General information

All restart information for CPMD simulations are stored within one binary file. There are very few exceptions we will discuss later. The name of the restart files is RESTART or RESTART.n, where $n$ stands for an integer number. If the keyword RESTART is found the program processes the file with the name RESTART. Using suboptions to the RESTART option, the information retained from the file can be specified. For example the suboptions COORDINATES WAVEFUNCTION will force the program to use the geometry and orbitals from the RESTART file.

At the end of a simulation or at regular intervals (using the keyword STORE) a restart file with the default name RESTART.1 is written. If this happens more than once (e.g. during a molecular dynamics run) the restart file is being overwritten. Using the keyword RESTFILE it can be specified that more than one restart file should be used for writing. If the RESTFILE parameter was set to 4, then 4 restart files with the names RESTART.1, $\ldots$ , RESTART.4 will be written. If more than 4 restart files are needed the first one will be overwritten. This option is useful if there is the possibility that restart files get corrupted (e.g. on unstable systems), or if simulations are performed that might lead to unphysical results. In this case it might be possible to go back to a restart file which contains still intact information.

The name of the last restart file written is stored in the file LATEST. Using the suboption LATEST to the keyword RESTART changes the default name of the file to be read from RESTART to the name found in the file LATEST. The danger of using this option is that the file from which the simulation is started gets overwritten during the simulation. Using the default (starting from RESTART) ensures that the original file stays intact. However, it requires the renaming of the final file of a simulation from RESTART.n to RESTART.