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Roadmap ​

What we are working on. Nothing on this page is available yet: names and interfaces may still change.

Ground metrics ​

  • Periodic metrics, beyond Ground Metrics: the CUDA solve with rotations and symmetries or an image that is not a constant, 1D ( the circle ).
  • Partial transport, beyond Ground Metrics: a source heavier than the target, the penalized variant ( a sink of fixed weight ), 3D, gaussian targets, an image on the card, the card's own linear solver for the bordered system.
  • Radial kernels: costs built from radial functions of ∥x−y∥, e.g. polynomials, piecewise functions... Beyond RadialExp ( Fokker-Planck ): 3D, the card, other densities than constant pieces, with a periodicity or a sink.

Derivatives ​

  • Aggregates with a periodicity: duplicates and close seeds in a periodic domain.
  • The frame of a target through a periodicity or in partial transport, and the nodes of a mesh.

Distributions ​

  • PolynomialCells: piecewise polynomial densities on a polyhedral cell decomposition, the most general target.

Tomography ​

  • Anisotropic tents on the card, with with_gradient, and in 3D from 2D projections ( Projected Sources ).

Parallel runs ​

Beyond Running in Parallel:

  • Derivatives of the measures, the cells travelling again in the backward pass.
  • The boxes made by the ranks: the seeds redistributed by exchanges instead of on the host, any number of seeds and of ranks.
  • More than the measures: moments, the transport itself ( a distributed Newton ), 3D, densities split like the boxes.
  • Out of core: more boxes than ranks, the boxes that do not fit kept in host memory or on disk ( dask or zarr arrays as inputs ).
  • Speed: loom.route and loom.scatter_add in parallel, irregular exchanges on GPUs, runs on several GPUs and nodes.

Norms ​

  • W1, ...

Examples in progress ​

  • Crowd motion: congested crowds as a Wasserstein gradient flow.
  • Incompressible Euler: geodesics in the space of measure-preserving maps ( Gallouët-Mérigot scheme ).
  • Fokker-Planck: Wasserstein gradient flow of entropy plus potential energy.

SDOT — H. Leclerc, Q. Mérigot, T. Gallouët · LMO / INRIA PARMA