An exact method of computing demagnetising fields in magnetic multilayers, which is able to handle layers with arbitrary spacing, arbitrary thicknesses, and arbitrary relative positioning between them without impacting on the computational performance, or sacrificing numerical accuracy, was developed. The multilayered convolution method is a generalisation of the well-known convolution method used to compute demagnetising fields in a single magnetic body. In typical use cases, such as multilayered stacks used to study skyrmions, the multilayered convolution method can be up to 8 times faster, compared to the simple convolution method.
A new paper has been sent out for review on this method, preprint available:
https://arxiv.org/ftp/arxiv/papers/1906/1906.00813.pdf
This has been implemented in Boris and will be available with the next release, coming soon (v2.3).