@feelpp/po a 2D and 3D example (same code thx to c++ templates)  of a generalized eigen value problem A x = lambda B
x where A is the stiffness matrix with 0 Dirichlet condition and B the mass matrix
@feelpp/po create solvereigen section for eigen solver options in config file
[solvereigen]
nev=10 # number of eigenvalues to be computed
ncv=20 # number of converged eigenvalues