Spectral density fitter for few-mode quantization

This package can be used to perform few-mode quantization for multiple emitters with arbitrary spectral densities as presented in

1. Few-Mode Field Quantization of Arbitrary Electromagnetic Spectral Densities, I. Medina, F. J. García-Vidal, A. I. Fernández-Domínguez, and J. Feist, Phys. Rev. Lett. 126, 093601 (2021)
2. Few-mode field quantization for multiple emitters, M. Sánchez-Barquilla, F. J. García-Vidal, A. I. Fernández-Domínguez, and J. Feist, Nanophotonics 11, 4363 (2022)

It is currently functional, but documentation is missing. To install, run

pip install git+https://github.com/jfeist/spectral_density_fit

NOTE that spectral_density_fit recently changed from forcing 64-bit mode for jax (which the code uses to get the gradients of the function to minimize in the fit, and to support running on GPUs) to not touching the configuration automatically. In practice, it is likely that you want to use 64-bit precision for the fitting, to do so, you need to run, before any other calculations, the following:

import jax
jax.config.update("jax_enable_x64", True)

If you want to develop the package, we recommend using uv to manage the project and dependencies. In particular, after checking out the git repository, you can simply run uv run pytest to run the tests, and uv run ruff check or uv run ruff format to lint and format the code.