Generative Modeling on Metric Graphs via Neural Optimal Transport
This work addresses the lack of deep generative models for continuous distributions on metric graphs, which is relevant for applications like urban mobility and network analysis.
The paper introduces the first deep generative model for probability distributions on metric graphs, using neural optimal transport with graph embeddings. It achieves competitive or better performance than discrete graph OT baselines and scales to one million Uber pickup locations in Manhattan.
We introduce, to our knowledge, the first deep generative modeling framework for probability distributions continuously supported on compact metric graphs. Given source and target measures on a metric graph, our method embeds the graph into a smooth ambient space, solves an entropic Kantorovich problem via a neural semidual parameterization, and projects generated samples back onto the original graph. We study two embedded geometries: an extrinsic Euclidean realization and the intrinsic tropical Abel--Jacobi embedding into the Jacobian torus. In both cases, the resulting generator is graph-supported by construction. We prove that, in the joint limit of increasing neural expressivity, the learned generator converges weakly to a valid transport coupling between the original graph measures. Empirically, across a range of geometrically distinct graphs, our method matches or improves upon heuristic transport baselines based on discrete graph OT, while scaling more favorably. Finally, we demonstrate scalability on real-world urban mobility data by training our model on one million Uber pickup locations in Manhattan, New York City.