pyeonclient 0.3.5

Nanobind bindings to the eOn C++ client (Matter, Parameters, Potential, Jobs, NEB, RGPOT)

pyeonclient

In-process eOn client for Python. First-class algorithm objects on Matter (not a workdir wrapper).

Class / function	Role
Matter	Geometry + PEF (ASE Atoms analogue)
ImprovedDimer / Dimer / Lanczos / Davidson	Min-mode
MinModeSaddleSearch	Single-ended saddle search
NudgedElasticBand	NEB band (list[Matter])
Hessian / get_prefactors	Vibrational analysis / HTST
make_job + Job.run	Full JobType factory (workdir jobs)

Docs: Python API

Install

pip install pyeonclient
pip install 'pyeonclient[ase]'           # Matter ↔ ASE geometry helpers
pip install 'pyeonclient[models]'        # optional Pydantic DimerSpec / NebSpec
# uv: uv pip install 'pyeonclient[models]'
# Core Dimer/NEB work without pydantic; C++ + light Python still enforce
# accelerant="gp" only with method="improved".

Example (dimer → saddle)

import numpy as np
import pyeonclient as pyec

params = pyec.Parameters()
params.potential = pyec.PotType.LJ
pot = pyec.make_potential(params.potential, params)
matter = pyec.Matter(pot, params)
# ... set positions / cell / numbers ...

matter.relax()
mode0 = np.random.default_rng(0).normal(size=matter.positions.shape)
dimer = pyec.ImprovedDimer(matter, params, pot)
dimer.compute(matter, mode0)

ss = pyec.MinModeSaddleSearch(
    matter, dimer.eigenvector, matter.potential_energy, params, pot
)
status = ss.run()
print(pyec.saddle_status_message(status), ss.eigenvalue)

NEB

path = [pyec.from_ase(img, pot, params) for img in images]
neb = pyec.NudgedElasticBand(path, params, pot)
neb.compute()
# Stamped ConFrames for plots (no neb.con write required):
frames = neb.path_frames()  # list[readcon.ConFrame]
path = list(neb.path_images())

Min / saddle movies (in-memory)

out, ok = matter.relax(retain_frames=True)  # default inplace=False returns working copy
movie = out.movie_frames()  # list[readcon.ConFrame]

ss = pyec.MinModeSaddleSearch(matter, mode, e0, params, pot)
ss.run_retain_frames()
climb = ss.climb_frames()

Build

meson setup build -Dwith_pyeonclient=true
meson compile -C build
pytest tests/test_pyeonclient_eigenmode.py tests/test_pyeonclient_neb.py -v