httk.atomistic.models.cell.params
=================================

.. py:module:: httk.atomistic.models.cell.params

.. autoapi-nested-parse::

   Backend wrapping cell parameters (a, b, c, alpha, beta, gamma).



Classes
-------

.. autoapisummary::

   httk.atomistic.models.cell.params.CellParams


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

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

   Bases: :py:obj:`httk.atomistic.models.cell.backend.CellBackend`


   Backend for a cell backed by cell parameters ``(a, b, c, alpha, beta, gamma)``.

   The native representation is a flat length-6 vector-like of the cell-vector lengths
   ``a``/``b``/``c`` and the angles ``alpha``/``beta``/``gamma`` in degrees, stored as exact
   :class:`~fractions.Fraction` values (parsed via
   :func:`~httk.core.exactmath.any_to_fraction`). The exact ``basis`` is derived lazily and
   cached using the standard crystallographic orientation convention (first cell vector along x,
   second in the xy-plane); for the common Niven angles it is exact (radicals intact). Since
   parameters carry no separate length factor, ``scale`` is the exact ``1`` and
   ``unscaled_basis == basis``. Parameters carry neither orientation nor periodicity, so a cell
   → parameters → cell round-trip reproduces lengths and angles, and reproduces volume only for
   a fully periodic source. Reconstruction uses the fully periodic default and therefore discards
   any non-3D periodicity as well as the original orientation.
   ``unwrap`` returns the original raw object.

   :param obj: The six cell parameters in crystallographic order.
   :param \**hints: Backend-selection hints.


   .. py:property:: basis
      :type: httk.core.SurdVector


      Return the basis derived from the stored parameters.

      :return: The standard-orientation cell vectors.


   .. py:property:: scale
      :type: httk.core.SurdScalar


      Return the unit scale factor.

      :return: The factor applied to ``unscaled_basis``.


   .. py:property:: unscaled_basis
      :type: httk.core.SurdVector


      Return the parameter-derived basis before scaling.

      :return: The cell vectors.


   .. py:property:: lengths
      :type: tuple[httk.core.SurdScalar, Ellipsis]


      Return the natively stored cell-vector lengths.

      :return: The exact stored ``a``, ``b``, and ``c`` lengths.


   .. py:property:: angles
      :type: tuple[fractions.Fraction, Ellipsis]


      Return the natively stored cell angles in degrees.

      :return: The exact stored ``alpha``, ``beta``, and ``gamma`` angles.


   .. py:property:: params
      :type: tuple[fractions.Fraction, Ellipsis]


      The stored ``(a, b, c, alpha, beta, gamma)`` in degrees.

      :return: The exact cell parameters.


   .. py:method:: unwrap()

      Return the original parameter object.

      :return: The raw parameter representation.