Exact_diagonalization

The simplest calculation is to diagonalize the discretized Hamliltonian to obtain the energy levels and eigenfunctions, and to compute e.g. the Inverse Participation Ratio or to study multifractality.

There are two methods : lapack for full diagonalization (scales as the cube of the matrix dimension) with all eigenpairs and sparse which computes few eigenvalues near a targeted energy.

This is only for non-interacting systems.