Tuning in multiple sessions

In the case of insufficient computing resources or sudden failure of your executing machine, it is useful to be able to continue a specific execution of OPTANO Algorithm Tuner (OAT) that was cancelled at an earlier time.

To make this possible, OAT regurlarly stores intermediate results to file. Usually, these .oatstat files will be stored in a folder status placed in the calling directory, but you can change the path via a parameter to prevent new runs from overwriting old ones.

The intermediate results include

execution results obtained on the tuneable algorithm,
current internal state, and
all parameters inherent to the tuning, e.g. the total number of iterations to run or the mutation rate.

Therefore, to continue with a tuning, all you have to do is to add the parameter --continue to your usual command. Make sure to leave all parameters that are tuning-specific unaltered. You can still set the following, technical parameters:

--statusFileDir={PATH}
--maxParallelEvaluations={NUMBER}
--maxParallelThreads={NUMBER}
--verbose={0, 1, 2, 3}
--ownHostName={FQDN/IP}
--port={NUMBER}
--faultTolerance={NUMBER}
--maxRepair={NUMBER}
--logFile={PATH}
--instanceFolder={PATH}
--trackConvergenceBehavior={BOOL}
--zipOldStatus={BOOL}
--allowLocalEvaluations={BOOL}

In addition, you might change trainModel from true to false.

Check the page about parameters for more information about each of these.

If you do not specify ownHostName, port, trainingInstanceFolder or testInstanceFolder, default values will be used. If you do not specify one of the other parameters, the stored values from the provided status file will be used.

A call to continue with a basic application of OAT may look like this:

dotnet Optano.Algorithm.Tuner.Application.dll --master --continue --maxParallelEvaluations=4 --basicCommand=<commandToExecuteYourAlgorithmWith> --parameterTree=<pathToXML> --trainingInstanceFolder=<instanceFolder> <optionalTechnicalParametersOverwrites>

Configuration changes

In the overwhelming majority of use cases, the functionality described above should suit your needs. Very rarely, you might find yourself in a situation where you want to change even more parameters between different runs. Be aware that in this case, tuning in multiple sessions is not equivalent to a single longer session of OAT.

If this is what you intend, you can set --strictCompatibilityCheck=false and overwrite almost all parameters in your continued run.