I am developing a numerical algorithm to find the ground state of a Hermitian matrix. Obvious applications are quantum many-body systems and particles in various potentials. I am a little stuck with the comparison for the latter example. Could anyone recommend a numerical package to find a ground state of a particle in a simple 3D domain, say, L-shape?
UPDATE: Having read the rules of phys.SE more accurately, I want to emphasise that the question is not about numerical algorithms, but about tools of the trade that people in physics community use and recommend.