Approximation Rates and VC-Dimension Bounds for (P)ReLU MLP Mixture of Experts

Fuente: arXiv
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Autores principales: Kratsios, Anastasis, Borde, Haitz Sáez de Ocáriz, Furuya, Takashi, Law, Marc T.
Formato: Preprint
Publicado: 2024
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author Kratsios, Anastasis
Borde, Haitz Sáez de Ocáriz
Furuya, Takashi
Law, Marc T.
author_facet Kratsios, Anastasis
Borde, Haitz Sáez de Ocáriz
Furuya, Takashi
Law, Marc T.
contents Mixture-of-Experts (MoEs) can scale up beyond traditional deep learning models by employing a routing strategy in which each input is processed by a single "expert" deep learning model. This strategy allows us to scale up the number of parameters defining the MoE while maintaining sparse activation, i.e., MoEs only load a small number of their total parameters into GPU VRAM for the forward pass depending on the input. In this paper, we provide an approximation and learning-theoretic analysis of mixtures of expert MLPs with (P)ReLU activation functions. We first prove that for every error level $\varepsilon>0$ and every Lipschitz function $f:[0,1]^n\to \mathbb{R}$, one can construct a MoMLP model (a Mixture-of-Experts comprising of (P)ReLU MLPs) which uniformly approximates $f$ to $\varepsilon$ accuracy over $[0,1]^n$, while only requiring networks of $\mathcal{O}(\varepsilon^{-1})$ parameters to be loaded in memory. Additionally, we show that MoMLPs can generalize since the entire MoMLP model has a (finite) VC dimension of $\tilde{O}(L\max\{nL,JW\})$, if there are $L$ experts and each expert has a depth and width of $J$ and $W$, respectively.
format Preprint
id arxiv_https___arxiv_org_abs_2402_03460
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Approximation Rates and VC-Dimension Bounds for (P)ReLU MLP Mixture of Experts
Kratsios, Anastasis
Borde, Haitz Sáez de Ocáriz
Furuya, Takashi
Law, Marc T.
Machine Learning
Numerical Analysis
Neural and Evolutionary Computing
Combinatorics
Mixture-of-Experts (MoEs) can scale up beyond traditional deep learning models by employing a routing strategy in which each input is processed by a single "expert" deep learning model. This strategy allows us to scale up the number of parameters defining the MoE while maintaining sparse activation, i.e., MoEs only load a small number of their total parameters into GPU VRAM for the forward pass depending on the input. In this paper, we provide an approximation and learning-theoretic analysis of mixtures of expert MLPs with (P)ReLU activation functions. We first prove that for every error level $\varepsilon>0$ and every Lipschitz function $f:[0,1]^n\to \mathbb{R}$, one can construct a MoMLP model (a Mixture-of-Experts comprising of (P)ReLU MLPs) which uniformly approximates $f$ to $\varepsilon$ accuracy over $[0,1]^n$, while only requiring networks of $\mathcal{O}(\varepsilon^{-1})$ parameters to be loaded in memory. Additionally, we show that MoMLPs can generalize since the entire MoMLP model has a (finite) VC dimension of $\tilde{O}(L\max\{nL,JW\})$, if there are $L$ experts and each expert has a depth and width of $J$ and $W$, respectively.
title Approximation Rates and VC-Dimension Bounds for (P)ReLU MLP Mixture of Experts
topic Machine Learning
Numerical Analysis
Neural and Evolutionary Computing
Combinatorics
url https://arxiv.org/abs/2402.03460