  Computer modelling of the integer quantum Hall effect based on
self-consistent Hartee-Fock calculations has now reached an astonishing level
of maturity. Spatially-resolved studies of the electron density at near
macroscopic system sizes of up to $\sim 1\ \mu m^2$ reveal self-organized
clusters of locally fully filled and locally fully depleted Landau levels
depending on which spin polarization is favoured. The behaviour results, for
strong disorders, in an exchange-interaction induced $g$-factor enhancement
and, ultimately, gives rise to narrow transport channels, including the
celebrated narrow edge channels. For weak disorder, we find that bubble and
stripes phases emerge with characteristics that predict experimental results
very well. Hence the HF approach has become a convenient numerical basis to
\emph{quantitatively} study the quantum Hall effects, superseding previous more
qualitative approaches.
