httk.atomistic.numeric_structure
================================

.. py:module:: httk.atomistic.numeric_structure

.. autoapi-nested-parse::

   The NumericStructure presentation: a Structure exposed as plain numpy numbers.



Classes
-------

.. autoapisummary::

   httk.atomistic.numeric_structure.NumericStructure


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

.. py:class:: NumericStructure(structure: httk.atomistic.structure_like.StructureLike)

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

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

   The presentation is numpy-backed, so constructing a ``NumericStructure`` **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`.


   .. py:property:: cell
      :type: httk.atomistic.numeric_cell.NumericCell


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


   .. py:property:: sites
      :type: httk.atomistic.numeric_sites.NumericSites


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


   .. py:property:: species
      :type: tuple[httk.atomistic.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:method:: cartesian_sites() -> httk.core.NumericVector

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



   .. py:property:: exact
      :type: httk.atomistic.structure.Structure


      The exact :class:`~httk.atomistic.Structure` this presentation wraps.