Let's say I had an arbitrarily shaped permanent magnet, with total magnetic moment $M_{0}$. Ways to calculate the magnetic field of this magnet include an analytic solution (if one exists), as well as finite element modeling.
Now lets say I wish to calculate the magnetic field if this arbitrarily shaped magnet by replacing it with $N$ identical magnetic dipoles, each with magnetic moment $\frac{M_{0}}{N}$. I then calculate the magnetic field at a point by considering the magnetic field from each of these $N$ magnetic dipoles.
What would you call such a method? I'm sure someone has described this in the literature, I just can't seem to find any references.