Variance-Reducing Couplings for Random Features

Fuente: arXiv
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Main Authors: Reid, Isaac, Markou, Stratis, Choromanski, Krzysztof, Turner, Richard E., Weller, Adrian
Format: Preprint
Published: 2024
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author Reid, Isaac
Markou, Stratis
Choromanski, Krzysztof
Turner, Richard E.
Weller, Adrian
author_facet Reid, Isaac
Markou, Stratis
Choromanski, Krzysztof
Turner, Richard E.
Weller, Adrian
contents Random features (RFs) are a popular technique to scale up kernel methods in machine learning, replacing exact kernel evaluations with stochastic Monte Carlo estimates. They underpin models as diverse as efficient transformers (by approximating attention) to sparse spectrum Gaussian processes (by approximating the covariance function). Efficiency can be further improved by speeding up the convergence of these estimates: a variance reduction problem. We tackle this through the unifying lens of optimal transport, finding couplings to improve RFs defined on both Euclidean and discrete input spaces. They enjoy theoretical guarantees and sometimes provide strong downstream gains, including for scalable approximate inference on graphs. We reach surprising conclusions about the benefits and limitations of variance reduction as a paradigm, showing that other properties of the coupling should be optimised for attention estimation in efficient transformers.
format Preprint
id arxiv_https___arxiv_org_abs_2405_16541
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Variance-Reducing Couplings for Random Features
Reid, Isaac
Markou, Stratis
Choromanski, Krzysztof
Turner, Richard E.
Weller, Adrian
Machine Learning
Random features (RFs) are a popular technique to scale up kernel methods in machine learning, replacing exact kernel evaluations with stochastic Monte Carlo estimates. They underpin models as diverse as efficient transformers (by approximating attention) to sparse spectrum Gaussian processes (by approximating the covariance function). Efficiency can be further improved by speeding up the convergence of these estimates: a variance reduction problem. We tackle this through the unifying lens of optimal transport, finding couplings to improve RFs defined on both Euclidean and discrete input spaces. They enjoy theoretical guarantees and sometimes provide strong downstream gains, including for scalable approximate inference on graphs. We reach surprising conclusions about the benefits and limitations of variance reduction as a paradigm, showing that other properties of the coupling should be optimised for attention estimation in efficient transformers.
title Variance-Reducing Couplings for Random Features
topic Machine Learning
url https://arxiv.org/abs/2405.16541