Data Analysis Frequently Asked Questions

How do I run a batch job?

Visit Submitting Batch Jobs

Why did my batch job failed? I'm getting 'command not found'

Before running your script, make sure you can run something, for instance do

...

Check that myscript is executable by yourself, check that you have the correct #! line to start the script.

Where is my epics variable?

Make sure it is a epics variable - it may be a control monitor variable. An easy way to see what is in the file is to use psana modules that dump data.  For instance:

...

will almost always show what control variables are defined. It defaults to use the standard Source "ProcInfo()" for control data. It is possible (though very unlikely) for control data to come from a different source. One can use the EventKeys module to see all Source's present, and then specify the source for  DumpControl through a config file.

How do I access data inside

...

a Psana class?

Look for an example in the psana_examples package that dumps this class. There should be both a C++ and Python module that dumps data for the class. 

How do I find out the experiment number (expNum) or experiment?

Psana stores both the experiment and expNum in the environment object - Env that Modules are passed, or that one obtains from the DataSource in interactive Psana. See Interactive Analysis document and the C++ reference for Psana::Env