An important feature when running a simulation is the ability to stop and restart it. This section explains how you can do it with TRUST.

Stop a Running Calculation

When using TRUST, your calculation will automatically stop if it has reached:

the end of the calculation time.
the maximal allowed CPU time.
the maximal number of iterations.
the threshold of convergence.

You may use the my_data_file.stop file if you want to stop your running calculation properly (i.e. with all saves).

When the simulation is running, you can see the 0 value in that file. To stop it, put a 1 instead of the 0 and at the next iteration the calculation will stop properly.

When you don't change anything in that file, at the end of the calculation, you can see that it is written Finished correctly.

Save

TRUST makes automatic backups during the calculation. The unknowns (velocity, temperature, ...) are saved in:

one .xyz file, written:
- at the end of the calculation.
- but the user may disable it with the specific keyword EcritureLectureSpecial 0 added just before the Solve keyword.
one (or several in case of parallel calculation) .sauv files, written:
- at the start of the calculation.
- at the end of the calculation.
- each 23 hours of CPU; to change it, use the periode_sauvegarde_securite_en_heure keyword (default value 23 hours).
- the user may also specify a physical time period with the dt_sauv keyword.
- periodically using the tcpumax keyword, for which the calculation stops after the specified time (default value \(10^{30}\)). Use it for calculations on CCRT/TGCC and CINES clusters for example.

Note: By default, the name for the .sauv files is filename_problemname.sauv for sequential calculations, filename_problemname_000n.sauv for parallel calculations (one per process). The format of these files is binary and the files are completed during successive saves.

You can change the behaviour using the following keywords just before the solve instruction:

sauvegarde binaire|xyz filename .sauv|filename .xyz

with xyz: the .xyz file is written instead of the .sauv files.

Note: You can use sauvegarde_simple instead of sauvegarde, where the .sauv or .xyz file is deleted before saves, in order to save disk space:

sauvegarde_simple binaire|xyz filename .sauv|filename .xyz

Resume

To resume your calculation, you may:

change your initial time; the new initial time will be the real final calculation time of the previous calculation (see the .err file).
change your final calculation time to the new desired value.
add the following block just before the Solve keyword:

reprise binaire|xyz filename .sauv|filename .xyz

Note
Instead of the reprise keyword, you can use resume_last_time where tinit is automatically set to the last time of the saved files (but you may still change tmax):

resume_last_time binaire|xyz filename .sauv|filename .xyz

You can resume your calculation:

from .sauv file(s) (one file per process): you can only resume the calculation with the same number of equations on the same number of processes.
or from a .xyz file: here you can resume your calculation by changing the number of equations solved and/or with a different number of processes.

Note: You can run a calculation with initial conditions read from a save file (.xyz or .sauv) from a previous calculation using Champ_Fonc_reprise, or read from a MED file with Champ_Fonc_MED.