  The long-range magnetic field is the most time-consuming part in
micromagnetic simulations. Improvements both on a numerical and computational
basis can relief problems related to this bottleneck. This work presents an
efficient implementation of the Fast Multipole Method [FMM] for the magnetic
scalar potential as used in micromagnetics. We assume linearly magnetized
tetrahedral sources, treat the near field directly and use analytical
integration on the multipole expansion in the far field. This approach tackles
important issues like the vectorial and continuous nature of the magnetic
field. By using FMM the calculations scale linearly in time and memory.
