WRspice contains an internal tunnel junction model (TJM) of a Josephson junction. The model requires pre-prepared tables of ``fit'' parameters, which avoid performing lengthly calculation at run time. The mmjco program generates the needed files.
In general, the user may not need to interact directly with mmjco, as WRspice will call mmjco when needed to create new fit files, and store these under a directory named .mmjco in the user's home directory. Once a fit file has been created for a particular parameter set, it will be reused in future WRspice sessions when needed,
The core functionality of mmjco is derived from the MiTMoJCo project by D. R. Gulevich (found on GitHub.com), specifically the mitmojco.py environment that provides an interface for creating tunnel junction amplitude (TCA) and fitting tables. This has been implemented in mmjco as two C++ classes, one for creating tunnel junction amplitudes, which basically evaluates the Werthamer model as formulated for MiTMoJCo by Gulevich, the second to compress the amplitudes into a compact representation. This representation is used by the TJM (JJ level=3) device model in WRspice. The method is that of Odintsov, Semenov, and Zorin (See below for a list of references).
The mmjco program has additional features.