Visualization illustrating the modular code structure of MoCSI. There are currently five module insertion points in the code, where users can insert modules to do calculations, change and insert physical parameters, or access and alter simulation parameters. Right after the simulation has been initialized (1), at the start of each iteration within a time step (2), after the update of the temperature within the iterations of a time step (3), after the time step has converged (4), and during the post-processing of the simulation (5). If there are no temperature-dependent parameters and no iteration is necessary, insertion points three and four are equivalent. Each module instance represents its own unique set of modules which can be freely selected by the user.