Improved stability for LCAO with orbital-dependent functionals for magnetic systems.

Description

In case of orbital-dependent functionals, we now force the code to do an normal calculation, but we avoid completely the orbital-dependent terms. The kinetic energy density is hence obtained from the GEA expansion, keeping only the lowest two terms, i.e., the Thomas-Fermi kinetic energy density plus 1/9 times the von Weizsacker kinetic energy density.

This avoids getting wrong results for magnetic systems, as otherwise the magnetization was not constrained, and improves the convergence of mGGA functionals.

News snippet

Improved stability for LCAO with orbital-dependent functionals for magnetic systems.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.