The Ritz method can be used to achieve this goal.

The Ritz method is a direct method to find an approximate solution for boundary value problems.

Ritz is also known for the variational method named after him, the Ritz method.

Then the generalised eigenvalue problem of the Ritz method turns into an eigenvalue problem.

The Hartree-Fock method and the Ritz method both apply the variational method.

Some time before I.G.Bubnov developed a similar approach for the variational problem solution, which he interpreted as a variant of Ritz method algorithm.

The Hückel method can be derived from the Ritz method, with a few further assumptions concerning the overlap matrix S and the Hamiltonian matrix H.

If ψ (α) is expressed as a linear combination of other functions (α being the coefficients), as in the Ritz method, there is only one minimum and the problem is straightforward.

Physicist Walther Ritz, who had formulated the Ritz method for analyzing combinations of particles, and who had contributed to the Rydberg formula, died of pleurisy in Göttingen at the age of 31.