Quadratic Eigenvalue Problem


I have a question on implementing Quadratic Eigenvalue Problem (QEP) in Netgen.

To solve the QEP, as I know, first I need to convert the QEP to the Linear Eigenvalue Problem which it will be in the form of Generalized Eigenvalue Problem (GEP) . In fact, if we consider f is the actual eigenfunction, a function g=lambda*f must be defined to reduce the QEP to GEP. Then I have an eigenpair of (lambda, u) where u = (f,g). Then I think this equivalent equation is solvable by Netgen. But I don’t know how to find the actual eigenfunction f. Any idea would be really appreciated. Thanks.