Metadata

ASSYST tracks several metadata keys in the info attribute of the ase.Atoms structures it generates and modifies. These keys allow for identification, lineage tracking, and understanding the symmetry and perturbations applied to each structure.

Identification & Lineage

These keys are managed by the assyst.utils.update_uuid() function and are used to track the derivation history of structures.

  • uuid: A Universally Unique Identifier (UUID) for the current structure.

  • seed: The UUID of the initial structure from which this structure was derived. It remains constant throughout a lineage.

  • lineage: A list of UUIDs of all parent structures, in the order they were generated.

For more details on how lineage is tracked through the workflow, see Lineage Tracking.

Symmetry

When structures are generated using assyst.crystals.sample_space_groups() or assyst.crystals.pyxtal(), the following symmetry-related keys are added:

  • requested spacegroup: The requested symmetry group number (e.g., space group 225).

  • symmetry: An alias for requested spacegroup.

  • spacegroup: The actual symmetry group number of the generated structure, which may be higher than the requested one.

  • repeat: The iteration index when multiple structures are generated for the same symmetry group.

Perturbation

When a perturbation is applied using a assyst.perturbations.PerturbationABC subclass, information about the perturbation is recorded:

  • perturbation: A string description of the perturbation(s) applied (e.g., rattle(0.05)+stretch(hydro=0.05, shear=0.05)). Multiple perturbations are concatenated with a +.