On the Wasserstein Geodesic Principal Component Analysis of probability measures

ICLR 2026 Conference SubmissionAnonymous Authors
wasserstein PCAoptimal transportdeep learning
Abstract:

This paper focuses on Geodesic Principal Component Analysis (GPCA) on a collection of probability distributions using the Otto-Wasserstein geometry. The goal is to identify geodesic curves in the space of probability measures that best capture the modes of variation of the underlying dataset. We first address the case of a collection of Gaussian distributions, and show how to lift the computations in the space of invertible linear maps. For the more general setting of absolutely continuous probability measures, we leverage a novel approach to parameterizing geodesics in Wasserstein space with neural networks. Finally, we compare to classical tangent PCA through various examples and provide illustrations on real-world datasets.

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Overview

Overall Novelty Assessment

The paper develops geodesic principal component analysis for probability distributions in Otto-Wasserstein space, addressing both Gaussian collections via Bures-Wasserstein geometry and general absolutely continuous measures through neural network parameterization. It resides in the 'Geodesic PCA Theory and Consistency' leaf alongside three sibling papers, forming a small but foundational cluster within the broader taxonomy of 28 papers across 17 leaf nodes. This leaf sits at the core of 'Theoretical Foundations and Methodological Development', indicating the work occupies a central but not overcrowded research direction focused on establishing rigorous properties of geodesic PCA.

The taxonomy reveals neighboring leaves addressing alternative PCA formulations: 'Convex PCA and Constrained Formulations' explores Hilbert space constraints, 'Projected and Representation-Based Methods' uses tangent space projections, and 'Comparative Analysis of PCA Variants' contrasts geodesic with log-PCA approaches. The paper's position suggests it contributes to the foundational geodesic framework rather than projection-based or convex alternatives. Sibling papers in the same leaf establish consistency and convergence properties, while the broader 'Computational Methods' branch addresses algorithmic efficiency—indicating the paper bridges theoretical development with practical implementation concerns through its neural network approach.

Among 17 candidates examined across three contributions, the Gaussian GPCA algorithm (4 candidates, 0 refutable) and theoretical equivalence result (3 candidates, 0 refutable) appear relatively novel within the limited search scope. The neural network parameterization contribution (10 candidates, 1 refutable) shows more substantial prior work overlap, with one candidate providing overlapping methodology. The statistics suggest the Gaussian-specific methods may represent more distinctive contributions, though the modest search scale (17 total candidates) means these findings reflect top semantic matches rather than exhaustive coverage of the field's approximately 28 documented papers.

Based on the limited literature search covering roughly 60% of the taxonomy's documented papers, the work appears to make incremental but meaningful contributions to geodesic PCA theory. The Gaussian case and theoretical results show less prior overlap, while the neural network approach connects to existing computational frameworks. The taxonomy structure indicates this is a moderately active research area with clear boundaries separating geodesic, convex, and projection-based methods, though the search scope precludes definitive novelty claims.

Taxonomy

Core-task Taxonomy Papers
28
3
Claimed Contributions
17
Contribution Candidate Papers Compared
1
Refutable Paper

Research Landscape Overview

Core task: Geodesic principal component analysis of probability measures using Wasserstein geometry. This field extends classical dimensionality reduction to spaces of probability distributions by leveraging the Wasserstein metric and its associated geodesic structure. The taxonomy reveals a rich landscape organized around several complementary themes. Theoretical Foundations and Methodological Development establishes the mathematical underpinnings of geodesic PCA in Wasserstein space, including consistency guarantees and convergence properties. Computational Methods and Algorithmic Implementations addresses the practical challenges of computing geodesics and principal components efficiently, often through discretization or approximation schemes. Domain-Specific Geometries and Extensions explores adaptations to specialized settings such as circular or functional data, while Clustering and Unsupervised Learning applies Wasserstein geometry to grouping and center-finding problems. Applications and Domain-Specific Implementations demonstrate the utility of these methods in areas like flow cytometry and portfolio theory, and Related Theoretical Topics and Extensions connect to broader questions in optimal transport and statistical learning. A particularly active line of work focuses on the interplay between geodesic and tangent-space approaches to PCA on probability measures. Early foundational studies such as Principal Geodesic Analysis[5] and Geodesic PCA Convex[13] laid the groundwork for understanding how principal geodesics capture variability in non-Euclidean spaces, while later works like Geodesic versus Log-PCA[10] and Geodesic PCA Wasserstein[20] have clarified trade-offs between geodesic methods and log-map-based alternatives. The original paper Wasserstein Geodesic PCA[0] sits squarely within this theoretical core, contributing to the rigorous development of geodesic PCA theory and consistency results. Its emphasis on foundational properties aligns closely with Geodesic PCA Convex[13] and Geodesic PCA Wasserstein[20], yet it also engages with the broader methodological questions that distinguish geodesic from tangent-space projections. Meanwhile, parallel branches explore robust variants, kernel extensions, and clustering formulations, reflecting the field's ongoing effort to balance mathematical elegance with computational feasibility and domain-specific demands.

Claimed Contributions

GPCA algorithm for centered Gaussian distributions using Bures-Wasserstein geometry

The authors develop an exact algorithm for Geodesic Principal Component Analysis on centered Gaussian distributions by lifting computations to the space of invertible linear maps, leveraging the Bures-Wasserstein geometry to avoid linearization approximations.

4 retrieved papers
GPCA algorithm for absolutely continuous probability measures using neural network parameterization

The authors propose an exact GPCA method for general absolutely continuous probability measures by parameterizing geodesics in Wasserstein space with multilayer perceptrons, lifting distributions to the space of maps that pushforward a reference measure following Otto's construction.

10 retrieved papers
Can Refute
Theoretical result on equivalence of GPCA for univariate Gaussians

The authors establish a theoretical result showing that for one-dimensional Gaussian distributions, performing GPCA in the full space of absolutely continuous distributions produces identical results to restricting GPCA to the Gaussian submanifold.

3 retrieved papers

Core Task Comparisons

Comparisons with papers in the same taxonomy category

Contribution Analysis

Detailed comparisons for each claimed contribution

Contribution

GPCA algorithm for centered Gaussian distributions using Bures-Wasserstein geometry

The authors develop an exact algorithm for Geodesic Principal Component Analysis on centered Gaussian distributions by lifting computations to the space of invertible linear maps, leveraging the Bures-Wasserstein geometry to avoid linearization approximations.

Contribution

GPCA algorithm for absolutely continuous probability measures using neural network parameterization

The authors propose an exact GPCA method for general absolutely continuous probability measures by parameterizing geodesics in Wasserstein space with multilayer perceptrons, lifting distributions to the space of maps that pushforward a reference measure following Otto's construction.

Contribution

Theoretical result on equivalence of GPCA for univariate Gaussians

The authors establish a theoretical result showing that for one-dimensional Gaussian distributions, performing GPCA in the full space of absolutely continuous distributions produces identical results to restricting GPCA to the Gaussian submanifold.

On the Wasserstein Geodesic Principal Component Analysis of probability measures | Novelty Validation