Restart#

This subsection controls the checkpointing and restarting of time-dependent simulations.

This feature is used both to write data at checkpoints (checkpointing) and restart a simulation (restarting) using data from the last checkpoint.

Tip

It is highly advised to use it if you fear you might either run out of memory/simulation time during the simulation.

The default parameters are:

subsection restart
  # Checkpointing parameters
  set checkpoint = false
  set frequency  = 1

  # Output/input files
  set filename   = restart

  # Restarting parameter
  set restart    = false
end

  • checkpoint: controls if a checkpoint of the simulation is created. All the files needed to restart the simulation from this checkpoint (such as .pvdhandler, .triangulation) will be written.

  • frequency: number of iteration before the first checkpoint, and between each subsequent checkpoint.

Tip

Checkpointing is very intensive from an I/O point of view, consequently it should not be done at every iteration. The checkpointing frequency is in accordance to the number of time step (see Simulation Control).

Warning

Each checkpoint erases the previous one, so a simulation can only be restarted from the last check-point.

  • filename: prefix for the files. This parameter is used to output checkpoint files as well as to load files during a restart.

Warning

Files are saved (when checkpointing) and searched for (when restarting) in the output path specified in subsection Simulation Control.

  • restart: controls if the simulation is to be restarted from a previous checkpoint.

    • set restart = false: for the first checkpoint creation.

    • set restart = true: the simulation will start from the last checkpoint and will finish at the provided time end (see Simulation Control).