arXiv Machine Learning

SOL: Measuring Gaps between Text Distributions by Double Sliced Wasserstein Metrics

The paper introduces SOL, a new metric for measuring gaps between text distributions using double sliced Wasserstein distances. It represents each sequence as an empirical measure of hidden states from a fixed transformer and compares these measures across distributions. The authors prove SOL is a metric when the transformer is injective and demonstrate its effectiveness in detecting distributional failures and recovering expected model trends in experiments on OpenWebText models.

arXiv Computation and Language
Oct 23

Hacking Generative Perplexity: Why Unconditional Text Evaluation Needs New Metrics

The paper critiques generative perplexity (gen‑PPL) as an unreliable metric for evaluating unconditional text generation, showing that it can be minimized by trivial, non‑diverse outputs. The authors demonstrate this by constructing simple samplers that achieve low gen‑PPL yet produce incoherent text, and they propose alternative evaluation tools—including distributional discrepancies, diversity diagnostics, and a compression‑based KL divergence measure—to better assess generative language models. They argue that future progress in diffusion language models should rely on a suite of metrics that capture diverse aspects of generated text quality.

By Antonio Franca, Alexander Tong
arXiv Machine Learning
Oct 16

Vertical Sliced Wasserstein Distances for Meta-Measures

arXiv:2610. 20743v1 Announce Type: new Abstract: Many modern learning problems require comparing probability distributions whose individual observations are themselves probability measures, naturally giving rise to meta-measures in $\mathcal{P}(\mathcal{P}(\Omega))$.

By Elaheh Akbari, Ahmadreza Moradipari, Kyungtae Han, Hamed Pirsiavash, Yikun Bai, Rocio Diaz Martin, Soheil Kolouri
arXiv Statistics ML
Oct 16

Optimal score function estimation via derivatives constraints

The paper develops a statistical framework showing that empirical score matching can achieve minimax optimal performance for diffusion generative models when data lie on a low‑dimensional manifold. It establishes convergence rates for empirical risk minimization over constrained Sobolev classes and demonstrates that the resulting score estimators yield minimax optimal Wasserstein‑1 rates for the generated distribution, up to logarithmic factors. The analysis reveals that the statistical rates depend on the intrinsic dimension of the data manifold rather than its ambient dimension, providing conditions under which score‑based generative modeling generalizes rather than overfits.

By Thomas Bonis, Thanh Mai Pham Ngoc, Viet Chi Tran
arXiv Machine Learning
Aug 18

The Observable Wasserstein Distance

arXiv:2605. 09916v2 Announce Type: replace-cross Abstract: We introduce the observable Wasserstein distance, a framework for deriving lower bounds on the Wasserstein distance between probability measures on Polish metric spaces, designed to bypass the computational intractability of exact optimal transport in large-scale, non-Euclidean datasets.

By Edivaldo Lopes dos Santos, Leandro Vicente Mauri, Washington Mio, Tom Needham
arXiv Statistics ML
Aug 24

Wasserstein Exponential Smoothing for Distributional Time Series Forecasting

The paper introduces Wasserstein Exponential Smoothing (WES), a single‑parameter recursive method for forecasting distributional time series on ℝ. WES updates forecast distributions along Wasserstein geodesics, allowing direct application to empirical distributions without parametric modeling. In high‑frequency equity‑index return and household electricity‑demand data, WES achieves the lowest one‑step‑ahead Wasserstein prediction error among existing benchmarks and is retained in the 90% model confidence set for all 20 series examined.

By Takuo Matsubara, Peiwen Jiang, Minh-Ngoc Tran, Wilson Ye Chen