pfield.m and simus.m are slightly modified versions of two of the files in the MUST package. MUST is an open source simulation tool,
under a GNU LESSER GENERAL PUBLIC LICENSE. To run the MUST simulation example, you need to download MUST from https://www.biomecardio.com/MUST/
Add the path to the MUST folder, and the Support folder. Make sure that the Support folder is added
after the MUST folder to let these files take precedence.