Frequently asked questions

Where does the name “Sumatra” come from?

It is based on the initial letters of “Simulation Management Tool”. (Sumatra was originally conceived for tracking simulations, it was only later that I realized it could equally well be used for any command-line driven computation). Despite a certain geographical proximity, it has nothing to do with Java :-) (although it has certain similarities to Madagascar).

When I run more than one simulation at once, Sumatra mixes up the output files. How can I make it associate the right files with the right simulation?

When you run a simulation/analysis, Sumatra looks for any new files within your datastore root directory, and associates them with your computation. This means that if you launch a second computation before the first one has finished Sumatra can’t distinguish which files were produced by which computation. The solution is to save the results for a given computation in a subdirectory whose name is a unique id, and for Sumatra to look only in this subdirectory for output files.

The easiest way to do this is to use the record label. First run:

$ smt configure --addlabel=cmdline

or:

$ smt configure --addlabel=parameters

Then Sumatra will add the record label (which is generated from the timestamp unless you use the ‘--label‘ option to smt run) to either the command line or the parameter file (as sumatra_label) for your script. It is then up to your script to read this value and use it to name your output files accordingly. Here is an example for a Python script, using the cmdline option and ”./Data” set as the datastore root:

import sys
import os
options = sys.argv[1:]
label = options[-1]  # label is added to the end of the command line

# computations happen here, results stored in `output_data`

output_dir = os.path.join("Data", label)
os.mkdir(output_dir)
with open(os.path.join(output_dir, "mydata.txt"), 'w') as fp:
    fp.write(output_data)