httk.atomistic.models.structure.numeric_view
============================================

.. py:module:: httk.atomistic.models.structure.numeric_view

.. autoapi-nested-parse::

   A plain-numpy presentation of a structure backend.



Classes
-------

.. autoapisummary::

   httk.atomistic.models.structure.numeric_view.NumericUnitcellStructureView


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

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

   Bases: :py:obj:`httk.atomistic.models.structure.semantics.StructureSemanticsMixin`, :py:obj:`httk.atomistic.models.structure.view.StructureView`


   A plain-numpy presentation of a :class:`~httk.atomistic.UnitcellStructure`.

   Where a ``UnitcellStructure`` holds its geometry exactly (a surd ``cell`` basis, rational reduced
   coordinates, and an exact Cartesian frame), this view mirrors that interface but returns
   plain numpy numbers: its :attr:`cell` is a :class:`~httk.atomistic.models.cell.numeric.NumericCell`, its
   :attr:`sites` a :class:`~httk.atomistic.models.sites.numeric.NumericSites`, and :meth:`cartesian_sites` a
   ``float64`` numpy array. The ``species``/``species_at_sites`` are passed through unchanged.
   It is for callers who do not need exact arithmetic and just want numpy arrays.

   The presentation is numpy-backed, so constructing it **requires numpy** (the
   ``httk-atomistic[numpy]`` extra) and raises :class:`ImportError` eagerly when it is unavailable.
   The exact object is always one hop away via :attr:`exact`.

   This is a view, not a ``UnitcellStructure`` subclass. Its exact ``UnitcellStructure`` is built lazily on
   first access to exact geometry.

   :param obj: The structure backend or source to present.
   :param \*\*hints: Backend-selection hints passed to structure coercion.


   .. py:property:: cell
      :type: httk.atomistic.models.cell.numeric.NumericCell


      The cell as a :class:`~httk.atomistic.models.cell.numeric.NumericCell`.


   .. py:property:: sites
      :type: httk.atomistic.models.sites.numeric.NumericSites


      The sites as a :class:`~httk.atomistic.models.sites.numeric.NumericSites`.


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


      The distinct species, passed through unchanged.


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


      The species name occupying each site, passed through unchanged.


   .. py:property:: charge
      :type: float | None


      Expose the explicitly assigned charge as a floating-point value.


   .. py:property:: site_moments
      :type: httk.core.NumericVector | None


      Expose Cartesian site moments as numeric values.


   .. py:property:: assemblies
      :type: tuple[httk.atomistic.composition.Assembly, Ellipsis] | None


      Expose site correlations.


   .. py:method:: cartesian_sites()

      The Cartesian site positions as an ``(N, 3)`` ``float64`` numpy array.



   .. py:property:: periodicity
      :type: tuple[bool, bool, bool]


      Expose the cell's periodic directions.


   .. py:property:: nperiodic_dimensions
      :type: int


      Expose the number of periodic directions.


   .. py:property:: site_coordinate_span
      :type: str


      Expose the presented structure's coordinate span.


   .. py:property:: lattice_vectors
      :type: list[list[float]]


      Expose the cell vectors as numeric coordinates.


   .. py:property:: fractional_site_positions
      :type: list[list[float]]


      Expose reduced site positions as numeric coordinates.


   .. py:property:: cartesian_site_positions
      :type: list[list[float]]


      Expose Cartesian site positions as numeric coordinates.


   .. py:property:: exact
      :type: httk.atomistic.models.structure.unitcell.UnitcellStructure


      The exact :class:`~httk.atomistic.UnitcellStructure` this view presents.


   .. py:method:: unwrap()

      Return the raw object wrapped by the backend.



   .. py:method:: unview()

      Reject conversion to a standalone plain numeric value.

      :return: Never; this view has no standalone plain value.
      :raises TypeError: Always, because this view has no standalone plain value.