FindSpinGroup Documentation

findspingroup is a Python package, command-line program, and web application for identifying oriented spin space group (OSSG) symmetry in magnetic crystal structures.

Given a structure with magnetic moments, FindSpinGroup identifies the OSSG, reports the corresponding magnetic space group (MSG), classifies the magnetic phase, and can generate symmetry data for downstream first-principles, high-throughput, and web-application workflows.

Where Things Belong

This documentation is split into three layers.

Guide explains how to complete user tasks. Start here if you are not sure which command or Python function to use.

Reference documents the exact Python functions, return objects, CLI flags, and output fields. Use it when you know the entry point and need precise parameter or output meaning.

Advanced Notes explain internal settings, transform terminology, and diagnostic routes that are useful for expert users and maintainers.

The repository README.md is intentionally shorter than this site. It is only the project entry point: what the package does, how to install it, and where to continue.

Start Here

Use the quick path if you only need the identified group labels and magnetic phase:

from findspingroup import example_path, find_spin_group_basic

summary = find_spin_group_basic(example_path("0.800_MnTe.mcif"))

print(summary["index"])
print(summary["magnetic_phase"])
print(summary["msg_bns_number"], summary["msg_symbol"])

Expected output:

194.164.1.1.L
AFM(Altermagnet)
63.457 Cmcm

Main Routes

Use find_spin_group_basic(...) or fsg file.mcif for compact identification.

Use find_spin_group(...) or fsg --all file.mcif for the full result object, generated SCIF, POSCAR, KPOINTS, tensor outputs, quasi-2D diagnostics, and audit information.

Use find_spin_group_input_ssg(...) or fsg -w file.mcif when you need SSG and MSG operations in the input-cell setting and optional helper files written to disk.

Next Steps