  We report on the design, verification and performance of mumax3, an
open-source GPU-accelerated micromagnetic simulation program. This software
solves the time- and space dependent magnetization evolution in nano- to micro
scale magnets using a finite-difference discretization. Its high performance
and low memory requirements allow for large-scale simulations to be performed
in limited time and on inexpensive hardware. We verified each part of the
software by comparing results to analytical values where available and to
micromagnetic standard problems. mumax3 also offers specific extensions like
MFM image generation, moving simulation window, edge charge removal and
material grains.
