievable via estimating the \emph{expected smoothed gradient outer product}, for a general class of distribution $P_{\mathbf{X}}$ admitting Gaussian or heavier distributions. When the link function is a polynomial with a degree of at most $r$ and $P_{\mathbf{X}}$ is the standard Gaussian, we show that the prefactor depends on the ambient dimension $d$ as $C_d \propto d^r$.
title Efficient Estimation of the Central Mean Subspace via Smoothed Gradient Outer Products
topic Machine Learning
Methodology
62B05, 62G08
url https://arxiv.org/abs/2312.15469