QARPACK is short for Quadratic Arnoldi Package. It is a Matlab Toolbox for solution of large sparse quadratic and more general nonlinear eigenvalue problems.
The nonlinear solver nra now supports problems with multiple eigenvalues.
Solver for general nonlinear eigenvalue problems satisfying variational principle or with dominating real or imaginary part.
We renamed the quadratic solver in version v.1.0 from nra to qra, nra is now the general nonlinear solver.
If you have queries about the code or if you have problems using the package drop me an email.