A simple program to calculate the HF/MP2 energy.
I developed this program based on a file of "evaleev/libint/tests/hartree-fock/hartree-fock++.cc". A key difference from "hartree-fock++.cc" is that I used <armadillo> for a linear algebra instead of Eigen. This code will be used in w-pimd (or w-bomd) for the calculation of the partial atomic charges of a molecule (see esp.cc).