论文标题

用欧拉粒子传输的生成学习

Generative Learning With Euler Particle Transport

论文作者

Gao, Yuan, Huang, Jian, Jiao, Yuling, Liu, Jin, Lu, Xiliang, Yang, Zhijian

论文摘要

我们提出了一种用于生成学习的欧拉粒子传输(EPT)方法。提出的方法是由找到从参考分布到以Monge-Ampere方程为特征的目标分布的最佳传输图的问题。从测量空间中的梯度流的角度来解释Monge-Ampere方程的无限线性化导致随机的McKean-Vlasov方程。我们使用正向Euler方法来求解该方程。由此产生的前进Euler地图将参考分布推向目标。该地图是一系列简单残差图的组成,它们在计算上稳定且易于训练。训练的关键任务是对确定残差图的密度比或差异的估计。我们使用深度密度比率(差)拟合,根据布雷格曼的差异来估计密度比(差异)。我们表明,如果在较低维歧管上支持数据,则提出的密度比率(差)估计器不会遭受“维度诅咒”。具有多模式合成数据集的数值实验以及与实际基准数据集上现有方法的比较支持我们的理论结果,并证明了该方法的有效性。

We propose an Euler particle transport (EPT) approach for generative learning. The proposed approach is motivated by the problem of finding an optimal transport map from a reference distribution to a target distribution characterized by the Monge-Ampere equation. Interpreting the infinitesimal linearization of the Monge-Ampere equation from the perspective of gradient flows in measure spaces leads to a stochastic McKean-Vlasov equation. We use the forward Euler method to solve this equation. The resulting forward Euler map pushes forward a reference distribution to the target. This map is the composition of a sequence of simple residual maps, which are computationally stable and easy to train. The key task in training is the estimation of the density ratios or differences that determine the residual maps. We estimate the density ratios (differences) based on the Bregman divergence with a gradient penalty using deep density-ratio (difference) fitting. We show that the proposed density-ratio (difference) estimators do not suffer from the "curse of dimensionality" if data is supported on a lower-dimensional manifold. Numerical experiments with multi-mode synthetic datasets and comparisons with the existing methods on real benchmark datasets support our theoretical results and demonstrate the effectiveness of the proposed method.

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