Calculating the forces between magnets and coils and multipole magnet arrays
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wspr add warning when magnets don't define their type
this was fine when we just had cubes and cylinders, but as we extend types don't leave it to chance to guess correctly!
Latest commit 6088c02 Aug 11, 2018


Calculating the force between magnets and multipole arrays of magnets

This repository contains code originally written for my PhD for calculating the forces (and stiffnesses) between permanent magnets and arrays of magnets.

It has been originally written in Matlab, and I plan on adding translations into other programming languages as time permits. Contributions happily accepted.


As time goes by, it becomes increasingly difficult to build on the work of our predecessors unless we build tools to abstract the ideas we invent in our research. This code marks my first attempt to freely share, in a useful way, the work of my PhD.

Installation and information

The matlab/ subdirectory of this repository contains both the source file magnetforces.web and the ready-to-use Matlab functions magnetforces.m and multipoleforces.m. After cloning this Git repository, you can simply add the matlab/ folder to your Matlab path in order to start using the code.

The documentation matlab/magcode-matlab.pdf contains both a user's guide and the documented source code in a literate programming style.

Examples and test suite

The examples/ subdirectory contains a number of files to illustrate the use of the magnetforces code (and other related things). These files are:

  • allag_torques.m is an implementation of the theory of Allag and Yonnet (2009) for calculating the torques between cuboid magnets. I believe their theory is incorrect and this example is supposed to illustrate why.
  • magnetforces_example.m contains a reproduction of the results of Akoun and Yonnet (1984) and of Janssen et al. (2009).
  • multipole_compare.m is an unfinished comparison between different configurations of multipole arrays.
  • multipole_example.m is a reproduction of the multipole results shown by Allag, Yonnet, and Latreche (2009).

The source code contains a number of automated tests to ensure that future changes don't break existing functionality or start producing incorrect results. These are not included in the repository for clarity; extract them with mtangle.

Licence for modification and distribution

This work is freely modifiable and distributable under the terms and conditions of the Apache License v2. In effect, you are free to do with this code as you wish for the development of free or proprietary software. Distributions of modified works must retain the original copyright notices and contain a list of modifications made, but this is only an expository notice; please see the licence text for complete details.

Copyright 2009–2010 Will Robertson
wspr81 at gmail dot com