On the question of calculating the demagnetization field by the fast multipole method

The most time consuming part of the modeling of magnetic materials is the calculation of the demagnetization field. There are two most often used methods: a fast multipole method and a method based on a fast Fourier transform. Each method has its own drawbacks and limitations. In this paper, the features of the realization of the fast multipole method for calculating the field of demagnetization with a micromagnetic approach and the atomistic approach were described. Moreover, the difficulties that arise when verifying the software on the standard MuMag tasks were described.