GPU-Accelerated Bregman Douglas–Rachford Splitting for Discrete Optimal Transport

We present GPU-accelerated Bregman Douglas–Rachford splitting algorithm (BDRS) for discrete optimal transport problem in three input formats: an explicit cost matrix, a point cloud with a ground cost between them, and a separable cost on a regular grid. For each input format, we propose hardware-aware designs of mathematically equivalent representations for the BDRS iterations to … Read more

BDRS Can Fail for Matrix Scaling and Optimal Transport

We show that the Bregman Douglas–Rachford splitting method (BDRS) can fail for matrix scaling and unregularized optimal transport. For matrix scaling, we construct a strictly positive \(36\times6\) integer matrix, positive rational marginals of equal mass, and a positive auxiliary initialization for which the matrix iterates enter a nonconstant six-cycle after one iteration. The construction prescribes … Read more