Is the convergence considered for the denxity matrix or the charge density?

[xhsh]

In siesta, the convergence is considered for the density matrix. In ATK, is it considered for density matrix or the charge density at each point in the real space? Thanks a lot.

[Nordland]

The hamiltonian. However the density matrix is always converged to same degree or better than the Hamiltonian when the Hamiltonian is converged.

[xhsh]

Thanks!

I want to further ask about the density matrix. For a two-probe system with different electrodes, how is the total charge calculated? By the formula Q=Tr(DS) (where D is the density matrix and S is the basis overlap matrix), just like in Siesta? Or just by integrating the electron density in the real space?

[Nordland]

Ahh, it is the older version?

Yes, the charge is calculated as the trace of the density matrix and the overlap.