layeroptics

WIP

Roadmap

Implement computation of transfer matrices.
Write flake.nix.
Decide on how to implement in/out field subspaces (Grassmanians).
Implement reflection, transmission computation.
Meditate on numerical stability, especially with relation to 2.
Write examples and docs.
Release 1.0, publish to PyPI.
Implement magnetic anisotropy models, Stoner-Wohlfarth.
Implement JAX backend.
Release 2.0.