Troubleshooting

This page answers common user questions that come up before reading the full reference.

Which Function Should I Use?

Use find_spin_group_basic(...) for the identified OSSG, MSG, and magnetic phase.

Use find_spin_group(...) for generated artifacts, operation payloads, quasi-2D diagnostics, tensor outputs, and audit information.

Use find_spin_group_input_ssg(...) when another program needs input-cell SSG or MSG operations.

Why Is The Full Output So Large?

find_spin_group(...) returns MagSymmetryResult, which contains summary fields, multiple cell settings, operation outputs, generated files, physical properties, and diagnostics.

Use result.to_summary_dict() first. Use result.to_structured_dict() when you need the full result grouped by meaning. Use result.to_dict() only when you need the raw compatibility surface.

Why Do I Get A Missing Magnetic Moment Error?

FindSpinGroup identifies magnetic symmetry. The input must contain magnetic moments in a supported format.

For POSCAR-like inputs, add embedded MAGMOM information or use the CLI from a VASP directory with a sibling INCAR that contains MAGMOM.

Why Does CLI POSCAR Behavior Differ From Python?

The CLI is optimized for VASP working directories and prefers a sibling INCAR MAGMOM when present.

Python calls read only the POSCAR content unless you opt into INCAR reading with poscar_allow_incar_magmom=True.

Does Quasi-2D Change The 3D SSG?

No. Quasi-2D analysis is an additive diagnostic layer. The ordinary 3D identification remains the base result.

Which Operation Setting Should I Use?

Use convention-setting outputs for public OSSG symbols and display.

Use input-cell outputs when a downstream tool expects the user-supplied cell.

Use ACC primitive outputs for downstream POSCAR and Brillouin-zone workflows.

Use database-standard outputs only when you need identify-index setting diagnostics or exact database-standard SCIF export.

Should I Change Tolerances?

Start with the defaults. Tighten tolerances only when your input structure is numerically clean enough. Loosen tolerances only when small structural or magnetic-moment noise prevents a physically expected match.