Lightweight. Fast.

Caffeine benchmarks

24 atoms · energy + forces

Benchmarks ↗

Apple M4 Max · CPU

DFT qc.rs ↗

PBE / def2-SVP

9.1× faster

vs PySCF

Time

Atomli1.70 s

PySCF15.5 s

Peak RSS90% less memory

Atomli394 MiB

PySCF3.87 GiB

Tight binding ctb.rs ↗

GFN2-xTB

3× faster

vs tblite

Time

Atomli3.89 ms

tblite11.7 ms

Peak RSS

Atomli86.6 MiB

tblite85.2 MiB

MLIP mlip.rs ↗

Nequix MP-1 PFT

1.7× faster

vs Nequix / JAX

Time

Atomli7.78 ms

Nequix / JAX12.8 ms

Peak RSS78% less memory

Atomli172 MiB

Nequix / JAX793 MiB

DFT / MLIP: Atomli 0.1.4 · xTB: Atomli 0.1.6 · development build, 2026-09-20 · DFT / xTB: 8 threads · MLIP: 1 thread

NVIDIA A100 · 40 GB

DFT qc.rs ↗

PBE / def2-SVP

1.3× faster

vs GPU4PySCF

Time

Atomli717 ms

GPU4PySCF927 ms

Peak RSS46% less memory

Atomli657 MiB

GPU4PySCF1.19 GiB

DFT qc.rs ↗

r²SCAN / def2-SVP

1.7× faster

vs GPU4PySCF

Time

Atomli710 ms

GPU4PySCF1.22 s

Peak RSS36% less memory

Atomli782 MiB

GPU4PySCF1.19 GiB

MLIP mlip.rs ↗

Nequix MP-1 PFT

2.7× faster

vs Nequix / JAX

Time

Atomli3.28 ms

Nequix / JAX9.01 ms

Peak RSS77% less memory

Atomli398 MiB

Nequix / JAX1.69 GiB

DFT: Atomli 0.1.5 · development build, 8 host threads · MLIP: Atomli 0.1.4, 1 host thread

Caffeine relaxation

pip install atomli

caffeine.xyz ↓

Tutorial →

relax.py

from atomli.io import read
from atomli.calculators import XTB
from atomli.optimize import BFGS

atoms = read("caffeine.xyz")
atoms.calc = XTB(method="gfn2")
BFGS(atoms).run(fmax=0.05)

print(atoms.get_potential_energy())

Guides

Calculators ↗DFT, tight binding, machine learning potentials, and classical models.Structure optimization ↗Optimizers, force tolerance, and constraints.Benchmarks ↗Calculation time and peak RSS on CPU and GPU.API reference ↗Classes, functions, and methods.

ASE interoperability

Use Atomli calculators with ase.Atoms, or assign an ASE calculator to atomli.Atoms. Read the compatibility guide before you migrate a workflow.

Python boundary units are angstrom, electronvolt, and femtosecond. See units for conversions and calculator guides for supported properties.