Approximating $f$-Divergences with Rank Statistics

Fuente: arXiv
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Main Authors: Stein, Viktor, de Frutos, José Manuel
Format: Preprint
Published: 2026
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_version_ 1866916073194913792
author Stein, Viktor
de Frutos, José Manuel
author_facet Stein, Viktor
de Frutos, José Manuel
contents We introduce a rank-statistic approximation of $f$-divergences that avoids explicit density-ratio estimation by working directly with the distribution of ranks. For a resolution parameter $K$, we map the mismatch between two univariate distributions $μ$ and $ν$ to a rank histogram on $\{ 0, \ldots, K\}$ and measure its deviation from uniformity via a discrete $f$-divergence, yielding a rank-statistic divergence estimator. We prove that the resulting estimator of the divergence is monotone in $K$, is always a lower bound of the true $f$-divergence, and we establish quantitative convergence rates for $K\to\infty$ under mild regularity of the quantile-domain density ratio. To handle high-dimensional data, we define the sliced rank-statistic $f$-divergence by averaging the univariate construction over random projections, and we provide convergence results for the sliced limit as well. We also derive finite-sample deviation bounds along with asymptotic normality results for the estimator. Finally, we empirically validate the approach by benchmarking against neural baselines and illustrating its use as a learning objective in generative modeling experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2601_22784
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Approximating $f$-Divergences with Rank Statistics
Stein, Viktor
de Frutos, José Manuel
Machine Learning
65C20 (Primary) 68T07, 94A15, 62G30, 62F07, 62Gxx, 94A17 (Secondary)
We introduce a rank-statistic approximation of $f$-divergences that avoids explicit density-ratio estimation by working directly with the distribution of ranks. For a resolution parameter $K$, we map the mismatch between two univariate distributions $μ$ and $ν$ to a rank histogram on $\{ 0, \ldots, K\}$ and measure its deviation from uniformity via a discrete $f$-divergence, yielding a rank-statistic divergence estimator. We prove that the resulting estimator of the divergence is monotone in $K$, is always a lower bound of the true $f$-divergence, and we establish quantitative convergence rates for $K\to\infty$ under mild regularity of the quantile-domain density ratio. To handle high-dimensional data, we define the sliced rank-statistic $f$-divergence by averaging the univariate construction over random projections, and we provide convergence results for the sliced limit as well. We also derive finite-sample deviation bounds along with asymptotic normality results for the estimator. Finally, we empirically validate the approach by benchmarking against neural baselines and illustrating its use as a learning objective in generative modeling experiments.
title Approximating $f$-Divergences with Rank Statistics
topic Machine Learning
65C20 (Primary) 68T07, 94A15, 62G30, 62F07, 62Gxx, 94A17 (Secondary)
url https://arxiv.org/abs/2601.22784