GhostUMAP2: Measuring and Analyzing (r,d)-Stability of UMAP

Fuente: arXiv
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Main Authors: Jung, Myeongwon, Fujiwara, Takanori, Jo, Jaemin
Format: Preprint
Published: 2025
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author Jung, Myeongwon
Fujiwara, Takanori
Jo, Jaemin
author_facet Jung, Myeongwon
Fujiwara, Takanori
Jo, Jaemin
contents Despite the widespread use of Uniform Manifold Approximation and Projection (UMAP), the impact of its stochastic optimization process on the results remains underexplored. We observed that it often produces unstable results where the projections of data points are determined mostly by chance rather than reflecting neighboring structures. To address this limitation, we introduce (r,d)-stability to UMAP: a framework that analyzes the stochastic positioning of data points in the projection space. To assess how stochastic elements, specifically initial projection positions and negative sampling, impact UMAP results, we introduce "ghosts", or duplicates of data points representing potential positional variations due to stochasticity. We define a data point's projection as (r,d)-stable if its ghosts perturbed within a circle of radius r in the initial projection remain confined within a circle of radius d for their final positions. To efficiently compute the ghost projections, we develop an adaptive dropping scheme that reduces a runtime up to 60% compared to an unoptimized baseline while maintaining approximately 90% of unstable points. We also present a visualization tool that supports the interactive exploration of the (r,d)-stability of data points. Finally, we demonstrate the effectiveness of our framework by examining the stability of projections of real-world datasets and present usage guidelines for the effective use of our framework.
format Preprint
id arxiv_https___arxiv_org_abs_2507_17174
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle GhostUMAP2: Measuring and Analyzing (r,d)-Stability of UMAP
Jung, Myeongwon
Fujiwara, Takanori
Jo, Jaemin
Graphics
Human-Computer Interaction
Machine Learning
Despite the widespread use of Uniform Manifold Approximation and Projection (UMAP), the impact of its stochastic optimization process on the results remains underexplored. We observed that it often produces unstable results where the projections of data points are determined mostly by chance rather than reflecting neighboring structures. To address this limitation, we introduce (r,d)-stability to UMAP: a framework that analyzes the stochastic positioning of data points in the projection space. To assess how stochastic elements, specifically initial projection positions and negative sampling, impact UMAP results, we introduce "ghosts", or duplicates of data points representing potential positional variations due to stochasticity. We define a data point's projection as (r,d)-stable if its ghosts perturbed within a circle of radius r in the initial projection remain confined within a circle of radius d for their final positions. To efficiently compute the ghost projections, we develop an adaptive dropping scheme that reduces a runtime up to 60% compared to an unoptimized baseline while maintaining approximately 90% of unstable points. We also present a visualization tool that supports the interactive exploration of the (r,d)-stability of data points. Finally, we demonstrate the effectiveness of our framework by examining the stability of projections of real-world datasets and present usage guidelines for the effective use of our framework.
title GhostUMAP2: Measuring and Analyzing (r,d)-Stability of UMAP
topic Graphics
Human-Computer Interaction
Machine Learning
url https://arxiv.org/abs/2507.17174