httk.atomistic.models.trajectory.plain
======================================

.. py:module:: httk.atomistic.models.trajectory.plain

.. autoapi-nested-parse::

   Map OPTIMADE trajectory properties to a backend.



Classes
-------

.. autoapisummary::

   httk.atomistic.models.trajectory.plain.PlainTrajectory


Module Contents
---------------

.. py:class:: PlainTrajectory(obj, **hints)

   Bases: :py:obj:`httk.atomistic.models.trajectory.backend.TrajectoryBackend`


   Represent a mapping whose structure properties have a frame axis.

   A compact constant property is represented by a one-element leading axis,
   e.g. ``nelements=[2]`` for any number of frames. Only properties declaring
   ``constant`` on that axis accept this compact form.

   :param obj: A trajectory property mapping.
   :param \**hints: Backend-selection hints.


   .. py:attribute:: kind
      :type:  ClassVar[str]
      :value: 'plain'



   .. py:method:: frame(i)

      Return one frame from the property mapping.

      :param i: Frame index; negative indexes count from the end.
      :return: The requested unit-cell structure.
      :raises IndexError: If the frame index is out of range.
      :raises KeyError: If a required trajectory property is absent.
      :raises TypeError: If the frame index is not an integer.
      :raises ValueError: If the frame cannot be represented as a structure.



   .. py:method:: frames()

      Iterate over all frames in source order.

      :return: An iterator of unit-cell structures.



   .. py:property:: nframes
      :type: int


      Return the number of frames.


   .. py:property:: reference_frames
      :type: tuple[int, Ellipsis] | None


      Return normalized reference-frame indexes, or ``None``.


   .. py:property:: species
      :type: tuple[httk.atomistic.models.species.species.Species, Ellipsis]


      Return the constant distinct species from the first frame.


   .. py:property:: species_at_sites
      :type: tuple[str, Ellipsis]


      Return the constant species name at each site.


   .. py:property:: observable_names
      :type: tuple[str, Ellipsis]


      Return names outside the recognized trajectory and structure properties.


   .. py:method:: observable(name)

      Return one mapped observable's values in frame order.

      :param name: Observable property name.
      :return: The observable values.
      :raises KeyError: If the property is not an observable.



   .. py:method:: unwrap()

      Return the original property mapping.