FlashSinkhorn 2: block-sparse GPU solver for large entropic optimal transport
FlashSinkhorn 2 (FS2) is a two-stage GPU solver for squared‑Euclidean entropic optimal transport on low-dimensional point clouds that combines a coarse centroid stage with a block‑sparse fine stage (Morton-ordered blocks, screening, and fused tensor-core execution). The authors report FS2 reaching target marginal residuals on benchmark problems and solving discrete EOT between two 1.34×10^8‑particle measures from a cosmological N‑body simulation on a single NVIDIA A100 to an all-particle marginal residual below 0.01 in under 2.5 hours; an open-source implementation is available at the linked GitHub repository.