subsequence.chord_graphs
========================

.. py:module:: subsequence.chord_graphs

.. autoapi-nested-parse::

   Chord graph builders for different harmonic transition models.







Package Contents
----------------

.. py:class:: ChordGraph

   Bases: :py:obj:`abc.ABC`


   Abstract base for chord transition graphs.


   .. py:method:: build(key_name: str) -> Tuple[subsequence.weighted_graph.WeightedGraph[subsequence.chords.Chord], subsequence.chords.Chord]
      :abstractmethod:


      Build the weighted graph and return it with the tonic chord.



   .. py:method:: gravity_sets(key_name: str) -> Tuple[Set[subsequence.chords.Chord], Set[subsequence.chords.Chord]]
      :abstractmethod:


      Return (diatonic_set, functional_set) for key gravity weighting.



.. py:function:: build_diatonic_chords(scale_pcs: List[int], degree_qualities: List[str]) -> List[subsequence.chords.Chord]

   Build chords for each scale degree.

   :param scale_pcs: Pitch class for each degree (e.g., from ``scale_pitch_classes(key_pc, mode)``)
   :param degree_qualities: Chord quality for each degree (e.g., ``["major", "minor", ...]``)

   :returns: List of Chord objects, one per scale degree


.. py:function:: validate_key_name(key_name: str) -> int

   Validate a key name and return its pitch class.

   Raises ValueError if the key name is not recognised.

   :param key_name: Note name (e.g., ``"C"``, ``"F#"``, ``"Bb"``)

   :returns: Pitch class integer (0-11)