RESTART is a sub-item, and must be defined within SIMULATION.
RESTART is used to restart a simulation from a given state, at a given time. The restart file to load must have been saved by the CHECKPOINT block, and it is specified by the RESTART keyword, see examples below.
If required, a reset time, i.e. a new initial time and its units can be specified after the name of the restart file. See example below:
restart test-23.0000y.h5 10 y
In the case above, the simulation state loaded from the restart file is associated to a physical time of 10 years.
Note that if the final simulation physical time specified in the TIME block of the restart run, is equal or less than the physical time for which the restart file was saved, the code will return an error.