Quasi-Newton methods for nonlinear eigenvalue problems:
quasinewton-2017-02-28.tgz
If you find this useful, please consider citing:
E. Jarlebring, A. Koskela, G. Mele,
Disguised and new Quasi-Newton methods for nonlinear eigenvalue problems
2018, Numer. Algor.
Implementations of methods are also available in NEP-PACK.