httk.atomistic.entries.precision
================================

.. py:module:: httk.atomistic.entries.precision

.. autoapi-nested-parse::

   Serving how precisely a structure's numbers were stated.

   OPTIMADE standardises nothing about data precision — the only ``standard_uncertainty`` in
   its structures definition is CODATA metadata inside a unit definition — so these are
   database-specific properties described by the published definitions in
   :mod:`~httk.atomistic.entries.definitions`.

   Serving them matters because a consumer choosing a matching tolerance or a symmetry
   ``symprec`` otherwise has to guess. With these two values it can derive one, exactly as
   :func:`~httk.atomistic.structure_tolerance` does locally.



Attributes
----------

.. autoapisummary::

   httk.atomistic.entries.precision.PRECISION_PROPERTY_KEYS


Functions
---------

.. autoapisummary::

   httk.atomistic.entries.precision.precision_definitions
   httk.atomistic.entries.precision.precision_properties


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

.. py:data:: PRECISION_PROPERTY_KEYS
   :type:  dict[str, str]

.. py:function:: precision_definitions()

   Load the vendored coordinate and basis precision definitions.

   :return: Definitions keyed by their served names.


.. py:function:: precision_properties(structure)

   Project the stated coordinate and basis precision.

   Both are ``null`` for a structure that does not say — one built by hand, or read from a
   source that does not write its numbers to a definite number of digits. That is the
   honest answer, and it is distinguishable from a claim of exactness.

   Rendered as floats, since that is what a JSON consumer will use them as; they are held
   exactly on the structure itself.

   :param structure: The structure to project, or ``None`` for an empty entry.
   :return: The ``_httk_coordinate_precision`` and ``_httk_basis_precision`` values.