  We present a method to correct the magnetic properties of itinerant systems
in local spin density approximation (LSDA) and we apply it to the
ferromagnetic-paramagnetic transition under pressure in a typical itinerant
system, Ni$_{3}$Al. We obtain a scaling of the critical fluctuations as a
function of pressure equivalent to the one obtained within Moryia's theory.
Moreover we show that in this material the role of the bandstructure is crucial
in driving the transition. Finally we calculate the magnetic moment as a
function of pressure, and find that it gives a scaling of the Curie temperature
that is in good agreement with the experiment. The method can be easily
extended to the antiferromagnetic case and applied, for instance, to the
Fe-pnictides in order to correct the LSDA magnetic moment.

Strongly Correlated Electrons;Superconductivity