pylhe

Active · Core maintainer

Lightweight, pure-Python library for reading and writing Les Houches Event (LHE) files, the standard Monte Carlo event format in high-energy physics. Part of the Scikit-HEP ecosystem.

Source Documentation PyPI DOI: 10.21105/joss.11128 Paper

pip install pylhe

Reads .lhe and compressed .lhe.gz files, including LHE 3.0 features (multiple event weights, generator metadata) and the HDF5-based LHEH5 format. Events are exposed through a pythonic iterator over shared data structures, allowing large samples to be processed without loading an entire file into memory, and can be converted into Awkward Array columnar structures for downstream statistical and machine-learning analysis.

import pylhe

events = pylhe.read_lhe("events.lhe.gz")
for event in events:
    for particle in event.particles:
        print(particle.id, particle.px, particle.py, particle.pz)

Originally developed independently, pylhe now lives under the Scikit-HEP organisation and is described in a peer-reviewed JOSS paper co-authored with Matthew Feickert, Lukas Heinrich and Eduardo Rodrigues.