peter-madigan / pyhepevt

pyhepevt

This is a lightweight python library to facilitate conversion and manipulation of HepEvt records using python. To install ::

pip install .

usage

Conversion scripts between HepEvt formats are provided within scripts/. These can be used to convert HepEvt records of one type to another, e.g. ::

python scripts/convert_marley_to_edepsim.py <MARLEY HepEvt file> <EDepSim HepEvt file>

Within python, file parsing is broken into reading a file (HepEvtReader) and writing a file (HepEvtWriter). Sub-classes are provided for each file format that can be parsed with a naming convention of (HepEvtReader<SoftwarePackage>/HepEvtWriter<SoftwarePackage>).

To facilitate the conversion, files are read into intermediate data object(s) (HepEvtEvent/HepEvtParticle). These objects use the fields listed in the MARLEY HepEvt format to store the representation of the event and particle. A HepEvtEvent also has a particles attribute that stores all of the particles associated with that event record. Similarly, a HepEvtParticle has an event attribute that stores a reference to the parent HepEvtEvent.

Below I provide a short example of how to open a file, modify an attribute and then save the data to a new file ::

from pyhepevt import HepEvtReaderMARLEY, HepEvtWriterEDepSim
with HepEvtReaderMARLEY(<input file>) as reader:
    with HepEvtWriterEDepSim(<output file>, 'w') as writer:
        for event in reader:
            event.p = [0, 0, 0, event.m[-1]] # force the particle momentum to zero
            writer.write(event)

extending

To add read compatibility with a new HepEvt format, one needs to:

1. implement the from_<package>(*args) method of the HepEvtEvent and HepEvtParticle

2. create a new HepEvtReader<SoftwarePackage> class inheriting from HepEvtReader

3. implement the _read_next(fh) method of the new reader class

To add write compatibility with a new HepEvt format, one needs to:

1. implement the dump_<package>() method of the HepEvtEvent and HepEvtParticle

2. create a new HepEvtWriter<SoftwarePackage> class inheriting from HepEvtWriter

3. implement the _write_event(event) method of the new reader class