Simcenter STAR-CCM+ How to save simulations that are running in batch?
Summary
This article will highlight the different techniques to save a simulation that has been started in batch mode, and more importantly how we can use the CHECKPOINT trigger
Details
This article will highlight the different techniques to save a simulation that has been started in batch mode. Especially when running on remote servers, it can be difficult to save a simulation at intermediate times, since this would either involve opening a GUI and setting an autosave, or actually stopping a simulation and manually saving it. This article will go through the advantages and disadvantages of all techniques that can be used to save a simulation that is running on a remote location
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Use Auto Save to save simulations at regular intervals; e.g. every 1000 iterations, every 0.1s of physical time, and so on. This will ensure we are regularly saving the simulation, but if it has not been set up beforehand, a client needs to be opened and Auto Save needs to be defined. Auto Saving can be a very good option since it protects us from unforeseen occurrences (for example power outs), but it also means we are using more disk space, and runtimes for the complete simulation will be slightly higher.
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Use a CHECKPOINT file. Similar to the ABORT file to stop simulations, we can create a CHECKPOINT file in the directory where the simulation file is located. Simcenter STAR-CCM+ will check for this checkpoint file every 60 seconds, and if found, will automatically trigger an autosave, regardless of whether autosave has been set up. This is great when we have not defined Auto Save and only want to save a simulation when we decide we want it. The name of this trigger file can be changed in File > Auto Save... > Trigger File
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Use -noexit when submitting jobs in batch mode. This means that when we stop the simulation, it will not exit the batch client, and we can make manual changes (i.e. save the simulation). However, this does mean the simulation is now in server mode, and we need to manually start, stop and exit the simulation, so we lose the advantages of running in batch. Also, when we don’t want to save, if it reaches the stopping criteria, it will remain occupying the cores on the server, so it would not be recommended practice.
See also:
How do I stop simulation running in a batch?
Automatically Saving at Regular Intervals
How do I run Simcenter STAR-CCM+ in batch mode?
How to reduce batch post-processing time without graphics hardware