FDS: SOFT vs HARD STOP
FDS provide different methods in order to stop your running simulation: SOFT and HARD STOP. Sometimes your analysis just crashes and you would lose all of your data. Other times, you might want to stop a calculation, make few variations, and restart the simulation from when it left off.
FDS gives you a method in order to softly stop your simulation. It is also possible to select how to stop your running simulation form the Cloud HPC Service web-app.
SOFT STOP in FDS
The soft stop can interrupt the simulation and save the results obtained until that moment. When you pursue a soft stop, it is possible to restart your simulation from the last saved results.
This is suggested when you don’t want to continue the simulation forward because you reached already the needed results or if you want to stop your simulation with the idea of making few adjustments or continuing it in another moment.
It is possible to stop your FDS simulation by creating a file in the output files folder named
CHID.stop. This file allows you to softly stop the simulation and dump the latest results. Then, you will be able to review the obtained results in Smokeview.
Moreover, you can stop the analysis in a determined time and save the results, by the use of specific control functions, such as
SETPOINT, shown in Section 20.5 of the FDS User Guide.
HARD STOP in FDS
The hard stop kills your simulation without saving any results. The hard stop can occur accidentally when you simulation fails or you lose internet connection. Or intentionally, when you harshly close the analysis.
STOP you calculation for the Cloud HPC Service Web-App
Cloud HPC Service allows you to stop your running simulation from the Simulation Menu selecting between the two options: Soft and Hard stop.
Restart your simulation
To restart a job that was softly stopped, create the file CHID.restart in the folder, and the insert the command RESTART=T in the MISC line of the FDS script.
It is possible to Restart a simulation from the web-app as explored in the dedicated post “Restart your FDS analysis on cloud HPC“.