zadorlab/sella v2.6.0 on GitHub

Packaging

Sella is now pure Python. The Cython extensions (force_match, utilities.blas, utilities.math) have been replaced with portable Python implementations. Releases ship a single py3-none-any wheel instead of per-platform compiled wheels, and installing no longer requires a C compiler.

Minimum ASE is now 3.26.0 (was 3.22). Sella's IRC logging uses the flat-gradient Optimizer.log API introduced in ASE 3.26; older ASE releases fail or hang. Users on ASE < 3.26 should stay on Sella 2.5.0.
Minimum Python is now 3.9 (was 3.8). Tested on 3.9 through 3.13.

configure_compute and set_cpu_threads for controlling thread and compute settings
Optional GPU acceleration for large linear-algebra operations when PyTorch with CUDA is present (PyTorch is not required; falls back to CPU)
hessian_progress option to log Hessian diagonalization progress
Accepted trajectory frame IDs are now recorded in the log
exact_geodesic option for the guess Hessian
Refactored optimizer steps and trust-region control; hardened PES, cell-optimization, and internal-coordinate construction

Fix constrained IRC force projection
Fix guess Hessian projector; revert rho_inc
Apply IRC first-step guard on ASE >= 3.28 via gradient_converged
Don't create the JAX compilation cache in the home directory when another path is given; an unwritable home no longer breaks import
PyPI metadata now includes project URLs and the supported Python versions

Full changelog: v2.5.0...v2.6.0