run_part both controls the timestepping and calls all the functions individually to progress an entire simulation (from time $t=0$ to $t=t_{\rm max}$. Instead it would be good to be able to run chunks of time, implemented with run_part_timeblock which will simulate from time $t$ to $t + t_{\rm progress}$ (or other specified interval), and a single timestep, implemented with run_part_timestep which runs from time $t$ to $t+\Delta t$.
run_partboth controls the timestepping and calls all the functions individually to progress an entire simulation (from time $t=0$ to $t=t_{\rm max}$. Instead it would be good to be able to run chunks of time, implemented withrun_part_timeblockwhich will simulate from time $t$ to $t + t_{\rm progress}$ (or other specified interval), and a single timestep, implemented withrun_part_timestepwhich runs from time $t$ to $t+\Delta t$.