A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal Distributions

We present a simple method to approximate the Fisher–Rao distance between multivariate normal distributions based on discretizing curves joining normal distributions and approximating the Fisher–Rao distances between successive nearby normal distributions on the curves by the square roots of their J...

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Main Author: Frank Nielsen
Format: Article
Language:English
Published: MDPI AG 2023-04-01
Series:Entropy
Subjects:
Online Access:https://www.mdpi.com/1099-4300/25/4/654
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author Frank Nielsen
author_facet Frank Nielsen
author_sort Frank Nielsen
collection DOAJ
description We present a simple method to approximate the Fisher–Rao distance between multivariate normal distributions based on discretizing curves joining normal distributions and approximating the Fisher–Rao distances between successive nearby normal distributions on the curves by the square roots of their Jeffreys divergences. We consider experimentally the linear interpolation curves in the ordinary, natural, and expectation parameterizations of the normal distributions, and compare these curves with a curve derived from the Calvo and Oller’s isometric embedding of the Fisher–Rao <i>d</i>-variate normal manifold into the cone of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><mi>d</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>×</mo><mo>(</mo><mi>d</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow></semantics></math></inline-formula> symmetric positive–definite matrices. We report on our experiments and assess the quality of our approximation technique by comparing the numerical approximations with both lower and upper bounds. Finally, we present several information–geometric properties of Calvo and Oller’s isometric embedding.
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spelling doaj.art-5a01b92c70e543b5ba600d8f8605547c2023-11-17T19:09:11ZengMDPI AGEntropy1099-43002023-04-0125465410.3390/e25040654A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal DistributionsFrank Nielsen0Sony Computer Science Laboratories, Tokyo 141-0022, JapanWe present a simple method to approximate the Fisher–Rao distance between multivariate normal distributions based on discretizing curves joining normal distributions and approximating the Fisher–Rao distances between successive nearby normal distributions on the curves by the square roots of their Jeffreys divergences. We consider experimentally the linear interpolation curves in the ordinary, natural, and expectation parameterizations of the normal distributions, and compare these curves with a curve derived from the Calvo and Oller’s isometric embedding of the Fisher–Rao <i>d</i>-variate normal manifold into the cone of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><mi>d</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>×</mo><mo>(</mo><mi>d</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow></semantics></math></inline-formula> symmetric positive–definite matrices. We report on our experiments and assess the quality of our approximation technique by comparing the numerical approximations with both lower and upper bounds. Finally, we present several information–geometric properties of Calvo and Oller’s isometric embedding.https://www.mdpi.com/1099-4300/25/4/654Fisher–Rao normal manifoldsymmetric positive–definite matrix coneisometric embeddinginformation geometryexponential familyelliptical distribution
spellingShingle Frank Nielsen
A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal Distributions
Entropy
Fisher–Rao normal manifold
symmetric positive–definite matrix cone
isometric embedding
information geometry
exponential family
elliptical distribution
title A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal Distributions
title_full A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal Distributions
title_fullStr A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal Distributions
title_full_unstemmed A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal Distributions
title_short A Simple Approximation Method for the Fisher–Rao Distance between Multivariate Normal Distributions
title_sort simple approximation method for the fisher rao distance between multivariate normal distributions
topic Fisher–Rao normal manifold
symmetric positive–definite matrix cone
isometric embedding
information geometry
exponential family
elliptical distribution
url https://www.mdpi.com/1099-4300/25/4/654
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