arXiv:2410.12176cs.LGmath.MG2024-10ICLR被引 18

提出一种新方法,让切片最优传输生成可解释的搬运方案。

Expected Sliced Transport Plans

  • 通过期望提升技术,将一维搬运计划还原为高维空间的完整搬运方案。
  • 用该方案加权计算的总成本,能构成两个概率分布间的有效度量。
  • 适合需要可解释搬运路径的生成模型、图像配准等任务。

最优传输(OT)在现代机器学习中备受关注,因其能提供如Wasserstein距离等灵活度量,并确定概率分布间的最优耦合。为降低OT求解的计算复杂度,已提出熵正则化和切片最优传输等方法。切片OT通过比较高维分布的一维投影(切片)来提升效率,但其缺乏输入分布间的显式搬运计划,限制了在需具体耦合场景中的应用。本文解决两个核心问题:能否在切片框架下构建两概率测度间的搬运计划?若能,该计划能否定义一个有效度量?我们提出一种“提升”操作,将一维最优传输计划映射回原始空间。通过对这些提升计划取期望,得到新的搬运计划,称为期望切片运输(EST)计划。证明了使用该计划加权各点间欧氏距离之和,可构造出离散概率测度间有效的度量。我们还揭示了本方法与近期提出的min-SWGG之间的联系,并通过数值示例验证了理论结果。

原文摘要 · Abstract (English)

The optimal transport (OT) problem has gained significant traction in modern machine learning for its ability to: (1) provide versatile metrics, such as Wasserstein distances and their variants, and (2) determine optimal couplings between probability measures. To reduce the computational complexity of OT solvers, methods like entropic regularization and sliced optimal transport have been proposed. The sliced OT framework improves efficiency by comparing one-dimensional projections (slices) of high-dimensional distributions. However, despite their computational efficiency, sliced-Wasserstein approaches lack a transportation plan between the input measures, limiting their use in scenarios requiring explicit coupling. In this paper, we address two key questions: Can a transportation plan be constructed between two probability measures using the sliced transport framework? If so, can this plan be used to define a metric between the measures? We propose a "lifting" operation to extend one-dimensional optimal transport plans back to the original space of the measures. By computing the expectation of these lifted plans, we derive a new transportation plan, termed expected sliced transport (EST) plans. We prove that using the EST plan to weight the sum of the individual Euclidean costs for moving from one point to another results in a valid metric between the input discrete probability measures. We demonstrate the connection between our approach and the recently proposed min-SWGG, along with illustrative numerical examples that support our theoretical findings.

最优传输切片方法度量学习

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