The multilayered convolution algorithm for demagnetising field computation in multilayers has now been published in the Journal of Applied Physics: JAP 126, 103903 (2019). Preprint was submitted to arxiv on 3rd June.
This algorithm for the first time allows computation of demagnetising fields in arbitrary multilayered structures with arbitrary spacing, thus including nonequispaced layers, and arbitrary thicknesses, without impacting on the computational performance or numerical accuracy. Moreover the algorithm can also be applied to 3D independently discretised layers. Typical use cases include ultrathin multilayers used to study skyrmions, stacks with layer thicknesses large relative to the spacing (e.g. synthetic antiferromagnetic and ferrimagnetic stacks), as well as stacks with a range of different layer thicknesses (e.g. spin valves), including in the same stack both 2D and 3D discretised layers with arbitrary thicknesses.
This algorithm is available in the current Boris v2.3 binary. The upcoming v2.4 binary will contain an extension to periodic boundary conditions (algorithm with PBC finished and tested, available on github) – I expect to release the v2.4 binary next week at the latest.