Add Event Classes

[tmcahill]

First of a series of updates for my implementation of Alisha Chromey's work for 4DMLM.

This update implements the EventClass object, a simple data structure by which event classes are implemented.

EventClasses are created when using event class mode (-ec). The user may provide one or more EAs per EA tag in the runlist to create an EventClass for each EA in the tag. Event classes are paired to the data files of the same ID. Example runlist

Giving event classes their own object is cleaner than passing event class data many times via function parameters. It also allows us to avoid redundant computations for input files which correspond to an already constructed event class.

Next patch will make use of these EventClasses to select events to separate .fits files.

Vegas-side run successful with this patch.

Itemized changes

EventClass.py

• new file
• object stores event class data (e.g the effective area file and its relevant cuts)

genHDUList.py

• optional keyword arg event_class to pass EventClasses to VegasDataSource
• exceptions to ensure event_class xor effective_area_file is None

v2dl3.py

• runlist_to_file_pair extended to support EventClass
• -ec flag added to trigger event class mode
• cleaned redundant loadROOTfiles() call by assigning file_type appropriately

VegasDataSource.py

• event_classes optional keyword argument and class member
• exceptions to ensure event_classes xor ea_file is None

parseSt6RunList.py

• validateRunlist() extended to support multiple EAs per tag in event class mode

util.py

• getCuts() added; retrieves cuts values from the given keys in a ROOT cuts text

[tmcahill]

Combed through every occurrence of 'v2dl3' in the code for the refactor from v2dl3.py -> v2dl3_for_vegas.py:

• Renamed environment.yml -> environment-vegas.yml
• Renamed v2dl3 conda env to v2dl3-vegas conda env
• Changed v2dl3.py to simply log a help message upon being called with any flags (or lack thereof)
• Added v2dl3-vegas entry point for v2dl3_for_vegas.py
• Updated README.md to reflect above changes

Tested the updated README commands on a fresh install to a new conda env; All working and successfully processed a runlist.

Other minor changes:

• EventClass moved to vegas-side
• small CPyCppyy exception bugfix for vegas-side