httk.atomistic.integrations.vasp.trajectory

Lazy VASP trajectory access through neutral httk payloads.

This backend is explicit-only: a generic trajectory source must not claim an OUTCAR/XDATCAR path.

Classes

VASPTrajectory

Read VASP OUTCAR and/or XDATCAR data lazily.

Module Contents

class httk.atomistic.integrations.vasp.trajectory.VASPTrajectory(source, **hints)

Bases: httk.atomistic.models.trajectory.backend.TrajectoryBackend

Read VASP OUTCAR and/or XDATCAR data lazily.

XDATCAR supplies geometry when present. OUTCAR observables use the per-frame energy_sigma0, parsed as a float, plus temperature and stress_gpa_voigt(). One bounded pass caches those three scalar/6-tuple sequences; frame geometry is never cached.

XDATCAR geometry is preferred when both files are available. Cartesian coordinates are reduced exactly against the frame cell. A mismatch between OUTCAR and XDATCAR frame counts raises an error.

Parameters:

• source (Any) – A VASP trajectory path, directory, payload, or VASP-outputs-like object.

• **hints (Any) – Backend-selection hints.

kind: ClassVar[str] = 'vasp'

property nframes: int

Return the validated number of frames.

property species: tuple[Any, Ellipsis]

Return the composition inferred from POSCAR, XDATCAR, or OUTCAR.

property species_at_sites: tuple[str, Ellipsis]

Return the species name at each site.

property reference_frames: None

Return None because VASP frames are not bounded references.

frame(i)

Read one VASP frame by index.

Parameters:

i (int) – Frame index; negative indexes count from the end.

Returns:

The requested unit-cell structure.

Raises:

• IndexError – If the frame index is out of range.

• ValueError – If the source has no complete frame geometry.

Return type:

httk.atomistic.models.structure.unitcell.UnitcellStructure

frames()

Stream VASP frame geometry without caching full frames.

Yields:

Unit-cell structures in source order.

property observable_names: tuple[str, Ellipsis]

Return available OUTCAR observable names.

observable(name)

Return one OUTCAR observable in frame order.

Parameters:

name (str) – Observable name.

Returns:

The observable values.

Raises:

KeyError – If the observable is unavailable.

Return type:

tuple[Any, Ellipsis]

unwrap()

Return the original VASP trajectory source.

property source_locator: str | None

Return the source path, if one is available.