OT-Flow Layers

[ChrisRackauckas]

Implementing https://arxiv.org/abs/2006.00104 to complement the FFJORD layers.

Pinging the authors @lruthotto @donken in case they are interested.

[lruthotto]

Thanks. This sounds like a good thrust. Our Julia implementation here may be useful as a starting guess: https://github.com/EmoryMLIP/MFGnet.jl

I won't have time to do much coding myself in the next few weeks, but am happy to discuss and help.