Implementation of FORMIDABLE: A generalized differential optical design library with NURBS capabilitiesJean-Baptiste Volatier, Stephane J. Beaussier, Guillaume Druart, Paul Jougla and Fanny KellerJ. Eur. Opt. Society-Rapid Publ., 20 1 (2024) 2DOI: https://doi.org/10.1051/jeos/2023043